Investigation of antibiotic resistance genes in clinical insulations of Escherichia coli and Klebsiella pneumoniae

Resistance to β-lactams in Enterobacteriaceae has been increasing worldwide. This study has aimed to determine the frequency of antibiotic resistance genes and antibiotic resistance rates in 50 clinical E.coli and 47 clinical Klebsiella pneumoniae isolates. 24 different antibiotics were used for antibiotic susceptibility testing. Antibiotic resistance profiles of bacterial isolates (E.coli and Klebsiella pneumoniae, respectively), cefixime (80%-97.7%), piperacillin/tazobactam (20%-97.7%), ampicillin (100%-100%), ceftriaxone (98%-91.1%), cefuroxime (100%-97.7%), cefuroxime axetil (100%-97.7%), ciprofloxacin (76%-100%), fosfomycin (6%-35.7%), gentamicin (38%-26.6%), ertapenem (26%-22.2%) and ceftazidime (80%-95.5%). Trimethoprim/sulfamethoxazole resistance in Klebsiella pneumoniae was detected as 76.5%. Multi-drug resistance rates in E.coli and Klebsiella pneumoniae isolates were determined as 42% and 42.2%, respectively. Multiplex PCR was used to detect blaOXA-51, blaOXA-23, blaOXA-48 and blaOXA-24 like genes. blaCTX-M1, blaTEM, blaKPC, blaGES, blaSHV, blaVIM, blaPER-2, blaVEB, blaIMP, blaCMY-2, blaCTX-M2, blaMOX, blaFOX, blaDHA, blaMIR, blaMCR-1, qnrS, qnrA, qnrB, fosA, fosC2, fosA3, murA, uhpT, glpT genes, detected by PCR. In multiplex PCR, one E.coli strain was found to carry blaOXA-51, and 5 Klebsiella pneumoniae strains, to carry blaOXA-48. OXA-23 and OXA-24 type carbapenemases were not detected in any of the isolates. CTX-M1 type beta lactamases were detected in 14 isolates and TEM type beta lactamases, in 10 isolates. Other resistance genes were not detected in any isolate. These results indicate that CTX-M1 beta-lactamase is the most common type of class A beta-lactamase among extended-spectrum beta-lactamase producing E. coli and Klebsiella pneumoniae strains.