With the introduction and implementation of rapid respiratory-based sterility methods, the need to ensure consistent and reproducible results for Cutibacterium acnes has increased dramatically. As more products are introduced to markets requiring validation with this organism, a robust and proven methodology is needed that allows any analyst to generate robust, reproducible recoveries. Experimentation with this organism was performed to develop a process that ensures consistent recovery for this organism.Testing involved assessment of different type strains from various vendors as well as numerous preparations from each vendor and in house isolates. Strain/sample preparation was assessed to determine if commercial preparations at ≤ 100 CFU were more consistent than those which required dilution to reach the desired inoculum level. Additionally, variations to the inoculum procedure itself (e.g., needle gauge used in inoculation) were assessed to determine specific inoculation techniques that provided the most consistent organism recovery. A technique was developed that allowed inoculation to be performed without the need for single source vendor materials or an overly complex inoculation procedure. The technique was then disseminated across the network to allow groups utilizing rapid sterility methods achieve similar reproducible and consistent results with C. acnes and other compendial microbes.
David Carpiniello (Thu,) studied this question.