1 Respiratory Unit, ASST Santi Paolo e Carlo, San Paolo Hospital, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy.
2 Clinic of Infectious and Tropical Diseases, Department of Health Sciences, University of Milan, Milan, Italy.
3 Lombardia Region TB Reference Clinic, Villa Marelli Institute/Niguarda, Ca' Granda Hospital, Milan, Italy.
4 Human Pathology and Molecular Pathology Unit, San Paolo Hospital, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy.
5 Clinical Epidemiology and Medical Statistics Unit, Department of Medical, Surgical and Experimental Medicine, University of Sassari, Via Padre Manzella, 4, Sassari, Italy. Electronic address: gsotgiu@uniss.it.