Evaluation of adenosine triphosphate (ATP) bioluminescence assay to confirm surface disinfection of biological indicators with vaporised hydrogen peroxide (VHP)

Background Decontamination of hospital isolation rooms can be conducted using vaporised hydrogen peroxide (VHP). A more rapid biological indicator, such as adenosine triphosphate (ATP) bioluminescence, could allow rooms to be reoccupied sooner and reduce down time. Aim This study examined the ATP bioluminescence assay as a way to evaluate biological indicators to confirm decontamination following the use of VHP. Methods Response to VHP exposure was evaluated using microbial inactivation by standard culture methods and by the ATP bioluminescence assay. Range finding determined the approximate exposure time necessary to achieve partial and complete inactivation of the organisms. Two-hundred-and-fifty parts per million of VHP was delivered to the chamber during the exposure cycle. Fifty cm² stainless steel coupons were inoculated with 50μL of organism suspensions containing >10⁹ colony forming units (CFU) of the following: Acinetobacter baumannii, Klebsiella pneumoniae, and methicillin-resistant Staphylococcus aureus. The standard manufactured biological indicator stainless steel discs containing concentrations of 10⁴, 10⁵ and 10⁶ CFU/surface of Geobacillus stearothermophilus spores were also evaluated. Findings Multiple log-reductions were shown utilising standard culture methods for each organism, but the ATP bioluminescence assay did not show a corresponding log-reduction. Conclusion The ATP bioluminescence assay was not considered an effective alternate to standard culture-based methodologies for the confirmation of VHP decontamination.