[1] Virginia Commonwealth Univ, Med Ctr, Div Qual Healthcare, Hosp Epidemiol, Richmond, VA 23284 USA
[2] Virginia Commonwealth Univ, Med Ctr, Div Infect Dis, Hosp Epidemiol, Richmond, VA USA
[3] Virginia Commonwealth Univ, Med Ctr, William Branch Porter, Dept Internal Med, Richmond, VA USA