1. Department of Infectious Diseases, Regional Hospital, Varese,1
2. Department of Infectious Diseases, University of Brescia,2
3. Department of Infectious Diseases, Regional Hospital, Verbania-Pallanza,3
4. Department of Infectious Diseases, Regional Hospital, Ravenna,4
5. Department of Infectious Diseases, Regional Hospital, Lecco,5
6. Department of Infectious Diseases, Universtiy of Bari,6 and
7. Department of Infectious Diseases, University of Bologna,7 Italy