Carbapenem and colistin resistance, integrons and plasmid replicon types in multi-drug resistant Klebsiella strains isolated in Turkey

Abstract

Background: Multidrug-resistant (MDR) Klebsiella is a globally important nosocomial pathogen. In the present study, 101 multidrug-resistant Klebsiella strains isolated from various clinical specimens obtained from two differ-ent Medical Faculties' hospitals were involved. We aimed to find out the prevalence of carbapenemase, mobile colistin resistance genes, and integrons in MDR Klebsiella strains. Methods: The antibiotic susceptibilities of strains were determined by Kirby Bauer disc-diffusion method and re-sistance to colistin was confirmed by detection of minimum inhibitory concentrations. The prevalence of carba-penemase genes (blaOXA-48, blaNDM, blaIMP, blaVIM, blaKPC), mobile colistin-resistance genes (mcr-1 and mcr-2), and integrons (class I, II and III) were examined in Klebsiella strains by polymerase chain reaction. Results: All strains were resistant to beta-lactam antibiotics, carbapenems, and quinolones. On the other hand, only nine (8.9%) strains were resistant to colistin. The most common carbapenemase genes were blaNDM (64.3%) and blaOXA-48 (53.5%). Besides, 28 (27.7%) strains were found to harbor both blaNDM and blaOXA-48. These 28 strains be-longed to the IncA/C (18.7%), IncL/M (7.7%), and IncFIIs (1.1%) plasmid replicon types. No strain was positive for blaIMP, mcr-1, and mcr-2. Class I and Class II integrons were shown to be harbored in 83.2% and 63.3% of strains, respectively. In total, 63 (63.6%) of strains harbored both classes I and II integrons. Class III integron was not detected. There was a statistically significant relationship between the presence of integrons and antibiotic re-sistance for cefotaxime (p = 0.024), ciprofloxacin (p < 0.001) trimethoprim/sulfamethoxazole (p < 0.001) and levo-floxacin (p = 0.002). To our knowledge, this study represents the first report of a human isolate for the co-presence of blaNDM, blaOXA-48 and both Class I and Class II integrons, from Turkey. Conclusions: Our findings also highlight the dissemination of integrons and carbapenemases and the importance of surveillance on emerging antibiotic resistance.