Genotypes of ESBL producing Escherichia coli and Klebsiella pneumoniae in relation to resistance to antimicrobial drugs.

The aim of the study was to evaluate the association of drug resistance with β�lactamase gene types in ESBL positive E. coli and Klebsiella pneumoniaeKp . Material and methods: A total of 251 ESBLpositive E. coli and Kp isolates obtained from urine, tracheal aspirate, wound swab and blood from patients hospitalised at the University Clinics in Skopje were detected using the ESBL set and automated Vitek 2 system. Vitek was also used for susceptibility testing (determination of MIC of 17 antimicrobial agents). Multiplex PCR was used to identify genes for different types of ESBLs in a 100 randomly selected, ESBL positive strains. Results: More of the 87 ESBL typeable isolates (61%) harbour two or more bla genes and the fre� quency of antibiotic resistance was high in these isolates, compared to those with a single gene. Iso� lates with ≥ 3 genes were highly resistant to betalactams and nonbeta lactams used. The degree of resistance to 3 rd generation cephalosporins was also high in these isolates (MIC ≥ 64). More of the ESBLpositive isolates showed higher resistance to cefotaxime than to ceftazidime. Conclusion: Identification of the genes is necessary for the surveillance of their transmission in hospitals. Surveillance of antibiotic resistance patterns are crucial to overcome the problems associated with ESBLs.