1. Bacteriology Division1 and Toxinology/Aerobiology Division2, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, MD 21702-5011, USA 3Microbiology, Dstl, CBS Porton Down, Salisbury SP4 0JQ, UK 4Orion Genomics, Center for Emerging Technologies, 4041 Forest Park, St. Louis, MO 63108, USA