Determination of the Efficacy of Two Building Decontamination Strategies by Surface Sampling with Culture and Quantitative PCR Analysis

Abstract

The efficacy of currently available decontamination strategies for the treatment of indoor furnishings contaminated with bioterrorism agents is poorly understood. Efficacy testing of decontamination products in a controlled environment is needed to ensure that effective methods are used to decontaminate domestic and workplace settings. An experimental room supplied with materials used in office furnishings (i.e., wood laminate, painted metal, and vinyl tile) was used with controlled dry aerosol releases of endospores of Bacillus atrophaeus ("Bacillus subtilis subsp. niger," also referred to as BG), a Bacillus anthracis surrogate. Studies were performed using two test products, a foam decontaminant and chlorine dioxide gas. Surface samples were collected pre-and posttreatment with three sampling methods and analyzed by culture and quantitative PCR (QPCR). Additional aerosol releases with environmental background present on the surface materials were also conducted to determine if there was any interference with decontamination or sample analysis. Culture results indicated that 10 5 to 10 6 CFU per sample were present on surfaces before decontamination. After decontamination with the foam, no culturable B. atrophaeus spores were detected. After decontamination with chlorine dioxide gas, no culturable B. atrophaeus was detected in 24 of 27 samples (89%). However, QPCR analysis showed that B. atrophaeus DNA was still present after decontamination with both methods. Environmental background material had no apparent effect on decontamination, but inhibition of the QPCR assay was observed. These results demonstrate the effectiveness of two decontamination methods and illustrate the utility of surface sampling and QPCR analysis for the evaluation of decontamination strategies.

Disinfection efficiency of chlorine dioxide gas in student cafeterias in Taiwan

“…Under room temperature conditions, the ClO 2 content within the water evaporates and propagates naturally through the local environment, providing a disinfection function. Being in a gaseous form, the ClO 2 molecules are able to penetrate deeply into building cavities, wall cavities, and other hard-to-access areas, and therefore provide an extremely thorough sterilization function (Buttner et al, 2004;Han et al, 2003). Gaseous ClO 2 has been approved by the EPA as a disinfectant, sanitizer, and sterilant for the paper, fruit, vegetable, dairy, poultry and beef processing industries (EPA, 2000), and for the processing of industrial wastewater (Lee et al, 2006).…”

Inactivation of Bacillus Endospores in Envelopes by Electron Beam Irradiation

“…niger) has historically been used as a B. anthracis surrogate due to its lack of pathogenicity and unique colonial characteristics, even though it is more closely related to B. subtilis (1,5,12,17,27). In fact, B. atrophaeus has been used as a genus-level representative for a number of inactivation techniques, such as chemical and gamma radiation sterilizations (4)(5)(6)24). While B. atrophaeus is an accepted surrogate for such studies, interspecies variations preclude complete correlation between B. anthracis and any surrogate when evaluating biological activities.…”

Effect of Chlorine Dioxide Gas on Fungi and Mycotoxins Associated with Sick Building Syndrome

“…The contents inside a contaminated structure may also be able to be sterilized (10) using this technique as well. A biocide, chlorine dioxide, has been previously been used in a gaseous form for bacterial decontamination (1,9). It has been also shown to have a degree of fungicidal activity in solution (15).…”