The poster illustrated the results of a study that examined the relative growth performance of three vendor preparations of standard USP organisms vs. freshly grown in-house cultures from Rapid Micro Biosystems. Comparison of the preparations was performed using the Growth DirectTM System. The poster is available here.
Validation and release testing often rely on the use of commercially prepared stocks of standard test organisms. For compendial methods, these stocks display acceptable results, however with rapid microbial testing systems that reduce the time to results for detection and enumeration, the relative performance of commercially prepared stocks can impact the potential time savings of the rapid method.
The study measured the mean detection rate of the test populations, the mean time point of 1st colony detection, and the time point at which 85% of the final count of the colonies was detected. The study revealed measurable differences in growth and detection as determined by the Growth DirectTM System.
Companies using commercially prepared organisms as part of their validation process should be aware of the differences as they plan their validations.