1. Laboratory of Epidemiology and Veterinary Microbiology, Institut Pasteur of Tunis; University of Tunis El Manar; PB 74, 1002 Tunis Tunisia
2. Department of Clinical and Biological Sciences; University of Torino; Orbassano 10043 Torino Italy
3. Department of Pharmacy; University “G. d'Annunzio” of Chieti-Pescara; Via dei Vestini 31 66100 Chieti Italy