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 beta -lactamases (CHDLs) and extended-spectrum beta -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 bla GES-11 ESBL gene and the bla O xA-23 CHDL gene. Analyses of the genetic location indicated that the bla GES-11 gene was plasmid located (Gr6). However, the bla O xA-23 gene was located on the chromosome. The second strain had only the bla O xA-23 CHDL gene, which was plasmid located. This study showed the first description of the GES-type beta -lactamase in A. baumannii in Tunisia.