Test method development to evaluate hot, humid air decontamination of materials contaminated with Bacillus anthracis ∆Sterne and B. thuringiensis Al Hakam spores

Authors

  • T.L. Buhr,

    Corresponding author
    • Dahlgren Division, CBR Concepts and Experimentation Branch (Z21) and Sensor Technology Branch (Q31), Naval Surface Warfare Center, Dahlgren, VA, USA
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  • A.A. Young,

    1. Dahlgren Division, CBR Concepts and Experimentation Branch (Z21) and Sensor Technology Branch (Q31), Naval Surface Warfare Center, Dahlgren, VA, USA
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  • Z.A. Minter,

    1. Dahlgren Division, CBR Concepts and Experimentation Branch (Z21) and Sensor Technology Branch (Q31), Naval Surface Warfare Center, Dahlgren, VA, USA
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  • C.M. Wells,

    1. Dahlgren Division, CBR Concepts and Experimentation Branch (Z21) and Sensor Technology Branch (Q31), Naval Surface Warfare Center, Dahlgren, VA, USA
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  • D.C. McPherson,

    1. Dahlgren Division, CBR Concepts and Experimentation Branch (Z21) and Sensor Technology Branch (Q31), Naval Surface Warfare Center, Dahlgren, VA, USA
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  • C.L. Hooban,

    1. Dahlgren Division, CBR Concepts and Experimentation Branch (Z21) and Sensor Technology Branch (Q31), Naval Surface Warfare Center, Dahlgren, VA, USA
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  • C.A. Johnson,

    1. Dahlgren Division, CBR Concepts and Experimentation Branch (Z21) and Sensor Technology Branch (Q31), Naval Surface Warfare Center, Dahlgren, VA, USA
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  • E.J. Prokop,

    1. Dahlgren Division, CBR Concepts and Experimentation Branch (Z21) and Sensor Technology Branch (Q31), Naval Surface Warfare Center, Dahlgren, VA, USA
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  • J.R. Crigler

    1. Dahlgren Division, CBR Concepts and Experimentation Branch (Z21) and Sensor Technology Branch (Q31), Naval Surface Warfare Center, Dahlgren, VA, USA
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Correspondence

Tony L. Buhr, Naval Surface Warfare Center, Dahlgren Division, CBR Concepts and Experimentation Branch (Z21), 4045 Higley Road, Suite 345, Dahlgren, VA 22448-5162, USA. E-mail: DLGR_NSWC_Z20@navy.mil

Abstract

Aims

To develop test methods and evaluate the survival of Bacillus anthracis ∆Sterne and Bacillus thuringiensis Al Hakam spores after exposure to hot, humid air.

Methods and Results

Spores (>7 logs) of both strains were dried on six different test materials. Response surface methodology was employed to identify the limits of spore survival at optimal test combinations of temperature (60, 68, 77°C), relative humidity (60, 75, 90%) and time (1, 4, 7 days). No spores survived the harshest test run (77°C, 90% r.h., 7 days), while > 6·5 logs of spores survived the mildest test run (60°C, 60% r.h., 1 day). Spores of both strains inoculated on nylon webbing and polypropylene had greater survival rates at 68°C, 75% r.h., 4 days than spores on other materials. Electron microscopy showed no obvious physical damage to spores using hot, humid air, which contrasted with pH-adjusted bleach decontamination.

Conclusions

Test methods were developed to show that hot, humid air effectively inactivates B. anthracis ∆Sterne and B. thuringiensis Al Hakam spores with similar kinetics.

Significance and Impact of the Study

Hot, humid air is a potential alternative to conventional chemical decontamination.

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