Prevalence of carbapenemase-encoding genes including New Delhi metallo-β-lactamase in Acinetobacter species, Algeria.

BACKGROUND

Nosocomial infections caused by carbapenem-resistant Acinetobacter spp are a global health problem. The aim of this study was to investigate the molecular epidemiology and the genetic support of carbapenem resistance in Acinetobacter spp clinical isolates recovered from three different hospitals in western Algeria from 2008 to 2012.

METHODS

A total of 113 Acinetobacter spp isolates were identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Antimicrobial susceptibility testing was carried out, and minimum inhibitory concentrations (MICs) were determined by the dilution method on Mueller-Hinton agar for β-lactams, aminoglycosides, fluoroquinolones, and colistin. The characterization of β-lactamases was investigated by phenotypic tests for the detection of metallo-β-lactamases and oxacillinases. Resistance genes were screened for by quantitative PCR and sequenced when positive.

RESULTS

Among the 113 isolates, 80 (70.8%) were found to be resistant to imipenem with MICs ranging from 64 to 512μg/ml. The blaOXA-23-like gene was detected in 50% (40/80) of the isolates and the blaOXA-24-like gene was detected in 21.2% (17/80) of the isolates. In addition, the metallo-β-lactamase blaNDM-1-like was detected in five isolates (6.2%).

CONCLUSIONS

This study represents the first description of autochthonous Acinetobacter spp producing metallo-β-lactamase blaNDM-1-like and oxacillinases blaOXA-23-like and blaOXA-24-like in western Algeria.