Comparison of the sporicidal activity of a UV disinfection process with three FDA cleared sterilants

Endocavitary probes are semi-critical devices and must undergo, at least, high level disinfection (HLD) between uses. Therefore, they should be high level disinfected between uses (i.e., with a product/process that kills all forms of microbial life; bacteria, fungi, mycobacteria, and virus, and in some countries, a demonstrated potential for sporicidal activity). In this study, the sporicidal activity of three common Food and Drug Administration cleared sterilants (CIDEX OPA Solution, SPOROX II Sterilizing and Disinfection Solution and CIDEX Activated Dialdehyde Solution) was compared with the sporicidal activity of an ultraviolet disinfection technology (Hypernova Chronos, Germitec) against Bacillus subtilis ATCC 19659 spores spread on silicone flat carriers in the presence of inorganic and organic soil.

The results indicate that the UV disinfection process presented within a 35 seconds exposure time a sporicidal efficacy substantially higher than the chemical sterilants used according to manufacturer instructions for HLD.

This study demonstrated that even if it cannot be tested/approved as a sterilant according to AOAC 966.04, the UV unit is much more effective than usual Food and Drug Administration approved chemical HLD products to kill spores in real use conditions. This finding questions the relevancy of evaluating product efficacy within extended conditions giving results that could mislead users to select the most effective HLD product/process for the reprocessing of their medical devices.