Detection of GES-2, a Class A β-Lactamase Produced by Pseudomonas aeruginosa in a Teaching Hospital in Iran

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Background: Guiana Extended-Spectrum (GES-2) as one of the Extended-spectrum β-lactamases (ESBLs), produced by Pseudomonas aeruginosa, is able to compromise the effectiveness of imipenem and tends to be geographically limited. Objectives: The aim of this study was to detect the spread of GES-2 β-lactamase gene among ESBL- producing P. aeruginosa isolates in a teaching hospital in Kashan, Iran. Materials and Methods: Detection of β-lactamase gene blaGES-2 in eight ESBL producing isolates of P. aeruginosa collected from 100 clinical and environmental specimens was performed by PCR method. The susceptibility of the isolates to eight antibacterial agents was determined by disk diffusion method. ESBL production of the isolates was detected by double disk synergy test. DNA sequencing and aligning with the reference sequence were performed using BLAST and CLUSTAL W for selected PCR products of the blaGES-2 gene. Results: A total of 100 environmental and clinical isolates of P. aeruginosa were collected. Eight of the isolates were found to be ESBL positive. The highest resistance rate was detected for piperacillin (75%), while the lowest resistance rate was for ciprofloxacin (12.5%). Fifty percent of the isolates (four out of eight) were imipenem-susceptible and MDR. The blaGES-2 gene was detected in all ESBL-producing isolates. Sequencing of both forward and reverse strands of the blaGES-2 gene were identified by BLASTn search as the ATP-binding cassette (ABC) transporter permease, partial cds, clone G-1 P. aeruginosa (Accession no. AB591379.1). Conclusions: According to the present data, this is the first report on the presence of blaGES-2 gene of ESBL-producing P. aeruginosa from teaching hospitals of Iran. Fifty percent of the blaGES-2 positive P. aeruginosa isolates were multi-drug resistance (MDR).