[1] Med Univ S Carolina, Dept Microbiol & Immunol, 173 Ashley Ave,BSB 214A, Charleston, SC 29425 USA
[2] Hosp Ninos Roberto del Rio, Pediat Intens Care Unit, Santiago, Chile
[3] Hosp Ninos Roberto del Rio, Microbiol Lab, Santiago, Chile
[4] Hosp Ninos Roberto del Rio, Infect Control Comm, Santiago, Chile
[5] Univ Chile, Dept Microbiol, Santiago, Chile
[6] Univ Chile, Fac Med, Sch Publ Hlth, Santiago 7, Chile