1、Designation: D7907 14Standard Test Methods forDetermination of Bactericidal Efficacy on the Surface ofMedical Examination Gloves1This standard is issued under the fixed designation D7907; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, 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.1. Scope1.1 The methods herein specify two analytical tests forquantitatively evaluating surface bactericidal eff
3、icacy of medi-cal examination gloves incorporated with bactericidal proper-ties. They may be used for the determination of bactericidalactivity on either the outer or inner glove surface. The methodsincorporate bacterial challenges in two different formats:Method (A) a saline or buffered saline solu
4、tion, and Method(B) a saline or buffered saline solution containing an organicload. Each method represents a different means of microbialcontamination that can be expected in the healthcare environ-ment.1.2 Methods described herein are not appropriate forvirucidal, fungicidal, tuberculocidal or spor
5、icidal evaluationsas each of these categories require unique culture techniquesand testing conditions. Results of the test methods described inthis document are limited to bactericidal efficacy againstvegetative bacteria.1.3 A more expansive glove description, such as broadspectrum antimicrobial eff
6、icacy, would require testing of abroader list of microbial species than vegetative bacteria alone.It is recommended that interested manufacturers discuss spe-cies and strain selections with appropriate regulatory agenciesbefore testing is commenced.1.4 Testing is to be performed by individuals train
7、ed inmicrobiological techniques under appropriate controlled con-ditions to ensure integrity of results and personnel safety.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all o
8、f thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Most regulatoryagencies require compliance with Biocompatibility
9、guidelinesunder ISO 10993.2. Referenced Documents2.1 ASTM Standards:2D7160 Practice for Determination of Expiration Dating forMedical GlovesE178 Practice for Dealing With Outlying ObservationsE1054 Test Methods for Evaluation of Inactivators of Anti-microbial Agents2.2 Other References:U.S. Pharmaco
10、peia General Notices in U.S. Pharmacopeia26th rev. Rockville, MD: U.S. Pharmacopeia; 2003. 2ndSupplement3. Terminology3.1 Definitions:3.1.1 active side, nrefers to the inside or outside surface ofthe glove on which the antimicrobial agent has been placed.This may be both sides if the active agent is
11、 placed on both theinside and outside surfaces or if the actives agent is incorpo-rated during compounding and is expressed onto both surfaces.3.1.2 aliquot, na portion of a total amount of a solution orsuspension.3.1.3 bactericide (or bacteriocide), na substance that killsor destroys bacteria.3.1.4
12、 bacteriostat, nchemical or biological material thatstops the growth (reproduction) of bacteria, but does NOT killthem.3.1.5 challenge inoculum, nthe viable microorganismsused to contaminate a specimen, device, or surface, oftenexpressed as to number and type.3.1.6 colony forming unit (CFU), na bact
13、erial colonypresumed to have originated from a single bacterium.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.40 on Consumer RubberProducts.Current edition approved May 1, 2014. Published May 2014. DOI: 10.1520/D7907-1
14、4.2For 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box
15、 C700, West Conshohocken, PA 19428-2959. United States13.1.7 control glove, nthe same glove formulation as thetest glove in every aspect, but without the addition of thebactericidal agent(s).3.1.8 coverslip (cover glass), na small, very thin piece ofglass used to cover a specimen or smear on a micro
16、scope slideor, in this case, to cover the bacterial inoculum on the surfaceof the glove specimen being tested.3.1.9 fastidious bacteria, nbacteria that are difficult togrow and keep stable often requiring complex nutritional orenvironmental factors to survive.3.1.10 inoculated, nindicates that the c
17、hallenge inoculumhas been delivered to the test specimen or control.3.1.11 kill rate, nthe rate at which microorganisms arekilled.3.1.12 minimum effective concentration (MEC), nthe low-est concentration of antibacterial agent per surface unit areawhich still kills the specified number of microorgani
18、sms in thetime stated.3.1.13 nave test specimen, nnot yet contaminated withthe target bacteria.3.1.14 neutralization, nthe process for inactivating orquenching the activity of a microbiocide, often achievedthrough physical (for example filtration or dilution) or chemi-cal means.3.1.15 nosocomial, np
19、ertaining to or from a hospital orhealthcare facility.3.1.16 nutrient media agar, na nutritious bacterial growthmedium appropriate for growth requirements of target bacteriato which agar has been added for solidification.3.1.17 organic load, namount of organic substances pres-ent.3.1.18 organic subs
20、tance (organic load), noccurs in vari-ous forms (serum, protein, blood) and may interfere with themicrobicidal activity of a bactericidal agent by reacting with orphysically blocking the activity of the agent resulting in onethat is less effective.3.1.19 outlier, nan outlier is an observation or sub
21、set ofobservations that appears to be inconsistent with the remainderof the data.3.1.20 recovery broth, na broth, usually containing aneutralizer that preserves and protects surviving microorgan-isms after they have been subjected to antimicrobial treatment.As it is also used to extract the survivin
22、g bacteria from the testsurface, the recovery broth may also be referred to as extrac-tion broth or media.3.1.21 target bacteria, nterm often used to refer to thespecific bacteria used in the challenge inoculum for the test.Also referred to as the challenge bacteria.3.1.22 titer, nconcentration of b
23、acteria; the number ofbacteria per specified aliquot.3.1.23 vegetative bacteria, nbacteria that are in thegrowth and reproductive phase; not in sporulated form.3.1.24 viable, ncapable of living, developing, or germi-nating under favorable conditions.4. Significance and Use4.1 In the course of patien
24、t care, gloves of healthcareproviders are often contaminated with microorganisms. Thismay occur when they come in direct or indirect contact withcontaminated skin, oozing wounds, respiratory droplets, blood,amniotic fluid, saliva, or other potentially infectious materials(OPIM). It has been demonstr
25、ated that several bacteria knownto be nosocomial pathogens, can survive for days, weeks andeven months on surfaces that are touched by gloved hands. Thepresence of an effective antibacterial treatment on or in theglove that can rapidly reduce the number of viable bacteria onits surface, may also dec
26、rease the number of bacteria trans-ferred from a contaminated source (reservoir) to a vulnerablepatient or nave site. These test methods enable assessment ofbactericidal efficacy against a broad spectrum of bacteria andconditions, providing a means of efficacy comparisons formanufacturers, purchaser
27、s and users.4.2 Four specific bacteria are listed to enable inter- andintra- laboratory test calibration and to provide common targetsagainst which to compare antibacterial efficacy among prod-ucts.4.3 Manufacturers may additionally develop their own listof bacteria against which they will evaluate
28、their productsreflecting the circumstances in which their product will beused, the requirements set forth by the various agencies withwhich they are regulated, and the claims they are seeking.Alterations in test parameters must be validated and docu-mented.5. Interferences5.1 Interfering substances
29、can be bactericide-specific andcan alter the results of this test. As they may impact bacteri-cidal efficacy in actual use, it is critical that potentiallyinterfering substances such as organic loads, ubiquitous inhospitals, be incorporated as part of the test challenge todetermine impact.5.2 Other
30、potentially interfering substances should be as-sessed depending on the anticipated use and exposure of themanufacturers glove.6. Apparatus6.1 Analytical balance.6.2 Bunsen burner or inoculation loop incinerator.6.3 Colony counter.6.4 Conical centrifuge tubes.6.5 Coverslips, non-coated Borosilicate
31、glass size 18mm 18mm sterile.6.6 Forceps.6.7 Freezer, at 20 to 10C.6.8 Glass rods, bent (a.k.a. hockey sticks).6.9 Glass tubes (vials), 20 mL.6.10 Incubator, capable of temperature and environmentrequired for test bacterium.6.11 Vertical Laminar Flow Cabinet (or Bio-safety hood).D7907 1426.12 McFarl
32、and Turbidity Standard 0.5 (or equivalent).6.13 Miscellaneous Laboratory Ware.6.14 Nephelometer (photometer) or other means of turbiditydetermination.6.15 Plastic vials.6.16 Petri plates (sterile).6.17 pH Meter.6.18 Pipettes-air displacement, Eppendorf or equivalent, 50to 1000 microliters with corre
33、sponding sterile disposable tips.6.19 Punch die or scissors for specimen preparation.6.20 Refrigerator at 2 to 8C.6.21 Saline (sterile normal/physiological saline).6.22 Spectrophotometer.6.23 Sterile centrifuge tubes, with caps, 50 mL.6.24 Sterile dispenser, 10 mL delivery capacity.6.25 Sterile disp
34、osable gloves, devoid of antibacterialagents.6.26 Steam sterilizer.6.27 Timer, 6 2 second accuracy6.28 Turn Table (optional).6.29 Vortex Mixer.7. Reagents and General Solutions7.1 Bovine Serum Albumin (BSA) powder.7.2 Challenge bacteria, shall be American Type CultureCollection (ATCC) strains identi
35、fied for Comparison andCorrelation verification (Table 1). Additional challenge bacte-ria may be selected from any of several worldwide officialbacterial culture registries. To ensure vital bacteria that are notfar removed from wild type characteristics, bacteria utilized inany phase of these studie
36、s should be no more than five passagesfrom the original stock received. The method for doing this ina practical manner is described in Note 1.7.3 Deionized Distilled Water.7.4 Ethyl alcohol, 70 %.7.5 Nutrient media agar plates, shall be appropriate forplate count recovery of the challenge (or target
37、) bacteria.7.6 Neutralizer, is necessary to block or inactivate thebactericide rapidly when the designated contact test time iscompleted. Utilize Test Methods E1054 for neutralizationefficacy verification. Whatever method is used, the samemethod must be utilized for all test and control specimens in
38、the session. Neutralizer shall not be toxic to the challengebacteria.7.7 Purity of Reagents and Chemicals, shall be Reagentgrade for all tests.7.8 Phosphate Buffered Saline (PBS), may be needed forfastidious bacteria if they die off in normal saline. PBS may bepurchased commercially (for example Ste
39、rile Dulbeccos Phos-phate Buffered Saline) or prepared in the laboratory using asimilar formulation.7.8.1 For example, the Association of Analytical Commu-nities (AOAC) formulation:7.8.1.1 In 800 mL distilled water:Solution A: 8.0 g sodium chloride (NaCl)0.2 g potassium chloride (KCl)1.15 g sodium p
40、hosphate dibasic (Na2HPO4)0.2 g potassium phosphate monobasic (KH2PO4)7.8.1.2 In 100 mL distilled water:Solution B: 0.1 g calcium chloride (CaCl2)7.8.1.3 In 100 mL distilled water:Solution C: 0.1 g magnesium chloride (MgCl2)7.8.1.4 Prepare each solution separately, and then combineinto one vessel.7.
41、8.1.5 While stirring, adjust to pH 6.9 to 7.1 using 1NNaOH. For most cells and culture conditions, the optimal pH ofthis solution after filtration is 7.0 to 7.4. To avoid fluctuationsin pH, keep the vessel closed until the solution is filtered.7.8.1.6 Sterilize the solution by filtration, using a 0.
42、22micron filter.7.8.1.7 Sterile solutions should be dispensed aseptically intosterile containers and stored at 15C to 30C.7.9 Standard saline, is 0.90 % w/v of sodium chloride(NaCl) in reagent grade water. Sterilized.TABLE 1 Calibration Bacteria for Comparison Testing and Correlation QualificationsN
43、OTE 1Although guidance for ordering and shipping ATCC strains is described on their website, anyone purchasing ATCC material is responsiblefor obtaining the permits. Information regarding the specific requirements for shipment to your location must be obtained from regional authorities.Contact infor
44、mation for ATCC is listed under references.Identification ATCC Strain General Characteristics Bio-safety LevelStaphylococcus aureus 6538 Gram positive cocciVarious human infectionsSensitive to antibiotics normally used for treatmentBSL 2Enterococcus faecalis 33186 Gram positive cocciVarious human in
45、fectionsSensitive to antibiotics normally used for treatmentBSL 2Pseudomonas aeruginosa 9027 Gram negative rodsVarious human infectionsSensitive to antibiotics normally used for treatmentBSL 2Klebsiella pneumoniae 4352 Gram negative rodsVarious human infectionsSensitive to antibiotics normally used
46、for treatmentBSL 2D7907 1437.10 BacteriaThere are two categories of bacteria used inthis standard: Calibration Bacteria (four specific bacteria) andEfficacy Test Bacteria (those that may be selected by themanufacturer for testing).7.10.1 Calibration BacteriaRequired test bacteria for as-say calibrat
47、ion are listed in Table 1. Utilizing the same bacteriaenables inter- and intra- laboratory test calibration as well asproviding four common bacterial targets against which onemay compare anti-bacterial efficacies among different prod-ucts. These calibration bacteria must be tested when perform-ing t
48、he test for any official comparison or submission purposesand should be performed, at least in part (ex: one gramnegative and one gram positive bacteria) to validate internalcompetency and to ensure test-to-test correlation.7.10.2 Effcacy Test BacteriaManufacturers wishing totest additional bacteria
49、 should do so based on the intended useof the glove, likely organisms that may be encountered,requirements set forth by the various agencies with which theyare regulated, and the claims they are seeking. Alterations intest parameters must be validated and documented. Bacteriaused in this test method shall be ATCC registered strains withno more than five transfers from the original ATCC vial asrecommended in the U.S. Pharmacopeia 26th rev, 2nd supple-ment. This requirement guards against loss of vitality andvirulence often noted after many tr
