[1] Hosp SS Pietro & Paolo, Div Pediat, Borgosesia, Italy
[2] Hosp Cardarelli, Div Pediat, Campobasso, Italy
[3] Univ Piemonte Orientale, Dept Med Sci, Novara, Italy
[4] Bolzano Cent Hosp, Div Infect Dis, Bolzano, Italy
[5] Univ Udine, Clin Infect Dis, I-33100 Udine, Italy