Emergence of SHV-12 extended spectrum beta-lactamase among clinical isolates of Enterobacter cloacae in Tunisia.

A collection of seven multidrug-resistant clinical isolates of Enterobacter cloacae with reduced susceptibility to ceftazidime and cefepime recovered from 2009 to 2010 at the University Hospital of Mahdia, Tunisia, was analysed. PCR analysis and sequencing demonstrated that all study isolates harbored SHV-12 β-lactamase that was transferred by conjugation. Characterization of the regions surrounding the bla(SHV-12) showed that this gene was flanked by two IS26 elements. pulsed-field gel electrophoresis (PFGE) revealed differents profiles indicating that the study isolates were not clonally related. Diffusion of E. cloacae producing SHV-12 ESBL in our hospital is the consequence of disseminations of plasmids harboring the SHV-12 gene.