Multidrug-resistant Acinetobacter baumannii strains carrying the bla(OxA-23) and the bla(GES-11) genes in a neonatology center in Tunisia.

Multidrug-resistant and difficult-to-treat Acinetobacter baumannii may be responsible for nosocomial infections. The production of carbapenem-hydrolyzing class D β-lactamases (CHDLs) and extended-spectrum β-lactamase (ESBLs) of the GES type possessing a carbapenemase activity has been increasingly reported worldwide in A. baumannii. The aim of this study was to analyze the resistance mechanisms of two carbapenem resistant A. baumannii clinical isolates recovered in a neonatology center in the center-east of Tunisia. Two carbapenem resistant A. baumannii isolates were recovered. The first isolate co-harbored the blaGES-11 ESBL gene and the blaOxA-23 CHDL gene. Analyses of the genetic location indicated that the blaGES-11 gene was plasmid located (Gr6). However, the blaOxA-23 gene was located on the chromosome. The second strain had only the blaOxA-23 CHDL gene, which was plasmid located. This study showed the first description of the GES-type β-lactamase in A. baumannii in Tunisia.