Antimicrobial Resistance Profile of Enterococcal Isolates From Clinical Specimens at a Tertiary Care Hospital in Western Maharashtra, India

Background <i>Enterococcus</i>, once benign intestinal flora, has transformed into formidable nosocomial pathogens as a result of the accelerated emergence of antibiotic resistance represents a major global health challenge, particularly within hospital settings. <i>Enterococcus</i> has grown more prevalent in nosocomial infections, such as urinary tract infections (UTIs), surgical site infections (SSIs) and bacteremia. The potential emergence of vancomycin-resistant <i>Enterococcus </i>(VRE) strains further complicates treatment choices for multi-drug resistant (MDR) infections. This study evaluated the magnitude of <i>Enterococcus</i> infections and their antibiotic resistance patterns in a tertiary care hospital. Material and methods A laboratory-based cross-sectional study was conducted from January 2023 to December 2023 (one year) at Krishna Hospital & Medical Research Centre, Karad, India. A total of 189 enterococcalisolates were identified from various clinical specimens, including urine, blood, pus, and other samples. These isolates were subjected to identification and antimicrobial susceptibility testing using the automated VITEK 2 (bioMérieux SA, Marcy-l'Étoile, France) system. VanA and VanB phenotypes were detected based on minimum inhibitory concentration (MIC) values using the VITEK 2 Advanced Expert System (AES) system (bioMérieux SA). Statistical analysis was done using Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 21.0, Armonk, NY). Results Among 189 culture-positive enterococcal isolates, the majority were obtained from urine 144 (76%), followed by blood 17 (9%), pus 12 (6%), etc. A larger proportion of these isolates were from female patients 97 (51%) aged over 60 years. A substantial proportion of these isolates originated from in-patient departments (IPD) 178 (94.2%) with intensive care units contributing the highest number 114 (60%) and out-patient departments (OPD) 11 (5.8%). The highest prevalence of infection was observed among patients with a hospital stay of 8 to 14 days (32.3%). <i>E. faecium</i> (57.7%) and <i>E. faecalis</i> (39.6%) were the predominant species with <i>E. faecium</i> displaying significant resistance to benzylpenicillin (96%) and nitrofurantoin (94%) whereas <i>E. faecalis</i> showed higher resistance to high-level gentamicin (80%). <i>E. gallinarum</i> (1.6%)showed complete resistance to benzylpenicillin (100%) and moderate resistance to nitrofurantoin (67%), and high-level gentamicin (67%). Conversely, <i>E. durans</i> showed complete resistance (100%) to both nitrofurantoin and benzylpenicillin. Among 31 VRE isolates, 16 (52%) showed the VanA and 15 (48%) showed the VanB phenotype. Conclusion Antimicrobial resistance among <i>E. faecium</i> and <i>E. faecalis</i>, particularly to benzylpenicillin, high-level gentamicin and nitrofurantoin along with the emergence of resistant species like <i>E. durans</i> and <i>E. gallinarum</i> underscores the urgent need for vigilant antimicrobial stewardship and continuous surveillance of the growing threat of MDR enterococci in clinical settings.