Drug resistance and genotype of ESBLs - producing Escherichia coil from clinical isolates

Objective To investigate the prevalence and drug resistance characteristics of extended spectrum β-lactamases (ESBLs) producing Escberichia coli isolated from clinical specimens for the basis of treating infections. Methods Clinically iso-lated 77 strains of the Escherichia coil were collected. The method of Kirby-Bauer agar diffusion with the standard of NCCLS was used for antibiotic susceptibility to 14 kinds of antibiotics. The isolates harboring ESBLs were examined by double disk syner-gy test (DDST), ESBLs genotypes were determined by polymerase chain reaction (PCR) initially. Results The resistant rates of 77 Escberichia coli strains were high to ampicillin, piperacillin, nalidixic acid, ciprofloxacin, levofloxacin and gentamicin, but lowto amikacin, eefepime. 28 isolates (36.36%) from 77 E. coil strains were obtained. The resistant rates of ESBLs producing Esch-erichia coil were significantly higher than those of non-producing ESBLs to cefuroxime and cefotaxime, Ceftriaxone. The total i-solates were susceptible to ceftazidime, but resistant to ampicillin,nalidixic acid. the strains of drug resistance weren't found to Imipenem, which showed the highest sensitivity. Genotypes of ESBLs producing E. coil were TEM type ESBLs (39.29%) SHV (21.43%) both TEM and SHV (7.14%) neither TEM nor SHV (32.14%) respectively. Conclusion The resistant status of ESBLs producing E. coil are severe. There is significance in the resistance rate between the ESBLs-producing and the non-ES-BLs-producing isolates. TEM-type ESBLs are the main genotypes in clinical ESBLs-producing E. coll. The high ratio of nei-ther TEM nor SHV-type isolates may be due to other ESBLs genotypes in these isolates. Carhapenems is the most effective anti-biotic for the treatment of infections caused by ESBLs producing strains. Key words: Extended spectrum β-lactamases;  Escherichia coil;  Drug resistance;  Genotype