First Detection of efrAB, an ABC Multidrug Efflux pump in Enterococcus faecalis in Tehran, Iran.

Background: One of the most significant of such bacteria is Enterococcus faecalis which are common contributor agent to both nosocomial and community acquired infections in patients. Reduced susceptibility to antibiotics was due to mechanisms such as efflux pumps. Methods: This study was conducted on 80 isolates of E.faecalis isolated from out-patients with Urinary tract infection (UTI) infection during a period of 1 year from April 2014 to April 2015. The antibiotic susceptibility patterns ofisolates were determined by the disk diffusion method and then presence of efr A and efrB genes was detected by PCR and Sequencing. Minimum inhibitory concentrations (MICs) to ciprofloxacin were measured with and without carbonyl cyanide 3-chlorophenylhydrazone (CCCP) by broth microdilution. Results: The highest resistance rate was observed to erythromycin (83.3%) and the prevalence of efrA and efrBgenes in all of isolates of E.faecalis were 100%. This study showed that 9 out of 13 (69.2%) ciprofloxacin resistant isolates became less resistant at least four-folds to ciprofloxacin in the presence of efflux pump inhibitor. Conclusion: In Our result showed that CCCP as an efflux inhibitor can decrease effect of ciprofloxacin as an efficient antibiotic and it is suggested that efrAB efflux pumps are involve in resistance to fluoroquinolone.

Keywords:

Enterococcus faecalis , efrAB efflux pumps , antibiotic resistance , CCCP