1. University Department of Infectious and Tropical Diseases, University of Brescia and ASST Spedali Civili, Brescia, Italy
2. Clinic of Infectious Diseases, Vita-Salute San Raffaele University, Milan, Italy
3. Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
4. Infectious Diseases Unit, EO Ospedali Galliera, Genoa, Italy
5. Infectious Diseases Unit, ASL-1 Imperiese, Sanremo, Italy
6. Infectious Diseases Unit, Policlinico San Martino Hospital, Genoa, Italy