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Published on: November 16, 2016
Customized antimicrobial efficacy tests offer superior evaluation of growth inhibitor efficacy for liquid microbial
John P Gorsuch1, Zachary Jones1
1BiOWiSH Technologies, 2724 Erie Avenue Suite C, Cincinnati, OH, 45208, USA.
Abstract:
Antimicrobial effectiveness tests are common methods used to assess the risk of microbial contamination in pharmaceuticals and cosmetics. These assays may be inappropriate for endospore-based microbial products which often carry a similar - if not greater - risk of microbial contamination. In the present study, we compared the antimicrobial efficacy assessment provided by United States Pharmacopeia Chapter <51> Antimicrobial Effectiveness Testing with a modified test which utilized a customized bacterial challenge. The customized challenge inoculum comprised an assemblage of 12 bacterial strains (both pathogens and spoilage organisms) isolated from the product's end-use geography. Results suggest that some microbial inhibitor systems which pass industry standard antimicrobial effectiveness tests may fail when challenged with a customized bacterial assemblage. In order to provide the best possible assessment of microbial inhibitor systems for liquid Bacillus products, we suggest that new antimicrobial effectiveness tests be developed for this product class which include the addition of field-relevant contaminants in addition to the industry standard pathogen challenge.
Insights
Standard antimicrobial tests may not adequately assess endospore-based products. A customized bacterial challenge revealed limitations in current methods, highlighting the need for improved antimicrobial effectiveness testing for Bacillus products.
Area of Science:
- Microbiology
- Pharmaceutical Sciences
- Cosmetic Science
Background:
- Antimicrobial effectiveness tests are standard for pharmaceuticals and cosmetics.
- Endospore-based products pose a significant microbial contamination risk, potentially inadequately assessed by current methods.
Purpose of the Study:
- To compare the standard United States Pharmacopeia Chapter <51> Antimicrobial Effectiveness Testing with a modified test using a customized bacterial challenge.
- To evaluate the efficacy of antimicrobial systems in endospore-based products against a broader range of contaminants.
Main Methods:
- A customized bacterial challenge inoculum was developed, comprising 12 bacterial strains (pathogens and spoilage organisms) from the product's end-use geography.
- The customized challenge was used to test microbial inhibitor systems, comparing results against the standard United States Pharmacopeia Chapter <51>.
Main Results:
- Some microbial inhibitor systems that passed standard antimicrobial effectiveness tests failed when challenged with the customized bacterial assemblage.
- The study identified potential inadequacies in current antimicrobial testing for endospore-based products.
Conclusions:
- Industry-standard antimicrobial effectiveness tests may not be sufficient for endospore-based products like liquid Bacillus.
- Development of new antimicrobial effectiveness tests incorporating field-relevant contaminants alongside standard pathogens is recommended for accurate assessment.
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