ASTM E2149 Test Method

What’s the Purpose of the ASTM E2149 Test?

The ASTM E2149 test method evaluates the antimicrobial efficacy of materials used under dynamic contact conditions. Sometimes referred to as a “shake flask test,” It measures the antimicrobial activity of substrate-bound antimicrobial surfaces as they are shaken around within a concentrated bacterial suspension.  The method allows the evaluation of many different types of test samples and a wide range of test organisms. Surface antimicrobial activity is determined by comparing the results from the test sample to controls run simultaneously.

How Is the ASTM E2149 Standard Used?

ASTM E 2149 was developed for routine quality control and screening tests to overcome difficulties using classical antimicrobial test methods to evaluate substrate-bound antimicrobials. Treated substrates that undergo a wide variety of physical/chemical stress can be tested using this method. The antimicrobial activity of some substrate-bound antimicrobial agents depends upon test organisms’ direct contact with the surface of the test sample containing the agent. In this test, test samples are vigorously agitated for a specified contact time to determine the antimicrobial activity. This quantitative method involves microbe enumeration to determine the percent and log reduction.

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Overview of the ASTM E2149 Test Method

Three (3) flasks are prepared (1 for the treated sample, 1 for the untreated control, and 1 for the inoculum only). A specified volume of bacterial suspension is added to each flask.  In this method, an inoculum-only flask was added to ensure no impact from the nonnutritive microbial suspension. The antimicrobial efficacy is determined by comparing the number of organisms present before and after the specified contact time or by comparing the performance of the treated sample with an untreated control or inoculum control sample.
At 0 time, an aliquot from the inoculum-only flask is plated to check the initial population. The test sample is then added to the appropriate flask, and all three flasks are placed on a wrist-action shaker for a specified contact time (1 hour per the standard). After the specified contact time, an aliquot from each flask is removed to quantify the microbial reduction as percent and log reduction.

Standards, Guidance, and Regulations

The most direct path to ensuring ASTM E2149 compliance during your device development is to partner with an experienced contract research organization. A CRO gives you access to timely testing, regulatory expertise, quality assurance and comprehensive reports.
Key standards and regulations include:

• • ASTM E2149 Standard Test Method: Provides detailed instructions for performing the test, including preparation, inoculation, incubation, and evaluation steps.
  • ISO 11737: Offers international guidelines for evaluating the antimicrobial properties of medical devices.
  • FDA Guidance: The U.S. Food and Drug Administration (FDA) provides specific guidance on validating antimicrobial claims for medical devices, including recommendations for conducting efficacy testing.

NAMSA can help with all your antimicrobial testing needs — including maintaining ASTM E2149 compliance from sample preparation to process documentation. Talk to a NAMSA representative to learn more.