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

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 2-3 h. S. aureus was found to be more resistant than E. coli and S. albus. Tests with VHP 8% and exposure for >3 h 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.