Genomic evaluation of the CTX-M enzymes and investigated for the transferability of resistance by transformation experiment in extended-spectrum beta-lactamase-producing Escherichia coli strains.

Genomic evaluation of the CTX-M enzymes and investigated for thetransferability of resistance by transformation experiment inextended-spectrum beta-lactamase-producing Escherichia colistrains.Extended-spectrum beta-lactamase (ESBL)-producing strainsare not limited in hospital settings have spread throughout communitysettings. Thus detection of beta-lactamase enzyme types in ESBL positivebacteria is important for the choice of appropriate antimicrobial agents fortreatment.The aim of this study was to determine the ESBL production,genomic analysis of CTX-M and investigation of the transferability ofresistance in CTX-M-positive Escherichia coli strains which were isolatedfrom patients applied to Gazi University Medical Faculty Hospital.The rates of antibiotic resistance in 280 strains werecephalothin (89%), amoxicillin/clavulanic acid (79.7%), ciprofloxacin(71.1%), trimethoprim/sulfamethoxazole (67.3%), aztreonam (65.2%),ceftriaxone (62.2%), gentamicin (42%), cefepime (36.5%), ceftazidime(26.8%), and piperacillin/tazobactam (5%). All strains were sensitive toimipenem, resistant to ampicilin. Piperacillin/tazobactam was the mosteffective combination of beta-lactam/beta-lactamase inhibitory.Analysis of these isolates by PCR revealed that 205 of 280were positive for the CTX-M gene. CTX-M-15 (89.2%) was the mostprevalent genotype. This was followed by CTX-M-1, (6.8%) CTX-M-3(3.4%) and CTX-M-33 (0.4%).Plasmid isolation and transformation were performed forCTX-M-positive 205 strains. CTX-M gene has been shown by PCR in 169transformants. This findings demonstrate that resistance genes are carriedon plasmids.As a result, there is a high prevalence of CTX-M-type ESBLsin our country. ESBLs, especially in this group, have also resistanceagainst many other antibiotics beside beta-lactam antibiotics. Therefore,similar researches are needed in order to take measures for preventionand control and for select appropriate antimicrobial agent in treatment notonly for nosocomial infections but also for community-acquired infections.Key Words: Extended-spectrum beta-lactamase, CTX-M, Escherichia coli,plasmid.