1. Department of Clinical and Experimental Medicine, Unit of Infectious Diseases, University of Messina, I-98124 Messina, Italy
2. Department of Biomedical and Biotechnological Sciences, Unit of Infectious Diseases, University of Catania, I-95122 Catania, Italy
3. Department of Clinical and Experimental Medicine, Unit of Infectious Diseases, University of Catania, I-95122 Catania, Italy