[1] Univ Hosp Geneva, Infect Control Program, CH-1211 Geneva 14, Switzerland
[2] Univ Hosp Geneva, WHO Collaborating Ctr Patient Safety, CH-1211 Geneva 14, Switzerland
[3] Fac Med, CH-1211 Geneva 14, Switzerland
[4] Univ Melbourne, Dept Med Austin, Melbourne, Vic, Australia
[5] Univ Zurich, Univ Zurich Hosp, Div Infect Dis & Hosp Epidemiol, Zurich, Switzerland
[6] Jewish Gen Hosp, Infect Prevent & Control Unit, Montreal, PQ, Canada
[7] McGill Univ, Fac Med, Montreal, PQ, Canada