1. Department of Dermatology; IRCCS A.O.U. San Martino-IST, DISSAL; Largo Rosanna Benzi, 10 16132 Genoa Italy
2. Department of Health Sciences; University of Milano-Bicocca; 20900 Monza Italy
3. Laboratory of Clinical Microbiology; Ospedale di Circolo e Fondazione Macchi and University of Insubria; 21100 Varese Italy