[1] Bambino Gesu Pediat Hosp, Neonatal Intens Care Unit, I-00165 Rome, Italy
[2] Bambino Gesu Pediat Hosp, Dept Lab, I-00165 Rome, Italy
[3] Le Scotte Univ Hosp, Neonatal Intens Care Unit, Siena, Italy
[4] Giannina Gaslini Pediat Hosp, Neonatal Intens Care Unit, Genoa, Italy
[5] Burlo Garofolo Res Inst, Neonatal Intens Care Unit, Trieste, Italy
[6] Di Venere Hosp, Neonatal Intens Care Unit, Bari, Italy
[7] Gen Hosp, Neonatal Intens Care Unit, Cosenza, Italy
[8] Bambino Gesu Pediat Hosp, Epidemiol Unit, I-00165 Rome, Italy