1. Section of Microbiology, DMCSS, University of Bologna, Bologna, Italy 2Institut für Mikrobiologie und Hygiene, Charitè Universitätsmedizin, Berlin, Germany 3Department of Oral Sciences, University of Bologna, Bologna, Italy 4Department of Surgical Sciences, Anaesthesiology and Transplants, University of Bologna, Bologna, Italy 5Centro Regionale di Riferimento per le Emergenze Microbiologiche, Bologna, Italy