THE FREQUENCY OF ANTIBIOTIC RESISTANCE AND CTX-M GENE IN ESCHERICHIA COLI ISOLATED

One of the most prevalent bacterial infections is urinary tract infection (UTI); and Escherichia coli has been isolated from 75-90 percent of UTI cases. On the other hand، the rate of community acquired UTI caused by extended spectrum beta-lactamase producing E. coli، in particular blaCTX-M is increasing worldwide. Therefore، this study aimed to assess the pattern of antibiotic resistance، ESBL frequency، and blaCTX-M gene in E. coli isolated from UTI of out-patients. This study was carried out on the urinary samples of out-patients and 140 E. coli strains isolated. Then the susceptibility of isolates to 10 selected antibiotics was tested using disc diffusion method. Later، the ESBL producer strains were confirmed using combined discs method. Finally، the blaCTX-M gene was determined in ESBL producer isolates using PCR. Of 140 isolates، 81. 43 % and 62. 13% showed resistance to ampicillin and Co-trimoxazole، respectively، but 100% were sensitive to imipenem. Moreover، 34 (24. 28%) isolates were ESBL producers. PCR showed that 30 (88%) of ESBL producer isolates contained CTX-M gene. Resistance to various beta-lactam antibiotics in particular the third generation of cephalosporins is a serious concern. The production of ESBL، in particular in isolates of out-patients، is a big threat for use of the broad spectrum cephalosporins. Given the presence of CTX-M gene in the high proportion of the isolates، more molecular and epidemiological studies on pathogenic bacteria in this region is required.