[1] Washington Univ, Sch Med, Dept Surg, St Louis, MO 63110 USA
[2] Washington Univ, Sch Med, Dept Anesthesiol, St Louis, MO 63110 USA
[3] Washington Univ, Sch Med, Dept Internal Med, St Louis, MO 63110 USA
[4] St Louis Univ, Sch Publ Hlth, Ctr Study Bioterrorism & Emerging Infect, St Louis, MO 63103 USA
[5] Barnes Jewish Hosp, Dept Hosp Epidemiol & Infect Control, St Louis, MO 63110 USA
[6] Barnes Jewish Hosp, Dept Nursing, St Louis, MO 63110 USA