ASTM E2149-10
(Test Method)Standard Test Method for Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions
Standard Test Method for Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions
SIGNIFICANCE AND USE
Immobilized, as chemically bonded, antimicrobial agents are not free to diffuse into their environment under normal conditions of use. Textile test methods, such as AATCC 147-2004, that are directly dependent on the ready leachability of the antimicrobial agent from the treated fabric are inappropriate for evaluating immobilized antimicrobial agents. This test method ensures good contact between the bacteria and the treated fiber, fabric, or other substrate, by constant agitation of the test specimen in a challenge suspension during the test period.
The metabolic state of the challenge species can directly affect measurements of the effectiveness of particular antimicrobial agents or concentrations of agents. The susceptibility of the species to particular biocides could be altered depending on its life stage (cycle). One-hour contact time in a buffer solution allows for metabolic stasis in the population. This test method standardizes both the growth conditions of the challenge species and substrate contact times to reduce the variability associated with growth phase of the microorganism.
Liquid analysis of antimicrobial activity of non-leaching agents provides the ability to completely wet-out a test substrate. With the use of wetting-agent surfactants, false negatives observed when comparing hydrophobic and hydrophilic substrates can be reduced.
This test method is not intended for directly comparing the activities of leaching and non-leaching antimicrobial agents. In liquid environments, leaching biocides may release the active ingredient at differential rates. Furthermore, residual antimicrobial activity of leaching biocides may be present in serial dilution and may exert additional activity after desired contact time, unless adequately sequestered at end of test. Controls for both of these factors are not included in this test method; therefore, screening protocols are introduced to identify the presence of leaching biocides.
The test is suitable for ...
SCOPE
1.1 This test method is designed to evaluate the resistance of non-leaching antimicrobial treated specimens to the growth of microbes under dynamic contact conditions. This dynamic shake flask test was developed for routine quality control and screening tests in order to overcome difficulties in using classical antimicrobial test methods to evaluate substrate-bound antimicrobials. These difficulties include ensuring contact of inoculum to treated surface (as in AATCC 100), flexibility of retrieval at different contact times, use of inappropriately applied static conditions (as in AATCC 147), sensitivity, and reproducibility. This test also allows for the versatility of testing contamination due to such things as hard water, proteins, blood, serum, various chemicals, and other contaminates or physical/chemical stresses or manipulations of the specimens of interest.
1.2 Surface antimicrobial activity is determined by comparing results from the test sample to simultaneously run controls.
1.3 The presence of a leaching antimicrobial is both pre- and post-determined by the presence of a zone of inhibition.
1.4 This test method should be performed only by those trained in microbiological techniques.
1.5 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E2149 − 10
StandardTest Method for
Determining the Antimicrobial Activity of Immobilized
1
Antimicrobial Agents Under Dynamic Contact Conditions
This standard is issued under the fixed designation E2149; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope establish appropriate safety and health practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 This test method is designed to evaluate the antimicro-
bial activity of non-leaching, antimicrobial-treated specimens
2. Referenced Documents
under dynamic contact conditions. This dynamic shake flask
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2.1 AATCC Documents:
test was developed for routine quality control and screening
AATCC147-2004AntibacterialActivityAssessmentofTex-
tests in order to overcome difficulties in using classical
tile Materials: Parallel Streak Method
antimicrobial test methods to evaluate substrate-bound antimi-
AATCC 100-2004Antibacterial Finishes on Fabrics
crobials. These difficulties include ensuring contact of inocu-
lum to treated surface (as in AATCC 100-2004), flexibility of
3. Summary of Test Method
retrieval at different contact times, use of inappropriately
3.1 The antimicrobial activity of a substrate-bound, non-
applied static conditions (as inAATCC 147-2004), sensitivity,
leaching antimicrobial agent is dependent upon direct contact
and reproducibility.
of microbes with the active chemical agent. This test deter-
1.2 This test method allows for the ability to evaluate many
mines the antimicrobial activity of a treated specimen by
different types of treated substrates and a wide range of
shaking samples of surface-bound materials in a concentrated
microorganisms. Treated substrates used in this test method
bacterial suspension for a one hour contact time. The suspen-
canbesubjectedtoawidevarietyofphysical/chemicalstresses
sion is serially diluted both before and after contact and
or manipulations and allows for the versatility of testing the
cultured.The number of viable organisms from the suspension
effect of contamination due to such things as hard water,
is determined and the percent reduction (or log reduction) is
10
proteins, blood, serum, various chemicals, and other contami-
calculated by comparing retrievals from appropriate controls.
nants.
4. Significance and Use
1.3 Surface antimicrobial activity is determined by compar-
ingresultsfromthetestsampletocontrolsrunsimultaneously.
4.1 Immobilized, as chemically bonded, antimicrobial
agents are not free to diffuse into their environment under
1.4 The presence of a leaching antimicrobial is determined
normalconditionsofuse.Textiletestmethods,suchasAATCC
both pre- and post-test.
147-2004, that are directly dependent on the ready leachability
1.5 This test method should be performed only by those
of the antimicrobial agent from the treated fabric are inappro-
trained in microbiological techniques.
priate for evaluating immobilized antimicrobial agents. This
1.6 The values stated in SI units are to be regarded as
test method ensures good contact between the bacteria and the
standard. No other units of measurement are included in this
treated fiber, fabric, or other substrate, by constant agitation of
standard.
the test specimen in a challenge suspension during the test
period.
1.7 This standard may involve hazardous materials,
operations, and equipment. This standard does not purport to
4.2 Themetabolicstateofthechallengespeciescandirectly
address all of the safety concerns, if any, associated with its
affect measurements of the effectiveness of particular antimi-
use. It is the responsibility of the user of this standard to
crobialagentsorconcentrationsofagents.Thesusceptibilityof
thespeciestoparticularbiocidescouldbealtereddependingon
itslifestage(cycle).One-hourcontacttimeinabuffersolution
1 allows for metabolic stasis in the population. This test method
This test method is under the jurisdiction of ASTM Committee E35 on
Pesticides, Antimicrobials, and Alternative Control Agents and is the direct
responsibility of Subcommittee E35.15 on Antimicrobial Agents.
2
Current edition approved May 1, 2010. Published May 2010. Originally Available from American Association of Textile Chemists and Colorists
approvedin2001.Lastpreviouseditionapprovedin2001asE2149–01,whichwas (AATCC), P.O. Box 12215, Research Triangle Park, NC 27709, http://
withdrawn in 2010 and reinstated in May 2010. DOI: 10.1520/E2149-10. www.aatcc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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