[1] Univ Geneva Hosp, Orthopaed Surg Serv, Med Econ Control, Geneva, Switzerland
[2] Univ Geneva Hosp, Serv Infect Dis, Med Econ Control, Geneva, Switzerland
[3] Univ Geneva Hosp, Infect Control Program, Med Econ Control, Geneva, Switzerland
[4] Univ Geneva Hosp, Serv Anesthesiol, Med Econ Control, Geneva, Switzerland
[5] Univ Oxford, Med Sci Div, Oxford, England
[6] WHO Collaborat Ctr Patient Safety, Geneva, Switzerland