[1] Univ Texas Med Branch, Dept Microbiol & Immunol, Galveston, TX 77555 USA
[2] Oklahoma Dept Hlth, Publ Hlth Lab, Oklahoma City, OK USA
[3] Univ Maryland, Sch Med, Dept Microbiol & Immunol, Inst Genome Sci, Baltimore, MD 21201 USA
[4] Univ Texas SW Med Ctr Dallas, Dept Microbiol, Dallas, TX 75390 USA
[5] Univ Texas Med Branch, Dept Pathol, Galveston, TX USA