Detection of Pseudomonas aeruginosa harboring blaCTX-M , blaOXA and blaSHV causing infections in Najaf city hospitals

Abstract

Nosocomial infections caused by P. aeruginosa presenting resistance to β-lactam drugs are one of the most challenging targets for antimicrobial therapy. P. aeruginosa harboring acquired mechanisms of resistance, such as production of extended-spectrum β-lactamases (ESBLs) have the highest clinical impact. Hence, this report was designed to investigate the presence of genes codifying for ESBLs among P. aeruginosa isolated from three hospitals in Najaf city. Thirty-six P. aeruginosa isolates were evaluated for the presence of ESBL genes. The isolates presenting ESBL genes were submitted to PCR for molecular evaluation. In all isolates, primary phenotypic test revealed that ESBL phenotype was recognized in isolates (100%) which were expressed resistance to any of the expanded-spectrum cephalosporins and monobactam. Genes encoding ESBLs were detected in 30(83.3%) of isolates. The bla_CTX-M was the most prevalent ESBL gene 20(55.6%), followed by bla_OXA 18(50.0%) and bla_SHV 15(41.7%). These findings raise the concern about the future of antimicrobial therapy, since simultaneous production of ESBLs is known to promote further complexity in phenotypic detection.