Antibiotic Resistance of Enterococcus faecium and Enterococcus faecalis (2010-2023)

Objective: Surveillance studies are essential to determine whether antibiotic resistance has increased over the years and to update hospital antibiotic use policies and empirical treatment protocols. In this report, we compared the antibiotic resistance of Enterococcus faecium and Enterococcus faecalis collected at Hacettepe University Hospitals between 2010-2023 within the scope of the "SENTRY Antimicrobial Surveillance Program" according to years. Methods: Enterococci have been isolated from blood, respiratory tract, skin and soft tissue, urine, intra-abdominal, and other sterile body samples between 2010-2023; a single sample from each patient was included. Microorganisms were identified by MALDI-TOF-MS. Ampicillin, piperacillin-tazobactam, ciprofloxacin, levofloxacin, linezolid, tigecycline, teicoplanin, vancomycin susceptibilities were assessed by microdilution method according to EUCAST criteria, and high-level-aminoglycoside susceptibility was assessed by disk-diffusion. Results: Isolates have been isolated from blood (n=161), respiratory tract (n=6), skin and soft tissue (n=166), urine (n=60), intra-abdominal (n=80), and other sterile specimens (n=7). A total of 480 Enterococci were identified as E. faecium (n=241) and E. faecalis (n=239). In E. faecium, resistance to ampicillin, piperacillin-tazobactam, ciprofloxacin, levofloxacin, tigecycline, teicoplanin, and vancomycin were 90.8%, 93.6%, 76.1%, 80.4%, 1.2%, 20.3%, and 20.3%, respectively. Linezolid resistance was not detected in E. faecium. Ciprofloxacin, levofloxacin and tigecycline resistance rates of E. faecalis were 26.5%, 22.3%, and 0.4%, respectively. None of the E. faecalis were resistant to ampicillin, piperacillin-tazobactam, linezolid, teicoplanin and vancomycin. There was no significant change in the resistance rates of E. faecium, and E. faecalis isolates during the 13 years. Conclusion: Resistance to antibiotics was higher in E. faecium isolates than in E. faecalis. Resistance to vancomycin and teicoplanin was found in E. faecium but not in E. faecalis. Linezolid and tigecycline were effective antibiotics in both Enterococci species.