Comparative Evaluation of the Microbicidal Activity of Low-Temperature Sterilization Technologies to Steam Sterilization

Abstract

Background: Most medical and surgical devices used in healthcare facilities are made of materials that are sterilized by heat (ie, heat stable), primarily steam sterilization. Low-temperature sterilization methods developed for heat and moisture sensitive devices include ethylene oxide gas (ETO), hydrogen peroxide gas plasma (HPGP), vaporized hydrogen peroxide (VHP), and hydrogen peroxide plus ozone. This study is the first to evaluate the microbicidal activity of the FDA-cleared VHP sterilizer and other methods (Table 1) in the presence of salt and serum (10% FCS). Methods: Brushed stainless steel discs (test carriers) were inoculated with test microbes (Table 1) and subjected to 4 sterilization methods: steam, ETO, VHP and HPGP. Results: Steam sterilization killed all 5 vegetative and 3 spore-forming test organisms in the presence of salt and serum (Table 1). Similarly, the ETO and the HPGP sterilizers inactivated the test organisms with a failure rate of 1.9% for each (ie, 6 of 310 for ETO and 5 of 270 for HPGP). Although steam had no failures compared to both ETO and HPGP, which demonstrated some failures for vegetative bacteria, there was no significant difference comparing the failure rate of steam to either ETO (P > .05) or HPGP (P > .05). However, the VHP system tested failed to inactivate all the test organisms in 76.3% of the tests (206 of 270; P < .00001) (Table 1). Conclusions: This investigation demonstrated that steam sterilization was the most effective method, followed by ETO and HPGP and, lastly, VHP.

Funding: None

Disclosures: Dr. Rutala was a consultant to ASP (Advanced Sterilization Products)