ASTM E3218-21. Method for Quantitative Testing of Antimicrobial Agents against Spores of Clostridioides difficile on Hard, Nonporous Surfaces.
Test not accredited yet in our laboratory
The ASTM E3218 standard describes a test to determine the effectiveness of antimicrobial chemicals in treating hard, non-porous surfaces contaminated with spores of Clostridioides difficile. The test product, at the concentration indicated by the client, is brought into contact with a dried suspension of Clostridiodes difficile spores and the interfering substance (a mixture of bovine albumin, yeast extract and mucin) on 10 stainless steel carriers at room temperature (22ºC± 2ºC) for the contact time indicated by the client. Each test also includes 3 untreated control carriers (exposed to phosphate buffered saline instead of to the test product) and 3 carriers treated with a reference test substance (NaOCl) as the test system control to ensure the validity of the test data. After the contact time, the CFUs obtained from each carrier are counted and, to determine the effectiveness of the product, the logarithmic reduction is calculated comparing the log density of C.difficile obtained from the treated carriers compared with the log density of C.difficile obtained from the untreated control carriers. The test system control carriers (treated with NaOCl) must exhibit a reduction <3.0 log for a valid test. For the test product, the standard does not indicate a criterion to determine whether or not a product shows sporicidal activity, therefore, as a conclusion only the logarithmic reduction obtained is reported.