BIOLOGICAL INDICATOR FOR LIQUID-CHEMICAL STERILIZATION SYSTEM
20200199517 ยท 2020-06-25
Assignee
Inventors
- Benjamin M. FRYER (Lake Forest, CA, US)
- Yan Fang (Irvine, CA, US)
- Prabhakaran Jayabalan (Lake Forest, CA, US)
Cpc classification
A01N25/02
HUMAN NECESSITIES
C12M1/34
CHEMISTRY; METALLURGY
A61L2202/24
HUMAN NECESSITIES
C12M37/06
CHEMISTRY; METALLURGY
A61L2202/15
HUMAN NECESSITIES
A01N59/00
HUMAN NECESSITIES
A61L2202/12
HUMAN NECESSITIES
A61L2/28
HUMAN NECESSITIES
A01N59/00
HUMAN NECESSITIES
A01N25/02
HUMAN NECESSITIES
International classification
C12M1/12
CHEMISTRY; METALLURGY
A61B90/70
HUMAN NECESSITIES
A61L2/28
HUMAN NECESSITIES
Abstract
Disclosed herein are biological indicators suitable for use in a liquid-chemical sterilization process that may be conducted by an automated endoscope reprocessor. The biological indicator may include one or more ports for introducing and removing a liquid-chemical sterilant therefrom. The biological indicators may include features, such as a declivity leading to a port opening or a pipette, that may assist in transferring the liquid-chemical sterilant. The system may additionally include a holder having features that facilitate use of the system and biological indicators.
Claims
1. A biological indicator, comprising: a vial including a first port disposed through a base of the vial; a cap disposed atop the vial, the cap including a second port; a first valve disposed in the first port; a second valve disposed in the second port; and a carrier impregnated with microorganisms disposed in the vial.
2. The biological indicator of claim 1, further comprising an exhaust port disposed through the cap.
3. The biological indicator of claim 2, wherein the first port includes an opening disposed inside the vial and the vial includes a bottom portion having a declivity directed toward the opening.
4. The biological indicator of claim 3, wherein the carrier is disposed above the opening and in contact with the declivity.
5. The biological indicator of claim 4, wherein the carrier includes a void disposed therethrough.
6. The biological indicator of claim 3, further comprising an ampule containing a growth medium disposed at least partially within the vial.
7. A biological indicator comprising: a vial having a base; a cap disposed atop the vial, the cap including a port; a pipette having a first end connected to the port and a second end disposed proximate to the base of the vial; and a carrier impregnated with microorganisms disposed in the vial.
8. The biological indicator of claim 7, further comprising a wing extending from the cap.
9. The biological indicator of claim 7, further comprising an ampule disposed at least partially within the vial.
10. The biological indicator of claim 9, further comprising an insert in contact with the ampule.
11. The biological indicator of claim 10, wherein the ampule includes an irregular cross-sectional shape.
12. The biological indicator of claim 11, wherein the pipette is disposed in an indent defined by the irregular cross-sectional shape.
13. A liquid-chemical sterilization system, comprising: a biological indicator, comprising a housing defining an interior and including a first port having a first valve and a second port having a second valve, a divider disposed within the interior, between the first port and the second port, defining two chambers, and a carrier impregnated with microorganisms disposed in one of the two chambers; a source of a liquid-chemical sterilant; a first fluid-delivery component connected to the source of the liquid-chemical sterilant; and a holder including at least one slot configured to contain the biological indicator, and at least a third port connected to the first fluid-delivery component and positioned at the base of the slot to mate with the first port.
14. The liquid-chemical sterilization system of claim 13, wherein the holder includes a fourth port disposed at the base of the slot positioned to mate with the second port.
15. The liquid-chemical sterilization system of claim 13, wherein the holder includes a window.
16. The liquid-chemical sterilization system of claim 15, wherein the holder is connected to a sterilization tray disposed inside the sterilization chamber.
17. The liquid-chemical sterilization system of claim 16, wherein a manifold is connected to the sterilization tray and the holder is connected to the manifold.
18. The liquid-chemical sterilization system of claim 17, wherein the first fluid-delivery component is connected to the manifold and the manifold is connected to the third port.
19. The liquid-chemical sterilization system of claim 18, further comprising a second fluid delivery component connected to the manifold and at least partially disposed in the sterilization tray.
20. The liquid-chemical sterilization system of claim 19, wherein the second fluid-delivery component is connected to a lumen of an instrument disposed in the sterilization tray.
21. The liquid-chemical sterilization system of claim 20, wherein the instrument comprises an endoscope.
22. The liquid-chemical sterilization system of claim 21, wherein the interior of the biological indicator contains a liquid-chemical sterilant that had previously been flowed through the endoscope.
23. The liquid-chemical sterilization system of claim 22, wherein a volume of liquid-chemical sterilant that had previously been flowed through the endoscope is disposed in the interior of the biological indicator.
24. The liquid-chemical sterilization system of claim 14, wherein the holder is disposed on an exterior surface of the sterilization system
25. The liquid-chemical sterilization system of claim 24, wherein the holder includes a screen.
26. The liquid-chemical sterilization system of claim 25, wherein the holder includes four slots.
27. The liquid-chemical sterilization system of claim 26, wherein each slot contains a different biological indicator.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] While the specification concludes with claims, which particularly point out and distinctly claim the subject matter described herein, it is believed the subject matter will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements and in which:
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MODES OF CARRYING OUT THE INVENTION
[0027] The following detailed description should be read with reference to the drawings, in which like elements in different drawings are identically numbered. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
[0028] As used herein, the terms about or approximately for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. More specifically, about or approximately may refer to the range of values 10% of the recited value, e.g. about 90% may refer to the range of values from 81% to 99%. In addition, 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 subject invention in a human patient represents a preferred embodiment.
[0029] Automated sterilization equipment and routines for endoscopes that employ a liquid-chemical sterilant, e.g., hydrogen peroxide or peracetic acid, are being developed to overcome certain shortcomings associated with sterilizing endoscopes using vapor-chemical sterilants. However, as with the vapor-based processes, development of a reliable technique for assessing whether the endoscope has been sterilized remains a challenge. Moreover, the biological indicators that are used in vapor-based processes are not suitable for use in liquid-based processes because such indicators are designed to have gaseous sterilant, but not liquid sterilant, removed therefrom. Thus, it would be advantageous to provide an indicator from which liquids may be readily removed and to which liquids may be readily introduced. Further, indicators for vapor-based processes typically require a user to break an ampule containing a growth medium and to transfer the indicator to an apparatus capable of incubating the indicator and detecting a change, such as a change in color or fluorescence of a growth medium in the indicator. When a liquid-chemical sterilant is used, precautions should be taken to avoid burns to the user that might result from residual liquid sterilant remaining on the indicator. Thus, it would be advantageous to provide a system capable of manipulating a biological indicator for use with a liquid-chemical sterilant that does not require user intervention. Proposed herein are devices and methods that may be used to determine whether an endoscope has been sterilized by a sterilization routine employing a liquid-chemical sterilant that further address these design inputs.
[0030]
[0031] The portion of port 110 that extends into vial 104 includes an opening 118. Ideally, vial 100 does not include any empty space or voids beneath the level of opening 118 such that when the longitudinal axis of BI 100 is aligned with the direction of gravity and valve 114 is open, all liquids in vial 104 may flow readily through port 110 without any becoming trapped in the vial. Thus, a bottom portion 120 of vial 104 that is proximate to the portion of port 110 that extends into the vial may be provided as having an angled surface or declivity 121 directed toward opening 118 such that any liquid disposed on the declivity while valve 114 is open would flow out of vial 104 through opening 118 and port 104. In those embodiments that include declivity 121, carrier 106 may be disposed somewhat above opening 118 to prevent it from blocking opening 118. Further, carrier 106 and may include one or more voids or perforations 107 therethrough to assist liquid to flow therethrough and towards opening 118 such that it may flow out of BI 100 when valve 114 is open.
[0032] Carrier 106 may have the form of a disk and contain or be impregnated with a source of microorganisms, e.g., spores, or active enzymes. Carrier 106 may be disposed in vial 104. Spores from Bacillus, Geobacillus, and Clostridia species are often used to monitor sterilization processes using chemical sterilants. Accordingly, carrier 106 may be impregnated with spores from Bacillus, Geobacillus, and/or Clostridia species. For example, 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.
[0033] Carrier 106 may be water-absorbent and may be formed of filter paper. Sheet-like materials such as cloth, nonwoven polypropylene, rayon or nylon, and microporous polymeric materials may also be used. Non-water absorbent materials are also appropriate for use, such as metals (e.g., aluminum or stainless steel), glass (e.g., glass beads or glass fibers), porcelain, or plastic. Additionally, carrier 110 can be constructed of a combination of the aforementioned materials. In some embodiments, carrier 110 may have a thickness of approximately 0.1 to 0.5 millimeters.
[0034] During use, carrier 106 becomes immersed in a growth medium. The growth medium may be introduced or flowed into the BI via port 108. Alternatively, as reflected in
[0035] Enzymes and enzyme substrates that may be used to detect efficacy of a sterilization cycle are identified in U.S. Pat. No. 5,073,488, entitled Rapid Method for Determining Efficacy of a Sterilization Cycle and Rapid Read-Out Biological Indicator, issued Dec. 17, 1991, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 5,418,167, entitled Rapid Read-Out Biological Indicator, issued May 23, 1995, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 5,223,401, entitled Rapid Read-Out Sterility Indicator, issued Jun. 29, 1993, the disclosure of which is incorporated by reference herein; and U.S. Pat. No. 9,322,046, entitled Biological Sterilization Indicator, issued Apr. 26, 2016, the disclosure of which is incorporated by reference herein.
[0036] Suitable enzymes may include hydrolytic enzymes and/or enzymes derived from spore-forming microorganisms, such as Bacillus subtilis. Enzymes from spore-forming microorganisms that can be useful in exemplary biological indicators may 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-glucosaminodase, beta-D-cellobiosidase, alanine aminopeptidase, proline aminopeptidase, fatty acid esterases and combinations thereof.
[0037] In some exemplary methods for determining efficacy of a sterilization cycle as disclosed herein, enzyme substrates are converted to detectable product. For instance, an enzyme substrate may be characterized by a first emission spectrum (e.g., a first fluorescent emission spectrum) and a detectable product may be characterized by a second emission spectrum (e.g., a second fluorescent emission spectrum).
[0038] In some exemplary methods for determining efficacy of a sterilization cycle as disclosed herein, suitable enzyme substrates of use may include fluorogenic enzyme substrates. Useful fluorogenic enzyme substrates may be selected from: fluorogenic 4-methylumbelliferyl derivatives (hydrolysable to 4-methylumbelliferone (4-Mu), derivatives of 7-amido-4-methyl-coumarin, diacetylfluorescein derivatives, fluorescamine and combinations thereof
[0039] Exemplary 4-methylumbelliferyl derivatives may be selected from: 4-methylumbelliferyl-2-acetamido-4,6-O-benzylidene-2-deoxy--D-glucopyranoside, 4-methylumbelliferyl acetate, 4-methylumbelliferyl-N-acetyl--D-galactosaminide, 4-methylumbelliferyl-N-acetyl--D-glucosaminide, 4-methylumbelliferyl-N-acetyl--D-glucosaminide, 2-(4-methylumbelliferyl)--D-N-acetyl neuraminic acid, 4-methylumbelliferyl -L-arabinofuranoside, 4-methylumbelliferyl -L-arabinoside, 4-methylumbelliferyl butyrate, 4-methylumbelliferyl 13-D-cellobioside, methylumbelliferyl -D-N,N diacetyl chitobioside, 4-methylumbelliferyl elaidate, 4-methylumbelliferyl -D-fucoside, 4-methylumbelliferyl -L-fucoside, 4-methylumbelliferyl -L-fucoside, 4-methylumbelliferyl -D-galactoside, 4-methylumbelliferyl -D-galactoside, 4-methylumbelliferyl -D-glucoside, 4-methylumbelliferyl -D-glucoside, 4-methylumbelliferyl (3-D-glucuronide, 4-methylumbelliferyl p-guanidinobenzoate, 4-methylumbelliferyl heptanoate, 4-methylumbelliferyl -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--L-arabinofuranoside, 4-methylumbelliferyl-p-trimethylammonium cinnamate chloride, 4-methylumbelliferyl -D-xyloside and combinations thereof.
[0040] In certain embodiments, the fluorescent response may be based on the naturally occurring alpha-glucosidase enzyme found in the Geobacillus stearothermophilus spore coat, which contains the enzyme and which is believed to be important in the germination of G. stearothermophilus. Alpha-glucosidase may be used to hydrolyze the bond between the glucose and 4-methylumbelliferyl moieties of 4-methylumbelliferyl -D-glucopyranoside (-MUG). -MUG is not fluorescent. However, following hydrolyzation and separation of the moieties, the 4-Methylumbelliferone (4-MU) product is fluorescent. 4-MU fluoresces when excited by an external energy source, such as a light source that emits light having a wavelength of between approximately 360 and 370 nanometers. So excited, 4-MU emits light having a wavelength of between approximately 440 and 460 nanometers. In certain embodiments, the light source emits light having a wavelength of approximately 365 nanometers and the 4-MU emits light having a wavelength of 450 nm. The fluorescence of 4-MU is pH dependent. For example, when excited by light having a wavelength of 365 nanometers, the intensity of the emitted light is highest at a pH of 10.3. The intensity decreases with pH until about a pH of 7. Below this pH the intensity becomes negligible.
[0041] Cap 102 and vial 104 may be fabricated from any suitable material, preferably a hard and inert plastic, such as polycarbonate. Ideally, at least vial 104 is transparent to facilitate monitoring the growth medium for a detectable change to color or fluorescence.
[0042]
[0043] A port 208 may be integrated into and through cap 202. Port 208 may further include an extension, such as pipette 216, which may include a first end connected (e.g., bonded) to port 208, such that any liquid introduced through port 208 exits pipette 216 inside vial 204, somewhat removed from cap 202. As shown, pipette 216 includes a second end disposed proximate to the base of vial 204. Thus, liquids may be introduced and withdrawn from BI 200 via a single port. Preferably, sufficient space between the base of vial 204 and the second end of pipette 216 should sufficient such that upon depression of cap 202, the second end of pipette 216 should contact or nearly contact carrier 206. Furthermore, by inclusion of pipette 216, inclusion of ampule 224 in BI 200 is optional. That is, ampule 224 may be excluded from the BI 200 to allow for introduction of the growth medium into the BI via port 208 and pipette 216. In further embodiments not shown, a tube may be integrated into a sidewall of vial 204, extending from a location between cap 202 and carrier 206 to a location proximate to carrier 206. The second end of pipette 216 may be disposed within the tube such that upon depression of cap 202 relative to vial 204, the second end of pipette 216 may move toward carrier 206 within the tube. Thus, pipette 216 and the tube are provided as having a telescoping relationship. A seal, e.g., a gasket, may be provided between the two to ensure that the mate between pipette 216 and the tube is fluid tight. Accordingly, fluids may be delivered into and removed from vial 204 by way of the passage defined by pipette 216 and the tube integrated into the wall of vial 204.
[0044] Biological indicators used in vapor-based sterilization processes do not require features concerning fluid management, such as the ports, pipette, and valves described above, because vapor may be readily introduced and removed from inside the biological indicator by way of pressurizing and depressurizing a vacuum chamber in which the biological indicator and instruments are disposed during the process. Such features are required for biological indicators used in liquid based chemical sterilization procedures at least because sterilant, e.g., peracetic acid or hydrogen peroxide, must be introduced and removed therefrom. Further, when a neutralizer e.g., sodium metabisulfite or sodium bisulfite, is used to neutralize any sterilant remaining in the biological indicator, the neutralizer must be introduced and removed therefrom. Further, in those embodiments where the biological indicator does not include an ampule containing a growth medium, the growth medium must also be introduced into the biological indicator. Such fluid management steps may be facilitated by way of a biological indicator that is designed to be plumbed by a liquid-chemical sterilization system, which may further include an integrated incubator and reader akin to the Reader (ASP part no. 43220) of the commercially available STERRAD VELOCITY system, manufactured by applicant.
[0045] One such exemplary biological indicator, BI 300, is shown in
[0046]
[0047] A holder 18 containing a slot 20 in which BI 300 may be disposed is attached to tray manifold 13. That is, slot 20 is configured to contain the biological indicator. Holder 18 also includes a window 22 through which BI 300 may be interrogated by a reading device 26 (
[0048] As seen in
[0049]
[0050] A technique for delivering liquids to a BI 500 is reflected in
[0051]
[0052] Any of the examples or embodiments described herein may include various other features in addition to or in lieu of those described above. The teachings, expressions, embodiments, examples, etc., described herein should not be viewed in isolation relative to each other. Various suitable ways in which the teachings herein may be combined should be clear to those skilled in the art in view of the teachings herein.
[0053] Having shown and described exemplary embodiments of the subject matter contained herein, further adaptations of the methods and systems described herein may be accomplished by appropriate modifications without departing from the scope of the claims. In addition, where methods and steps described above indicate certain events occurring in certain order, it is intended that certain steps do not have to be performed in the order described but in any order as long as the steps allow the embodiments to function for their intended purposes. Therefore, to the extent there are variations of the invention, which are within the spirit of the disclosure or equivalent to the inventions found in the claims, it is the intent that this patent will cover those variations as well. Some such modifications should be apparent to those skilled in the art. For instance, the examples, embodiments, geometrics, materials, dimensions, ratios, steps, and the like discussed above are illustrative. Accordingly, the claims should not be limited to the specific details of structure and operation set forth in the written description and drawings.