Antibiotic Resistant Patterns of Enterococcus Species Isolated from Clinical Samples in a Nigerian Private Tertiary Medical Centre

Abstract

Enterococci cause serious nosocomial infections which are characteristically associated with high mortality rates and treatment challenges because the bacteria are not only innately resistant to some antibiotics but also possess the ability to develop acquired resistance to virtually all clinically beneficial antimicrobial agents. This study was carried out to determine the antibiotics resistant patterns among isolates of Enterococci from clinical samples so as to provide knowledge that will inform the appropriate antimicrobial choice for its infections in this setting. It was a descriptive, cross-sectional retrospective study conducted over a period of 18 months (February 2024 – August 2025) at the medical microbiology laboratory of Nisa Premiers Hospital. Laboratory records of all Enterococci isolated from various clinical specimens submitted for culture as well as their susceptibility rates to variously tested antibiotics were extracted, reviewed and analyzed., Specimen culture and antimicrobial sensitivity testing of isolates were performed following standard microbiological methods. Forty-one (41) isolates of Enterococci were recovered from the various clinical samples processed. Thirty-five (85.4%) of all the isolates were Enterococcus faecalis, while 6 (14.6%) were Enterococcus faecium. Enterococci were most frequently isolated from urine 36 (87.8%). The prevalence rate of vancomycin-resistant Enterococcus(VRE) was 27.5%. Enterococcus was highly resistant to ciprofloxacin (85.7%) and doxycycline (57.9%), relatively highly resistant to linezolid (25%), but displayed the least resistance to nitrofurantoin (18.7%). In conclusion, the most frequent enterococcal infection was UTI, and Enterococcus faecalis was the most frequent species causing infections in this study. There were relatively high prevalence rates of both VRE and Linezolid-resistant Enterococcus. There is, therefore, a need for strengthening of antimicrobial stewardship program, implementation of infection control measures and routine surveillance in order to reduce the emergence of resistant strain and control its spread.