Antimicrobial Susceptibility Testing for Enterococci from Clinical Isolates in Phichit Hospital
Suchada Wongphachan¹, Tanate Suttisaewan², Somporn Srifuengfung³
Affiliation : ¹ Microbiology Laboratory, Phichit Hospital, Phichit, Thailand; ² CGH Saimai Hospital, Bangkok, Thailand; ³ Faculty of Pharmacy, Siam University, Bangkok, Thailand
Objective: To determine antimicrobial susceptibility testing of enterococci in Phichit Hospital.
Materials and Methods: A retrospective study was carried out to determine the species distribution and antimicrobial susceptibilities of enterococci isolated from clinical samples between January 2020 and April 2023. The antimicrobial susceptibility testing of the 969 clinical isolates enterococci collected was performed by disk diffusion and VITEK 2 automated system. Eleven antimicrobial agents including ampicillin (AMP), penicillin (PEN), erythromycin (ERY), gentamicin (GEN), levofloxacin (LEV), linezolid (LIN), streptomycin (STR), teicoplanin (TCO), tigecycline (TGC), tetracycline (TET), and vancomycin (VAN) were tested.
Results: In the 969 isolates of enterococci collected, 170 out of 969 (17.5%) were vancomycin-resistant enterococci (VRE). Of the 170 isolates, 161 (94.7%) were Enterococcus faecium, eight (4.7%) were Enterococcus faecalis, and one (0.6%) was Enterococcus species. One hundred seventy patients positive for VRE were female (63.53%) and the age ranged from 3 years to 99 years. VRE isolates mainly came from patients aged older than 50 years, as was the case in 81.76% of the patients. The median age of patients was 71 years with an interquartile range of 49 to 79 years. VRE was isolated from urine in 83.53%, pus in 7.06%, and blood in 5.88%. VRE demonstrated susceptibility to LIN in 98.80% and TGC in 98.82%, but less susceptibility to STR in 71.18%, GEN in 68.24%, TET in 53.53%, TCO in 22.35%, AMP in 4.12%, PEN in 3.33%, LEV in 3.23%, and ERY in 1.18%. For non-VRE, which was 799 isolates, they demonstrated more susceptibility than VRE to most drugs tested such as LIN, TGC, and VAN in 100%, followed by TCO in 99.48%, ERY in 7.99%, AMP in 56.57%, STR in 44.97%, GEN in 43.05%, LEV in 26.19%, PEN in 24.76%, and TET in 15.95%.
Conclusion: These results suggested the importance of monitoring the isolation of VRE and non-VRE at a hospital. The antibiogram of susceptibility testing can help clinicians on empirical treatment.
Received 28 January 2024 | Revised 21 May 2025 | Accepted 26 May 2025
DOI: 10.35755/jmedassocthai.2025.6.477-482-02696
Keywords : Vancomycin-resistant enterococci; VRE; Non-VRE; Drug resistance
