Detection of fluoroquinolone genes and spread of antibiotic resistance profile of Enterococcus strains isolated from clinical specimens

Abstract Enterococci are a significant source of hospital-acquired infection with Enterococcus faecalis and Enterococcus faecium being the third and fourth most common nosocomial pathogens in the world. Enterococci infections have become important to healthcare practitioners due to their high rate of antibiotic resistance. We aimed to determine the fluoroquinolone genes and spread of the antibiotic resistance profile of Enterococcus strains isolated from clinical specimens. This study was performed on 101 clinical samples of enterococci species isolated from patients in different hospital wards (Rasol Akram hospital in Tehran, from Jun 2018 to Apr 2019). Antibiotic susceptibility tests using the disc diffusion method and biofilm formation assay were performed on isolated species. To detect the presence of resistant genes, polymerase chain reaction (PCR) assay was performed for the detection of Gyr a, Gyr b, Par E, and Par C. In the isolation of 76.2% E. faecalis (77 samples) and 23.8% (24 samples) E. faecium from the clinical samples. Also, antibiotic susceptibility tests demonstrated that the Enterococcus species had the least and the most sensitivity to nalidixic acid/gentamicin and vancomycin, respectively. However, no correlation was found between biofilm formation ability and the region of isolated samples (P-value = 0.3). The prevalence of parE, gyrB, and parC genes were 100%, 40.6%, and 15.8%, respectively among ciprofloxacin resistant enterococci species. These results show a higher occurrence of parE, and gyrB than ciprofloxacin resistance genes in Enterococcus species. This study also revealed an alarmingly high frequency of multidrug-resistant enterococci in clinical samples and the ability of biofilm formation in enterococci which can increase bacterial pathogenicity in patients.