1. III Infectious Diseases Unit, Azienda Socio-Sanitaria Territoriale-Fatebenefratelli-Sacco, Milan, Italy
2. Luigi Sacco Department of Biomedical and Clinical Sciences, University of Milan, Italy
3. Department of Infectious Diseases, Azienda Socio-Sanitaria Territoriale Fatebenefratelli Sacco University Hospital, Milan, Italy
4. School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa