Dynamics of abundance and diversity of extended-spectrum β-lactamase (ESBL)-producing bacteria in aquatic ecosystems of Foumbot, an agricultural area of Cameroon (Central Africa)

ABSTRACT Antimicrobial resistance is a major public health challenges of the 21st century with a rapid increase in strains producing extended-spectrum β-lactamases (ESBL). This study examined the abundance and diversity of ESBL-producing bacteria in the aquatic ecosystems of Foumbot, an agricultural region. Sixteen sampling points were chosen to collect wastewater, surface, well and spring water. ESBL-producing bacteria were isolated on Chromagar-ESBL culture medium using filtration membrane method and identified using API 20E systems while physicochemical parameters were measured using appropriate techniques. The bacterial diversity was assessed by calculating specific richness, Shannon and Weaver diversity index, Sorensen similitude index and Pielou equitability index. Statistical analysis were performed using PAST software 16.0. Results showed that abundance mean values varied from one sampling point to the other. They fluctuated from 20×10 4 to 13×10 5 CFU/100 mL in wastewater, 18×10 2 to 13×10 3 CFU/100 mL in surface water, 141 to 80×10 2 CFU/100 mL in well water and 14 to 366 CFU/100 mL in spring water. 37 ESBL-producing species were isolated with 22 belonging to the Enterobacteriaceae family ( Cedecea lapagei, Citrobacter braakiii, Citrobacter freundii, Enterobacter aerogenes, Enterobacter cloacae, Enterobacter gergoviae, Escherichia coli, Klebsiela oxytoca, Klebsiella pneumonia, Rahnella aquatilis, Raoultella ornithinolytica, Salmonella choleraesuis, Salmonella paratyphi A, Salmonella spp, Serratia ficaria, Serratia liquefaciens, Serratia marcescens, Serratia odorifera, Serratia phymuthyca, Serratia rubidaea, Shigella spp, and Yersinia pestis ). Surface water was the most diversified ecosystem whereas groundwater was the least. A high equitability (H’>0.7) was recorded at almost all the sampling points and a high similarity (S>0.7) of bacteria community was noted between surface, well and spring water. The bacterial abundance and species richness were significantly influenced by factors such as pH, nitrites, ammonia nitrogen (affecting only the abundance), phosphates, phosphorus, color, and turbidity. This study revealed the health risk for humans and aquatic environment of Foumbot.