Prevalence, Antimicrobial Resistance Patterns, and Emerging Carbapenemase-Producing Enterococcus Species from Different Sources in Lagos, Nigeria.

Background

Enterococcus species present significant health risks due to their widespread presence in humans, animals, and the environment. This study examined the patterns of antimicrobial resistance (AMR) and the presence of carbapenemase-producing Enterococcus species from various sources.

Methods

Between November 2023 and February 2024, 500 samples were collected in Lagos State, including 350 clinical human samples, 50 environmental samples, and 100 animal samples. The samples were processed, and Enterococcus isolates were identified and subjected to antimicrobial susceptibility tests (AST) by standard methods. Furthermore, carbapenemase (blaKPC and oxa-48) and virulence genes (gelE) were detected by real-time polymerase chain reaction (RT-PCR) methods using specific primers.

Results

The overall prevalence of Enterococcus isolates was 4.6% (23/500), including 18 E. faecalis and 5 E. faecium. The source prevalence was 24% (12/50) from the environmental samples, 5% (5/100) from animal sources, and 1.7% (6/350) from the clinical samples. All Enterococcus isolates were 100% resistant to ciprofloxacin, erythromycin, imipenem, vancomycin, and ampicillin. However, 91% were susceptible to gentamicin. Six (6) distinct resistance profiles were observed, with the pattern AMP-ERY-TGC-CIP-TS-VA-CHL-AUG-MEM-IMI being the most frequent in 12 E. faecalis (4 isolates from humans, 2 from animals, and 6 from the environment). Notably, 39.1% (9/23) of multiple-drug resistant Enterococcus isolates harbored the gelE virulence gene, including seven E. faecalis (five environmental and two human) and two E. faecium from animal sources. The E. faecalis strains HB003 and HB050, from human bacteremia cases carrying gelE, were the first in Nigeria to produce blaKPC and oxa-48 carbapenemase genes.

Conclusions

This study revealed the emergence of carbapenemase-producing Enterococcus species in our environment. A one-health approach and further molecular studies are essential to mitigate the spread and understand the transmission dynamics.