[1] Univ Ulsan, Coll Med, Div Neonatol, Dept Pediat, Seoul, South Korea
[2] Univ Ulsan, Coll Med, Div Microbiol, Dept Lab Med, Seoul, South Korea
[3] Univ Ulsan, Coll Med, Div Infect Dis, Dept Internal Med, Seoul, South Korea
[4] Univ Ulsan, Coll Med, Dept Hosp Infect Control, Seoul, South Korea
[5] Univ Ulsan, Coll Med, Div Epidemiol & Biostat, Clin Res Ctr, Seoul, South Korea