HIGH PREVALENCE OF TRANSFERABLE INTEGRON-ASSOCIATED DRUG RESISTANCE IN Escherichia coli STRAINS ISOLATED FROM BLOOD CULTURES IN A UNIVERSITY HOSPITAL IN TRABZON, TURKEY

Objective: This study aimed to determine the carriage of transferable integron-associated drug resistance in Escherichia coli (E. coli) strains isolated from blood cultures. Materials and Methods: A total of 111 E. coli isolates were included in this study. Antimicrobial susceptibility testing of the isolates against 17 antibiotics was performed using an automated microbiology system. Integron-specific polymerase chain reactions (PCR) were used to detect the presence of integrons. The antibiotic resistance gene cassettes in the variable regions of integrons were analyzed by DNA sequencing. Plasmid transfer assays were performed using the broth mating method. The clonal relationships among integron-carrying strains were evaluated by pulsed-field gel electrophoresis (PFGE). Results: Resistance rates to antibiotics ranged from 0.9% to 63%. Thirty-eight strains carried gene cassettes encoding dfrA7, dfr17-aadA5, dfrV, dfrA1-aadA1, and dfrA12-aadA2. Seven strains possessed class 2 integrons with gene arrays dfrA1-sat2-aadA1 and dfrA1-sat2-aadA30. Twenty-two integron-carrying isolates harbored conjugative resistance plasmids, three of which were identified as belonging to the IncN group. Two strains with class 1 integrons, isolated from different clinics, exhibited similar patterns in the PFGE analysis. Conclusion: Approximately 50% of E. coli isolates from blood cultures at our hospital were found to carry integron-associated transferable drug resistance, suggesting their potential role in the horizontal dissemination of resistance genes. Further research is needed to understand the prevalence of E. coli strains of blood origin and the role of integrons and gene cassette arrays in the spread of resistance.