Prevalence and characterization of antibiotic resistance genes of Vibrio species from Asata River, Enugu, Southeast Nigeria

Infections caused by multidrug-resistant (MDR) Vibrio pathogenic species are associated with high cases of fatalities. This study evaluated the antibiotic resistance in Vibrio species from the Asata River in Enugu, Southeast Nigeria. River water samples (72) were collected over a year sampling duration and processed for Vibrio isolation using the sample enrichment procedure. Deoxyribonucleic acid (DNA) of the isolates were extracted by boiling method and identified by the polymerase chain reaction (PCR) assay using the Vibrio - genus universal primer and Vibrio species-specific genes: its , tlh , and vvh . Susceptibility to nine commonly prescribed antibiotics was examined by the Kirby-Bauer disk diffusion assay. Confirmed Vibrio isolates were further screened for the possible presence of seven antibiotic resistance genes (ARGs). All isolates were resistant to metronidazole, followed by clarithromycin (84%), tetracycline (82%), streptomycin (81%), doxycycline (75%) and amoxicillin (69%). Some isolates were susceptibility to sulphamethoxazole/trimethroprim (55%) and chloramphenicol (49%). Approximately 88% (138/156) of the isolates were MDR, with multiple antibiotic resistance index ranging from 0.33-0.99. The ARGs were detected in the order: tet S (7%), flo R (9%), sul 2 (24%), dfr 18 (25%), erm B (34%), dfr A1 (38%) and str A (40%). Approximately, 72% (112/156) of the Vibrio strains harboured at least one ARG. Screening for Vibrio speciation confirmed, Vibrionaceae (80%), V. cholerae (54%), V. parahaemolyticus (2%) and V. vulnificus (2%). The result indicates that MDR including extensively drug-resistant (XDR) and pan-drug-resistant (PDR) Vibrio species are present in the Asata River water. Therefore, continuous surveillance and antibiotic resistance stewardship could help combat the dissemination of antibiotic-resistant Vibrio species and safeguard the health of all who depend on Asata River for water needs. • Rivers serves as reservoir for disseminating human pathogenic Vibrio species. • Human pathogenic Vibrio species were confirmed by molecular studies. • Resistance to multiple antibiotics was recorded in 88% of the Vibrio isolates. • Possession of resistance genes correlated with antibiotic resistant phenotype.