1. Clinical Department of Medical, Surgical and Health Sciences, Trieste University, Trieste, Italy
2. Infectious Diseases Unit, Trieste University Hospital (ASUGI), Trieste, Italy
3. Microbiology and Virology Unit, Great Metropolitan Hospital “Bianchi-Melacrino-Morelli”, Reggio Calabria, Italy
4. Department of Internal Medicine (Digestive Diseases), Yale School of Medicine, Yale University, New Haven, Connecticut, USA
5. Infectious Diseases Unit, ARNAS Civico-Di Cristina Hospital, Palermo, Italy