the prevalence of tem and shv genes among extended-spectrum beta-lactamases producing escherichia coli and klebsiella pneumoniae

objective(s) production of extended-spectrum beta-lactamases (esbls) by enteric bacteria continues to be a major problem in hospitals and community. esbls producing bacteria cause many serious infections including urinary tract infections, peritonitis, cholangitis and intra-abdominal abscess. the aim of this study was to determine the prevalence of esbls producing escherichia coli and klebsiella pneumoniae                   bacteria isolated from clinical samples of patients attending imam reza and ghaem university hospitals, mashhad, northeast of iran. materials and methods during 2009 and 2010, 82 strains of e. coli and 78 strains of k. pneumoniae were isolated from out-patients and hospitalized patients and they were examined by oxoid combination disk test and pcr methods. results we found that 43.9% of e. coli and 56.1% of k. pneumoniae produced esbls. the frequency of shv and tem among the esbls producing isolates were 14.4% and 20.6%, respectively. ratios of esbls positive isolates from out-patients to hospitalized patients were 24/33. conclusion this study shows that the prevalence of esbls producing e. coli and k. pneumoniae is high in both study groups (out-patients and hospitalized patients). therefore it seems that continuous surveillance is essential to monitor the esbls producing microorganisms in hospitals and community.