Monitoring the Decontamination of Bacterial Spores Using Fluorescent Viability Assays

摘要

Plate count methods are used to determine the efficacy of decontaminants against pathogenic bacteria. However, they are costly, labor intensive and time-consuming. With recent concerns of biowarfare, a simple and rapid means for characterizing decontaminant formulations and monitoring clean up efforts are greatly needed. Luna has developed several fluorescence-based assays to monitor the viability of microbes such as E. coli, S. aureus and B. globigii, the anthrax simulant. Dose-response and time-course lethalities to decontaminants can be determined within 1-2 hours. During this special contract, Luna Innovations adapted the fluorescent viability assays to monitor the decontamination of bacterial spores. With the addition of an acceleration step, the resazurin viability assay monitored the lethal effects of decontaminants on spores of B. globigii with good correlation to decreases in plate counts (spores/ml). Spores were recovered from glass surfaces decontaminated with DF- 200 and processed using a novel syringe/filter sampling format. By combining the acceleration step with the syringe/filter formats, as few as 5-50 spores were detected from swabbed surfacesin 8-10 hours. This rapid, fluorescence-based viability assay has been formatted for high throughput use with a fluorescent microplate reader and provides a rapid alternative to extensive primary plate count screening.