1. Department of Medical Sciences, Infectious Diseases, University of Turin, 10124 Turin, Italy
2. School of Medicine, Tufts University School of Medicine, Boston, MA 02111, USA
3. Department of Anesthesia, Intensive Care and Emergency—‘Città della Salute e della Scienza’ Hospital, 10126 Turin, Italy
4. Infectious Diseases Unit, Cardinal Massaia Hospital, 14100 Asti, Italy
5. Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, 10126 Turin, Italy