Phenotypic Characterisation of Antibiotic-Resistant Enterococcus faecium in Bats from Lambaréné (Gabon)

Enterococci are gram-positive, non-spore-forming bacteria commonly found in the intestinal tracts of mammals, including humans. The emergence of antibiotic-resistant Enterococcus spp., such as vancomycinresistant Enterococcus (VRE), in wild mammals is a growing concern, as these animals can act as reservoirs and vectors for resistant bacteria, facilitating their spread in the environment and increasing the risk of infections in humans and other species. Research on the microbiome of bats, particularly concerning antibiotic resistance, has gained attention in recent years, although no studies on Enterococcus resistance have been conducted in Gabonese bats. The aim of this study was to assess the prevalence of antibioticresistant enterococci in bats from Lambaréné, Gabon. Bat faeces were collected and cultured to isolate Enterococcus spp. Colonies, which was identified using the Api 20 Strept galleries and antibiotic susceptibility testing. The antibiotics tested included amoxicillin, vancomycin, teicoplanin, tetracycline, and tobramycin. The study found that 54.3% of isolates were resistant to tobramycin, 33.7% to tetracycline, 25% to vancomycin, and 20.7% to teicoplanin. Multidrug resistance (MDR) was observed in 2.2% of the isolates, with two distinct resistance phenotypes: Van B (resistant only to vancomycin) and Van A (resistant to both vancomycin and teicoplanin), both of which are monitored by the WHO. This study is the first to report the presence of vancomycin-resistant Enterococcus faecium in bats from Gabon. While vancomycin-resistant Enterococci are more common in humans (38.5%) than in bats (15%), the findings highlight a significant concern for antibiotic resistance in wild mammals, particularly in urban environments like Lambaréné.