[1] Univ Bologna, Policlin S Orsola Malpighi, Dept Clin & Expt Med, Microbiol Sect, I-40138 Bologna, Italy
[2] Univ Bologna, Dept Oncol, Sect Anat Pathol, I-40138 Bologna, Italy
[3] Univ Bologna, Dept Prevent Pediat & Neonatol, I-40138 Bologna, Italy
[4] Univ Bologna, Dept Obstet & Gynecol, I-40138 Bologna, Italy