Detection of Antibiotic Resistance Genes in Salmonella, Klebsiella and Shigella species from Household Water Sources in Ibadan

Research Summary
Feco-orally transmitted infectious diseases are common in Nigeria, where potable water access is poor. In the south-western Nigerian Ibadan metropolis, the supply of municipal water is meagre as residents depend on household wells and boreholes. The aim of the study was to possibly detect antibiotic resistance genes in Enterobacteriaceae, notably Escherichia coli, Salmonella enterica, Klebsiella pneumoniae, and Shigella species from peri-urban Ibadan household water sources as a correlate of infection reservoir.
Over a period of three seasons, household well (n = 66) and borehole water (n = 30) samples were seasonally collected from January 2019 to March 2020 at Akinyele and Lagelu communities in Ibadan. Asejire municipal water samples (eight at the treatment point, seven at the household distribution point) were also collected. Using the pour plate method, samples were analysed for Total Heterotrophic Bacterial Counts (THBC), Total Coliform Counts (TCC), and Total Escherichia coli Counts (TEC). Escherichia coli, Salmonella enterica, Klebsiella pneumoniae, and Shigella species were isolated using differential media and identified using polymerase chain reaction (PCR). Antibiotic susceptibility testing was done using the Kirby-Bauer disc diffusion assay. Antibiotic-resistant genes were detected in the Klebsiella pneumoniae species using modified multiplex PCR. Data were analysed using a paired-mean t-test at α0.05
There was a season-independent abundance of THC and TCC in the well and borehole, with significant recovery of E. coli in the wells in the wet compared to the dry season (P = 0.0001). No Enterobacteriaceae were found in the borehole and Asejire treatment water samples. Twenty-five E. coli, 21 Enterobacter spp., five Citrobacter spp., five Kluyvera spp., and one Salmonella enterica were isolated during the wet season, while 73 K. pneumoniae, 26 K. quasipneumoniae, and 13 K. variicola were found across the seasons. Multi-drug resistant phenotypes were detected in 35.7% Klebsiella spp., 40.0% E. coli, and 52.4% Enterobacter spp. Of the 295 household water samples examined, 220 (182/198 well, 31/90 borehole, and 7/7 household taps) did not meet potability standards.
Peri-urban household water sources in Akinyele and Lagelu, Ibadan, were contaminated with multidrug-resistant Enterobacteriaceae capable of causing untreatable infections.