1、Designation: E1837 96 (Reapproved 2014)Standard Test Method toDetermine Efficacy of Disinfection Processes for ReusableMedical Devices (Simulated Use Test)1This standard is issued under the fixed designation E1837; the number immediately following the designation indicates the year oforiginal adopti
2、on or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONWhen special tests designed to register or validate a disinfection process
3、 currently are used, theprocedures, their statistical considerations (usually all negatives at a given time point), and thephysical problems of applying organisms to surfaces, such as sutures and unglazed porcelain carriers,may cause inaccurate and confusing results. Practical, in-use testing of rep
4、rocessing techniques andconditions are needed. Exaggerated conditions for testing can be achieved with the use of actualinstruments contaminated with high numbers of organisms. The addition of serum as an organic loador hard water minerals as an inorganic load can be made to enhance worst-case condi
5、tions.When theseelements are coupled with the processing, as actually performed, the result is a structured test that isa simulated-use procedure. This test method is designed to incorporate several elements ofreprocessing, including cleaning, rinsing, and disinfection (including optional treatment
6、of the internalchannels of devices, such as endoscopes) with a terminal alcohol rinse rather than examining only theeffectiveness of the entire disinfection process. A simulated-use test to examine the effectiveness ofreprocessing procedures is valuable because several incidents of contamination of
7、instruments in usehave been recorded with vegetative cells of bacteria, for example, Pseudomonas and the mycobacteria.When this procedure is performed with a representative mycobacterial culture, it is necessary to usea nonpathogenic strain such as Mycobacterium terrae (isolated from soil) that can
8、be manipulated onan open bench. This strain is used in tuberculocidal testing in Europe, and published informationshows comparable resistance to antimicrobials as that displayed by human tuberculosis strains ofMycobacterium tuberculosis. This organism can be handled easily and grows faster than othe
9、r teststrains, such as M. bovis (1-5).2Because contamination of the surfaces of instruments has occurred from rinsing with tap water,bacteria-free water should be used for all rinsing during reprocessing in this test procedure when awater rinse step is part of the reprocessing directions.1. Scope1.1
10、 This test method is intended to describe a procedure fortesting the effectiveness of a disinfection process for reprocess-ing reusable medical devices when it is tested with a challengeof vegetative cells including mycobacteria. Disinfection nor-mally deals with testing activity against vegetative
11、cells ofbacteria, viruses, and fungi. Since this test method is processoriented, the user may wish to examine a variety of testorganisms.1.2 This test method is designed to provide a reproducibleprocedure to verify the effectiveness of a previously validateddisinfectant or disinfection procedure for
12、 reusable medicalinstruments and devices.1.3 This test method is not meant to define the effectivenessof or validation of the particular disinfection process used or itskinetics, but rather, it is devised to confirm the effectiveness ofthe disinfection process by simulating use situations with apart
13、icular test process using medical devices and instruments.Either manual or machine reprocessing can be tested.1This test method is under the jurisdiction of ASTM Committee E35 onPesticides, Antimicrobials, and Alternative Control Agents and is the directresponsibility of Subcommittee E35.15 on Antim
14、icrobial Agents.Current edition approved Oct. 1, 2014. Published December 2014. Originallyapproved in 1996. Last previous edition approved in 2007 as E1837 96(2007).DOI: 10.1520/E1837-96R14.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM
15、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.4 This test method is intended for use with reusablecleaned and previously sterilized or disinfected (high level)medical instruments and devices. Endoscopes are described inthis test method as a wor
16、st-case example for contamination andsampling. The selected sterilization or disinfection processes,or both, should have been validated previously, as well as theeffectiveness of rinsing for residual sterilant/disinfectant re-moval determined.1.5 An inoculum with high numbers of selected microor-gan
17、isms is applied to both test and control, cleaned andsterilized, or disinfected medical instruments. Strains of mi-croorganisms with a recorded resistance to disinfectants areused to contaminate the instrument sites known or suspected tobe the most difficult to reprocess.1.6 It is impractical to tes
18、t for recovery of survivors byimmersion of some instruments, for example, endoscopes orsome laproscopic instruments, in growth medium because ofcomplexity, size, difficulty in long-term incubation, or deteri-ous effects resulting from incubation. Elution of organismsfrom the inoculated surfaces, the
19、refore, may be performed toestimate the number of recoverable organisms. Immersion canbe used for smaller instruments.1.7 Control instruments are inoculated in the same manneras the test instruments and elution or immersion methods areperformed to determine the number of organisms recoverablefrom th
20、e instrument. For channeled devices, such as endo-scopes testing, the number of organisms recoverable from theinstrument (inside and outside) will serve as the initial controlcount. It is expected that some fraction of the number oforganisms inoculated will be lost in the process of inoculation/dryi
21、ng.1.8 A testing procedure can be performed on a completereprocessing cycle or can be limited to just the cleaning ordisinfection portions of the cycle whether reprocessing is donein a machine or manually.1.9 After the test cycle has been completed, remaininginoculated bacteria will be recovered fro
22、m test instrumentsusing the same elution procedures as for the control instru-ments.1.10 Efficacy of a disinfection cycle or reprocessing cycle,or any part thereof, may be determined by comparison of thenumber of microorganisms recovered from the control instru-ment (initial recoverable control coun
23、t) to the recovery deter-mined for the test instruments.1.11 Aknowledge of microbiological techniques is requiredto conduct these procedures.31.12 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standar
24、d to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4E1054 Test Methods for Evaluation of Inactivators of Anti-microbial Agents3. Terminology3.1 Definitions:3.1.1 bioburden, nthe num
25、ber and type of viable micro-organisms that can be recovered from surfaces using standardrecovery procedures.3.1.2 CFUcolony forming units.3.1.3 disinfectantany biocidal chemical that produces ma-terials free from vegetative microorganisms that may contami-nate them and potentially cause infection.3
26、.1.3.1 DiscussionThe definitions included are the tradi-tional ones. The user may choose to conform to other criteriathat specify elimination of a certain number of test microor-ganisms. Other definitions describe the action as application ofa process resulting in elimination of microorganisms.Whate
27、vercriteria is selected, it should be stated before initiation of thetest procedure.3.1.3.2 DiscussionA series of three definitions devised bySpaulding (6, 7) separated the activity of germicides againstspores and mycobacteria and non-lipid viruses and are there-fore defined by activity against grou
28、ps of microorganisms.These definitions are as follows:(1) High-level disinfectants must inactivate bacteriaendospores, mycobacteria, non-lipid viruses, fungi, vegetativebacteria, and lipid viruses. If exposure time is extended longenough, this type of germicide can be used as a sterilant.(2) Medium-
29、level disinfectants inactivate mycobacteria,vegetative bacteria, fungi including asexual spores, and lipidand non-lipid viruses.(3) Low-level disinfection inactivate vegetative bacteria,most fungi, and lipid viruses.3.1.4 disinfector, nany device or physical process thatprovides a biocidal process t
30、hat produces materials free fromvegetative microorganisms that may contaminate them andpotentially cause infection.3.1.5 inoculumthe number (usually expressed in colonyforming units, cfu) and type (genus and species) of viablemicroorganisms used to contaminate a given sample or object.Strain identif
31、ication and the means used to identify the organ-ism should be indicated.3.2 Definitions of Terms Specific to This Standard:3.2.1 accessible site, na location on or in a reusablemedical instruments that can be contacted by bioburden anddisinfectants.3.2.2 reusable medical device, nany medical instru
32、mentthat is claimed at manufacture to be usable after reprocessing.3.2.3 worst-case, nthe intentional exaggeration of one ormore parameters of test compared to normal condition.3CDC-NIH Biosafety in Microbiological and Biomedical Laboratories, 3rd ed.,U.S. Department of Health and Human Services, Wa
33、shington, DC, 1993.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.E1837 96 (2014)24. Summary of Test Method4
34、.1 This test method is performed by contamination ofaccessible, interior, and exterior surfaces of instruments ordevices intending to reach the sites identified as the leastac-cessible or most difficult to reach sites.4.2 The number of microorganisms contaminating the testinstruments or devices prio
35、r to processing is determined bycontamination and elution of at least two control unprocessedunits (representing a large complex instrument). More controlunits of smaller instruments may be used. Contamination withan inoculum with high numbers of microorganisms to achieveat least 106cfu/instrument,
36、recoverable is required.4.3 After inoculation, the test instrument(s) are processedaccording to the manufacturers instructions for use of thereprocessing cycle, the disinfectant, or disinfector. Either thedisinfectant, disinfector cycle alone, or the disinfectant (disin-fector) cycle plus any cleani
37、ng, rinsing, or other contributorysteps in the directions for use, may be tested.4.4 Following processing, the test instruments are sampledusing specified elution and culture techniques to determine thenumber of surviving bacteria in colony forming units (cfu).5. Significance and Use5.1 This test me
38、thod is designed to demonstrate and docu-ment that reusable devices and medical instruments can bedisinfected using a specified technique.5.2 This test method can be used to verify claims ofdisinfection of recesses, hinged sites, lumina, or other difficult-to-reprocess areas of reusable medical devi
39、ces and instruments.5.3 This test method also can be used to document thecontribution of each element of the reprocessing cycle forreusable medical devices and instruments.5.4 The number of surviving bacteria may be assessed usingswabbing and irrigation or total immersion.5.5 This test method may be
40、 used to produce quantitative orqualitative results.6. Apparatus6.1 Syringes, 10 to 50 mL, sterile.6.2 Sterile Cotton, dacron or other swabs.6.3 Sterile Petri Dishes.6.4 Sterile Tubes, to hold 10 mL.6.5 Sterile Bottles, to hold 50 mL and sterile flasks to hold250 to 500 mL.6.6 Steam, or other type o
41、f sterilizer.6.7 Water Bath, to maintain temperatures from 20 to 50 62C.6.8 Incubator(s), to maintain 35 6 2C.6.9 Membrane Filters and Filter Supports, for membranefilters.6.10 Colony Counter.6.11 Disposable Plastic Pipettes, various sizes.6.12 Medical Devices or Instruments, cleaned in accordancewi
42、th the manufacturers direction and sterilized or disinfected(high level) prior to use.6.13 Devices or Apparatus Specified by the Instrument,Disinfectant or Disinfector Manufacturer.6.14 Vortex Mixer or Sonicator, or Both.7. Reagents7.1 Media:7.1.1 Sterile buffered elution fluid containing 0.1 % Trit
43、onX-100 prepared in Type III or better ASTM water. Specificneutralizers for the test disinfectant may be added.7.1.2 Soybean-Casein Digest Broth, USP, with and withoutappropriate neutralizers for the specific test disinfectant chemi-cal.7.1.3 Soybean-Casein Digest Agar, USP, with and withoutappropri
44、ate neutralizers in 10 to 50-mL tubes or bottlestempered to 50 6 10C.7.1.4 Middlebrook 7H9 Broth, with and without appropriateneutralizers in 10 to 50-mL tubes or 250 to 500-mL flask (formycobacteria).7.1.5 Middlebrook 7H11 Agar, with and without appropriateneutralizers in 10 to 500-mL tubes or bott
45、les tempered to 50 61C (for Mycobacteria ).7.1.6 Mycophil or Potato Dextrose Agar, with and withoutappropriate neutralizers in 10 to 500-mL tubes or bottlestempered to 50 6 1C (for fungi). Soybean-Casein DigestBroth or agar, or both, may be used for many fungi.7.1.7 Bacteria-Free Water (when a water
46、 rinse step is part ofthe reprocessing procedures).7.2 Test OrganismsSuspensions of selected testorganisms, appropriate for test.NOTE 1Strains such as those identified in AOAC disinfectant testprocedures or other publications or resistant environmental isolates thathave demonstrated resistance to an
47、timicrobials should be selected.7.2.1 Bacterial cultures are incubated until they reach atleast 1 108cfu/mL. For most test strains, this can be achievedwith a 48-h suspension of bacterial vegetative cells of teststrains prepared in tubes or flasks of appropriate media andincubated at the appropriate
48、 optimal growth temperature,62C. Strains of mycobacteria are slow growing and must beincubated for longer times depending on the strain. M. terrae isnormally countable using magnification and lateral lighting in21 days, although it may be counted as early as 14 days.7.2.2 Any test strain which is ea
49、sy to identify, such asSerratia marcescens, Escherichia coli, Mycobacterium bovisor Mycobacterium terrae, Pseudomonas aeruginosa, orStaphylococcus aureus, and has documented disinfectant resis-tance selected. Suspensions should be grown for sufficient timeto achieve a 108-cfu/mL level.7.3 Neutralizers (appropriate for test system)For neutral-izer selection and testing refer to Practice E1054. Neutralizersmay be added to dilution fluids.8. Procedure8.1 Use pre-cleaned and pre-sterilized or pre-disinfectedinstruments or devices.E1837 96 (2014)38.2 Inoculation
