Characterisation and Antibiotic Susceptibility Pattern of Enterococci in a Tertiary Care Hospital of North East India

Introduction: Enterococci are important agents of nosocomial infection, ranking as the second most common organisms causing complicated urinary tract infections, bacteraemia, endocarditis, intra-abdominal and pelvic infections, wound and soft tissue infections, neonatal sepsis, and, rarely, meningitis. Infections by enterococci have traditionally been treated with cell wall active agents (e.g., penicillin or ampicillin) in combination with an aminoglycoside (streptomycin/gentamicin); however, emergence of High Level Aminoglycoside Resistance (HLAR), β lactam antibiotics resistance and vancomycin resistance by some strains has led to failure of synergistic effects of combination therapy. Aim: To characterise enterococci up to the species level and study their antibiotic susceptibility pattern. Materials and Methods: The present study was a cross-sectional study in which a total of 14114 clinical specimens, obtained during the period from September 2018 to August 2020 in this cross-sectional study, were tested to identify and speciate enterococcal isolates using standard microbiological methodology. Antibiotic susceptibility testing was done by Kirby Bauer disc diffusion method. Data was analysed using descriptive statistics (percentage and proportion). Results: During the study period of two years, 146 enterococci were recovered from 14114 different clinical samples, accounting for an infection rate of 1.03%. Among 146 enterococcal isolates, 116 (79.5%) were obtained from urine, 13 (8.9%) from blood, 10 (6.8%) from pus, 4 (2.7%) from wound swab and 3 (2.1%) from catheter tip. The predominant isolates were E. faecalis (82.2%) followed by E. faecium (15.8%), E.durans (1.3%) and E.gallinarum (0.7%). On studying the antibiotic susceptibility pattern, most of enterococcal isolates were predominantly resistant to ampicillin and ciprofloxacin (73.9% in both) and least resistant to linezolid (3.4%). Conclusion: Enterococcus faecalis and Enterococcus faecium were the predominant species in present study and majority of the isolates was sensitive to linezolid (96.6%). Therefore, it is necessary to implement infection control measures like antimicrobial stewardship especially restricting the use of antibiotics to minimum.