Multidrug-Resistant Vibrio species recovered from some Freshwater Resources in Southwest Nigeria: a public health concern

Globally, pathogens that cause infectious water-related diseases such as diarrhea and cholera are beginning to manifest with unusual antibiotic resistance characteristics and virulence, posing a huge threat to public health. Vibrio species are a leading cause of water-and food-borne outbreaks and is widely distributed in the water environments making it a significant threat to human health worldwide. A total of 315 Vibrioisolates recovered from different freshwater resources in southwest Nigeria were confirmed by simplex PCR using toxR gene. All confirmed isolates were tested for In vitro susceptibility to 18 antibiotics using agar disc-diffusion assay and the phenotypic tetracycline-resistant isolates were further profiled for their genotypic antimicrobial resistance determinants by PCR assay. The isolates were variously susceptible to the antibiotics tested as follows: norfloxacin 308 (98%), ciprofloxacin 293 (93%), meropenem 287 (91%), cefotaxime 279 (88%), amikacin 238 (75%). Conversely, resistance to erythromycin 300 (95%), sulphamethoxazole 297 (94%), rifampicin 289 (92%), doxycycline 260 (82%), tetracycline 237 (75%) were equally observed. Tetracycline resistance isolates were assessed for resistance determinant and the following prevalence were obtained; tetA (28), tetE (20), and tet39 (3). The MAR index across the sampling locations of 0.8 to 0.94 exceeds the threshold value of 0.2, suggesting excessive antimicrobial usage at the sample source. Our findings reveal high incidence ofVibrio species in the selected freshwater resources and also signify high resistance towards some conventionally used antibiotics. Consequently, this portends that the waters are unfit for domestic, industrial and recreational purposes and a reservoir of antibiotic resistance determinants in the environment.