Liquid-chemical sterilization system with biological indicator

Abstract

A liquid-chemical sterilization system with a biological indicator is disclosed. The sterilization system includes a vial, a carrier of microorganisms disposed in the vial, and a fluid management system having an output connectable to the vial for delivering a liquid chemical sterilant and a neutralizing agent to the vial. Additionally, a growth medium can be delivered to the vial so that the vial and growth medium can be evaluated for a change in a visual characteristic indicative of a sterilization failure.

Description

[0001] This application is a divisional application of the parent application having application number 201980084698.0, filing date of December 19, 2019, and title of “Liquid-chemical sterilization system with biological indicator”. TECHNICAL FIELD

[0002] The subject matter disclosed herein relates to devices and techniques for assessing the adequacy of liquid chemical sterilization procedures, particularly as applied to endoscope sterilization. BACKGROUND

[0003] Medical devices are typically sterilized prior to use to minimize the possibility that a contaminated device can be used on a subject, which can result in infection of the subject. Various sterilization techniques can be employed, such as steam, hydrogen peroxide, and vapor phase sterilization, with or without gas plasma and ethylene oxide (EtO).

[0004] Certain sterilization techniques are performed at pressures other than ambient or atmospheric pressure. For example, the STERRAD® NX System, STERRAD® NX- G2® System, or STERRAD® 100NX System by Advanced Sterilization Products, Division of Ethicon US, LLC, a Johnson & Johnson company, vaporizes hydrogen peroxide and operates at low pressures, such as below 200 milliTorr. Systems, NX System, or 100NX System are examples of sterilization systems or sterilizers that vaporize hydrogen peroxide and operate at low pressures, such as below 200 milliTorr.

[0005] For various reasons, various elongated medical devices having lumens, such as endoscopes, are challenging to sterilize with a vaporized sterilant, such as vaporized hydrogen peroxide. For example, because pressure in the lumen decreases from the inlet of the lumen according to length and diameter, pressure drop must be overcome to ensure that the sterilant passes through the entire lumen and reaches all surfaces of the lumen. In addition, the lumen can collect debris or become clogged with fluids, such as irrigation water.

[0006] Sterilization procedures that are generally based on steam incorporate sterilization indicators, such as biological or chemical indicators, that can provide an indication of the effectiveness of the sterilization cycle. Even though such indicators can be positioned in the sterilization chamber proximate to the endoscope, they can be unreliable for assessing the sterility of the endoscope because the most difficult-to-sterilize portions of the endoscope are typically deep within the lumen of the endoscope. SUMMARY

[0007] A sterilization system is disclosed herein that includes a vial, a carrier disposed in the vial, and a fluid management system. The fluid management system includes an output that is connectable to the vial so as to deliver a liquid to the vial. Such a liquid includes at least a liquid-chemical sterilant (e.g., peracetic acid) and a neutralizing agent (e.g., sodium metabisulfite). Accordingly, the fluid management system can include a source of the liquid-chemical sterilant and a source of the neutralizing agent. The sterilization system can also include a fixture that includes a first segment having a needle connected to the output of the fluid management system and a second segment having a cavity that houses the vial. The first and second segments can be connected by a hinge such that rotation of the first segment about the hinge causes the needle to pierce the vial. The vial can include a cover that can also be pierced by the needle. A medical device (e.g., an endoscope) having a lumen can be connected between the needle and the output.

[0008] The carrier in the vial includes, for example, spores or microorganisms disposed on or in the carrier. For example, the carrier can include Bacillus stearothermophilus spores. The sterilization system can include a growth medium (e.g., a-MUG) that can be used to promote growth of the spores or microorganisms. Accordingly, the fluid management system can include a source of the liquid growth medium. Alternatively or additionally, the growth medium can be provided in a second vial and disposed in a second cavity.

[0009] The sterilization system can be used to determine the sterility (or lack thereof) of a medical device that has undergone or is undergoing a sterilization cycle in the sterilization system. The method can include the steps of inserting a vial containing a carrier of microorganisms into a cavity of a fixture, piercing a needle into the vial, and introducing a liquid-chemical sterilant into the vial through the needle. Further, a lumen of a medical device, such as an endoscope, can be connected between a source of the sterilant and the needle such that the sterilant flows through the lumen before it is introduced into the vial. The vial can then be incubated at between about 30°C and about 50°C, such as at 35°C, while the liquid-chemical sterilant is disposed therein. After incubation, the liquid chemical sterilant can be withdrawn from the vial through the needle.

[0010] Next, a neutralizing agent can be introduced into the vial through the needle and subsequently withdrawn from the vial through the needle. A growth medium can then be introduced into the vial through the needle from a source of the growth medium of the fluid management system or from a second vial disposed in a second cavity of the fixture. Subsequently, the vial, i.e., the vial having the carrier and the growth medium disposed therein, can be incubated at between about 50°C and about 60°C, such as at 57°C.

[0011] While the vial is incubated, a visual characteristic of the growth medium can be monitored so as to determine a change in the visual characteristic. The visual characteristic can include a fluorescence intensity.

[0012] At any step of the sterilization cycle, but preferably at the first or last step, the system can sterilize at least some of its fluidic components, e.g., tubes, valves, and pumps, by flowing the liquid-chemical sterilant through these components. BRIEF DESCRIPTION OF DRAWINGS

[0013] While the specification concludes with claims particularly pointing out and distinctly claiming that which is regarded as the present application, it is believed the present application will be better understood from the following description of certain examples, presented in conjunction with the following drawings, wherein like reference notations are used to refer to like elements throughout, and in which:

[0014] Figure 1 depicts a schematic of a fixture in an open configuration for use with a liquid-chemical sterilization system to aid in assessing sterilization efficacy;

[0015] Figure 2 depicts a schematic of a fixture in a closed configuration for use with a liquid-chemical sterilization system to aid in assessing sterilization efficacy; Figure 1

[0016] Figure 3 depicts a block diagram of a fluid management system for use with a fixture and a liquid-chemical sterilization system of Figure 1 and Figure 2 DETAILED DESCRIPTION

[0017] The following detailed description should be read with reference to the drawings in which like elements in different drawings are identically numbered. The drawings depict only selected embodiments and are not therefore necessarily drawn to scale. The detailed description illustrates by way of example, not by way of limitation, the principles of the application. This description will clearly enable one skilled in the art to make and use the application, and describes several embodiments, adaptations, variations, alternatives and uses of the same, including what is presently believed to be the best mode of carrying out the application.

[0018] As used herein, the term "about" or "approximately," with reference to any numerical or range of values, means a suitable dimensional tolerance that allows for a collection of parts or components to function for their intended purpose as described herein. More specifically, "about" or "approximately" can mean a range of values ±10% of the stated value, for example "about 90%" can mean a range of values from 81% to 99%. Additionally, as used herein, the terms "patient," "host," "user," and "subject" refer to any human or animal subject and are not intended to limit the systems or methods to human use, although use of the present application in a human patient represents a preferred embodiment.

[0019] ​​Automated sterilization equipment and procedures for endoscopes employing liquid-chemical sterilants, such as hydrogen peroxide or peracetic acid, are being developed to overcome certain shortcomings associated with sterilizing endoscopes using steam-chemical sterilants. However, as with steam-based processes, the development of reliable techniques for assessing whether an endoscope has been sterilized remains a challenge. Furthermore, biological indicators used in steam-based processes are not suitable for use in liquid-based processes because such indicators are designed to remove gaseous sterilants therefrom, not liquid sterilants. Moreover, such indicators typically require user disruption of an ampoule containing growth media. Thus, when liquid-chemical sterilants are used, there remains a risk of residual liquid sterilant burning the user. It would therefore be advantageous to provide a system that does not require user intervention, which is capable of manipulating a biological indicator for use with liquid-chemical sterilants. However, such a system should be designed to withstand sterilization to avoid the accumulation of contaminants therein. Presented herein are devices and methods that further address these design needs, which can be used to determine whether an endoscope has been sterilized by a sterilization procedure employing liquid-chemical sterilants.

[0020] Figure 1 and Figure 2 A fixture 100 is reflected that can be used in conjunction with or form part of a liquid-chemical sterilization system. The fixture 100 can aid in assessing medical devices, particularly endoscopes, subjected to a sterilization procedure by the system. Figure 1 A fixture 100 is reflected in an open and unused configuration, while Figure 2 A fixture 100 is reflected in a closed configuration. The fixture 100 includes a first section 102 coupled to a second section 104 by a hinge 106, such as a living hinge. A first cavity 108 and a second cavity 110 can be formed in the second section 104. A tubular passage can be formed in the first section 102 that is adapted to hold a capillary tube or hollow needle, such as first needle 116 and second needle 118. Furthermore, heating elements, such as heating coils 136 and 138, can be disposed in the second section 104. The heating coils 136 and 138 are preferably disposed adjacent to the cavity 108 so that they can be used to heat a liquid disposed within the cavity 108. The heating coils 136 and 138 can include contacts on the bottom to pass electricity through. Although not shown, the fixture 100 can also include components, such as a light source and light detector, that are capable of assessing changes in visual characteristics of a liquid, such as a color change or fluorescence intensity change of a liquid in the first cavity 108. Alternatively, such components can be located adjacent to where the cavity 108 can be disposed in the sterilization system.

[0021] The first and second chambers 108 and 110 are adapted to contain a liquid. Alternatively or additionally, they are adapted to maintain the position of a vial disposed therein. For example, as reflected in Figure 1 The first vial 112 can be disposed in the first chamber 108 and the second vial 114 can be disposed in the second chamber 110. In those embodiments where a liquid is disposed directly in one or both chambers, i.e., without a vial, the chamber can be sealed with a cover which can be broken to access the fluid. For example, a layer of foil, e.g., aluminum, can be used to cover the chamber 108, chamber 110, or both. The layer of foil can be broken or punctured, for example, by a needle 116, 118, or both. In those embodiments incorporating the first vial 112, the second vial 114, or both, the vials can be individually covered to seal the vial. As reflected in Figure 1 and Figure 2 The first vial 112 includes a cover 120 and the second vial 114 includes a cover 122. Thus, the vials 112 and 114 can be provided as sterilized consumables which can be disposed in the chambers 108 and 110 prior to the initiation of a sterilization procedure and removed from the chambers 108 and 110 after the sterilization procedure.

[0022] The vials 112 and 114 can also include features of a biological indicator. In particular, a disk or carrier 132 contains or is impregnated with a source of microorganisms, such as spores or active enzymes. The carrier 132 can be disposed in the first vial 112. Spores from the genera Bacillus, Geobacillus, and Clostridium are commonly used to monitor sterilization processes using chemical sterilants. Thus, the carrier 132 can be impregnated with spores from the genera Bacillus, Geobacillus, and / or Clostridium. For example, the sterilization process resistant spores can include, but are not limited to, at least one of Geobacillus stearothermophilus spores, Bacillus subtilis spores, Bacillus atrophaeus spores, Bacillus megaterium spores, Bacillus coagulans spores, Clostridium sporogenes spores, Bacillus pumilus spores, and combinations thereof.

[0023] The carrier 132 can be water absorbent and can be formed of filter paper. Sheet materials such as cloth, non-woven polypropylene, rayon or nylon, and microporous polymeric materials can also be used. Non-water absorbent materials are also suitable for use, such as metals (e.g., aluminum or stainless steel), glass (e.g., glass beads or glass fibers), porcelain, or plastics. Additionally, the carrier 110 can be constructed of a combination of the above materials. In some embodiments, the carrier 110 can have a thickness of about 0.1 to 0.5 millimeters.

[0024] In addition, a growth medium 134 can be disposed in the second vial 114. The growth medium should be capable of promoting growth of any living microorganism or other biologically active source disposed on the carrier 132. Preferably, the microorganism is selected to produce an enzyme that interacts with an enzyme substrate of the growth medium to produce a change in a visual characteristic of the growth medium, for example, by causing a change in color or a change in fluorescence intensity of the growth medium. Continued growth of the microorganism in the growth medium results in an increase in the concentration of a detectable product in the growth medium. In certain embodiments, the detectable product is a fluorophore. Thus, the increase in the concentration of the detectable product causes an increase in fluorescence. That is, the detectable product can be detected by a change in fluorescence intensity.

[0025] Enzymes and enzyme substrates that can be used to detect efficacy of a sterilization cycle are identified in U.S. Patent No. 5,073,488, entitled “Rapid Method for Determining Efficacy of a Sterilization Cycle and Rapid Read-Out Biological Indicator,” issued December 17, 1991, the disclosure of which is incorporated herein by reference; U.S. Patent No. 5,418,167, entitled “Rapid Read-Out Biological Indicator,” issued May 23, 1995, the disclosure of which is incorporated herein by reference; U.S. Patent No. 5,223,401, entitled “Rapid Read-Out Sterility Indicator,” issued June 29, 1993, the disclosure of which is incorporated herein by reference; and U.S. Patent No. 9,322,046, entitled “Biological Sterilization Indicator,” issued April 26, 2016, the disclosure of which is incorporated herein by reference.

[0026] Suitable enzymes can include hydrolases and / or enzymes derived from spore-forming microorganisms such as Bacillus subtilis. Enzymes from spore-forming microorganisms that can be used in exemplary biological indicators can include beta-D-glucosidase, alpha-D-glucosidase, alkaline phosphatase, acid phosphatase, butyrate esterase, caprylate esterase lipase, myristate lipase, leucine aminopeptidase, valine aminopeptidase, chymotrypsin, phosphohydrolase, alpha-D-galactosidase, beta-D-galactosidase, tyrosine aminopeptidase, phenylalanine aminopeptidase, beta-D-glucuronidase, alpha-L-arabinofuranosidase, N-acetyl-beta-glucosaminidase, beta-D-cellobiosidase, alanine aminopeptidase, proline aminopeptidase, fatty acid esterase, and combinations thereof.

[0027] In some exemplary methods for determining efficacy of a sterilization cycle as disclosed herein, the enzyme substrate is converted to a detectable product. For example, the enzyme substrate can be characterized by a first emission spectrum (e.g., a first fluorescent emission spectrum), and the detectable product can be characterized by a second emission spectrum (e.g., a second fluorescent emission spectrum).

[0028] In some exemplary methods for determining efficacy of a sterilization cycle as disclosed herein, suitable enzyme substrates used can include fluorescent enzyme substrates. Useful fluorescent enzyme substrates can be selected from the group consisting of fluorescent 4-methylumbelliferone derivatives (hydrolyzable to 4-methylumbelliferone ("4-Mu")), derivatives of 7-amido-4-methyl-coumarin, diacetylfluoroscein derivatives, fluorosamine, and combinations thereof.

[0029] Exemplary 4-methylumbelliferone derivatives can be selected from the group consisting of 4-methylumbelliferyl-2-acetamido-4,6-0-benzylidene-2-deoxy- -D-glucopyranoside, 4-methylumbelliferyl acetate, 4-methylumbelliferyl-N-acetyl- -D-galactosamine, 4-methylumbelliferyl-N-acetyl-a-D-glucosaminide, 4-methylumbelliferyl-N-acetyl- -D-glucosaminide, 2'-(4-methylumbelliferyl)-a-D-N-acetylneuraminic acid, 4-methylumbelliferyl a-L-arabinofuranoside, 4-methylumbelliferyl a-L-arabinoside, 4-methylumbelliferyl butyrate, 4-methylumbelliferyl 13-D-cellobioside, methylumbelliferyl -D-N,N'-diacetylchitobioside, 4-methylumbelliferyl ester, 4-methylumbelliferyl -D-fucoside, 4-methylumbelliferyl a-L-fucoside, 4-methylumbelliferyl -L-fucoside, 4-methylumbelliferyl a-D-galactoside, 4-methylumbelliferyl -D-galactoside, 4-methylumbelliferyl a-D-glucoside, 4-methylumbelliferyl -D-glucoside, 4-methylumbelliferone (3-D-glucuronic acid, 4-methylumbelliferyl p-guanidobenzoate, 4-methylumbelliferyl heptanoate, 4-methylumbelliferyl a-D-mannopyranoside, 4-methylumbelliferyl -D-mannopyranoside, 4-methylumbelliferyl oleate, 4-methylumbelliferyl palmitate, 4-methylumbelliferyl phosphate, 4-methylumbelliferyl propionate, 4-methylumbelliferyl stearate, 4-methylumbelliferyl sulfate, 4-methylumbelliferyl -D-N,N',N"-triacetylchitotriose, 4-methylumbelliferyl 2,3,5-tri-o-benzoyl-a-L-arabinofuranoside, 4-methylumbelliferyl-p-trimethylcinnamic acid chloride, 4-methylumbelliferyl -D-xyloside, and combinations thereof.

[0030] In certain embodiments, the fluorescent response can be based on a naturally occurring alpha-glucosidase enzyme found in the spore coat of G. stearothermophilus, which comprises the enzyme and is believed to be important in the germination of G. stearothermophilus. The alpha-glucosidase enzyme can be used to hydrolyze the bond between glucose and the 4-methylumbelliferyl moiety of 4-methylumbelliferyl alpha-D-glucopyranoside (a-MUG). a-MUG does not fluoresce. However, after partial hydrolysis and separation of the moiety, the 4-methylumbelliferyl (4-MU) product is fluorescent. The 4-MU fluoresces when excited by an external energy source, such as a light source that emits light having a wavelength of between about 360 and 370 nanometers. Upon such excitation, the light emitted by the 4-MU has a wavelength of between about 440 and 460 nanometers. In certain embodiments, the light source emits light having a wavelength of about 365 nanometers, and the 4-MU emits light having a wavelength of 450 nm. The fluorescence of 4-MU is dependent on pH. For example, the intensity of the light emitted is highest at a pH of 10.3 when excited by light having a wavelength of 365 nanometers. The intensity decreases with pH until a pH of about 7. Below this pH, the intensity becomes negligible.

[0031] Based on the foregoing, the vials 112 can be considered a biological indicator because the carriers 132 and growth media 134 are combined in the vials 112.

[0032] The needles 116 and 118 are aligned with the cavities 108 and 110, respectively, such that when the fixture 100 is transitioned from the open configuration of Figure 1 to the closed configuration of Figure 2 the needles 116 and 118 pierce the covers 120 and 122 to respectively penetrate into the vials 112 and 114 such that liquid can be introduced into or removed from the vials 112 and 114. The needles 116 and 118 should be long enough that they can contact or nearly contact the bottom of the respective vial in the closed configuration to enable removal of all or substantially all of the liquid therefrom. When the carrier 132 is disposed on the bottom of the vial 112, the needle 116 can contact or nearly contact its surface.

[0033] The fixture 100, i.e., at least the first segment 102, the second segment 104, and the hinge 106, can be manufactured by any appropriate manufacturing method, such as injection molding, machining, or 3D printing. In those embodiments where certain features, such as the needles 116 and 118 and the heating coils 136 and 138, are manufactured by separate processes, they can be assembled and secured into the fixture, such as by press fitting or using an adhesive, such as epoxy.

[0034] Tubes can be connected to the needles 116 and 118 to enable fluid transfer from the chamber or vials. For example, a first tube 124 can be connected to the needle 116 and a second tube 126 can be connected to the needle 118. The tubes 124 and 126 can each be connected to a third tube 128 via a multi-way valve 130. The tube 128 can be connected to a fluid management system 200 of a liquid sterilization system, such that the system can introduce and remove various liquids to and from the vials 112 and 114.

[0035] The fluid management system 200 of a liquid sterilization system is shown in block form in Figure 3 . The system 200 includes sources of various liquids, such as a source 250 of a liquid-chemical sterilant, such as peracetic acid or hydrogen peroxide, and a source 252 of a liquid reductant or neutralizer that can be used to neutralize the sterilant, such as sodium metabisulfite or sodium bisulfite. Optionally, a source 254 of a growth medium can additionally be provided. In those embodiments that include the source 254 of growth medium, the system 200 can be used with a fixture 100 that lacks the chamber 110, the vial 114, and the growth medium 134. The system 200 can additionally include a drain 256.

[0036] Various tubes and valves connect the sources 250 and 252 (and 254, when employed) and the drain 256 to the fixture 100 via the tubes 124 and 128 (and 126, when not employing the source 254). In some embodiments, the endoscope 10 can be disposed between the system 200 and the tube 128, such that liquid from any of the sources 250, 252, or 254 can first flow through the lumen of the endoscope before entering the vial 112. However, typically, only the sterilant from the source 250 flows through the endoscope 10, which can help to assess the sterility of the use of the vial 112 to provide a more accurate indication of the endoscope, including its lumen.

[0037] As Figure 3As seen herein, system 200 includes pipes 260, 262, 264, 266, 268, 269, 270, 272, 274, 278, 280, 281, and 283. Pipe 280, valve 289, or the junction between valve 289 and pipe 128 can be considered as an output from system 200, and therefore may be referred to herein as one or more outputs. System 200 also includes valves 282, 284, 286, 288, and 289, which may be three-way valves. System 200 also includes pumps 290 and 292. Therefore, sterilizing agent from source 250 can be propelled from source 250 by pump 292 through tube 260, valve 282, tube 269, valve 284, tube 270, valve 286, tube 272, valve 288, tube 278, and tube 280 into vial 112, and subsequently discharged from system 200 via valve 289 to tubes 128, tube 124, and needle 116. Optionally, before a portion of the sterilizing agent is discharged from system 200 via valve 289, the sterilizing agent can flow through a recirculation line including tube 281, the lumen of a medical device (e.g., endoscope 10), tube 283, tube 278, tube 280, and valve 289. The neutralizing agent from source 252 can be pumped from source 252 via pipe 262, valve 282, pipe 269, valve 284, pipe 270, valve 286, pipe 272, valve 288, pipe 278, pipe 280 into vial 112, and then discharged from system 200 via valve 289 into pipe 128, pipe 124 and needle 116.

[0038] Growth medium can be provided from vial 114 or source 254 to vial 112. (Reference) Figure 2 In cases where growth medium 134 is supplied from vial 114 to vial 112, valve 130 is oriented such that tubes 128 and 126 are in fluid communication but not with tube 124. Growth medium 134 can be removed from vial 114 under pressure generated by pump 290 until it is contained in tube 128. Then, the orientation of valve 130 is changed so that tubes 128 and 124 are in fluid communication but not with tube 126. Growth medium 134 can then proceed from tube 128 into vial 112 under pressure generated by pump 292. When the growth medium is supplied from source 254, it can be propelled from source 254 by pump 292 through tube 264, valve 284, tube 270, valve 286, tube 272, valve 288, tube 278, tube 280 into vial 112, and then output from system 200 through valve 289 to tube 128, tube 124 and needle 116.

[0039] The system can be drained or flushed by opening these valves and operating pump 290 to allow liquid to flow through pipes 266 and 268 into discharge section 256. Drainage can aid in perfusion of system 200, sterilization of system 200, or preparation of system 200 for reuse.

[0040] The sterilization system can also include a processor, a non-transitory storage medium, and a user interface. The non-transitory storage medium can include computer executable instructions or software that are capable of instructing the processor to activate various pumps and direct various valves so that fluid can be transferred from sources 250, 252, and 254 (if included) and to vials 112 and 114 (if included) as described above. The processor can also be capable of receiving input from the light detector so that it can determine whether there is any change in the color or fluorescence of the growth medium and can abort the sterilization cycle or provide feedback to the user via the user interface based on this.

[0041] With the embodiments illustrated and described herein, the Applicant has devised a method and variations thereof for assessing the efficacy of a sterilization procedure performed by an automated liquid-chemical sterilization system. The method and variations can include the following steps. First, a vial (e.g., 112) including a carrier (e.g., 132) of microorganisms can be provided. The vial can be placed in a cavity to contain it and position it relative to a tube or needle (e.g., 116, 280) that can be inserted therein, which can include the step of piercing a barrier (e.g., 120) that seals the top of the vial. Moreover, the step of piercing the barrier can include closing a fixture (e.g., 100) to change the configuration of the fixture from an open configuration (e.g., Figure 1 ) to a closed configuration (e.g., Figure 2 ), which causes the needle to penetrate the barrier to place it in the vial. The fixture 100 can be placed in a sterilization chamber of the sterilization system so that it and the exterior of the vial 112 can be subjected to a sterilization procedure along with a medical device such as an endoscope.

[0042] After the tube or needle is positioned in the vial, the various steps of liquid delivery can begin. First, a volume of liquid chemical sterilant, such as peracetic acid or hydrogen peroxide, sufficient to fill the vial is introduced into the vial from a source of liquid chemical sterilant, such as source 250. In certain variations, the liquid chemical sterilant can flow through at least one lumen of the endoscope before reaching the vial 112. The vial and sterilant can then be heated, such as by heating elements 136 and 138, to between about 30°C and about 60°C, which helps the sterilant kill microorganisms within the BI by increasing the sterilization energy between the sterilant and the microorganisms. When peracetic acid is used, the sterilization energy can be maximized at about 35°C. Subsequently, the liquid chemical sterilant can be removed from the vial and expelled from the system. Second, a volume of neutralizer, such as sodium pyrosulfite or sodium bisulfite, sufficient to fill the vial is introduced into the vial from a source of neutralizer, such as source 252. The volume of neutralizer can then be removed from the vial and expelled from the system. In preferred variations, the peracetic acid and neutralizer remain in the vial for approximately the same amount of time as they are in contact with the endoscope. Third, growth medium can be introduced into the vial. Two techniques for doing so have been detailed above.

[0043] With the growth medium in the vial, the efficacy of the sterilization cycle can be assessed. First, the heating elements (e.g., 136 and 138) can be activated to incubate the vial and stimulate the growth of any spores that can have survived the removal of the sterilant. For example, the incubation can maintain the temperature of the vial at between about 50°C and about 60°C, such as 57°C, for about thirty minutes. In those embodiments in which the fixture 100 includes a light source and detector, the sterilization system can assess changes in the visual characteristics of the growth medium in the vial during the entire thirty minutes or a portion thereof to determine whether any spores can have survived and, based thereon, whether the sterilization cycle was effective. In those embodiments in which the fixture 100 does not include heating elements, a light source, a detector, or a combination thereof, the vial can be removed from the fixture 100 and the sterilization system and placed into a well of a biological indicator assessment device, such as the STERRAD VELOCITY TM System Reader, which is commercially available from the Applicant. The STERRAD VELOCITY TM Reader, ASP Part No. 43220, can then incubate the vial and assess the growth medium therein for any color or fluorescence changes that occur to determine whether the sterilization cycle was effective.

[0044] In further variations of the method, the system 200 can flow the liquid-chemical sterilant through all of its components to sterilize itself. Additionally, the system 200 can fill its components with one of the liquids to prime the system with the liquid before beginning the step of introducing a volume of the liquid into the vial.

Claims

1. A sterilization system comprising: a first vial; a carrier disposed in the first vial, the carrier impregnated with a source of microorganisms comprising spores; a fluid management system having an output connectable to the first vial for delivering a liquid to the first vial, the fluid management system comprising: a valve; a tube; a source of liquid-chemical sterilant; and a source of neutralizing agent, the source of neutralizing agent connected to the output via the valve and the tube; and a fixture, the fixture comprising: a first segment comprising a needle connected to the output; a second segment comprising a first cavity housing the first vial and a second cavity housing a second vial, the second vial containing a growth medium; and a hinge connecting the first segment to the second segment, the hinge configured such that rotation of the first segment about the hinge causes the needle to penetrate the first vial.

2. The sterilization system of claim 1, further comprising a medical device having a lumen connected between the needle and the output.

3. The sterilization system of claim 2, wherein, The medical device comprises an endoscope.

4. The sterilization system of claim 1, wherein, The fluid management system further comprises a source of growth medium.

5. The sterilization system of claim 4, wherein, The fixture further comprises a heating element disposed adjacent the first cavity.

6. The sterilization system of claim 4, wherein, The liquid-chemical sterilant comprises peroxyacetic acid.

7. The sterilization system of claim 6, wherein, The growth medium comprises a-MUG.

8. The sterilization system of claim 7, wherein, The spores comprise Geobacillus stearothermophilus spores.

9. The sterilization system of claim 1, wherein, The first vial comprises a cover.

10. The sterilization system of claim 1, wherein, The second vial comprises a cover.

11. A method of determining sterility of a medical device, the method comprising: inserting a vial into a cavity of a fixture, the vial housing a carrier of microorganisms; moving a first segment of the fixture relative to a second segment of the fixture to penetrate the vial with a needle; introducing at least one fluid into the vial through the needle; incubating the vial with the at least one fluid disposed therein; and retrieving the at least one fluid from the vial through the needle, wherein the at least one fluid is a liquid-chemical sterilant or a growth medium.

12. The method of claim 11, further comprising the step of introducing a neutralizing agent into the vial through the needle. The step of introducing is performed by a first pump fluidly connected to the vial through at least one valve and at least one tube, and the step of retrieving is performed by a second pump fluidly connected to the vial through at least one valve and at least one tube.

13. The method of claim 11, wherein, A non-transitory storage medium instructs a processor to activate the first and second pumps and to orient at least one valve such that the at least one fluid is introduced into or retrieved from the vial.

14. The method of claim 13, wherein, The fixture further comprises a heating element disposed adjacent the vial, and the step of incubating is performed by the heating element.

15. The method of claim 11, wherein, The medical device is an endoscope.

16. The method of claim 11, further comprising passing a volume of at least one fluid through a lumen of the medical device prior to introducing the volume of the at least one fluid into the vial, wherein, 17. A method of determining sterility of a medical device, the method comprising: inserting a vial into a cavity of a fixture, the vial housing a carrier of microorganisms; moving a first segment of the fixture relative to a second segment of the fixture to penetrate the vial with a needle; introducing a liquid-chemical sterilant into the vial through the needle; ​ incubating the vial with the liquid-chemical sterilant disposed therein; retrieving the liquid-chemical sterilant from the vial through the needle; introducing a neutralizing agent into the vial through the needle; retrieving the neutralizing agent from the vial through the needle; introducing a growth medium into the vial through the needle; and incubating the vial with the growth medium disposed therein.

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