[1] Rush Med Coll, Dept Immunol Microbiol, Chicago, IL 60612 USA
[2] Rush Med Coll, Dept Med, Infect Dis Sect, Chicago, IL 60612 USA
[3] Cook Cty Hosp, Dept Emergency Med, Chicago, IL 60612 USA
[4] Univ Illinois, Sch Publ Hlth, Chicago, IL USA
[5] Cook Cty Hosp, Dept Obstet & Gynecol, Chicago, IL 60612 USA