Instrumented device used for detecting the presence of microorganisms in a liquid sample

Abstract

The invention relates to an instrumented device adaptable to a container (1) comprising a casing for receiving a liquid sample (LSE), the device comprising at least two electrodes, referred to as a measuring electrode (E1) and a reference electrode (E2). The instrumented device includes at least one measuring element (2) made of an electrically insulating material. Said measuring element (2) has means for removably cooperating with the casing of said container. Said measuring element (2) has a first surface intended to come into contact with an internal volume of said container when said measuring element (2) is adapted to the container (1), and a second opposing surface accessible from the outside, the first surface of said measuring element (2) carrying said measuring electrode (E1) and said reference electrode (E2). Figure to be published with the abbreviation: Figure 2A

Description

Title of the invention: Instrumented device used for detecting the presence of microorganisms in a liquid sample. Technical field of the invention

[0001] The present invention relates to an instrumented device adaptable to a container containing a liquid sample, said device being able to be used for the detection of the presence of microorganisms in said sample. State of the art

[0002] Blood is normally completely sterile. Any microorganism present in the bloodstream therefore represents a vital threat to the human body. Blood culture is currently a known method for diagnosing blood infections. It is a common test in clinical microbiology. Blood culture primarily consists of culturing blood in a nutrient broth under aerobic and anaerobic conditions, incubated at 36-37°C in automated systems adapted for this type of sample, in order to obtain bacterial growth. The objective is to increase the quantity of bacteria present in the sample by providing favorable growth conditions, and thus to detect the presence of bacteria in the blood of a patient with a septic condition.This amplification is all the more necessary because the bacterial concentration in the blood during bacteremia is always low, on the order of one or a few bacteria per milliliter of blood sampled. This first step of blood culture therefore consists of a simple detection of presence, without identification, from a sample without normal flora: any presence of bacteria or fungi thus leads to a positive test.

[0003] This detection will then be followed by subculture on agar medium to isolate the pathogen in colony form, allowing for subsequent identification of the pathogen and its antibiogram. In the case of bloodstream infections, examinations are urgent, and the time to obtain results (positive blood culture, pathogen identification, antibiogram) has an undeniable impact on patient outcomes (mortality, length of hospital stay, complications, etc.). Blood culture results allow antibiotic therapy to be tailored to the patient's specific case: the earlier appropriate and effective antibiotic therapy is administered, the greater the patient's chances of survival. Each hour of delay in initiating appropriate antibiotic therapy is associated with an increase in mortality.

[0004] Diagnostic manufacturers have worked for many years to reduce the time it takes for blood cultures to become positive, as well as to reduce analysis times for tests identification and antibiogram testing. Currently, two main types of automated systems coexist: - Devices that monitor the amount of carbonic acid generated in the liquid phase, using a polymer matrix (silicone) loaded with a pH-sensitive chromophore or fluorophore. - Devices used to detect an increase in total pressure in the gas phase.

[0005] These two technologies share the common feature of being implemented in automated systems, often large ones, with the impossibility of starting the test until the vial is in the system (pre-incubation can generate false negatives), hence the loss of precious hours before the implementation of optimized antibiotic therapy. A 2013 study showed that the average transport time was 9 hours (interquartile range: 3-15 hours), with 6% of vials having a transport time exceeding 20 hours.

[0006] Patent application EP4018191A1 describes the use of an instrumented container equipped with measuring electrodes, capable of holding a liquid sample for analysis. The detection of microorganisms is notably achievable by electrochemistry, by placing the container in a suitable chamber. This patent application proposes a simple solution for reducing the time between sample collection and the start of the analysis. This solution is also easily transportable, making it readily available in the field, and easy to implement, even by unskilled personnel.

[0007] However, this solution requires the development of specific and non-standard containers, which represents a significant cost.

[0008] The object of the invention is to provide a solution for detecting the presence of a microorganism in a liquid sample, which can be rapidly deployed after collection, thus minimizing the time between sample collection and the start of analysis, while also being compatible with existing collection bottles. These bottles are pre-filled with a culture medium whose composition is optimized for sterility testing. Description of the invention

[0009] This goal is achieved by an instrumented device adaptable to a container comprising an envelope intended to receive a liquid sample, the device comprising at least two electrodes, called a measuring electrode and a reference electrode: - The instrumented device comprising at least one measuring element (2) made of electrically insulating material, - Said measuring element comprising means for cooperating removably with the casing of said container, - Said measuring element comprising a first surface intended to come into contact with an internal volume of said container when said measuring element is fitted onto the container, and a second opposing surface accessible from the outside, - The first surface of said measuring element bearing said measuring electrode and said reference electrode, - The second surface of said measuring element bearing a first electrically conductive part and a second electrically conductive part, - Said measuring element incorporating a first electrical passage connecting said reference electrode to the first conductive element and a second electrical passage connecting said measuring electrode to the second conductive element.

[0010] According to a particular embodiment, the measuring element comprises a cap made of electrically insulating material and including means for cooperation by screwing or fitting, intended to cooperate with complementary means arranged on a neck of the container.

[0011] According to another particular embodiment, the measuring element comprises an elongated rod along a so-called longitudinal axis made of electrically insulating material, the rod comprising a proximal end and a distal end, said rod carrying at its proximal end said first electrically conductive organ and said second electrically conductive organ, the rod comprising an external surface intended to come into contact with the liquid sample, on which said measuring electrode and said reference electrode are made.

[0012] According to one particular feature, the rod has a first cavity made on its external surface, said reference electrode being deposited in said first cavity.

[0013] According to another feature, the rod has a second cavity made on its external surface, said measuring electrode being deposited in said second cavity.

[0014] According to another feature, the stem has a point at its distal end.

[0015] According to another feature, the stem is hollow along its entire length.

[0016] According to another feature, the measuring element comprises a head positioned at the proximal end of the stem, the head bearing said first conducting organ and said second conducting organ.

[0017] According to another feature, the device includes means for assembling the head onto the rod.

[0018] According to another feature, the stem and the head cooperate with each other by screwing.

[0019] According to another feature, the head includes means for cooperation by screwing or fitting, intended to cooperate with complementary means arranged on a neck of the container.

[0020] According to a particular variant, the rod is made from an electronic board made of flexible material and wound on itself.

[0021] According to one particular feature, said measuring electrode is made in the form of a deposit of a conductive ink or an electro-deposition of a conductive measuring element.

[0022] According to another feature, said reference electrode is made in the form of a deposit of an Ag / AgCl ink covered with a polymer layer. Brief description of the figures

[0023] Other features and advantages will become apparent in the detailed description that follows, given in relation to the accompanying drawings, in which: - Figures IA to IC show a first embodiment of the instrumented device according to the invention; - Figures 2A and 2B show a second embodiment of the instrumented device according to the invention; - Figures 3A and 3B represent a third embodiment of the instrumented device according to the invention; - Figures 4 to 6 illustrate different embodiment variants of the instrumented device, applicable to the second embodiment and the third embodiment;

[0024] Detailed description of at least one embodiment

[0025] The invention relates to an instrumented device used for the detection of the presence of microorganisms in a liquid sample ECH, placed in a container 1.

[0026] The ECH liquid sample may be a biological fluid, advantageously chosen from the group consisting of blood such as whole blood or anticoagulated whole blood, blood serum, blood plasma, lymph, tears, semen, urine, milk, cerebrospinal fluid, interstitial fluid, joint fluid, pericardial fluid, isolated bone marrow fluid, cell extract, tissue extract, organ extract, and mixtures thereof. Thus, the biological fluid may be any fluid naturally secreted or excreted from a human or animal body or any fluid recovered from a human or animal body by any technique known to those skilled in the art, such as extraction, sampling, puncture, or washing. The steps of recovering and isolating these various fluids from the human or animal body are carried out beforehand and are not part of the invention.

[0027] The ECH liquid sample can also be a liquid product from the food, pharmaceutical, or cosmetic industries. In a particular embodiment, the object from which the sample is taken can be chosen from large installations such as an industrial object like an electronic device or a machine used in the food, pharmaceutical, or cosmetic industries, a tank, a restaurant kitchen, a cold room, a sanitary facility, a container, and small objects such as medical devices or pipes.

[0028] The liquid sample ECH can also be a sterile culture medium surrounding a solid or powdered sample whose sterility is to be tested, for example a biopsy, tissues for grafts, a medical device (heart valve, prosthesis, contact lens, syringe, needle, etc.), a powdered active ingredient, single-use laboratory equipment, surgical equipment...

[0029] In a more particular embodiment, the liquid sample is blood, such as human or animal blood. The latter is normally sterile but may contain microorganisms such as bacteria.

[0030] With reference to the attached figures, the device comprises a measuring element carrying at least two different electrodes El, E2, used to analyze the liquid sample ECH, a measuring electrode El and a reference electrode E2.

[0031] The measuring electrode El used in the device of the invention is advantageously an electrode made in the form of a deposit of a conductive ink or an electrode made in the form of an electrodeposition of a conductive measuring element. Any conductive ink known to those skilled in the art can be used. In one particular embodiment, the conductive ink used is a metal ion-based ink or a conductive organic polymer such as polythiophene (PT), polyaniline (PANI) optionally doped with dodecylbenzenesulfonic acid (DBSA), poly(3,4-ethylenedioxythiophene) coupled to sodium poly(styrene sulfonate) (PEDOT:PSS), polypyrrole, or polyphthalocyanine. In another particular embodiment, the conductive ink used in the context of the invention is a carbon ink optionally comprising an additional conductive measuring element.By "conductive measuring element", we mean a measuring element selected from the group consisting of conductive organic polymers such as those listed above, and metal-based compounds such as, for example, a metal oxide such as iridium oxide (IrOx), a metal-based pigment such as Prussian blue (Fe(III) 5 ferrocyanide) or an organic or organo-inorganic catalyst such as cobalt phthalocyanine.

[0032] Advantageously, the reference electrode E2 used in the context of the invention is made in the form of a deposit of an Ag / AgCl ink.

[0033] Optionally, it is possible to put a counter electrode in contact with the liquid culture medium.

[0034] The device of the invention is integrated into a system configured to detect and possibly identify a microorganism contained in the ECH liquid sample placed in the container 1.

[0035] The system also includes: - A measuring unit U1 for the potential difference between the measuring electrode El and the reference electrode E2, configured to measure the potential difference continuously and / or at a plurality of time instants, - An electronic acquisition unit U2 for measuring the potential difference, connected to the measuring unit, - A processing unit U3 connected to the electronic acquisition unit U2 and configured to process the measurement of the potential difference, - A power supply unit U4 to power the electronic acquisition unit U2 and possibly the processing unit. U3

[0036] A heating unit may also be added, as well as a temperature measurement and control unit. Heating must be carried out uniformly around the container. The temperature measurement and control unit may include a temperature probe and means for regulating said temperature to a predetermined fixed value. The temperature value is chosen according to the type of culture being performed. In the case of a blood culture, the incubation temperature is chosen to be 35°C + / - 2°C.

[0037] The power supply unit U4 may consist of a rechargeable battery intended to power the various units of the device.

[0038] The processing unit U3 may include a microprocessor and storage means. It may also include a communication module. This module may be wireless to communicate via a wireless link, for example according to the Bluetooth protocol, with the corresponding module of the acquisition unit.

[0039] By way of example, the U3 processing unit can be configured to: - Receive measurement data from the acquisition unit, for example via wireless connection, - Establish an electrochemical monitoring of the mixture as a function of time, - Process the curve obtained and determine the presence of microorganisms. - Order a human-machine interface designed to indicate the presence bacteria - Read an RFID tag present on container 1 in order to collect and store data related to the sampling, - Ensure the regulation of the heating unit to ensure the most constant incubation temperature possible.

[0040] The device of the invention has the particularity of cooperating in a removable manner with the container 1 in which the liquid sample ECH to be analyzed is placed.

[0041] It is presented in the form of a measuring element 2 equipped with means adapted to cooperate with the container 1.

[0042] Container 1 can be a standard container, commonly used for storing a sample such as a blood sample. Such a container 1 can, in particular, be hermetically sealed using a septum (see embodiments in Figures 2A and 2B). Container 1 can also be any receptacle whose liquid contents (physiological saline, injectable medication, nutrient medium) are intended to be used for a sterility test.

[0043] Several distinct embodiments of the device can be distinguished: - In a first embodiment shown in figures IA to IC, the measuring element 2 includes a cap 20 which is screwed or fitted onto the container 1, this cap directly carrying the two electrodes El, E2; - In a second embodiment shown in figures 2A and 2B, the measuring element 2 comprises a rod 21 carrying the two electrodes El, E2, the rod being intended to be inserted inside the container 1, immersed at least partially in the liquid sample ECH, for example by passing through the septum 10 which closes the container 1 hermetically; - In a third embodiment shown in Figures 3A and 3B, the measuring element 2 is in the form of a single unit consisting of a cap 22 and a rod 21, assembled on said cap 22 and carrying the two electrodes E1, E2, the cap 22 being provided with means to fit onto the container, the rod 21 inserted into the internal volume of the container 1 to be immersed at least partially in the liquid sample ECH;

[0044] The first embodiment is illustrated in Figures IA to IC. The cap 20 is made of an electrically insulating material, for example rubber or plastic. It includes fastening means 201, by screwing or snap-fitting, intended to cooperate with complementary means 100 present on the container 1, for example at its neck. It includes an accessible external surface. from the outside and an internal surface, intended to be oriented towards the inside of the container when fitted onto the container.

[0045] The plug 20 has on its external surface two electrically conductive elements 201, 202 and on its internal surface the two electrodes, the measuring electrode El and the reference electrode E2, advantageously each made in the form of a deposit of a layer of material, according to one of the embodiments proposed above.

[0046] Between the first conductive element and the measuring electrode, the plug 20 incorporates a first electrical feedthrough 203 to ensure the electrical connection. Between the second conductive element and the reference electrode, the plug incorporates a second electrical feedthrough 204 to ensure the electrical connection.

[0047] The measuring unit described above is connected between the two electrodes, to measure the potential difference between the two electrodes.

[0048] In operation, the cap 20 is positioned on the neck of the container 1 ([Fig.1A]). Once the cap is in place on the container ([Fig.1B]), the container can be turned upside down to bring the liquid sample ECH into contact with the two electrodes for the duration of the measurement ([Fig.1C]).

[0049] The cap 20 is of course fitted onto the container 1 to close it in a completely airtight manner, despite the overpressure inherent in the microbial growth which may occur.

[0050] In the second embodiment shown in Figures 2A and 2B, the rod 21 is made of an electrically insulating material. It has a proximal end and a distal end. The rod 21 has an external surface, in particular a lateral surface on which the two electrodes E1, E2 are formed. Each electrode is, for example, deposited as a layer of material on this lateral surface of the rod 21.

[0051] Advantageously, the lateral wall of the rod is hollowed out, for example with two cavities, for example in the form of longitudinal trenches ([Fig. 4]). Each cavity or trench receives a deposit of material forming respectively the measuring electrode E1 and the reference electrode E2. The cavity or trench allows the contact surface of the electrode to be recessed relative to the external surface of the rod 21, preventing its degradation, particularly during insertion of the rod through the septum.

[0052] The rod 21 can be configured so as to have a point 217 at its distal end (as in Figures 2A and 2B), so as to be able to pierce the septum 10 closing the container hermetically.

[0053] A contact re-establishment is made on the proximal end side of the rod to connect each electrode El, E2 to the measuring unit Ul.

[0054] In this variant, advantageously, the measuring element 2 may also include a head 210 assembled on the rod 21, on the side of its proximal end. The head 210 is made of an electrically insulating material. The head 210 is accessible from the outside when the measuring element 2 is fitted onto the container. The head 210 thus carries a first conductive element 211 and a second conductive element 212. The first conductive element is connected to the measuring electrode E1 and the second conductive element is connected to the reference electrode E2, each via an electrical feedthrough 213, 214 integrated into the head 210 of the measuring element 2.

[0055] During operation, the rod 21 is inserted into the container 1 containing the liquid sample ECH, its pointed distal end piercing the septum 10 ([Fig. 2A]). The rod is pushed into the container until the two electrodes El, E2 are immersed in the liquid sample ECH to perform the measurements ([Fig. 2B]). The head 210 remains accessible from the outside to connect the measuring unit Ul.

[0056] The rod 21 may have a solid cross-section. However, as illustrated in [Fig. 5], the rod 21 may be hollow, i.e., with an internal channel 215 along its entire length, along its longitudinal axis. This feature has the advantage of also allowing the device to be used for collecting the liquid sample ECH, during or after the electrochemical measurement performed between the two electrodes E1, E2.

[0057] With reference to [Fig.6], the head 210 can be assembled onto the rod 21 by screwing (with a screw thread 216).

[0058] The third embodiment is a combination of the first two embodiments, in that the measuring element 2 has a rod 21 carrying the two electrodes El, E2, identical to that described above, and a head in the form of a cap 22 to which the rod 21 is attached. The cap 22 has fastening means 220 for screwing or snap-fitting, allowing the measuring element 2 to be fitted directly onto the neck of the container 1 to seal it hermetically, the rod 21 being inserted into the container 1 to be immersed in the liquid sample. The other features described above for the second embodiment are identical. The cap 22 has two electrical contact members 221, 222 and incorporates two electrical feedthroughs 223, 224 for connecting them to the two electrodes El, E2. In this embodiment: - The cap 22 can be assembled onto the rod 21, in a removable manner, for example by screwing; - The pointed configuration of the stem at its distal end is optional, as is the presence of the internal channel;

[0059] In [Fig. 3A], the cap 22 carrying the rod 21 is inserted into the container 1 until it fits onto the neck of the container 1. In [Fig. 3B], the cap is positioned to hermetically seal the container 1, with the rod immersed in the liquid sample ECH so as to bring the electrodes El, E2 into contact with the liquid sample ECH. The measuring unit U1 can then be ordered to carry out the measurements.

[0060] Based on these different embodiments, it should be noted that: - It is possible to have more than two electrodes on the measuring element. The number of electrical connections will need to be adapted - this provides multiparameter electrochemical monitoring; - The presence of the trenches has the advantage of preventing any deterioration of the deposits when the stem is inserted into the container through the septum; - Each cavity / trench made on the rod can accommodate several electrodes juxtaposed along its length; It is also possible to make several separate cavities, one for each electrode; - The rod can be made in the form of a flexible electronic board on one side of which the electrodes are deposited, the electronic board being wound on itself to give its elongated shape to said rod;

Claims

11 Demands

1. Instrumented device adaptable to a container (1) comprising an envelope for receiving a liquid sample (ECH), the device comprising at least two electrodes, referred to as a measuring electrode (E1) and a reference electrode (E2), characterized in that: The instrumented device comprises at least one measuring element (2) made of electrically insulating material. Said measuring element (2) comprises means for cooperating removably with the casing of said container. Said measuring element (2) comprises a first surface intended to come into contact with an internal volume of said container when said measuring element (2) is fitted onto the container (1), and a second opposing surface accessible from the outside, The first surface of said measuring element (2) carries said measuring electrode (E1) and said reference electrode (E2), The second surface of said measuring element (2) carries a first electrically conductive element (201, 211, 221) and a second electrically conductive element (202, 212, 222), The measuring element (2) includes a first electrical feedthrough (203, 213, 223) connecting the measuring electrode to the first conductive member and a second electrical feedthrough (204, 214, 224) connecting the reference electrode to the second conductive member. The measuring element (2) comprises a rod (21) elongated along a longitudinal axis made of electrically insulating material, the rod (21) having a proximal end and a distal end, the rod (21) having at its proximal end the first electrically conductive member (211, 221) and the second electrically conductive member (212, 222), the rod (21) having an external surface intended to come into contact with the liquid sample (ECH), on which the measuring electrode (E1) and the reference electrode (E2) are formed. The rod (21) has a first cavity formed on its external surface, said reference electrode being deposited in said first cavity, - The rod (21) has a second cavity made on its external surface, said measuring electrode being deposited in said second cavity.

2. Device according to claim 1, characterized in that the measuring element (2) comprises a cap (20) made of electrically insulating material and comprising means for cooperation by screwing or fitting, intended to cooperate with complementary means arranged on a neck of the container (1).

3. Device according to claim 1 or 2, characterized in that the rod (21) has a tip (217) at its distal end.

4. Device according to any one of claims 1 to 3, characterized in that the rod (21) is hollow along its entire length.

5. Device according to any one of claims 1 to 4, characterized in that the measuring element (2) comprises a head (210, 22) positioned at the proximal end of the rod (21), the head carrying said first conducting member (211, 221) and said second conducting member (212, 222).

6. Device according to claim 5, characterized in that it comprises means for assembling the head (210, 22) onto the rod (21).

7. Device according to claim 6, characterized in that the rod (21) and the head (210, 22) cooperate with each other by screwing.

8. Device according to any one of claims 5 to 9, characterized in that the head (22) comprises means for cooperation by screwing or fitting, intended to cooperate with complementary means arranged on a neck of the container.

9. Device according to any one of claims 1 to 8, characterized in that the rod (21) is made from an electronic board made of flexible material and wound on itself.

10. Device according to any one of claims 1 to 9, characterized in that said measuring electrode (El) is made in the form of a deposit of a conductive ink or an electro-deposition of a conductive measuring element.

11. Device according to any one of claims 1 to 10, characterized in that said reference electrode (E2) is made in the form of a deposit of an Ag / AgCl ink covered with a polymer layer.

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