First report of extensively-drug-resistant Proteus mirabilis isolate carrying plasmid-mediated bla in a Tunisian intensive care unit.

Emergence of the New Delhi metallo-β-lactamase (NDM-1), an Ambler class B metallo-β-lactamase able to hydrolyse all β-lactams except monobactams, constitutes a critical and increasingly important medical issue. The acquisition of bla is of particular concern for Proteus mirabilis, which is intrinsically resistant to tetracycline, tigecycline and colistin, as this will make clinical treatment extremely difficult. To the authors' knowledge, this is the first report of the bla gene in an extensively-drug-resistant P. mirabilis clinical isolate carrying plasmid-mediated resistance to carbapenems (bla), cephalosporins (bla), aminoglycosides (aph3 VIa and aph3 Ia) and fluoroquinolones (qnrA6).