Unravelling vancomycin resistance in newly emerging Enterococcus species

BACKGROUND: Enterococci, commonly found in the gastrointestinal, biliary, and genitourinary tracts, are increasingly implicated in a wide range of clinical infections worldwide. Although E. faecalis and E. faecium account for the majority of enterococcal infections, diseases caused by emerging Enterococcus spp. are being reported with increasing frequency and are often associated with higher levels of antimicrobial resistance. OBJECTIVE: This study aimed to investigate vancomycin resistance patterns among various Enterococcus spp. isolated from clinical specimens. MATERIALS AND METHODS: This cross-sectional study was conducted at a tertiary care hospital in Nagpur, India, and analyzed vancomycin resistance patterns among 224 Enterococcus isolates obtained from 17,231 clinical specimens collected over a two-year period. Species identification was performed using standard microbiological methods. Antimicrobial susceptibility testing was carried out in accordance with the Clinical and Laboratory Standards Institute (CLSI) 2024 guidelines, with particular emphasis on vancomycin resistance. RESULTS: E. faecium was the most frequently isolated species. UTIs were the most common clinical presentation, followed by bacteremia and wound infections. We observed high resistance rates for penicillin (81.2%) and ampicillin (64.7%), along with high-level gentamicin resistance (58.5%). Vancomycin resistance was detected in 14.3% of the isolates, with significantly higher resistance observed in E. faecium than in other species (p < 0.05). Linezolid resistance was identified in 5.8% of the isolates. Although less frequently isolated, non- E. faecium and non- E. faecalis strains demonstrated notable resistance to multiple antimicrobial agents. CONCLUSIONS: The emergence of vancomycin resistance across diverse Enterococcus spp. highlights the importance of routine species-level identification and comprehensive antimicrobial susceptibility testing. Judicious antibiotic use, coupled with stringent infection prevention and control measures, is essential to limit the dissemination of multidrug-resistant enterococci.