1. Department of Veterinary Public Health; Section of Inspection of Food of Animal Origin; Faculty of Veterinary Medicine; University of Messina; Viale Annunziata-98168 Messina Italy
2. Regional Reference Centre for Pathogenic Enterobacteria; Istituto Zooprofilattico Sperimentale delle Regioni Lazio e Toscana; Via Appia Nuova 1411-00178 Rome Italy