Molecular characterization of carbapenemases of clinical - complex isolates from a University Hospital in Tunisia.

The aim of this study was to identify the carbapenemases from clinical carbapenem-resistant complex (CRABC) isolates and to assess their potential dissemination by conjugation and natural transformation. CRABC ( = 101) were collected consecutively from inpatients of the University Hospital of Monastir, Tunisia, from 2013 to 2016. Antimicrobial susceptibility was determined by the disk diffusion method and E-test.

ISAba1 and Tn6168 acquisition by natural transformation leads to third-generation cephalosporins resistance in Acinetobacter baumannii.

Acinetobacter baumannii has intrinsic beta-lactamase genes, namely ampC and bla-like, which are only strongly expressed when the ISAba1 insertion sequence is upstream the 5' end of the genes. A second ampC gene has also been identified in some clinical A. baumannii strains.