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 beta-lactams, aminoglycosides, fluoroquinolones, and colistin. The characterization of beta-lactamases was investigated by phenotypic tests for the detection of metallo-beta-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 512 mu g/ml. The bla(OXA 23) (like) gene was detected in 50% (40/80) of the isolates and the bla(OXA) (24) (like) gene was detected in 21.2% (17/80) of the isolates. In addition, the metallo-beta-lactamase bla(NDM-1) (like) was detected in five isolates (6.2%). Conclusions: This study represents the first description of autochthonous Acinetobacter spp producing metallo-beta lactamase bla(NDM-1) (like) and oxacillinases bla(OX) (23) (like) and bla(OXA 24) (like) in western Algeria. (C) 2013 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.