Decontamination of Bacillus subtilis var. niger spores on selected surfaces by chlorine dioxide gas

Abstract

Abstract:Objective: Chlorine dioxide (CD) gas has been used as a fumigant in the disinfection of biosafety laboratories. In this study, some experiments were conducted to assess the inactivation of spores inoculated on six materials [stainless steel (SS), painted steel (PS), polyvinyl chlorid (PVC), polyurethane (PU), glass (GS), and cotton cloth (CC)] by CD gas. The main aims of the study were to determine the sporicidal efficacy of CD gas and the effect of prehumidification before decontamination on sporicidal efficacy. Methods: Material coupons (1.2 cm diameter of SS, PS, and PU; 1.0 cm×1.0 cm for PVC, GS, and CC) were contaminated with 10 μl of Bacillus subtilis var. niger (ATCC 9372) spore suspension in mixed organic burden and then dried in a biosafety cabinet for 12 h. The spores were recovered by soaking the coupons in 5 ml of extraction liquid for 1 h and then vortexing the liquid for 1 min. Results: The log reductions in spore numbers on inoculated test materials exposed to CD gas [0.080% (volume ratio, v/v) for 3 h] were in the range of from 1.80 to 6.64. Statistically significant differences were found in decontamination efficacies on test material coupons of SS, PS, PU, and CC between with and without a 1-h prehumidification treatment. With the extraction method, there were no statistically significant differences in the recovery ratios between the porous and non-porous materials. Conclusions: The results reported from this study could provide information for developing decontamination technology based on CD gas for targeting surface microbial contamination.

Response surface modeling for the inactivation ofBacillus subtilissubsp.nigerspores by chlorine dioxide gas in an enclosed space

“…Filter paper strip is one of the most common carrier types and is widely used for the validation of space decontamination (Jeng and Woodworth, 1990;Jia et al, 2013). However, materials of the spore carrier greatly affected the inactivation efficiency (Li et al, 2012;Rogers et al, 2007). It is important to note that the predicted results are based on a certain carrier of spores and that use of different indoor surface materials and/or treatment conditions may result in altered inactivation characteristics.…”

“…niger is one of the most common sporeforming strains and has the strongest resistance to the sanitizer among different types of pathogens. This strain has been used as a biological indicator in several evaluations of disinfection efficiency (Li et al, 2012;Jeng and Woodworth, 1990;Pottage et al, 2012). Furthermore, B. subtilis subsp.…”

Inactivation ofBacillus AnthracisSpores on All-Weather Paper

“…However, any unintentional contamination coupled with the inherent porosity of paper presents a potential hazard to laboratory staff who may come into contact with this paper, and may lead to an increase in laboratory-acquired infections. This is a concern for porous surfaces such as paper, since vegetative bacteria, spores, and viruses can remain viable for much longer and are more difficult to decontaminate when compared to non-porous surfaces (Han et al, 2003;Li et al, 2012;Portner & Hoffman, 1968;Rogers et al, 2005;Sinclair et al, 2008). This persistence in pathogen viability presents a potential aerosol and contact hazard.…”

Inactivation Kinetics and Mechanism of a Human Norovirus Surrogate on Stainless Steel Coupons via Chlorine Dioxide Gas

“…ClO 2 gas is a strong oxidizer and is one of the emerging technologies for decontamination of contact surfaces and fresh produce. Besides being an effective biocidal agent (25,26), ClO 2 is dispersed through the air and can be distributed to areas beyond the reach of liquid sanitizers. It has been shown that gaseous ClO 2 is a rapid and effective sterilizing agent active against bacteria, yeasts, and molds; however, its ability to inactivate foodborne viruses is less established.…”