Detection of Virulence Factors and Antimicrobial Susceptibility among Clinical Strains of Enterococcus faecalis

Enterococci are common commensals in the gastrointestinal tract and are opportunistic organisms that can cause urinary tract infections, bacteremia, endocarditis, and pelvic infections. The study aimed to investigate antibiotic resistance, biofilm formation, and the presence and expression of virulence factors in clinical isolates of E. faecalis from Jordan.

Clinical isolates (n=89) of E. faecalis isolated from patients in Jordan were collected. Antibiotic resistance, biofilm formation, and the presence/expression of virulence genes asa1, gelE, esp, cylA, and efaA were examined.

High resistance of E. faecalis was detected for ampicillin (98.9%), followed by quinupristin-dalfopristin (96.6%), tetracycline (83.1%), erythromycin (78.6%), and rifampin (68.5%). Most isolates (93.3%) were found to be biofilm producers. The prevalence of virulence genes was efaA (77.5%), asa1 (77.5%), gelE (69.7%), esp (50.6%), and cylA (30%). About 25.8% of the isolates were found to be gelatinase producers. In addition, hemolysin production was observed in 37.1% of the isolates.

The esp gene was associated with tetracycline resistance. The asa1 gene was associated with susceptibility to vancomycin. CylA was associated with resistance to tetracycline and erythromycin, as well as susceptibility to ciprofloxacin and gentamicin. The presence of gelE was associated with susceptibility to chloramphenicol, tetracycline, levofloxacin, and erythromycin. The cylA gene was associated with esp and asa1 genes, while the efaA was found to be associated with gelE and asa1 genes (P<0.05). Finally, biofilm formation was not associated with antimicrobial resistance (P > 0.05).

The antibiotic resistance profiles and associated genes of E. faecalis isolates from Jordanian patients were reported. The efaA, asa1, and gelE virulence genes were highly prevalent among the isolates. The present findings can be used in the management of E. faecalis infection in Jordan.