New Biocide Foam Containing Hydrogen Peroxide for the Decontamination of Vertical Surface Contaminated With Bacillus thuringiensis Spores.

Esther Le Toquin,Nicole Orange,Sylvain Faure,Fabienne Gas

doi:10.3389/fmicb.2018.02295

Abstract

Despite scientific advances, bacterial spores remain a major preoccupation in many different fields, such as the hospital, food, and CBRN-E Defense sector. Although many disinfectant technologies exist, there is a lack for the decontamination of difficult to access areas, outdoor sites, or large interior volumes. This study evaluates the decontamination efficiency of an aqueous foam containing hydrogen peroxide, with the efficiency of disinfectant in the liquid form on vertical surfaces contaminated by Bacillus thurengiensis spores. The decontamination efficiency impact of the surfactant and stabilizer agents in the foam and liquid forms was evaluated. No interferences were observed with these two chemical additives. Our results indicate that the decontamination kinetics of both foam and liquid forms are similar. In addition, while the foam form was as efficient as the liquid solution at 4°C, it was even more so at 30°C. The foam decontamination reaction follows the Arrhenius law, which enables the decontamination kinetic to be predicted with the temperature. Moreover, the foam process used via spraying or filling is more attractive due to the generation of lower quantity of liquid effluents. Our findings highlight the greater suitability of foam to decontaminate difficult to access and high volume facilities compared to liquid solutions.

Highlights

Certain Gram-positive bacteria, like Bacillus and Clostridium species, are able to protect themselves from environmental stress or nutrient depletion by a sporulation process
The spores recovery injected inside foam or liquid forms was determined with S5 solution that did not contain disinfectant (Table 1)
The hydrogen peroxide was known to be neutralized by catalase positive bacteria (McDonnell and Russell, 1999; Pottage et al, 2012)

Summary

Introduction

Certain Gram-positive bacteria, like Bacillus and Clostridium species, are able to protect themselves from environmental stress or nutrient depletion by a sporulation process. Vegetative cells that pass into a dormant spore state are known to be much more resistant to the environment and to disinfection treatments than growing cells of the same species (Nicholson et al, 2000; Driks, 2002b; Piggot and Hilbert, 2004; Higgins and Dworkin, 2012; Wood et al, 2015). A thick spore coat protects the inner layers from lytic enzymes and from many chemicals, including chlorine dioxide and sodium hypochlorite (Driks, 1999, 2002a). The reduced water content in the core protects the spore from dry and wet heat, enabling it to survive for longer periods of time in a hostile environment (Setlow, 2006; Leggett et al, 2012). Bacterial spores have always been considered as a threat either through their potential for use as biological weapons (e.g., the 2001 anthrax attack in the United States) (Schmitt and Zacchia, 2012), or because of food and hospital contaminations (Faille et al, 2014; Yi et al, 2016; Fernandes et al, 2017)

Methods

Results

Conclusion