Devices, systems, and methods for antimicrobial susceptibility testing

Abstract

Various devices, systems, and methods are disclosed for determining the susceptibility of an infectious agent to one or more anti-infective agents. In one embodiment, a multiplex system can include a well plate, a sensor array lid configured to cover the well plate, and a reader for receiving the well plate covered by the sensor array lid. The well plate can include wells, including test wells containing the anti-infective agent and at least one control well lacking the anti-infective agent. Each of the wells can be configured to receive and contain an aliquot of a sample. The sensor array lid can include multiple sensor units. Each of the sensor units can be configured to extend into a well of the well plate. Each of the sensor units can include an active electrode and a reference electrode that are read by the reader to determine the susceptibility of the infectious agent to the anti-infective agent.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 507,956, filed June 13, 2023, and U.S. Provisional Application No. 63 / 373,777, filed August 29, 2022, the contents of which are incorporated herein by reference in their entireties.

[0002] The present disclosure relates generally to diagnostic devices, systems, and methods, and more particularly to devices, systems, and methods for determining the susceptibility of an infectious agent to one or more anti-infective agents. [Background technology]

[0003] An increasing number of pathogenic bacteria are becoming resistant to antibiotics, and new forms of resistance are continually emerging across borders at an alarming rate. The U.S. Centers for Disease Control (CDC) has called antimicrobial resistance one of the greatest public health challenges of our time. In the United States alone, more than 2 million people contract antibiotic-resistant infections each year, with mortality rates continually rising. Providing rapid, low-cost antibiotic susceptibility tests (ASTs) that can test multiple samples at once will become increasingly important in controlling this rapidly growing problem.

[0004] Current gold-standard AST laboratory procedures typically require multiple days or more of demanding overnight incubation and require highly trained personnel to perform the procedure. These typically involve the following steps: i) blood culture, ii) pathogen isolation on agar plates, iii) preparation of a 0.5 McFarland (MF) standardized inoculum from bacterial colonies, and iv) AST for identification of antibiotic treatment. Speeding up this process could dramatically impact patient survival, reduce costs, and reduce the likelihood of physicians prescribing broad-spectrum antibiotics, which can lead to antibiotic resistance.

[0005] Although new technologies are under development, most still require results to be interpreted visually, which can affect the accuracy of such results. In addition, some rapid AST systems that use light-based detection methods cannot process samples that contain blood, as blood samples can absorb light and distort the results.

[0006] Therefore, there is a need for a solution that can detect bacterial growth in the presence of blood and does not require labor-intensive steps. Such a solution should be cost-effective to manufacture and provide accurate results. Such a solution should also allow for multiplexed detection, including simultaneous reading of multiple wells to rapidly determine the minimum inhibitory concentration (MIC). Summary of the Invention [Means for solving the problem]

[0007] Disclosed herein are diagnostic testing devices, systems, and methods for determining the susceptibility of an infectious agent to one or more anti-infective agents. In one embodiment, a system for determining the susceptibility of an infectious agent to one or more anti-infective agents is disclosed. The system can include a well plate including a plurality of wells. The plurality of wells can include test wells and at least one control well. Each of the wells can be configured to contain an aliquot of a sample containing the infectious agent. At least one of the test wells can include the anti-infective agent, and the control well can lack the anti-infective agent.

[0008] In some embodiments, the sensor array lid can include a lid top and a flexible substrate coupled to a lower surface of the lid top. The sensor array lid can be configured to cover a well plate.

[0009] The flexible substrate can include a plurality of substrate strips or segments partially cut away from the remainder of the flexible substrate, and at least one substrate strip or segment of the flexible substrate can curl or bend downward in a direction perpendicular to the perimeter of the flexible substrate.

[0010] An active electrode can be disposed on each of the vertically downward curled or bent substrate strips or segments, and a reference electrode can be disposed on each of the vertically downward curled or bent substrate strips or segments. Each of the substrate strips or segments containing an active electrode and a reference electrode can be considered a sensor unit.

[0011] The sensor array lid can include a plurality of sensor units extending from a bottom surface of the sensor array lid, each of which can be configured to extend into a well of the well plate such that the sensor unit is at least partially immersed in an aliquot of sample in the well.

[0012] The system can further include a reader configured to receive the well plate and the sensor array lid covering the well plate in a receiving slot of the reader. The reader can include conductive contacts for contacting the active and reference electrodes of the sensor unit.

[0013] The reader can be configured to determine the susceptibility of the infectious agent to the anti-infective drug based on changes in the solution properties of the aliquots of sample in the test wells containing the anti-infective drug and changes in the solution properties of the aliquots of sample in the control wells over a period of time.

[0014] Also disclosed is a method for determining the susceptibility of an infectious agent to one or more anti-infective agents. The method can include introducing an aliquot of a sample containing the infectious agent into wells of a well plate. The wells can include test wells and at least one control well. At least one of the test wells can contain the anti-infective agent, and the control well can lack the anti-infective agent.

[0015] The method can also include covering the well plate with a sensor array lid. The sensor array lid can include a plurality of sensor units extending from a lower surface of the sensor array lid. Each of the sensor units can be configured to extend into one of the wells of the well plate such that the sensor unit is at least partially immersed in an aliquot of sample in the well. Each of the sensor units can include an active electrode and a reference electrode.

[0016] The method can also include inserting the well plate covered by the sensor array lid into a reader. The reader can include conductive contacts for contacting the active and reference electrodes of the sensor units. The method can also include determining the susceptibility of the infectious agent to the anti-infective drug based on changes in solution properties of the aliquots of sample in the test wells containing the anti-infective drug and changes in solution properties of the aliquots of sample in the control wells over a period of time.

[0017] The method can further include diluting the sample with a diluent solution to a dilution ratio of about 1:1 to about 1:10000 before introducing the sample into the wells of the well plate. The method can also include inoculating the well plate covered by the sensor array lid in a reader at an inoculation temperature of about 30°C to about 40°C.

[0018] In some embodiments, the well plate can include 24 to 96 wells, and the sensor array lid can include 24 to 96 sensor units.

[0019] In some embodiments, the anti-infective agent in the test wells can be lyophilized or dried.

[0020] In some embodiments, the anti-infective agent in the test well can be in aqueous form.

[0021] In some embodiments, the change in the solution properties of the well can be detected in the absence of an exogenous reporter molecule added to the well.

[0022] In some embodiments, the sample can include a bodily fluid or a bacterial culture derived therefrom, for example, the sample can be a positive blood culture.

[0023] In some embodiments, the infectious agent can include a bacterium.

[0024] In some embodiments, the anti-infective agent can include a bacteriostatic anti-infective agent, a bacteriocidal anti-infective agent, or a combination thereof.

[0025] In some embodiments, the infectious agent can include a fungus.

[0026] In some embodiments, the anti-infective agent can include an anti-fungal agent.

[0027] In some embodiments, the active electrode can include a redox active material.

[0028] In some embodiments, the redox active material can be a noble metal. For example, the noble metal can be platinum or gold. In other embodiments, the redox active material can be a conductive metal oxide, such as iridium oxide, ruthenium oxide, or any combination or alloy of such materials with noble metals. In additional embodiments, the redox active material can be a carbon-based electrode.

[0029] In some embodiments, the reference electrode can include a reference electrode material.

[0030] In some embodiments, the reference electrode material can include at least one of silver / silver chloride (Ag / AgCl) and carbon.

[0031] In some embodiments, the reference electrode material can be coated or covered with an ion exchange membrane.

[0032] In some embodiments, the ion exchange membrane can be a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer or polyaromatic polymer anion exchange membrane.

[0033] In some embodiments, the lid top can include support posts extending from the underside of the lid top, which can be configured to press or urge against the substrate strip or segment such that the substrate strip or segment maintains its curled or bent configuration.

[0034] In some embodiments, at least one of the substrate strips or segments can be pushed or urged by at least one of the support posts such that a portion of the substrate strip or segment is substantially perpendicular to the portion of the flexible substrate that is coupled to the lid top.

[0035] In some embodiments, the flexible substrate can be made in part from a flexible polymeric material.

[0036] In some embodiments, the flexible polymeric material can be made in part from polyethylene terephthalate (PET).

[0037] In some embodiments, the flexible polymer material can be a flexible printed circuit board (PCB) material.

[0038] In some embodiments, the flexible PCB material can be polyimide.

[0039] In some embodiments, the flexible substrate can be made in part from a conductive metal substrate, for example, the conductive metal substrate can be a stainless steel foil.

[0040] In some embodiments, the lid top can be made in part from at least one of polystyrene, polypropylene, and cyclic olefin copolymer.

[0041] In some embodiments, at least one of the active electrode and the reference electrode can be a screen-printed electrode (SPE), where at least one of the redox-active material of the active electrode and the reference electrode material of the reference electrode is screen-printed onto a flexible substrate.

[0042] In some embodiments, at least one of the active electrode and the reference electrode can be an electroplated electrode, such that at least one of the redox-active material of the active electrode and the reference electrode material of the reference electrode is electroplated onto a flexible substrate.

[0043] In some embodiments, at least one of the active electrode and the reference electrode can be a sputter-deposited electrode, such that at least one of the redox-active material of the active electrode and the reference electrode material of the reference electrode is sputter-deposited onto a flexible substrate.

[0044] In some embodiments, the sensor array lid can be disposable or single use.

[0045] In some embodiments, the flexible substrate can include electrical contact pads disposed on the flexible substrate. The electrical contact pads can be left exposed by the lid top. The active electrode can be electrically connected to the electrical contact pads via conductive traces. The reference electrode can be electrically connected to the electrical contact pads via additional conductive traces.

[0046] In some embodiments, the reference electrode can be a pseudo reference electrode.

[0047] In some embodiments, the flexible substrate can be coupled to the underside of the lid top by at least one of a biocompatible adhesive and fasteners. [Brief explanation of the drawings]

[0048] [Figure 1A] FIG. 1 is a perspective view of one embodiment of a test device including a sensor array lid and a well plate. [Figure 1B] FIG. 2 is a perspective view of the underside of the sensor array lid. [Figure 1C] FIG. 1 is a perspective view of one embodiment of a test device in an assembled configuration. [Figure 1D] FIG. 1 is a top view of a test device in an assembled configuration. [Figure 1E] FIG. 1 is a bottom plan view of the test device in an assembled configuration. [Figure 1F]FIG. 1 is a perspective view of one embodiment of a test device in an assembled configuration, with a lateral side of the device shown in cross section for illustrative purposes. [Figure 1G] FIG. 10 is a close-up view of the posts that press against the substrate strip to allow the substrate strip to maintain a curled or bent configuration. [Figure 1H] FIG. 1 is a schematic diagram showing a sensor unit including an active electrode and a reference electrode of the sensor unit immersed in an aliquot of sample in a well of a well plate. [Figure 2A] 1 is a black and white image showing one embodiment of a sensor array lid. [Figure 2B] 1 is a black and white image showing a close-up of a sensor unit implemented as a substrate strip that is immersed in an aliquot of sample in a well of a well plate. [Figure 3A] FIG. 1 illustrates a method for producing screen-printed electrodes on a flexible substrate. [Figure 3B] 1 is a schematic diagram illustrating a portion of a reference electrode material disposed on a flexible substrate, the reference electrode material being completely covered by an ion exchange membrane. [Figure 4A] 1 shows ORP bacterial growth curves obtained using an embodiment of a diagnostic device with screen-printed electrodes, and ORP bacterial growth curves obtained using a commercially available ORP sensor. [Figure 4B] FIG. 1 shows various ORP bacterial growth curves showing the growth behavior of sensitive and resistant bacteria in both test and control wells. [Figure 5] 1 shows ORP bacterial growth curves obtained using an embodiment of a test device with sputter-deposited electrodes, and ORP bacterial growth curves obtained using a commercially available ORP sensor. [Figure 6] FIG. 10 shows ORP bacterial growth curves obtained using an embodiment of a test device with electroplated electrodes. [Figure 7A] FIG. 1 is a perspective view of a reader for receiving a test device and for detecting changes in the solution properties of a sample in a well of the test device. [Figure 7B] FIG. 1 is a front view of a reader for receiving a test device and for detecting changes in the solution properties of a sample in the well of the test device. [Figure 7C] FIG. 1 shows a high-level circuit diagram illustrating how the reader reads the electrodes (active and reference electrodes) of the sensor unit. [Figure 7D] FIG. 1 is a schematic diagram showing certain electronic components of the reader involved in processing the signals obtained from the sensor units. [Figure 8] FIG. 1 illustrates the various steps for determining the susceptibility of an infectious agent to one or more anti-infective drugs. [Figure 9A] 1 is a table showing performance results for gram-negative contrived positive blood cultures (PBC) in the presence of several antibiotics. [Figure 9B] 1 is a table showing performance results for prospective gram-negative PBC in the presence of several antibiotics. [Figure 9C] FIG. 9B is a graph showing the times-to-result for the Gram-negative, contrasted PBC shown in FIG. 9A. [Figure 10A] 10 is a side cross-sectional view of another embodiment of a testing device including a sensor array lid containing sensor units with active electrodes implemented as pins that extend into the wells of a well plate. [Figure 10B] 1 is a black and white image illustrating a platinum coated pin serving as the active electrode. DETAILED DESCRIPTION OF THE INVENTION

[0049] The variations of the devices, systems, and methods described herein are best understood from the detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, various features of the drawings may not be to scale. Dimensions of certain features have been expanded or reduced for clarity, and not all features may be visible or labeled in every drawing. The drawings are to be construed for illustrative purposes only and are not intended to define and limit the scope of the claims to that shown.

[0050] 1A illustrates a perspective view of one embodiment of a test device 100 including a sensor array lid 102 and a well plate 104. The test device 100 can be used as part of a system for determining the susceptibility of an infectious agent to an anti-infective drug. As will be described in more detail in the following sections, the system can further include a reader 700 (see FIGS. 7A and 7B), which is configured to detect changes in the solution properties of an aliquot of sample within the test device 100. The system can assay the aliquot of sample for the presence or absence of microbial growth as part of an antibiotic susceptibility testing (AST) procedure.

[0051] 1A, the sensor array lid 102 can be configured to cover or cap the well plate 104 when placed on the well plate 104. The well plate 104 can include a plurality of wells 105 or microwells. For example, the well plate 104 can include between 12 and 192 wells. As a more specific example, the well plate 104 can include between 64 and 96 wells.

[0052] When the well plate 104 contains 96 wells, the wells 105 can be arranged in an 8x12 array of wells. In another embodiment, when the well plate 104 contains 48 wells, the wells 105 can be arranged in a 6x8 array of wells.

[0053] Each of the wells 105 can be designed to receive an aliquot of a sample containing an infectious agent. The sample can be diluted before introducing the aliquot of the sample into the wells 105.

[0054] In some embodiments, the wells 105 of the well plate 104 can include test wells and control wells. The test wells can each contain a type of anti-infective agent, and the control wells can lack any anti-infective agent (e.g., positive control wells).

[0055] For example, when well plate 104 includes 96 wells, 1 to 20 wells of well plate 104 can be used as control wells. In other examples, the number of control wells can be more than 20 wells (e.g., half of the wells can be control wells).

[0056] The wells 105 of the well plate 104 containing anti-infective agents can have the anti-infective agent already present in the wells 105 or pre-loaded into the wells 105. In some embodiments, the anti-infective agent in the test wells can be lyophilized or dried. For example, the anti-infective agent in the test wells can be in the form of a lyophilized disk, pellet, or powder.

[0057] In other embodiments, the anti-infective agent in the test wells can be in aqueous form.

[0058] In some embodiments, the anti-infective agent can be added, disposed, or otherwise introduced into the wells 105 of the well plate 104 prior to introducing the aliquots of sample into the wells 105 (test wells and control wells).

[0059] In some embodiments, each well plate 104 can contain different types of anti-infectives, such that some of the wells 105 of the well plate 104 are dedicated to a particular anti-infective and other wells of the well plate 104 are dedicated to a different anti-infective. In these embodiments, a single well plate 104 can contain between 2 and 100 test wells with anti-infectives. In additional embodiments, a single well plate 104 can contain more than 100 test wells with anti-infectives (depending on the size of the well plate 104).

[0060] In other embodiments, one well plate 104 may contain only one anti-infective agent, such that all test wells of the well plate 104 are dedicated to the same anti-infective agent.

[0061] The sensor array lid 102 and the well plate 104 can be made in part from a polymeric material or a thermoplastic. In some embodiments, a portion of the sensor array lid 102, the well plate 104, or a combination thereof can also be made from a metallic material, a ceramic, or a combination of such materials, with or without a polymeric material.

[0062] In certain embodiments, well plate 104 can be a commercially available or prefabricated well plate, such as a microtiter or microwell plate supplied by ThermoFisher Scientific, Beckman Coulter, VWR International, or MilliporeSigma. As a more specific example, well plate 104 can be a commercially available or prefabricated AST well plate.

[0063] In some embodiments, the well plate 104 and a portion of the sensor array lid 102 can be made in part from at least one of polystyrene, polypropylene, cyclic olefin copolymer, or another biocompatible polymeric material.

[0064] The sensor array lid 102 can be made from a material that can withstand sterilization by radiation (e.g., gamma radiation), heat, or a combination thereof. In certain embodiments, the sensor array lid 102 can be individually packaged and provided separately from the well plate 104.

[0065] In some embodiments, the sensor array lid 102 may be disposable or single use, in which case the sensor array lid 102 may be discarded after the testing procedure is completed.

[0066] 1B illustrates a perspective view (with the underside facing upward) of sensor array lid 102. As shown in FIGS. 1A and 1B, sensor array lid 102 can include a lid top 106 and a flexible substrate 108, where flexible substrate 108 is coupled to the underside of lid top 106.

[0067] The flexible substrate 108 can include multiple substrate strips 110 or substrate segments that are partially cut away or otherwise separated from the remainder of the flexible substrate 108 (i.e., the parts of the flexible substrate 108 that are coupled to the underside of the sensor array lid 102). The substrate strips 110 can be curled or bent downward in a direction perpendicular to the perimeter of the flexible substrate 108. The substrate strips 110 can maintain their curled or bent configuration even when the sensor array lid 102 covers or caps the well plate 104.

[0068] As will be described in more detail in the following sections, each of the substrate strips 110 can include an active electrode 118 and a reference electrode 120 disposed thereon (see FIG. 1H). The active electrode 118 and the reference electrode 120 can each be connected to electrical contact pads 115 on the sensor array lid 102 by one or more conductive traces 122 (see FIG. 1H). In some embodiments, the electrical contact pads 115 can be attached to, connected to, or electrically coupled to the flexible substrate 108.

[0069] For the purposes of this disclosure, each of the substrate strips 110 (including the active electrode 118 and the reference electrode 120 ) may also be referred to as a sensor unit 112 .

[0070] In some embodiments, the flexible substrate 108 can be made at least in part from a flexible polymeric material. For example, the flexible substrate 108 can be made in part from a flexible sheet of polyethylene terephthalate (PET).

[0071] The flexible substrate 108 may also be made partially from a flexible printed circuit board (PCB) material, for example, the flexible substrate 108 may be made partially from polyimide or polyamide.

[0072] In alternative embodiments, the flexible substrate 108 may be made in part from a conductive metal substrate. For example, in these embodiments, the flexible substrate 108 may be made in part from a sheet of stainless steel foil.

[0073] In some embodiments, the flexible substrate 108 can be coupled to the underside of the lid top 106 by a biocompatible adhesive (e.g., a biocompatible polymer adhesive, a cyanoacrylate adhesive, etc.) and fasteners (e.g., screws, clips, clasps, etc.).

[0074] 1C-1E illustrate a perspective view, a top view, and a bottom view, respectively, of one embodiment of test device 100 in an assembled configuration. As shown in FIGS. 1C-1E, sensor array lid 102 can completely cover or fit over the top of well plate 104 when test device 100 is in the assembled configuration. Moreover, as shown in FIG. 1C, the sides of sensor array lid 102 can at least partially cover or surround the sides of well plate 104. This allows test device 100 to have a low or compact profile when test device 100 is in the assembled configuration, allowing test device 100 to fit into receiving slot 702 of reader 700 (see FIGS. 7A, 7B, and 8).

[0075] 1C and 1D also illustrate that the lid top 106 of the sensor array lid 102 can protect the sample aliquots in the wells 105 from contamination and can prevent the sample aliquots from spilling or inadvertently leaking.

[0076] In an assembled configuration, test device 100 can have a device length, a device width, and a device height. In some embodiments, test device 100 in an assembled configuration can have a device length of about 80.0 mm to 160.0 mm (e.g., about 122.5 mm), a device width of about 60.0 mm to 100.0 mm (e.g., 81.0 mm), and a device height of about 10.0 mm to 30.0 mm (e.g., about 20.0 mm).

[0077] As will be described in more detail in the following sections, each of the sensor units 112 (e.g., implemented as a curled or bent substrate strip 110) can extend into a well 105 of the well plate 104 when the sensor array lid 102 covers or caps the well plate 104. When the wells 105 of the well plate 104 are filled with an aliquot of inoculum material or sample, at least a portion of the sensor unit 112 can be immersed in the aliquot of inoculum material or sample.

[0078] 1F illustrates a perspective view of one embodiment of test device 100 in an assembled configuration, with a lateral side of test device 100 shown in cross section for illustrative purposes. In this embodiment, sensor units 112 are implemented as curled or bent substrate strips 110 extending downward from flexible substrate 108. As will be described in more detail in the following sections, each of substrate strips 110 can include an active electrode 118 and a reference electrode 120 printed, deposited, or electroplated on a distal end or portion of substrate strip 110.

[0079] The substrate strip 110 can extend into the wells 105 of the well plate 104. When the wells 105 of the well plate 104 are filled with an aliquot of sample (e.g., a positive blood culture), at least a distal segment or portion of each of the substrate strips 110 (the distal segment or portion including the active electrode 118 and the reference electrode 120) can be immersed in the aliquot of sample.

[0080] The sensor units 112 can be aligned to match the alignment or arrangement of the wells 105. For example, when the well plate 104 includes 96 wells arranged as an 8x12 array of wells 105, the sensor array lid 102 can include 96 sensor units 112 arranged as an 8x12 array of sensor units 112.

[0081] In some embodiments, the sensor units 112 can be spaced approximately 6.00 mm to 12.0 mm (approximately 9.00 mm) apart from one another.

[0082] In certain embodiments, the sensor units 112 can be positioned so that when the sensor array lid 102 covers or caps the well plate 104, none of the sensor units 112 touches or comes into contact with the walls of the wells 105.

[0083] In other embodiments, the sensor unit 112 can be positioned so that when the sensor array lid 102 covers or caps the well plate 104, the sensor unit 112 rests against or contacts one or more walls of the well 105.

[0084] 1F illustrates that when the sensor units 112 are implemented as substrate strips 110, the sensor array lid 102 can include a plurality of support posts 114 extending from the underside of the lid top 106. The support posts 114 can be configured to press or compress the substrate strip 110 such that the substrate strip 110 maintains its curled or bent configuration.

[0085] For example, the posts 114 can be angled so that they press or push against the substrate strip 110 to ensure that the substrate strip 110 maintains its curled or bent configuration. As a more specific example, the posts 114 can be positioned at an oblique angle relative to the underside of the lid top 106.

[0086] Sensor array lid 102 may further include electrical contact pads 115 disposed on one end, corner, or edge of sensor array lid 102. In some embodiments, electrical contact pads 115 may be attached to, connected to, or electrically coupled to flexible substrate 108.

[0087] For example, the entire electrical contact pads 115 can be left exposed by the lid top 106. As a more specific example, the electrical contact pads 115 can be located on a ledge or step-down portion of the sensor array lid 102.

[0088] In other embodiments, at least a portion of the electrical contact pads 115 may be exposed by one or more openings or apertures defined along the lid top 106 .

[0089] The contact pads 115 can be electronically connected or coupled to the respective active and reference electrodes 118, 120 of the sensor unit 112 by a plurality of conductive traces 122 (see FIG. 1H). In some embodiments, the conductive traces 122 can be routed along a surface or side of the flexible substrate 108 (e.g., a side or surface that is attached to or coupled to the underside of the lid top 106).

[0090] In other embodiments, the conductive traces 122 can be routed or extended through the flexible substrate 108 or through the main body of the lid top 106. For example, when the flexible substrate 108 is made from PCB material, the conductive traces 122 can be routed or directed through vias or through-holes located along the flexible substrate 108.

[0091] The contact pads 115 can be configured to contact or otherwise engage with conductive connections in the reader 700 when the entire test device 100 (in its assembled configuration) is inserted or introduced into the receiving slot 702 of the reader 700 to enable the reader 700 to acquire a signal from the sensor unit 112.

[0092] 1G is a close-up view of the support posts 114 that press against the substrate strip 110 to enable the substrate strip 110 to maintain its curled or bent configuration. As shown in FIG. 1G, the support posts 114 can press or force the substrate strip 110 so that a distal segment 116 of the substrate strip 110 (e.g., a distal segment including the active electrode 118 and the reference electrode 120; see FIG. 1H) is substantially perpendicular to the portion of the flexible substrate 108 that is coupled to the underside of the lid top 106.

[0093] In other embodiments, the support posts 114 can push or press the substrate strip 110 such that the distal segment 116 of the substrate strip 110 is positioned at an oblique angle (more specifically, an angle between 60° and 90°) relative to the portion of the flexible substrate 108 that is coupled to the underside of the lid top 106.

[0094] As shown in FIG. 1G, the substrate strip 110 can be formed by cutting along three sides surrounding the substrate strip 110.

[0095] In some embodiments, the substrate strip 110 can be substantially rectangular in shape. For example, the substrate strip 110 can be formed as a rectangular tab or a rectangular strip.

[0096] In other embodiments, the substrate strips 110 can be substantially triangular, oval, or semicircular in shape. In further embodiments, the substrate strips 110 can be leaf or leaflet shaped.

[0097] In these and other embodiments, the posts 114 can be made from the same non-conductive material (eg, a polymeric material) used to make the lid top 106 .

[0098] In some embodiments, the posts 114 can be rods or pins extending from the underside of the lid top 106. In further embodiments, the posts 114 can be attached or otherwise fastened to the lid top 106.

[0099] In certain embodiments, the posts 114 can be replaced by protrusions or other types of surface features that protrude from the underside of the lid top 106 .

[0100] Although the figures illustrate the substrate strip 110 being pushed or urged into a curled or bent configuration by the posts 114, it is contemplated by the present disclosure that the substrate strip 110 may also achieve and maintain that curled or bent configuration without the assistance of the posts 114 (e.g., by being pre-formed, pre-set, pre-trained, or otherwise manipulated into such a configuration).

[0101] FIG. 1H is a schematic diagram showing a sensor unit 112 of the sensor array lid 102 including the active electrode 118 and reference electrode 120 of the sensor unit 112 immersed in an aliquot of sample in a well 105 of a well plate 104.

[0102] The wells 105 of the well plate 104 can be sized to hold a sufficient amount of sample to allow at least the distal segments 116 of the sensor units 112 to be immersed in the sample when the sensor array lid 102 covers or caps the well plate 104.

[0103] 1H, each of the wells 105 of the well plate 104 can include a substantially cylindrical cavity for receiving and holding a sample. In other embodiments, each of the wells 105 of the well plate 104 can include a substantially rectangular cavity, an oval cavity, or a frusto-conical cavity.

[0104] As previously described, the sensor units 112 extending from the underside of the sensor array lid 102 can be arranged or positioned so that the sensor units 112 are aligned with the wells 105 of the well plate 104 and so that at least the distal segment 116 of each of the sensor units 112 extends into the respective cavities of the wells 105.

[0105] When the sensor unit 112 is implemented as a curled or bent substrate strip 110 , the distal segment 116 of the sensor unit 112 can be a distal segment or portion of the substrate strip 110 .

[0106] 1H, the distal segment 116 of the sensor unit 112 can include an active electrode 118 and a reference electrode 120 disposed on the substrate strip 110. As will be described in more detail in the following sections, at least one of the active electrode 118 and the reference electrode 120 can be screen printed, electroplated, or sputter deposited on the substrate strip 110.

[0107] The active electrode 118 can include a redox active material. In some embodiments, the redox active material can be a noble metal. For example, the redox active material can be platinum, gold, or a combination or alloy thereof. In other embodiments, the redox active material can be a redox-sensitive metal oxide.

[0108] In other embodiments, the redox active material can be a conductive metal oxide, such as iridium oxide, ruthenium oxide, or any combination or alloy of such materials with a noble metal, hi additional embodiments, the redox active material can be a carbon-based electrode.

[0109] The reference electrode 120 can include a reference electrode material. In some embodiments, the reference electrode material can include at least one of silver / silver chloride (Ag / AgCl) and carbon. For example, when the reference electrode material is Ag / AgCl or carbon, the reference electrode material can be screen printed onto the substrate strip 110.

[0110] The reference electrode 120 can be considered a pseudo-reference electrode because the reference electrode 120 operates without a reference buffer. A pseudo-reference electrode can be used in these cases because measurements are made by comparing signal changes rather than comparing absolute values.

[0111] As will be explained in more detail in a later section, the reference electrode material can be coated with an ion exchange membrane or ionomer coating.

[0112] In alternative embodiments, the active electrode 118 can be implemented as a pin, rod, or wire segment made from a redox-active material. In these and other embodiments, the reference electrode 120 can also be implemented as a pin, rod, or wire segment coated or covered with the reference electrode material, an ion exchange membrane / ionomer coating, or a combination thereof.

[0113] Additionally, the active electrodes 118 and reference electrodes 120 may be electrically connected to the electrical contact pads 115 of the sensor array lid 102 by a plurality of conductive traces 122. In some embodiments, the conductive traces 122 may be platinum traces or routing lines. In other embodiments, the conductive traces 122 may be made from another conductive material, such as gold, copper, or the like.

[0114] 2A is a black and white image showing one embodiment of sensor array lid 102. As shown in FIG. 2A, sensor array lid 102 can be made from a transparent polymer material to allow a medical or laboratory professional or technician to see wells 105 of well plate 104 and to see the sample aliquots in wells 105 during a testing procedure. Additionally, sensor array lid 102 can be made from a transparent polymer material to allow a medical or laboratory professional or technician to see sensor units 112 and to ensure that sensor units 112 are immersed in the sample aliquots in wells 105.

[0115] As previously mentioned, in some embodiments, the sensor array lid 102 can be made in part from at least one of polystyrene, polypropylene, cyclic olefin copolymer, or another biocompatible polymeric material.

[0116] FIG. 2B is a black and white image showing a close-up view of a sensor unit 112 implemented as a substrate strip 110 immersed in an aliquot of sample in a well 105 of a well plate 104 .

[0117] The sample shown in Figure 2B is an aliquot of a positive blood culture (PBC) containing an infectious agent. The sample can be diluted in a bacterial growth medium such as Mueller-Hinton Broth (MHB).

[0118] Moreover, as shown in FIG. 2B , a distal portion or segment of the sensor unit 112 (implemented as a substrate strip 110) including electrodes (e.g., active electrode 118 and reference electrode 120; see also FIG. 1H ) can be immersed in the sample when the sensor array lid 102 covers or caps the well plate 104.

[0119] One technical problem faced by the applicant is how to design a low-cost, accurate antimicrobial susceptibility testing device that is easy to handle and measures multiple samples simultaneously. One technical solution discovered and developed by the applicant is a sensor array lid disclosed herein, which includes a lid top, a flexible substrate coupled to the underside of the lid top, and a flexible substrate strip partially cut out of the flexible substrate, the flexible substrate strip serving as a carrier for active and reference electrodes disposed on the substrate strip. The sensor array lid can be configured to cover well plates (including commercially available well plates) containing 12 to 192 wells. The flexible substrate strip containing the active and reference electrodes can extend into the wells of the well plate, and the electrodes can be immersed in samples in the wells when the sensor array lid covers the well plate. The entire test device (sensor array lid covering the well plate) can then be inserted into a reader (e.g., as a cartridge or cassette) to determine whether the infectious agent in the sample is susceptible to the anti-infective or antibiotic in the well.

[0120] FIG. 3A illustrates a portion of a method 300 for producing screen-printed electrodes on a flexible substrate 108. The method 300 may include covering the flexible substrate 108 with a stencil 302 or mesh. The stencil 302 or mesh may include a stencil or mesh pattern. The stencil or mesh pattern may conform to a desired layout or footprint of a material 304 (e.g., electrode material, coating, etc.) to be printed on the flexible substrate 108. A blade 306 (e.g., a squeegee blade) may be used to apply, transfer, or otherwise deposit the material 304 through the cutouts or openings that make up the stencil pattern. The blade 306 may be pushed or pulled to apply, transfer, or otherwise direct a thin layer of the material 304 onto the flexible substrate 108 in a desired shape or pattern.

[0121] The deposited material 304 can then be dried and / or cured, and in some cases one or more solvents can be used to ensure proper adhesion of the material 304 to the flexible substrate 108. The process can be repeated until a sufficient amount of material 304 has been adhered to the flexible substrate 108.

[0122] In some embodiments, the reference electrode material of reference electrode 120 can be screen printed onto flexible substrate 108. In these and other embodiments, the redox active material of active electrode 118 can also be screen printed onto flexible substrate 108.

[0123] In additional embodiments, the ion exchange membrane 308 or ionomer coating can also be screen printed onto at least a portion of the flexible substrate 108. For example, as will be described in more detail in the following section, the ion exchange membrane 308 or ionomer coating can be screen printed onto a reference electrode material (e.g., Ag / AgCl or carbon / graphite) that has already been screen printed onto the flexible substrate 108.

[0124] As previously described, in some embodiments, the redox active material can be a precious metal, such as platinum, gold, or a combination or alloy thereof. In these embodiments, the redox active material can initially be in the form of an ink or paste (e.g., a platinum or gold ink or paste). The ink or paste (e.g., a platinum or gold ink or paste) can be screen printed onto the flexible substrate 108 using a previously disclosed method (e.g., method 300).

[0125] In other embodiments, the redox active material can be a conductive metal oxide, such as iridium oxide, ruthenium oxide, or any combination or alloy of such materials with a noble metal, hi additional embodiments, the redox active material can be a carbon-based electrode.

[0126] Also, as previously described, the reference electrode material can include at least one of silver / silver chloride (Ag / AgCl) and carbon. In these embodiments, the reference electrode material can also initially be in the form of an ink or paste (e.g., a silver / silver chloride or graphite ink or paste). This ink or paste (e.g., a silver / silver chloride or graphite ink or paste) can be screen printed onto another portion of the flexible substrate 108.

[0127] For example, the redox active material can be screen printed onto the distal segment 116 of the substrate strip 110. In this example, the reference electrode material can be screen printed onto this same distal segment 116 of the substrate strip 110, but next to or in close proximity to the redox active material.

[0128] In an alternative embodiment, Ag / AgCl reference electrode material can also be made by chlorinating silver with an electric current in a chlorinating solution.

[0129] FIG. 3B is a schematic diagram illustrating the reference electrode material disposed on the flexible substrate 108, where the reference electrode material is completely covered by an ion exchange membrane 308.

[0130] In some embodiments, the ion exchange membrane 308 may be configured to filter out specific ions (e.g., Ag) that may interact with or adversely affect certain microbial organisms or other infectious agents. + ions). For example, the ion exchange membrane 308 can be a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer, such as Nafion™. Sulfonated tetrafluoroethylene-based fluoropolymer-copolymers can also be referred to as proton exchange membranes because they can block positively charged ions (e.g., H + ions) can be designed to flow freely through the polymer layer, while other ions (e.g., Ag) that may interact with or be harmful to certain microbial organisms or other infectious agents can be blocked. + ions) and keeps such ions close to the reference electrode material.

[0131] In other embodiments, the ion exchange membrane 308 can be a polyaromatic polymer anion exchange membrane, such as Fumion™. The polyaromatic polymer anion exchange membrane can be designed so that only anions pass through the polymer layer. Ag + Since certain harmful ions, such as ions, are positive ions, such ions are prevented from entering the sample.

[0132] In some embodiments, the ion exchange membrane 308 can be screen printed onto the flexible substrate 108 and then screen printed onto the reference electrode material disposed on the flexible substrate 108. In certain embodiments, the reference electrode material can first be screen printed onto the flexible substrate 108, and the ion exchange membrane 308 can then be screen printed onto the reference electrode material and a portion of the flexible substrate 108.

[0133] One technical problem faced by the applicant is how to prevent harmful ions from the electrode from entering the sample and adversely affecting the growth and metabolism of infectious agents. One technical solution discovered and developed by the applicant is to screen print an ion exchange membrane onto the portion of the electrode (e.g., the reference electrode) that may give off interfering or harmful ions.

[0134] In an alternative embodiment, at least one of the active electrode 118 and the reference electrode 120 can be formed via sputter deposition. For example, at least one of the redox active material (e.g., platinum) of the active electrode 118 and the reference electrode material of the reference electrode 120 can be sputter deposited on the flexible substrate 108 to form such an electrode. As will be described in more detail in connection with FIG. 5 , the performance of a sensor unit 112 including electrodes formed via sputter deposition was compared to a commercially available ORP sensor, and such a sputter-deposited sensor provided results comparable to the commercially available ORP sensor.

[0135] In an alternative embodiment, at least one of the active electrode 118 and the reference electrode 120 can be formed via electroplating. For example, at least one of the redox-active material (e.g., platinum and / or gold) of the active electrode 118 and the reference electrode material of the reference electrode 120 can be electroplated onto the flexible substrate 108 to form such electrodes. As a more specific example, when the flexible substrate 108 is made of a flexible PCB material (e.g., polyimide / polyamide), at least one of the redox-active material (e.g., platinum and / or gold) of the active electrode 118 and the reference electrode material of the reference electrode 120 can be electroplated onto the flexible PCB material. As will be described in more detail in connection with FIG. 6 , the performance of two sensor units 112 including electrodes formed via electroplating was compared to each other to determine the accuracy of such sensors.

[0136] 4A illustrates an ORP bacterial growth curve for a sample containing E. coli (e.g., the ATCC-25922 strain of E. coli) obtained using an embodiment of the test device 100 with a screen-printed platinum active electrode 118 and a screen-printed carbon reference electrode 120. Also shown is an ORP bacterial growth curve obtained using a commercially available ORP sensor. The sample can be diluted using Mueller-Hinton broth as a diluent before being introduced into the wells 105 of the well plate 104. The commercially available ORP sensor is an ORP sensor supplied by Mettler Toledo.

[0137] As shown in FIG. 4A, ORP growth curves obtained using a test device 100 including a screen-printed platinum active electrode 118 and a screen-printed carbon reference electrode 120 demonstrated comparable performance to commercially available ORP sensors.

[0138] Figure 4B illustrates various ORP bacterial growth curves showing the growth behavior of susceptible and resistant bacteria in both test wells containing anti-infective drugs and control wells lacking any anti-infective drug. Also shown are ORP bacterial growth curves obtained using a commercially available ORP sensor.

[0139] The anti-infective agent used was ceftriaxone. Ceftriaxone was present only in the test wells, while the control wells contained no anti-infective agent. The susceptible bacteria used was the CDC-650 strain of Escherichia coli, which is known to be highly susceptible to ceftriaxone. The resistant bacteria used was the CDC-846 strain of Escherichia coli, which is known to be resistant to ceftriaxone. The commercially available ORP sensor was an ORP sensor supplied by Mettler Toledo.

[0140] Samples containing both susceptible and resistant bacteria were first diluted using Mueller-Hinton broth as the diluent and then introduced into both test and control wells of the well plate 104. A sensor array lid 102 with a substrate strip 110 containing a screen-printed platinum active electrode 118 and a screen-printed carbon reference electrode 120 served as the sensor unit 112. All samples were inoculated at 37°C.

[0141] As shown in FIG. 4B, ORP growth curves obtained using test device 100, including a screen-printed platinum active electrode 118 and a screen-printed carbon reference electrode 120, performed as expected, and ORP growth curves obtained using test device 100 were comparable to ORP growth curves obtained using commercially available ORP sensors.

[0142] 5 illustrates ORP bacterial growth curves obtained using an embodiment of the test device 100 with a sensor unit 112 that includes a sputter-deposited platinum active electrode 118. Also shown is an ORP bacterial growth curve obtained using a commercially available Mettler Toledo ORP sensor.

[0143] As shown in FIG. 5 , ORP growth curves obtained using a test device 100 equipped with a sensor unit 112 including a sputter-deposited platinum active electrode 118 were comparable to ORP growth curves obtained using commercially available ORP sensors.

[0144] 6 illustrates an ORP bacterial growth curve obtained using an embodiment of a test device 100 with a sensor unit 112 that includes an electroplated platinum active electrode 118. The platinum active electrode 118 is electroplated onto a flexible substrate 108 made from flexible PCB material.

[0145] As shown in FIG. 6 , ORP growth curves obtained using test devices 100 equipped with sensor units 112 containing electroplated platinum active electrodes 118 were comparable to each other, demonstrating the accuracy of the sensor units 112.

[0146] 7A and 7B illustrate perspective and front views, respectively, of a reader 700 for receiving a test device 100 (well plate 104 covered by a sensor array lid 102) and for detecting changes in the solution properties of a sample in a well 105 of the test device 100.

[0147] The reader 700 can include multiple receiving slots 702 for receiving and holding the test devices 100. In some embodiments, the reader 700 can include between 4 and 12 receiving slots 702 (e.g., 10 receiving slots 702).

[0148] Each of the receiving slots 702 can accommodate a test device 100 (a well plate 104 covered by a sensor array lid 102). In certain embodiments, the test devices 100 can be placed in a cartridge or cassette before being inserted into the receiving slots 702.

[0149] As previously described, sensor array lid 102 of test device 100 may further include electrical contact pads 115 located on one end, corner, or edge of sensor array lid 102. In some embodiments, electrical contact pads 115 may be attached to, connected to, or electrically coupled to flexible substrate 108.

[0150] For example, the entire electrical contact pads 115 can be left exposed by the lid top 106. As a more specific example, the electrical contact pads 115 can be located on a ledge or step-down portion of the sensor array lid 102.

[0151] In other embodiments, at least a portion of the electrical contact pads 115 may be exposed by one or more openings or apertures defined along the lid top 106 .

[0152] The active electrodes 118 and reference electrodes 120 on the sensor array lid 102 can be electrically connected to the electrical contact pads 115 via conductive traces 122. The conductive traces 122 can be routed along one side of the flexible substrate 108 or along both sides of the flexible substrate 108. In certain embodiments, the conductive traces 122 can be routed through the body of the flexible substrate 108 and along one or both sides of the lid top 106.

[0153] In some embodiments, all of the reference electrodes 120 on the sensor array lid 102 can be connected by one conductive trace 122. In other embodiments, the electrodes 120 on the sensor array lid 102 can be connected by multiple conductive traces 122.

[0154] The contact pads 115 can be configured to contact or otherwise engage with conductive connections or conductive contacts in the reader 700 when the test device 100 (in its assembled configuration) is inserted or introduced (e.g., via a cartridge or cassette) into the receiving slot 702 of the reader 700. For example, the conductive connections in the reader 700 can engage or otherwise contact the electrical contact pads 115 of the test device 100 when the test device 100 (well plate 104 covered by the sensor array lid 102) is pushed, inserted, or otherwise introduced into the receiving slot 702.

[0155] The reader 700 can automatically begin reading signals from the sensor units 112 of the sensor array lid 102 when the test device 100 is inserted into the reader 700 via the receiving slot 702. The reader 700 can be configured to read signals from the sensor units 112 to detect changes in the solution properties of the microbial sample in the well 105 over time. The reader 700 can also be configured to determine the susceptibility of the microorganisms in an aliquot of the sample to a particular anti-infective drug.

[0156] The reader 700 may also include specific thermal circuits and heating blocks that can be used to inoculate aliquots of sample into the wells 105 of the test devices 100. For example, the test devices 100 containing the aliquots of sample may be inoculated at an inoculation temperature of about 30° C. to about 40° C. In an alternative embodiment, the test devices 100 containing the aliquots of sample may be inoculated outside of the reader 700.

[0157] As shown in Figures 7A and 7B, the reader 700 may also include a display 704. In some embodiments, the display 704 may be an interactive touchscreen display. The display 704 may render graphics, messages, or other types of text, or a combination thereof, regarding the results of the antimicrobial susceptibility test. In certain embodiments, the display 704 may allow a user to input commands into the reader 700 regarding upcoming, ongoing, or completed tests.

[0158] 7C illustrates a high-level circuit diagram showing how a reader 700 reads the electrodes (active electrode 118 and reference electrode 120) of a sensor unit 112 (see also FIGS. 1H and 7D). The reader 700 can act as a high-impedance voltmeter to measure the potential difference between the indicator or active electrode 118 of the sensor unit 112 immersed in a sample and the reference electrode 120 or pseudo-reference electrode of the sensor unit 112 immersed in the sample.

[0159] The oxidation-reduction potential (ORP) of a sample can be the ratio of oxidized to reduced molecules in a sample and is an effective metric for monitoring the presence or absence of infectious agent growth and metabolism. Oxygen and other electron donors are consumed as infectious agents grow and metabolize. This results in a higher proportion of reduced molecules and therefore a more negative ORP.

[0160] To measure the ORP of the culture medium, a redox-sensitive but inert electrode material (e.g., made from a noble metal such as platinum or gold) can be used as the active electrode 118. The reference electrode 120 can be a silver / silver chloride pseudo-reference electrode or a carbon reference electrode. The reference electrode 120 does not respond to redox changes in the sample, while reduced molecules (molecules with excess electrons) readily release electrons at the active electrode 118, resulting in the accumulation of negative charges. Thus, as infectious agent growth / metabolism progresses, the ORP in the sample becomes more negative. In the absence of infectious agent growth / metabolism, the ORP of the sample remains constant for the duration of the measurement.

[0161] 7D is a schematic diagram illustrating certain steps performed by the electronic components of the reader 700 when processing signals obtained from the sensor units 112. As shown in FIG. 7D, the analog signals read from each of the sensor units 112 can first be buffered by a buffering circuit within the reader 700. The buffered signals can then be provided as inputs to an analog multiplexer (MUX) within the reader 700. The analog multiplexer can then iterate for each sensor unit 112. The analog signals from the multiplexer can then be converted to digital signals that can be analyzed by a microcontroller within the reader 700 to determine whether the infectious agent is susceptible (shows no signs of growth), intermediately susceptible (shows some signs of growth), or resistant (shows signs of growth).

[0162] 8 illustrates various steps of one embodiment of a method for determining the susceptibility of an infectious agent to one or more anti-infective drugs. The method can utilize the devices, apparatus, and systems disclosed herein, including the test device 100 including the sensor array lid 102 and the reader 700.

[0163] The method can include diluting the sample with a diluent solution to a dilution ratio of about 1:1 to about 1:10,000.

[0164] In some embodiments, the sample may be obtained from a subject or patient, hi other embodiments, the sample may be a biological sample, an environmental sample, or a food sample.

[0165] When the sample is an environmental sample, the sample may be obtained from a stream, river, lake, ocean, pollution site, quarantine zone, emergency area, or some combination thereof.

[0166] When the sample is a food sample, the sample can be obtained from a food preparation facility, a food service facility, a waste facility, or a combination thereof.

[0167] When a sample is obtained from a patient or subject, the sample may comprise at least one of a bodily fluid of the subject or patient or a resuspended swab obtained from the subject or patient.

[0168] In some embodiments, the subject or patient can be a human subject or patient.

[0169] In other embodiments, the subject or patient can be a non-human animal subject or patient.

[0170] In some embodiments, the sample can include blood, urine, serum, plasma, saliva, sputum, semen, breast milk, joint fluid, spinal fluid such as cerebrospinal fluid, wound secretions, mucus, fluid associated with stool, vaginal secretions, synovial fluid, pleural fluid, peritoneal fluid, pericardial fluid, amniotic fluid, or a combination thereof.

[0171] In some embodiments, the sample can include or be a bacterial culture derived from at least one of a sample obtained from a subject or patient, a biological sample, an environmental sample, and a food sample. For example, the sample can include or be a bacterial culture or resuspended bacterial culture derived from a bodily fluid or swab obtained from a subject or patient.

[0172] As a more specific example, the sample can include or be a bacterial culture derived from blood or other bodily fluid obtained from a patient or subject that has tested positive for microbial growth. When the sample is a bacterial culture derived from blood, the sample can be or can be referred to as a positive blood culture (PBC).

[0173] A PBC can be a bacterial culture derived from blood drawn from a test subject or patient that tests positive for bacterial growth. For example, a patient may exhibit symptoms of sepsis (e.g., high fever, chills, etc.), and blood (e.g., 5 mL to 10 mL) can be drawn from the patient and transferred to a commercially available blood culture container containing bacterial growth medium (e.g., 30 mL to 40 mL of growth medium). The blood culture container can then be inoculated at 35°C ± 2°C to allow bacterial proliferation. If the patient's blood is contaminated with bacteria, the bacteria will replicate in the container, and the blood culture system or device can determine the sample as testing "positive" for bacterial growth. Depending on the pathogen type and growth rate, the blood culture can turn positive within 7 hours to 3 days. Such a PBC can then be used for further downstream testing (e.g., antimicrobial susceptibility testing) using the apparatus, devices, systems, and methods disclosed herein.

[0174] In some embodiments, the sample can include bacteria, such as Acinetobacter, Acetobacter, Actinomyces, Aerococcus, Aeromonas, Agrobacterium, Anaplasma, Azorhizobium, Azotobacter, Bacillus, Bacteroides, Bartonella, Bordetella, Borrelia, Brucella, Burkholderia, Callimatobacterium, Campylobacter, Chlamydia, Chlamydophila, Citrobacter, Clostridium, Corynebacterium, Coxiella, Ehrlichia, Enterobacter, Enterococcus, Escherichia, Francisella, Fusobacterium, Gardnerella, Haemophilus, Helicobacter, Klebsiella, Lactobacillus, Legionella, or the like. The bacteria may be of a genus selected from the group consisting of Bacillus subtilis, Bacillus casei, Bacillus subtilis ...

[0175] More specifically, the bacteria include Acinetobacter baumannii (A. baumannii), Actinobacillus species, Actinomyces, Actinomyces species (including, but not limited to, Actinomyces isulaeri and Actinomyces naeslundii), Aeromonas species (including, but not limited to, Aeromonas hydrophila, Aeromonas veronii biovar sobria (Aeromonas sobria), and Aeromonas caviae), Anaplasma phagocytophilum, Alcaligenes xylooxidans, Actinobacillus actinomycetemcomitans, Bacillus species (Bacillus anthracis, Bacillus cereus, Bacteroides spp. (including but not limited to Bacillus subtilis, Bacillus thuringiensis, and Bacillus stearothermophilus), Bacteroides spp. (including but not limited to Bacteroides fragilis), Bartonella spp. (including but not limited to Bartonella bacilliformis and Bartonella henselae), Bifidobacterium spp., Bordetella spp. (including but not limited to Bordetella pertussis, Bordetella parapertussis, and Bordetella bronchiseptica), Borrelia spp. (including but not limited to Borrelia relapsing fever and Borreli burgdorferi), Brucella spp. (including but not limited to Brucella abortus, Brucella canis, Brucella melitensis, and Brucella suis), Burkholderia spp. (including but not limited to Burkholderia pseudomallei and Burkholderia cepacia), Campylobacter spp. (including but not limited to Campylobacter jejuni, Campylobacter coli, Campylobacter lari, and Campylobacter fetus), Capnocytophaga spp., Cardiac Obacterium hominis, Chlamydia trachomatis, Chlamydophila pneumoniae, Chlamydophila sitassi, Citrobacter spp., Coxiella burnetii, Corynebacterium spp. (including but not limited to Corynebacterium diphtheriae, Corynebacterium jacum, and Corynebacterium tetani), Clostridium spp. (including but not limited to Clostridium perfringens, Clostridium difficile, Clostridium botulinum, and Clostridium tetani), Eikenella corrodens,Enterobacter spp. (including, but not limited to, Enterobacter aerogenes, Enterobacter agglomerans, Enterobacter cloacae, and Escherichia coli (including opportunistic Escherichia coli (E. coli) (including, but not limited to, enterotoxigenic E. coli, enteroinvasive E. coli, enteropathogenic E. coli, enterohemorrhagic E. coli, enteroaggregative E. coli, and uropathogenic E. coli))), Enterococcus spp. (including, but not limited to, Enterococcus faecalis and Enterococcus faecium), Ehrlichia spp. (including, but not limited to, Ehrlichia chaffeensis and Ehrlichia canis), Erysipelothrix rhusiopathiae, Eubacterium spp. , Francisella tularensis, Fusobacterium nucleatum, Gardnerella vaginalis, Gemella morvirorum, Haemophilus spp. (including but not limited to Haemophilus influenzae, Haemophilus ducreyi, Haemophilus aegyptius, Haemophilus parainfluenzae, Haemophilus haemolyticus, and Haemophilus parahaemolyticus), Helicobacter spp. (including but not limited to Helicobacter pylori, Helicobacter cinedii, and Helicobacter fenneliae), Kingella kingae, Klebsiella spp. (including but not limited to Klebsiella pneumoniae, Klebsiella granulomatis, and Klebsiella oxytoca) Lactobacillus spp., Listeria monocytogenes, Leptospira interrogans, Legionella pneumophila, Leptospira interrogans, Peptostreptococcus spp., Moraxella catarrhalis, Morganella spp., Mobiluncus spp., Micrococcus spp., Mycobacterium spp. (including, but not limited to, Mycobacterium leprae, Mycobacterium tuberculosis, Mycobacterium intracellulare, Mycobacterium avium, Mycobacterium bovis, and Mycobacterium marinum), Mycoplasma spp. (including, but not limited to, Mycoplasma pneumoniae, Mycoplasma hominis, and Mycoplasma genitalium), Nocardia spp. (including, but not limited to, Nocardia asteroides, Nocardia ciliasigeorgica, and Nocardia brasiliensis), Neisseria spp. (including, but not limited to, Neisseria gonorrhoeae and Neisseria meningitidis,(including but not limited to), Pasteurella multocida, Plesiomonas shigelloides, Prevotella spp., Porphyromonas spp., Prevotella melaninogenica, Proteus spp. (including but not limited to Proteus vulgaris and Proteus mirabilis), Providencia spp. (including but not limited to Providencia alcalifaciens, Providencia rettgeri, and Providencia stuartii), Pseudomonas aeruginosa (P. aeruginosa), Propionibacterium acnes, Rhodococcus equi, Rickettsia spp. (including but not limited to Rickettsia rickettsii, Rickettsia akari and Rickettsia prowatzekii, Orientia tsutsugamushi (formerly Rickettsia tsutsugamushi) and Rickettsia typhi), Rhodococcus spp., Stenotrophomonas maltophilia, Salmonella spp. (including but not limited to Salmonella enterica, Salmonella typhi, Salmonella paratyphi, Salmonella enteritidis, Salmonella choleraeusis, and Salmonella typhimurium), Serratia spp. (Serratia marcescens (S. marcescens and Serratia liquefaciens), Shigella species (including, but not limited to, Shigella flexneri, Shigella boidii, and Shigella sonnei), Staphylococcus species (including, but not limited to, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus saprophyticus), Streptococcus species (including, but not limited to, Streptococcus pneumoniae (e.g., chloramphenicol-resistant serotype 4 Streptococcus pneumoniae, spectinomycin-resistant serotype 6 Type B Streptococcus pneumoniae, streptomycin-resistant serotype 9Vc, erythromycin-resistant serotype 14 Streptococcus pneumoniae, optocin-resistant serotype 14 Streptococcus pneumoniae, rifampicin-resistant serotype 18C Streptococcus pneumoniae, tetracycline-resistant serotype 19F Streptococcus pneumoniae, penicillin-resistant serotype 19F Streptococcus pneumoniae, and trimethoprim-resistant serotype 23F Streptococcus pneumoniae, chloramphenicol-resistant serotype 4 Streptococcus pneumoniae,Spectinomycin-resistant serotype 6B Streptococcus pneumoniae, streptomycin-resistant serotype 9V Streptococcus pneumoniae, opioid-resistant serotype 14 Streptococcus pneumoniae, rifampicin-resistant serotype 18C Streptococcus pneumoniae, penicillin-resistant serotype 19F Streptococcus pneumoniae, or trimethoprim-resistant serotype 23F Streptococcus pneumoniae), Streptococcus Group B Streptococcus, Streptococcus agalactiae, Streptococcus mutans, Streptococcus pyogenes, Group A Streptococcus, Streptococcus pyogenes, Group B Streptococcus, Streptococcus agalactiae, Group C Streptococcus, Streptococcus anginosus, Streptococcus extremilis, Group D Streptococcus, Streptococcus bovis, Group F Streptococcus, Streptococcus anginosus, and Group G Streptococcus), Rat-Bite Spirochetes rum, Streptobacillus moniliforme, Treponema spp. (including, but not limited to, Treponema carateum, Treponema pertenae, Treponema pallidum, and Treponema endemicum), Tropheryma hopellii, Ureaplasma urealyticum, Veillonella spp., Vibrio spp. (Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio argininolyticus) The bacterial strain may be of a species selected from the group consisting of Vibrio gallus, Vibrio mimicus, Vibrio horice, Vibrio fulvialis, Vibrio metsnikofii, Vibrio damsela, and Vibrio furnici), Xanthomonas maltophilia, and Yersinia species (including, but not limited to, Yersinia enterocolitica, Yersinia pestis, and Yersinia pseudotuberculosis).

[0176] In embodiments in which the sample contains bacteria, the anti-infective agent can include or be a bacteriostatic anti-infective agent, a bacteriocidal anti-infective agent, or a combination thereof.

[0177] In certain embodiments, the bacteriostatic anti-infective agent is a beta-lactam (including but not limited to, penicillins such as ampicillin, amoxicillin, flucloxacillin, penicillin, amoxicillin / clavulanate, and ticarcillin / clavulanate, and monobactams such as aztreonam), beta-lactams and beta-lactam inhibitor combinations (including but not limited to, piperacillin-tazobactam and ampicillin-sulbactam), aminoglycosides (including but not limited to, amikacin, gentamicin, kanamycin, neomycin, netilmicin, paromomycin, streptomycin, spectinomycin, and tobramycin), ansamycin, or the like. antihistamines (including but not limited to rifaximin), carbapenems (including but not limited to ertapenem, doripenem, imipenem, and meropenem), cephalosporins (including but not limited to ceftaroline, cefepime, ceftazidime, ceftriaxone, cefadroxil, cephalothin, cefazolin, cephalexin, cefaclor, cefprozil, fecloxime, cefixime, cefdinir, cefditoren, cefotaxime, cefpodoxime, ceftibuten, and ceftobiprole), chloramphenicol, glycopeptides (including but not limited to vancomycin, teicoplanin, telavantin, dalbavantin, and oritavantin), folate synthesisInhibitors (including but not limited to trimethoprim-sulfamethoxazole), fluoroquinolones (including but not limited to ciprofloxacin), lincosamides (including but not limited to clindamycin, lincomycin, azithromycin, clarithromycin, dirithromycin, roxithromycin, telithromycin, and spiramycin), lincosamine, lipopeptides, macrolides (including but not limited to erythromycin), monobactams, nitrofurans (including but not limited to furazolidone and nitrofurantoin), oxazolidinones (including but not limited to linezolid, pozizolid, radezolid, and torezolid), quinolones (enoxacin, gatifloxacin, gemifloxacin, levofloxacin, lomefloxacin, moxifloxacin, naldiqui, The antiviral agent may include an antiviral agent such as cyclosporin, norfloxacin, trovafloxacin, grepafloxacin, sparfloxacin, and temafloxacin, rifampin, streptogramins, sulfonamides (including but not limited to mafenide, sulfacetamide, sulfadiazine, sulfadimethoxine, sulfamethizole, sulfamethoxazole, sulfasalazine, and sulfisoxazole), tetracyclines (including but not limited to oxycycline, minocycline, demeclocycline, doxycycline, oxytetracycline, and tetracycline), polypeptides (including but not limited to cyclic lipopeptides such as bacitracin, polymyxin B, colistin, and daptomycin), phage, or a combination or derivative thereof.

[0178] In other embodiments, the anti-infective agent can include clofazimine, ethambutol, isoniazid, rifampicin, arsphenamine, chloramphenicol, fosfomycin, metronidazole, tigecycline, trimethoprim, or combinations or derivatives thereof.

[0179] In embodiments in which the sample may contain a fungus, the anti-infective agent can include an antifungal agent, for example, amphotericin B, anidulafungin, caspofungin, fluconazole, flucytosine, itraconazole, ketoconazole, micafungin, posaconazole, ravuconazole, voriconazole, or combinations or derivatives thereof.

[0180] As previously described, in some embodiments, the anti-infective agent may be pre-loaded or otherwise present in the test wells of the well plate 104. In other embodiments, the anti-infective agent may be added or otherwise introduced into the test wells of the well plate 104 prior to adding the aliquot of sample to the well 105 of the well plate.

[0181] In some embodiments, the anti-infective agent in the test wells can be lyophilized or dried, hi other embodiments, the anti-infective agent in the test wells can be in aqueous form.

[0182] The method can further include introducing an aliquot of a sample containing the infectious agent into wells 105 of well plate 104. As previously described, wells 105 can include test wells and control wells (e.g., positive control wells).

[0183] In some embodiments, the well plate 104 can contain multiple anti-infective agents, with particular wells 105 of the well plate 104 dedicated to particular anti-infective agents. In other embodiments, the well plate 104 can contain only one type of anti-infective agent.

[0184] The method may further include placing the sensor array lid 102 over the well plate 104 filled with the aliquot of sample or covering the well plate 104 with the sensor array lid 102 .

[0185] As previously described, the sensor array lid 102 can include a plurality of sensor units 112 extending from a bottom surface of the sensor array lid 102. Each of the sensor units 112 can be configured to extend into a well 105 of the well plate 104 such that when the sensor array lid 102 is placed on or covering the well plate 104, the sensor unit 112 is at least partially immersed in an aliquot of sample in the well 105.

[0186] The method may also include inserting or otherwise loading the well plate 104 covered by the sensor array lid 102 into the reader 700. The reader 700 may include conductive contacts or connections for electrically contacting the active and reference electrodes 118, 120 of the sensor units 112.

[0187] In some embodiments, the assembled test device 100 (well plate 104 covered by sensor array lid 102) in the reader 700 is heated to approximately 30 o C~about 40 o The cells can be inoculated in the reader 700 at an inoculation temperature of 0.5°C.

[0188] The method can further include determining the susceptibility of the infectious agent to the anti-infective drug based on changes in the solution properties of the aliquots of sample in the test wells containing the anti-infective drug and changes in the solution properties of the aliquots of sample in the control wells over a period of time.

[0189] In some embodiments, the reader 700 is capable of monitoring the growth of microorganisms in the wells 105 by tracking or monitoring for changes in the solution properties of the aliquots of sample in the test wells and the control wells. The reader 700 then compares the changes in the solution properties of the aliquots of sample in the test wells with the changes in the solution properties of the aliquots of sample in the control wells to determine the susceptibility of the infectious agent to the anti-infective drug.

[0190] The reader 700, together with one or more computing devices communicatively coupled to the reader 700, can analyze signals obtained from the multiple sensor units 112 of the test device 100 and provide information regarding the minimum inhibitory concentration (MIC) as well as information regarding the susceptibility (e.g., level of susceptibility) of the infectious agent to the anti-infective drug.

[0191] In some embodiments, the results of the test procedure (e.g., MIC and susceptibility levels) can be obtained and displayed or otherwise communicated in 4 to 10 hours. In certain embodiments, the results of the test procedure (e.g., MIC and susceptibility levels) can be obtained and displayed or otherwise communicated in 2 to 4 hours.

[0192] Figure 9A is a table illustrating performance results for 293 Gram-negative controlled PBCs in the presence of several antibiotics, including amikacin (AMK), ceftriaxone (CRO), aztreonam (ATM), cefazolin (CFZ), imipenem (IPM), piperacillin-tazobactam (TZP), and trimethoprim-sulfamethoxazole (SXT).

[0193] Contribed PBCs were prepared in standard aerobic bottles using 293 frozen Gram-negative isolates obtained from the Centers for Disease Control (CDC) and various hospitals. The 293 contribed PBCs were processed within 5 hours of flag time and tested in singlets.

[0194] Gram-negative isolates included E. coli, Klebsiella spp., Enterobacter spp., P. aeruginosa, A. baumannii, S. marcesans, Proteus spp., and Citrobacter spp.

[0195] All contrived PBCs were diluted using Mueller-Hinton broth (MHB), and aliquots of the diluted samples were transferred to wells 105 of several well plates 104 (e.g., 96-well well plates 104). Test wells of well plates 104 contained the seven clinically important antibiotics described above in lyophilized form.

[0196] The sensor array lid 102 was placed over the well plate 104 containing the diluted PBCs. The entire test device 100 was then loaded into the reader 700 for antimicrobial susceptibility testing. Results for a specific antibiotic were obtained in as little as four hours (see FIG. 9C). The sensor array lid 102 contained a sensor unit 112 that included a screen-printed platinum active electrode 118 and a screen-printed Ag / AgCl reference electrode 120.

[0197] Clinical and Laboratory Standards Institute (CLSI) interpretations (see CLSI. Performance Standards for Antimicrobial Susceptibility Testing. 30th ed. CLSI supplement M100) were applied, and all MIC results were compared to MICs determined using standard broth microdilutions. Broth microdilutions were prepared using 0.5 McFarland standard samples diluted according to the manufacturer's recommended guidelines. Broth microdilution results were read manually following a 21-hour inoculation period.

[0198] As shown in Figure 9A, essential agreement (EA), categorical agreement (CA), minor difference (mD), major difference (MD), and very major difference (VMD) rates were calculated according to FDA guidelines. Testing resulted in an overall EA of 98.1% and CA of 95.2%, with an mD rate of 4.0%, an MD rate of 1.1%, and a VMD rate of 0.4%. These results easily met the FDA-proposed criteria of >90% EA and CA, <3% MD, and <3% VMD. This demonstrates that the systems, devices, and methods disclosed herein are capable of producing accurate AST results compared to methods currently considered the gold standard in the field.

[0199] Figure 9B is a table illustrating performance results for 34 prospective Gram-negative PBC in the presence of several antibiotics, including AMK, CRO, ATM, CFZ, IPM, TZP, and SXT.

[0200] Prospective PBCs were obtained from local hospitals. Thirty-four prospective PBCs were processed within 12 hours of flag time and tested in triplicates.

[0201] Identified bacteria included E. coli, Klebsiella spp., Enterobacter spp., P. aeruginosa, S. marcesans, and Proteus spp.

[0202] All prospective PBCs were diluted using Mueller-Hinton broth (MHB), and aliquots of the diluted samples were transferred to wells 105 of several well plates 104 (e.g., 96-well well plates 104). The test wells contained the seven clinically important antibiotics mentioned above in lyophilized form.

[0203] The sensor array lid 102 was placed over the well plate 104 containing the diluted PBCs. The entire test device 100 was then loaded into the reader 700 for antimicrobial susceptibility testing. Results for specific antibiotics were obtained in as little as four hours.

[0204] Clinical and Laboratory Standards Institute (CLSI) interpretations (see CLSI. Performance Standards for Antimicrobial Susceptibility Testing. 30th ed. CLSI supplement M100) were applied, and all MIC results were compared to MICs determined using standard broth microdilutions. Broth microdilutions were prepared using 0.5 McFarland standard samples diluted according to the manufacturer's recommended guidelines. Broth microdilution results were read manually following a 21-hour inoculation period.

[0205] As shown in Figure 9B, testing resulted in an overall EA of 96.5% and CA of 95.0%, with a 3.0% mD rate, a 2.5% MD rate, and a 0.0% VMD rate. These results easily met the FDA-proposed criteria of >90% EA and CA, <3% MD, and <3% VMD. This demonstrates that the systems, devices, and methods disclosed herein are capable of producing accurate AST results compared to methods currently considered the gold standard in the field.

[0206] FIG. 9C is a graph showing the time-to-result (TTR) (in hours) for the Gram-negative controlled PBC described above in connection with FIG. 9A. As shown in FIG. 9C, the TTR for Gram-negative PBC for cefazolin (CFZ) and ceftriaxone (CRO) approached 4 hours, while the TTR for other anti-infectives was approximately 5 to 9 hours. Because results obtained using standard broth microdilution require 21 hours or more, FIG. 9C demonstrates that the systems, devices, and methods disclosed herein can produce accurate AST results in significantly less time than standard methods.

[0207] FIG. 10A illustrates a side cross-sectional view of another embodiment of a test device 1000 including a sensor array lid 1002 containing a sensor unit 1012 with active electrodes 1018 implemented as pins 1001 extending into wells 1005 of a well plate 1004.

[0208] The test device 1000 shown in FIG. 10A can be similar to the test device 100 shown in FIGS. 1A-1H , except that each of the sensor units 1012 includes an active electrode 1018 made from a pin 1001 coated with a redox-active material. In some embodiments, the redox-active material can be a precious metal. For example, the redox-active material can be partially made from a precious metal (e.g., platinum, gold, or a combination or alloy thereof). As a more specific example, the active electrode 1018 can be implemented as a platinum-coated pin 1001.

[0209] In other embodiments, the redox active material can be a conductive metal oxide such as iridium oxide, ruthenium oxide, or any combination or alloy of such materials with noble metals.

[0210] Test device 1000 can also be used as part of a system for determining the susceptibility of an infectious agent to one or more anti-infective agents. For example, the entire test device 1000 (including well plate 1004 covered by sensor array lid 1002) can be inserted or otherwise introduced into receiving slot 702 of reader 700 (see FIGS. 7A and 7B). The system can assay aliquots of sample in wells 1005 for the presence or absence of microbial growth as part of an antibiotic susceptibility testing (AST) procedure.

[0211] 10A, the sensor array lid 1002 can be configured to cover or cap the well plate 1004 when placed over the well plate 1004. The well plate 1004 can include a plurality of wells 1005 or microwells. For example, the well plate 1004 can include between 12 and 192 wells. As a more specific example, the well plate 1004 can include between 64 and 96 wells.

[0212] Each of the wells 1005 can be designed to receive a sample containing an infectious agent. The sample can be diluted before introducing an aliquot of the sample into the wells 1005. In certain embodiments, the well plate 104 can be a commercially available or pre-made well plate or microtiter plate.

[0213] The sensor array lid 1002 can include a lid top 1006 and a flexible substrate 1008 coupled to the underside of the lid top 1006 .

[0214] In the embodiment of test device 1000 shown in FIG. 10A , the flexible substrate 1008 can include multiple substrate strips 1010 or substrate segments that are partially cut away or otherwise separated from the remainder of the flexible substrate 1008 (i.e., the parts of the flexible substrate 1008 that are coupled to the underside of the sensor array lid 1002). The substrate strips 1010 can be curled or bent downward in a direction perpendicular to the perimeter of the flexible substrate 1008. The substrate strips 1010 can maintain their curled or bent configuration even when the sensor array lid 1002 covers or caps the well plate 1004. In this embodiment, the substrate strips 1010 can include a reference electrode 1020 disposed on the substrate strip 1010. For example, the reference electrode 1020 can be screen printed, sputter deposited, or electroplated on the substrate strip 1010.

[0215] The reference electrode 1020 can include a reference electrode material. In some embodiments, the reference electrode material can include at least one of silver / silver chloride (Ag / AgCl) and carbon. For example, when the reference electrode material is Ag / AgCl or carbon, the reference electrode material can be screen printed onto the substrate strip 1010.

[0216] The reference electrode 1020 can be considered a pseudo-reference electrode because the reference electrode 1020 operates without a reference buffer.

[0217] The reference electrode material can be coated with an ion exchange membrane or ionomer coating. In some embodiments, the ion exchange membrane can be a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer or polyaromatic polymer anion exchange membrane. The ion exchange membrane can be screen printed onto the reference electrode material and a portion of the substrate strip 1010.

[0218] The sensor array lid 1002 can also include a plurality of active electrodes 1018 implemented as pins 1001 extending from the underside of the sensor array lid 1002. The pins 1001 can be coated with a redox active material (e.g., platinum) to enable the pins 1001 to serve as the active electrodes 1018.

[0219] In some embodiments, the pins 1001 can be partially coupled to the flexible substrate 1008. The pins 1001 can also be coupled to the lid top 1006 of the sensor array lid 1002.

[0220] The active electrode 1018 (coated pin 1001) and reference electrode 1020 can be connected by one or more conductive traces to electrical contact pads on the sensor array lid 1002. The electrical contact pads can be attached to, connected to, or electrically coupled to the flexible substrate 1008.

[0221] The contact pads of the sensor array lid 1002 can be electronically connected or coupled to the active electrodes 1018 (e.g., coated pins 1001) and reference electrodes 1020 by a plurality of conductive traces. In some embodiments, the conductive traces can be routed along a surface or side of the flexible substrate 1008 (e.g., a side or surface that is attached to or coupled to the underside of the lid top 1006). The contact pads can be configured to contact or otherwise engage conductive connections in the reader 700 when the entire test device 1000 (in its assembled configuration) is inserted or introduced into the receiving slot 702 of the reader 700 to enable the reader 700 to acquire signals from the active electrodes 1018 and reference electrodes 1020.

[0222] In some embodiments, the flexible substrate 1008 can be made at least in part from a flexible polymeric material. For example, the flexible substrate 1008 can be made in part from a flexible sheet of polyethylene terephthalate (PET).

[0223] Additionally, the flexible substrate 1008 may be partially made from a flexible printed circuit board (PCB) material. For example, the flexible substrate 1008 may be partially made from polyimide or polyamide.

[0224] In alternative embodiments, the flexible substrate 1008 may be made in part from a conductive metal substrate. For example, in these embodiments, the flexible substrate 1008 may be made in part from a sheet of stainless steel foil.

[0225] In some embodiments, the flexible substrate 1008 can be coupled to the underside of the lid top 1006 by a biocompatible adhesive (e.g., a biocompatible polymer adhesive, a cyanoacrylate adhesive, etc.) and fasteners (e.g., screws, clips, clasps, etc.).

[0226] The sensor array lid 1002 can completely cover or fit over the top of the well plate 1004 when the test device 1000 is in an assembled configuration. The sensor array lid 1002 (including the lid top 1006) can protect the sample aliquots in the wells 1005 from contamination and can prevent the sample aliquots from spilling or inadvertently leaking.

[0227] For purposes of this disclosure, the sensor unit 1012 may be a substrate strip 1010 including a reference electrode 1020 and an active electrode 1018 implemented as a coated pin 1001 located in the same well 1005 as the substrate strip 1010.

[0228] In other embodiments, both the active electrode 1018 and the reference electrode 1020 can be implemented as coated pins. In these embodiments, the active electrode 1018 can be a pin coated with a redox-active material (e.g., platinum or gold), and the reference electrode 1020 can be a pin coated with or made from the reference electrode material. The pin serving as the reference electrode can be further coated with an ion-exchange membrane or ion-exchange or ionomer coating.

[0229] Each of the sensor units 1012 (e.g., implemented as a curled or bent substrate strip 110) can extend into a well 1005 of the well plate 1004 when the sensor array lid 1002 covers or caps the well plate 1004. When the wells 1005 of the well plate 1004 are filled with an aliquot of inoculum material or sample, at least a portion of the sensor unit 1012 can be immersed in the aliquot of inoculum material or sample.

[0230] The sensor units 1012 can be aligned to match the alignment or arrangement of the wells 1005. For example, when the well plate 1004 includes 96 wells arranged as an 8x12 array of wells 1005, the sensor array lid 1002 can include 96 sensor units 1012 arranged as an 8x12 array of sensor units 1012.

[0231] Figure 10B is a black and white image illustrating platinum coated pins 1001 that serve as active electrodes 1018 of sensor array lid 1002. As shown in Figure 10B, pins 1001 can be shaped as small cylindrical rods.

[0232] In some embodiments, the platinum coated pins 1001 can be coupled to the flexible substrate 1008 via a biocompatible adhesive. In other embodiments, the platinum coated pins 1001 can be coupled to the flexible substrate 1008 via a mechanical fastening or securing mechanism (e.g., a threaded connection, an interference fit, etc.).

[0233] The following clauses define certain aspects and embodiments of the present disclosure.

[0234] Clause 1. A sensor array lid, the sensor array lid comprising: a lid top; a flexible substrate coupled to an underside of the lid top, the flexible substrate including a plurality of substrate strips or segments that are partially cut away from the remainder of the flexible substrate, at least one substrate strip or segment of the flexible substrate curling or bending downward in a vertical direction relative to a perimeter portion of the flexible substrate; an active electrode disposed on each of the substrate strips or segments that curl or bend downward in the vertical direction; and a reference electrode disposed on each of the substrate strips or segments that curl or bend downward in the vertical direction.

[0235] Clause 2. The sensor array lid of clause 1, wherein the active electrode comprises a redox-active material.

[0236] Clause 3. The sensor array lid of clause 2, wherein the redox active material is a noble metal.

[0237] Clause 4. The sensor array lid of clause 2, wherein the redox active material is a metal oxide.

[0238] Clause 5. The sensor array lid of clause 1, wherein the reference electrode comprises a reference electrode material.

[0239] Clause 6. The sensor array lid of clause 5, wherein the reference electrode material comprises at least one of silver / silver chloride (Ag / AgCl) and carbon.

[0240] Clause 7. The sensor array lid of clause 6, wherein the reference electrode material is coated or covered by an ion exchange membrane.

[0241] Clause 8. The sensor array lid of clause 7, wherein the ion exchange membrane is a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer or polycyclic aromatic polymer anion exchange membrane.

[0242] Clause 9. The sensor array lid of clause 1, wherein the lid top includes support posts extending from a lower surface of the lid top, the support posts configured to press or compress against the substrate strip or segment such that the substrate strip or segment maintains its curled or bent configuration.

[0243] Clause 10. A sensor array lid as described in clause 9, wherein at least one of the substrate strips or segments is pressed or urged by at least one of the support posts such that a portion of the substrate strip or segment is substantially perpendicular to the portion of the flexible substrate that is connected to the top of the lid.

[0244] Clause 11. The sensor array lid of clause 1, wherein the flexible substrate is fabricated in part from a flexible polymer material.

[0245] Clause 12. The sensor array lid of clause 11, wherein the flexible polymer material is made in part from polyethylene terephthalate (PET).

[0246] Clause 13. The sensor array lid of clause 11, wherein the flexible polymer material is a flexible printed circuit board (PCB) material.

[0247] Clause 14. The sensor array lid of clause 13, wherein the flexible PCB material is polyimide.

[0248] Clause 15. The sensor array lid of clause 1, wherein the flexible substrate is fabricated in part from a conductive metal substrate.

[0249] Clause 16. The sensor array lid of clause 15, wherein the conductive metal substrate is stainless steel foil.

[0250] Clause 17. The sensor array lid of clause 1, wherein the top lid is fabricated in part from at least one of polystyrene, polypropylene, and cyclic olefin copolymer.

[0251] Clause 18. The sensor array lid of clause 1, wherein at least one of the active electrode and the reference electrode is a screen-printed electrode (SPE), and at least one of the redox-active material of the active electrode and the reference electrode material of the reference electrode is screen-printed onto a flexible substrate.

[0252] Clause 19. The sensor array lid of clause 1, wherein at least one of the active electrode and the reference electrode is an electroplated electrode, and at least one of the redox-active material of the active electrode and the reference electrode material of the reference electrode is electroplated onto a flexible substrate.

[0253] Clause 20. The sensor array lid of clause 1, wherein at least one of the active electrode and the reference electrode is a sputter-deposited electrode, and at least one of the redox-active material of the active electrode and the reference electrode material of the reference electrode is sputter-deposited on a flexible substrate.

[0254] Clause 21. The sensor array lid of clause 1, wherein the sensor array lid is disposable or single use.

[0255] Clause 22. A sensor array lid as described in clause 1, wherein the flexible substrate includes electrical contact pads disposed on the flexible substrate, the electrical contact pads being left exposed by the top of the lid, the active electrode being electrically connected to the electrical contact pads via conductive traces, and the reference electrode being electrically connected to the electrical contact pads via additional conductive traces.

[0256] Clause 23. The sensor array lid of clause 1, wherein the reference electrode is a pseudo reference electrode.

[0257] Clause 24. The sensor array lid of clause 1, wherein the flexible substrate is coupled to the underside of the lid top by at least one of a biocompatible adhesive and fasteners.

[0258] Clause 25. A system for determining the susceptibility of an infectious agent to one or more anti-infective agents, the system comprising: a well plate including a plurality of wells, the plurality of wells including a test well and at least one control well, each configured to contain an aliquot of a sample including the infectious agent, at least one of the test wells including the anti-infective agent and the control well lacking the anti-infective agent; and a sensor array lid configured to cover the well plate, the sensor array lid including a plurality of sensor units extending from a bottom surface of the sensor array lid, each of the sensor units configured to extend into one of the wells of the well plate; a sensor array lid, wherein the sensor units are adapted to be at least partially immersed in an aliquot of sample in the well, each of the sensor units including an active electrode and a reference electrode; and a reader, wherein the reader is configured to receive the well plate and the sensor array lid covering the well plate into a receiving slot of the reader, the reader including conductive contacts for contacting the active electrode and the reference electrode of the sensor units, and the reader is configured to determine susceptibility of the infectious agent to the anti-infective drug based on changes in solution characteristics of the aliquot of sample in the test wells containing the anti-infective drug and changes in solution characteristics of the aliquot of sample in the control wells over a period of time.

[0259] Clause 26. The system of clause 25, wherein the well plate contains 24 to 96 wells and the sensor array lid contains 24 to 96 sensor units.

[0260] Clause 27. The system of clause 25, wherein the anti-infective agent in the test well is lyophilized or desiccated.

[0261] Clause 28. The system of clause 25, wherein the anti-infective agent in the test well is in aqueous form.

[0262] Clause 29. The system of Clause 25, wherein the change in the solution properties of the well is detected in the absence of an exogenous reporter molecule added to the well.

[0263] Clause 30. The system of clause 25, wherein the sample comprises a body fluid or a bacterial culture derived therefrom.

[0264] Clause 31. The system of clause 25, wherein the sample is a positive blood culture.

[0265] Clause 32. The system of clause 25, wherein the infectious agent comprises a bacterium.

[0266] Clause 33. The system of clause 32, wherein the anti-infective agent comprises a bacteriostatic anti-infective agent, a bacteriocidal anti-infective agent, or a combination thereof.

[0267] Clause 34. The system of clause 25, wherein the infectious agent comprises a fungus.

[0268] Clause 35. The system of clause 34, wherein the anti-infective agent comprises an anti-fungal agent.

[0269] Clause 36. The system of clause 25, wherein the sensor array lid further comprises a lid top and a flexible substrate coupled to the underside of the lid top, wherein each of the sensor units is implemented as a substrate strip or segment that is partially cut out from the remainder of the flexible substrate, and the substrate strip or segment of the flexible substrate is curled or bent downward in a vertical direction relative to a peripheral portion of the flexible substrate, and wherein the active electrode is disposed on the substrate strip or segment that is curled or bent downward in a vertical direction, and the reference electrode is disposed on the substrate strip or segment that is curled or bent downward in a vertical direction.

[0270] Clause 37. The system of clause 36, wherein the lid top includes a support post extending from a lower surface of the lid top, the support post configured to press or compress the substrate strip or segment such that the substrate strip or segment maintains its curled or bent configuration.

[0271] Clause 38. The system of clause 36, wherein the flexible substrate is made in part from a flexible polymer material.

[0272] Clause 39. The system of clause 38, wherein the flexible polymer material is made in part from polyethylene terephthalate (PET).

[0273] Clause 40. The system of clause 38, wherein the flexible polymer material is a flexible printed circuit board (PCB) material.

[0274] Clause 41. The system of clause 36, wherein the flexible substrate is fabricated in part from a conductive metal substrate.

[0275] Clause 42. The system of clause 41, wherein the conductive metal substrate is a stainless steel foil.

[0276] Clause 43. The system of clause 36, wherein the lid top is made in part from at least one of polystyrene, polypropylene, and cyclic olefin copolymer.

[0277] Clause 44. The system described in Clause 36, wherein the flexible substrate includes electrical contact pads disposed on the flexible substrate for connection to conductive contacts of the reader, the electrical contact pads being left exposed by the lid top, the active electrode being electrically connected to the electrical contact pads via conductive traces, and the reference electrode being electrically connected to the electrical contact pads via additional conductive traces.

[0278] Clause 45. The system of clause 25, wherein the solution characteristic is oxidation-reduction potential (ORP) and the active electrode comprises a redox-active material.

[0279] Clause 46. The system of clause 45, wherein the redox active material is a noble metal.

[0280] Clause 47. The system of clause 45, wherein the redox active material is a metal oxide.

[0281] Clause 48. The system of clause 25, wherein the reference electrode comprises a reference electrode material.

[0282] Clause 49. The system of clause 48, wherein the reference electrode material comprises at least one of silver / silver chloride (Ag / AgCl) and carbon.

[0283] Clause 50. The system of clause 49, wherein the reference electrode material is coated or covered by an ion exchange membrane.

[0284] Clause 51. The system of clause 50, wherein the ion exchange membrane is a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer or polycyclic aromatic polymer anion exchange membrane.

[0285] Clause 52. The system of clause 25, wherein at least one of the active electrode and the reference electrode is a screen-printed electrode (SPE).

[0286] Clause 53. The system of clause 25, wherein at least one of the active electrode and the reference electrode is an electroplated electrode.

[0287] Clause 54. The system of clause 25, wherein at least one of the active electrode and the reference electrode is a sputter-deposited electrode.

[0288] Clause 55. The system of clause 25, wherein the sensor array lid is disposable or single-use.

[0289] Clause 56. A method for determining the susceptibility of an infectious agent to one or more anti-infective agents, the method comprising the steps of: introducing an aliquot of a sample containing the infectious agent into wells of a well plate, the wells including test wells and at least one control well, at least one of the test wells including the anti-infective agent and the control well lacking the anti-infective agent; and covering the well plate with a sensor array lid, the sensor array lid including a plurality of sensor units extending from a lower surface of the sensor array lid, each of the sensor units configured to extend into one of the wells of the well plate. the sensor units being adapted to be at least partially immersed in the aliquots of sample in the wells, each of the sensor units including an active electrode and a reference electrode; inserting the well plate covered by the sensor array lid into a reader, the reader including conductive contacts for contacting the active and reference electrodes of the sensor units; and determining the susceptibility of the infectious agent to the anti-infective drug based on changes in solution properties of the aliquots of sample in the test wells containing the anti-infective drug and changes in solution properties of the aliquots of sample in the control wells over a period of time.

[0290] Clause 57. The method of clause 56, wherein the method further comprises the step of diluting the sample with a dilution solution to a dilution ratio of about 1:1 to about 1:10,000 before introducing the sample into the wells of the well plate.

[0291] Clause 58. The method comprises: placing a well plate covered by a sensor array lid in a well plate holder for about 30 minutes; o C~about 40 o 57. The method of clause 56, comprising inoculating in the reader at an inoculation temperature of C.

[0292] Clause 59. The method of clause 56, wherein the well plate contains between 24 and 96 wells and the sensor array lid contains between 24 and 96 sensor units.

[0293] Clause 60. The method of clause 56, wherein the anti-infective agent in the test well is lyophilized or dried.

[0294] Clause 61. The method of clause 56, wherein the anti-infective agent in the test well is in aqueous form.

[0295] Clause 62. The method of Clause 56, wherein the change in the solution properties of the well is detected in the absence of an exogenous reporter molecule added to the well.

[0296] Clause 63. The method of Clause 56, wherein the sample comprises a body fluid or a bacterial culture derived therefrom.

[0297] Clause 64. The method of clause 56, wherein the sample is a positive blood culture.

[0298] Clause 65. The method of Clause 56, wherein the infectious agent comprises a bacterium.

[0299] Clause 66. The method of Clause 65, wherein the anti-infective agent comprises a bacteriostatic anti-infective agent, a bacteriocidal anti-infective agent, or a combination thereof.

[0300] Clause 67. The method of Clause 56, wherein the infectious agent comprises a fungus.

[0301] Clause 68. The method of Clause 67, wherein the anti-infective agent comprises an anti-fungal agent.

[0302] Clause 69. The method of clause 56, wherein the sensor array lid further comprises a lid top and a flexible substrate coupled to the underside of the lid top, wherein each of the sensor units is implemented as a substrate strip or segment that is partially cut out from the remainder of the flexible substrate, and the substrate strip or segment of the flexible substrate is curled or bent downward in a vertical direction relative to a peripheral portion of the flexible substrate, and wherein the active electrode is disposed on the substrate strip or segment that is curled or bent downward in a vertical direction, and the reference electrode is disposed on the substrate strip or segment that is curled or bent downward in a vertical direction.

[0303] Clause 70. The method of clause 69, wherein the lid top includes a support post extending from a lower surface of the lid top, the support post being configured to press or compress the substrate strip or segment such that the substrate strip or segment maintains its curled or bent configuration.

[0304] Clause 71. The method of clause 69, wherein the flexible substrate is made in part from a flexible polymer material.

[0305] Clause 72. The method of clause 71, wherein the flexible polymeric material is made in part from polyethylene terephthalate (PET).

[0306] Clause 73. The method of clause 71, wherein the flexible polymer material is a flexible printed circuit board (PCB) material.

[0307] Clause 74. The method of clause 69, wherein the flexible substrate is fabricated in part from a conductive metal substrate.

[0308] Clause 75. The method of clause 74, wherein the conductive metal substrate is a stainless steel foil.

[0309] Clause 76. The method of Clause 69, wherein the lid top is made in part from at least one of polystyrene, polypropylene, and cyclic olefin copolymer.

[0310] Clause 77. The method of clause 69, wherein the flexible substrate includes electrical contact pads disposed on the flexible substrate for connection to conductive contacts of the reader, the electrical contact pads being left exposed by the lid top, the active electrode being electrically connected to the electrical contact pads via conductive traces, and the reference electrode being electrically connected to the electrical contact pads via additional conductive traces.

[0311] Clause 78. The method of clause 56, wherein the solution characteristic is oxidation-reduction potential (ORP) and the active electrode comprises a redox-active material.

[0312] Clause 79. The method of clause 78, wherein the redox active material is a noble metal.

[0313] Clause 80. The method of Clause 78, wherein the redox active material is a metal oxide.

[0314] Clause 81. The method of clause 56, wherein the reference electrode comprises a reference electrode material.

[0315] Clause 82. The method of clause 81, wherein the reference electrode material comprises at least one of silver / silver chloride (Ag / AgCl) and carbon.

[0316] Clause 83. The method of clause 82, wherein the reference electrode material is coated or covered by an ion exchange membrane.

[0317] Clause 84. The method of clause 83, wherein the ion exchange membrane is a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer or polycyclic aromatic polymer anion exchange membrane.

[0318] Clause 85. The method of clause 56, wherein at least one of the active electrode and the reference electrode is a screen-printed electrode (SPE), such that at least one of the redox-active material of the active electrode and the reference electrode material of the reference electrode is screen-printed onto the sensor unit.

[0319] Clause 86. The method of clause 56, wherein at least one of the active electrode and the reference electrode is an electroplated electrode.

[0320] Clause 87. The method of clause 56, wherein at least one of the active electrode and the reference electrode is a sputter-deposited electrode.

[0321] Clause 88. The method of clause 56, wherein the sensor array lid is disposable or single-use.

[0322] Multiple embodiments have been described. Nevertheless, it will be understood by those skilled in the art that various changes and modifications can be made to the present disclosure without departing from the spirit and scope of the embodiments. Elements of the systems, devices, apparatus, and methods shown in connection with the embodiments are exemplary with respect to particular embodiments and can be used in combination with or otherwise with other embodiments within the present disclosure. For example, the steps of the methods depicted in the figures or described in the present disclosure do not require the particular order or sequential order shown or described to achieve desired results. In addition, other step actions can be provided, or steps or actions can be excluded or omitted from the described method or process. Moreover, components or parts of the apparatus or systems described or depicted in the figures in the present disclosure can be removed, excluded, or omitted to achieve desired results. In addition, certain components or parts of the systems, devices, or apparatus shown or described herein have been omitted for simplicity and clarity.

[0323] Accordingly, other embodiments are within the scope of the following claims, and the specification and / or drawings can be regarded in an illustrative rather than a restrictive sense.

[0324] Each individual variation or embodiment described and illustrated herein comprises discrete components and features that may be readily separated from or combined with the features of any of the other variations or embodiments. Modifications may be made to adapt a particular situation, material, composition of matter, process, process acts, or steps to the objective, spirit, or scope of the present invention.

[0325] Methods recited herein may be carried out in any order of the recited events which is logically possible, and additional steps or actions may be provided or steps or actions may be omitted to achieve desired results.

[0326] Moreover, when a range of values ​​is provided, all intervening values ​​between the upper and lower limits of that range, and any other stated or intervening values ​​within that stated range, are encompassed within the present invention. Also, any optional features of the described inventive variations can be set forth and claimed independently or in combination with any one or more of the features described herein. For example, description of a range of 1 to 5 should be considered to disclose subranges such as 1 to 3, 1 to 4, 2 to 4, 2 to 5, 3 to 5, etc., as well as individual numbers within that range, e.g., 1.5, 2.5, etc., and any whole or partial increments therebetween.

[0327] All pre-existing subject matter (e.g., publications, patents, patent applications) mentioned herein is incorporated herein by reference in its entirety, except to the extent that it may conflict with the subject matter of the present invention, in which case the present disclosure shall control. The referenced items are provided solely for their disclosure prior to the filing date of the present application. Nothing herein should be construed as an admission that the present invention is not entitled to antedate such material by virtue of prior invention.

[0328] Reference to a singular item includes the possibility that there are plural of the same items. More specifically, as used herein and in the appended claims, the singular forms "a," "an," "said," and "the" include plural references unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as a predicate for the use of such exclusive terms, such as "solely" and "only," in connection with the recitation of claim elements, or for the use of a "negative" limitation. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0329] References to the phrase "at least one of," when such phrase modifies multiple items or components (or an enumerated list of items or components), mean any combination of one or more of those items or components. For example, the phrase "at least one of A, B, and C" means (i) A, (ii) B, (iii) C, (iv) A, B, and C, (v) A and B, (vi) B and C, or (vii) A and C.

[0330] In understanding the scope of the present disclosure, the term "comprising" and its derivatives, as used herein, are intended to be open-ended terms that specify the presence of stated features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other, unstated features, elements, components, groups, integers, and / or steps. The foregoing also applies to phrases having similar meanings, such as the terms "including," "having," and their derivatives. Additionally, the terms "part," "section," "portion," "member," "element," or "component," when used in the singular, can have the dual meaning of a single part or multiple parts. As used herein, the following directional terms "forwardly, backwardly, upwardly, downwardly, vertically, horizontally, downwardly, transversely, laterally, and vertically" and any other similar directional terms refer to the location of a device or piece of equipment or the direction of a device or piece of equipment being translated or moved.

[0331] Finally, terms of degree, such as "substantially," "about," and "approximately," as used herein, refer to a stated value or to a stated value and a reasonable amount of deviation from the stated value (e.g., up to ±0.1%, ±1%, ±5%, or ±10%, where such variation is appropriate) so that the end result is not significantly or substantially altered. For example, "about 1.0 cm" can be interpreted to mean "1.0 cm" or "0.9 cm to 1.1 cm." When terms of degree, such as "about" or "approximately," are used to refer to numbers or values ​​that are part of a range, the term can be used to modify both the minimum and maximum numbers or values.

[0332] The present disclosure is not intended to be limited in scope to the particular forms described, but is intended to cover alternatives, modifications, and equivalents of the variations or embodiments described herein. Moreover, the scope of the present disclosure fully encompasses other variations or embodiments that may become apparent to those skilled in the art in view of the present disclosure. [Explanation of symbols]

[0333] 100 test devices 102 Sensor array cover 104-well plate 105 wells 106 Lid top 108 Flexible PCB 110 PCB Strip 112 Sensor Unit 114 Post 115 Electrical Contact Pad 116 Distal Segment 118 Active electrode 120 Reference electrode 122 Conductive Traces 300 ways 302 Stencil 304 Material 306 Blade 308 Ion exchange membrane 700 Leaders 702 Reception Slots 704 Display 1000 test devices 1001 pins 1002 Sensor array lid 1004 well plate 1005 wells 1006 Lid top 1008 Flexible PCB 1010 PCB Strip 1012 Sensor Unit 1018 Active electrode 1020 Reference electrode

Claims

1. The top of the lid and a flexible substrate coupled to the underside of the lid top, the flexible substrate including a plurality of substrate strips or segments partially cut away from the remainder of the flexible substrate, at least one substrate strip or segment of the flexible substrate curling or bending downward in a direction perpendicular to a perimeter of the flexible substrate; an active electrode disposed on each of said substrate strips or segments that curls or bends vertically downward; a reference electrode disposed on each of said substrate strips or segments that curl or bend vertically downward; a sensor array lid.

2. The sensor array lid of claim 1 , wherein the active electrode comprises a redox-active material.

3. The sensor array lid of claim 2 , wherein the redox active material is a noble metal.

4. The sensor array lid of claim 2 , wherein the redox active material is a metal oxide.

5. The sensor array lid of claim 1 , wherein the reference electrode comprises a reference electrode material.

6. The sensor array lid of claim 5 , wherein the reference electrode material comprises at least one of silver / silver chloride (Ag / AgCl) and carbon.

7. The sensor array lid of claim 6 , wherein the reference electrode material is coated or covered by an ion exchange membrane.

8. The sensor array lid of claim 7, wherein the ion exchange membrane is a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer or polycyclic aromatic polymer anion exchange membrane.

9. 10. The sensor array lid of claim 1, wherein the lid top includes support posts extending from the underside of the lid top, the support posts configured to press or compress the substrate strips or segments so that the substrate strips or segments maintain their curled or bent configuration.

10. 10. The sensor array lid of claim 9, wherein at least one of the substrate strips or segments is pressed or urged by at least one of the support posts such that a portion of the substrate strip or segment is substantially perpendicular to a portion of the flexible substrate that is coupled to the lid top.

11. The sensor array lid of claim 1 , wherein the flexible substrate is made in part from a flexible polymer material.

12. 12. The sensor array lid of claim 11, wherein the flexible polymer material is made in part from at least one of polyethylene terephthalate (PET) and flexible printed circuit board (PCB) material.

13. The sensor array lid of claim 1 , wherein the flexible substrate is made in part from a conductive metal substrate.

14. 10. The sensor array lid of claim 1, wherein at least one of the active electrode and the reference electrode is a screen-printed electrode (SPE), and at least one of a redox-active material of the active electrode and a reference electrode material of the reference electrode is screen-printed onto the flexible substrate.

15. 10. The sensor array lid of claim 1, wherein at least one of the active electrode and the reference electrode is an electroplated electrode, such that at least one of a redox active material of the active electrode and a reference electrode material of the reference electrode is electroplated onto the flexible substrate.

16. 10. The sensor array lid of claim 1, wherein at least one of the active electrode and the reference electrode is a sputter-deposited electrode, such that at least one of a redox-active material of the active electrode and a reference electrode material of the reference electrode is sputter-deposited onto the flexible substrate.

17. 10. The sensor array lid of claim 1, wherein the flexible substrate includes electrical contact pads disposed on the flexible substrate, the electrical contact pads remaining exposed by the lid top, the active electrodes electrically connected to the electrical contact pads via conductive traces, and the reference electrodes electrically connected to the electrical contact pads via additional conductive traces.

18. The sensor array lid of claim 1 , wherein the reference electrode is a pseudo reference electrode.

19. 1. A system for determining the susceptibility of an infectious agent to one or more anti-infective agents, comprising: a well plate including a plurality of wells, the plurality of wells including a test well and at least one control well, each of the wells configured to contain an aliquot of a sample including the infectious agent, at least one of the test wells including an anti-infective agent, and the control well lacking the anti-infective agent; a sensor array lid configured to cover the well plate, the sensor array lid comprising: a plurality of sensor units extending from a lower surface of the sensor array lid, each of the sensor units configured to extend into one of the wells of the well plate such that the sensor unit is at least partially immersed in the aliquot of the sample in the well, each of the sensor units comprising: an active electrode, and reference electrode a sensor array lid including: a reader configured to receive the well plate and the sensor array lid covering the well plate in a receiving slot of the reader, the reader including conductive contacts for contacting the active electrode and the reference electrode of the sensor unit, and the reader configured to determine the susceptibility of the infectious agent to the anti-infective drug based on changes in solution properties of the aliquots of the sample in the test wells containing the anti-infective drug and changes in the solution properties of the aliquots of the sample in the control wells over a period of time; Including, the system.

20. 1. A method for determining the susceptibility of an infectious agent to one or more anti-infective agents, comprising: introducing aliquots of samples containing the infectious agent into wells of a well plate, the wells including test wells and at least one control well, at least one of the test wells containing an anti-infective agent and the control well lacking the anti-infective agent; covering the well plate with a sensor array lid, the sensor array lid including a plurality of sensor units extending from a lower surface of the sensor array lid, each of the sensor units configured to extend into one of the wells of the well plate such that the sensor units are at least partially immersed in the aliquot of the sample in the well; Each of the sensor units includes an active electrode and a reference electrode. Steps and inserting the well plate covered by the sensor array lid into a reader, the reader including conductive contacts for contacting the active and reference electrodes of the sensor units; determining the susceptibility of the infectious agent to the anti-infective agent based on changes in solution properties of the aliquots of the sample in the test wells containing the anti-infective agent and changes in the solution properties of the aliquots of the sample in the control wells over a period of time; A method comprising:

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