Background and objective : As very little is known about extended spectrum beta lactamases (ESBLs) prevalence and genotypes in our locality , a study for the detection and characterization of ESBL production in clinical isolates of Enterobacteriaceae with reduced susceptibilities to oxyimino-cephalosporins from routine diagnostic samples was necessary . Materials and Methods: One hundred and twenty four samples were collected in the period from March to May 2007 from clinical samples(urine ,nasopharyngeal aspirate , sputum , stool , blood culture ,surgical and pyogenic infections ) referred to the laboratory in Benha University hospital . From them, 71 Enterobacteriaceae were isolated and subjected to (i) combined disc diffusion (CDD) as a phenotypic method to detect ESBL-producing strains (ii) samples showing ESBL phenotype by CDD ,underwent molecular analysis for detection of the most prevalent p-lactamase genes (blarEnt hiasuv) by multiplex real time polymerase chain reaction (PCR) using specific primers , to detect if isolates were TEM , SHV , TEM and SHV or non TEM non SHV producers Results:26 isolates out of 71 (36.6%)gave ESBL phenotype by CDD. (11/26,42.3% ) of isolates expressed TEM only ,(4/26,15.4% )SHV only ,(9/26,34.6%) TEM and SHV and (2/26,7.7%) were non TEM or SHV producers. Conclusion: ESBL producing Enterobacteriaceae resemble a great threat to the use of clinically important expanded spectrum cephalosporins , and a big challenge for accurate diagnosis and treatment . TEM genotype is the most common in Enterobacteriaceae in our hospital and multiplex PCR appears to provide efficient differentiation of ESBLs among bacterial isolates. |
