1. Department of Infectious Diseases, Galliera Hospital, 16128 Genoa, Italy
2. Operating Unit Hospital Hygiene, Galliera Hospital, 16128 Genoa, Italy
3. Department of Health Sciences, University of Genoa, 16132 Genoa, Italy
4. Hospital Infection Control Committee, Galliera Hospital, 16128 Genoa, Italy
5. Anaesthesia and Intensive Care Unit, E.O. Ospedali Galliera, 16128 Genoa, Italy
6. Medical Service Management, Galliera Hospital, 16128 Genoa, Italy