Antimicrobial resistance and virulence factors in clinical isolates of enterococci

Introduction: Enterococci are significant as healthcare-associated pathogens. Resistance to multiple antibiotics is characteristic of enterococci in healthcare settings. The study aimed to discern the species of clinical enterococci isolates and investigate their levels of antimicrobial resistance and virulence. Materials and methods: Standard methods were employed to isolate and identify enterococci to the species level. Kirby–Bauer disk diffusion was used to conduct antimicrobial susceptibility testing, whilst agar dilution method was employed to ascertain the minimum inhibitory concentration (MIC). Haemolysis on blood agar, and biofilm formation was detected using the microtitre plate method, and gelatinase production was assessed by the gelatine tube method. Results: Out of the 295 enterococci tested, Enterococcus faecalis was the most prevalent, accounting for 162 cases (54.9%), whilst Enterococcus faecium followed closely with 113 cases (38.3%). Among the clinical conditions, the predominant were urinary tract infection 115 (39.0%), wound infection 78 (26.4%), and sepsis 73 (24.8%). One hundred and seventy-seven (60%) isolates produced gelatinase and 2 (0.68%) were β-haemolytic, and 71.2% were biofilm formers. Of 295 enterococci assessed, 28 exhibited resistance to vancomycin (9.5%) and 153 (51.9%) displayed resistance to high-level gentamicin. Furthermore, gelatinase was linked to urinary tract infection. Conclusion: Urinary tract infection, wound infection, and sepsis were predominant clinical conditions attributed to enterococci. E. faecalis and E. faecium were the most frequently encountered species. Among the 295 enterococci studied, 51.9% exhibited resistance to high-level gentamicin, whilst 9.5% were resistant to vancomycin. A substantial 71.2% of the enterococci formed biofilm, and 60% produced gelatinase. Notably, gelatinase production was found to be associated with urinary tract infection.