[1] Univ Modena & Reggio Emilia, Azienda Policlin, Clin Infect & Trop Dis, I-41100 Modena, Italy
[2] Univ Barcelona, Hosp Clin, IDIBAPS, Barcelona, Spain
[3] Royal Free Hosp, Ian Charleson Ctr, London NW3 2QG, England
[4] San Paolo Univ Hosp, Clin Infect Dis, Milan, Italy
[5] Univ Vita & Salute, Clin Infect Dis, Milan, Italy
[6] IRCCS, Natl Inst Infect Dis L Spallanzani, Rome, Italy
[7] So Alberta Clin, Calgary, AB, Canada
[8] St Anna Hosp, Dept Infect Dis, Ferrara, Italy
[9] Royal Free & Univ Coll Med Sch, Div Populat Hlth, Res Dept Infect & Populat Hlth, Royal Free Ctr HIV Med, London WC1E 6BT, England