Bactericidal efficacy of a low concentration of vaporized hydrogen peroxide with validation in a BSL-3 laboratory

Abstract

Highly infective pathogens are cultured and studied in biosafety laboratories. It is critical to disinfect these laboratories thoroughly in order to prevent laboratory infection. A whole-room, non-contact, reduced corrosion disinfection strategy using hydrogen peroxide was proposed and evaluated. To evaluate the bactericidal efficacy of 8% and 10% vaporized hydrogen peroxide (VHP) in a laboratory setting, with spores and bacteria used as bioindicators. Spores of Bacillus atrophaeus and Bacillus stearothermophilus, along with Escherichia coli, Staphylococcus aureus and Staphylococcus albus bacteria were placed in pre-selected locations in a sealed laboratory, and an OXY-PHARM NOCOSPRAY2 VHP generator was applied. Spore killing efficacy was evaluated qualitatively, bactericidal efficacy was analysed quantitatively, and the mean log10 reduction was determined. Finally, the optimized disinfection strategy was verified in a biosafety level 3 (BSL-3) laboratory. Significant reductions in microbial load were obtained for each of the selected spores and bacteria when exposed to VHP 8% and 10% for 2-3h. S.aureus was found to be more resistant than E.coli and S.albus. Tests with VHP 8% and exposure for >3h showed a 100% kill rate for B.atrophaeus on surfaces and equipment in the BSL-3 laboratory. The VHP generator has good diffusivity and low corrosiveness, and is a time-saving method for removal of disinfectant residue. This study provides reference for the precise disinfection of air and the surfaces of objects in biosafety laboratories under various conditions.