Extended Data Fig. 5: Differential fluorescence intensity curves based on the amount of anaerobic microbial cell input.
From: One-day rapid sterility test for human-derived biopharmaceuticals
The differential intensity signals were measured over time using NEST, from samples spiked with varying amount of C. sporogenes in FTM media (N = 3). Unlike aerobic species, anaerobic microbes utilize alternative molecules instead of oxygen during their metabolic processes which is less efficient in generating reducing equivalents. As a result, the conversion of resazurin to resorufin mainly occurred due to the influence of medium components, causing delays in the increase of fluorescence intensity signals from wells containing microorganisms compared to controls (negative changes in differential intensity). We utilized this effect to detect the presence of anaerobic contaminants which revealed a limit of detection of 10 CFU using NEST. The colored areas in the graph indicate the standard deviation associated with each measurement condition. The gray bar depicted below represents the range of the detection time.
