prevalence of tem and shv genes in clinical isolates of klebsiella pneumonia from mashhad, north- east iran

background & objectives:extended-spectrum-b-lactamase (esbl)-producing strains of klebsiella pneumoniaare an important cause of many serious infections in hospitalized and nonhospitalized patients and delayed treatment of these infections in crease chance of death in patients. this study was performed to determine the prevalence of esbl-producing k. pneumonia and to evaluate the frequency of tem and shv genes among the clinical samples.methods:one hundred and thirty isolates of k. pneumoniawere collected at imam reza hospital in mashhad (iran) from may 2011 to july 2012. esbl production was determined by the double disk diffusion (dds) test. pcr method was used to detect tem and shv genes.results:of 130 patients withk. pneumoniainfection 28 were out-patients and 102 hospitalized patients. the most specimens was urine samples (n=25 in out-patients, n=39 in hospitalized patients, totally 49.2%) followed by wound samples (n=3 in out-patients, n=21 in hospitalized patients, totally 21.5%), blood samples (n=19 in hospitalized, 14.6%). the prevalence of esbl producingk. pnemoniaewas estimated 43% (n=56) including three of esbls positive isolates from out-patients and 53 from hospitalized patients. of 56 esbls positive isolates, 44(87.54%) tem, 39(69.64%) shv and in 27 cases (48.21%) both tem and shv were detected. conclusion:a high prevalence of esbl-producing k. pneumoniaamong the hospital isolates obtained of urinary followed by blood and wound samples were documented. the majority of them carried both tem and shv genes. results of this study alarm for the physicians because treatment and control nosocomial infections for them were difficult.