Evaluation and application of Bacillus subtilis standard strains for validation of terminal disinfection efficacy in high-level biosafety laboratories

Objective To establish standard strains of Bacillus subtilis for evaluation of terminal disinfection in high-level biosafety laboratories according to the Technical Requirements for Evaluation of National Standard Strains of Pathogenic Microorganisms (WS/T 812—2022) .

Methods Four strains of Bacillus subtilis isolated in China were used to study the colony morphology, staining characteristics, biochemical characteristics and whole genome sequencing of standard Strain, the biological and molecular characteristics of the standard strains were analyzed, and then the four standard strains were made into a certain concentration of bacterial tablets, evaluate the final disinfection efficacy of Animal Biosafety Level Ⅲ Laboratory and key protective equipment with commercially available bacterial tablets.

Results All four candidate strains were identified as Bacillus subtilis, with a circular genome and no plasmids; Under the same disinfection conditions, like ATCC9372, the bacterial tablets of the four candidate strains placed in rooms, biosafety cabinets, and mouse ventilation cages can all be completely killed.

Conclusion The standard strains of Bacillus subtilis for the evaluation of terminal disinfection in high-level biosafety laboratories were established in this study.