[1] Univ Michigan, Dept Internal Med, Div Infect Dis, Ann Arbor, MI 48109 USA
[2] Vet Affairs Ann Arbor Healthcare Syst, Div Infect Dis, Ann Arbor, MI USA
[3] William S Middleton Mem Vet Adm Med Ctr, Madison, WI USA
[4] Univ Wisconsin, Sch Med & Publ Hlth, Infect Dis Sect, Dept Med, Madison, WI 53705 USA