Decontamination of a Hospital Room Using Gaseous Chlorine Dioxide: Bacillus anthracis, Francisella tularensis, and Yersinia pestis

Abstract

This study assessed the efficacy of gaseous chlorine dioxide for inactivation of Bacillus anthracis, Francisella tularensis, and Yersinia pestis in a hospital patient care suite. Spore and vegetative cells of Bacillus anthracis Sterne 34F2, spores of Bacillus atrophaeus ATCC 9372 and vegetative cells of both Francisella tularensis ATCC 6223 and Yersinia pestis A1122 were exposed to gaseous chlorine dioxide in a patient care suite. Organism inactivation was then assessed by log reduction in viable organisms postexposure to chlorine dioxide gas compared to non-exposed control organism. Hospital room decontamination protocols utilizing chlorine dioxide gas concentrations of 377 to 385 ppm maintained to exposures of 767 ppm-hours with 65% relative humidity consistently achieved complete inactivation of B. anthracis and B. atrophaeus spores, as well as vegetative cells of B. anthracis, F. tularensis, and Y. pestis. Decrease in exposure (ppm-hours) and relative humidity (<65%) or restricting airflow reduced inactivation but achieved >8 log reductions in organisms. Up to 10-log reductions were achieved in a hospital room with limited impact on adjacent areas, indicating chlorine dioxide concentrations needed for decontamination of highly concentrated (>6 logs) organisms can be achieved throughout a hospital room. This study translates laboratory chlorine dioxide fumigation studies applied in a complex clinical environment.

Keywords:

• Bacillus anthracis
• Yersinia pestis
• Francisella tularensis
• chlorine dioxide
• decontamination

ACKNOWLEDGMENTS

The authors thank Michelle Schwedhelm from the Nebraska Medical Center for coordinating access to Nebraska Patient Care Biocontainment and Kevin Lorcheim from Clordisys Solutions, Inc. for providing technical support. This work was financially supported by the Nebraska Patient Care Biocontainment at the Nebraska Medical Center. The Minidox-M Decontamination System is on loan to the research group from Clordisys Solutions, Inc. However, Clordisys is not part of the research team, party to experimental design, or aware of the results of this article ahead of print. Clordisys has put no conditions on our use of the Minidox system beyond that we return it when we are done. All authors declare no financial interests.