1. University of Sassari, Sassari, Italy
2. University Medical Center Goettingen, Goettingen, Germany
3. Clinical-Chemical Analysis and Microbiology Laboratory, “San Francesco” Hospital, Nuoro, Italy
4. University of Trieste, Department of Medical, Surgical & Health Sciences, Triste, Italy
5. Occupational Medicine Unit, University Health Agency Giuliano Isontina (ASUGI), Trieste, Italy