1 Department of Medical Biotechnologies, University of Siena, Siena, Italy.
2 Institute of Microbiology, Catholic University of the Sacred Heart, Agostino Gemelli Hospital, Rome, Italy.
3 Department of Medical Biotechnologies, University of Siena, Siena, Italy; Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Florence, Italy; Don Carlo Gnocchi Foundation, Florence, Italy. Electronic address: gianmaria.rossolini@unifi.it.