prevalence of extended-spectrum beta-lactamases (esbls) in pseudomonas aeruginosa isolated from hospitalized patients in imam reza and imam khomeini hospitals in kermanshah, 2013

abstract background: pseudomonas aeruginosa is one of the most common gram negative bacteria involved in nosocomial infections. presence of extended-spectrum beta-lactamases (esbls) genes, play an important role in induction of resistance in beta-lactamase producing species to beta lactam antibiotics. frequency of resistance to these antibiotics is increasing. in this study, antibiotic sensitivity and frequency of esbls in pseudomonas aeruginosa which had been isolated from clinical specimens, was assessed by phenotypic methods. methods: this study was performed on 200 isolated pseudomonas aeruginosa from clinical specimens in imam khomeini and imam reza hospitals, kermanshah during 2013. specimens were determined and cultured by standard conventional methods. antibiotic sensitivity test on 14 antibacterial agents was performed according to clsi criteria. then, frequency of esbls producing isolates was determined by combined disk test (cdt) and double disk synergy test (ddst) methods. results: this study revealed that the highest and lowest resistance rate were against to cefpodoxime (100%) and piperacilin-tazobactam (34%), respectively. using cdt and ddst methods, 41% of isolates were esbl positive. conclusion: considering high resistance rate of pseudomonas aeruginosa to majority of antibiotics and increasing frequency of esbls producing isolates, we need for infection control criteria and use of appropriate therapeutic protocols according to antibiogram test patterns.