Phenotypic and genotypic characterization of clinical multidrug resistant Acinetobacter baumannii from Algerian intensive care units

Abstract

The aim of this study was to evaluate molecular epidemiology and mechanisms of β-lactams resistance in multidrug resistant Acinetobacter baumannii strains causing pneumoniae in two intensive care units (ICUs) of two Algerian University hospitals. Between January 2010 and May 2011, 23 strains were collected. Antibiotics susceptibility testing was performed by the disk diffusion method and agar dilution technique. blaOXA-23, blaOXA-24, blaOXA-58, blaOXA-51, blaTEM, blaSHV, blaCTX-M, and blaPER β-lactamase genes were searched by polymerase chain reaction and sequencing.Clonally, relationships between strains were performed by pulsed field gel electrophoresis (PFGE) after macro-restriction by Apal enzyme. Nineteen (19) strains were resistant to allβ-lactams, two were susceptible only to carbapenems. They also exhibited resistance to the majority of the other antibiotics tested, except to colistin. blaOXA-51 gene was found in all isolates, blaOXA-23 in 14, and blaTEM-1 in three. PFGE analysis showed different patterns in one ICU; however, a clonal diffusion was identified in the second ICU. These results underline the necessity of a surveillance program that would include monitoring of ICU-acquired infections, antibiotic usage and molecular typing of multidrug resistant A. baumannii isolates. Key words: Acinetobacter baumannii, multidrug resistance, β-lactamases, epidemiology.