Escherichia coli contamination and risk exposure assessment of humans consuming water from unprotected wells in Chaona community, Mwachisompola area of Chibombo District of Zambia

Abstract

A quantitative cross-sectional study was conducted to detect the presence of E. coli in unprotected water wells of Chaona community in Mwachisompola area, Chibombo District of Zambia. 48 wells drawn from four villages were sampled from the study area. Laboratory processes of culturing, isolation and identification of E. coli confirmed the occurrence of the bacterium in well water. The identified E. coli was subjected to antibiotic resistance testing, and PCR was used to detect the resistant genes further. Of the 48 unprotected wells sampled, 38 (79%, 95% CI: 77.3 – 80.7%) were found contaminated with E. coli. Meanwhile, 16/48 (33.3%; CI: 31.4 – 35.2%) samples were found with an average CFU of between 1000 and 10,000, the highest range. E. coli isolates were also tested for Multi-Drug Resistance (MDR), of which one isolate indicated being resistant to eight antibiotics and another to five antibiotics presenting (5.88%; CI: 3.2 – 8.6%) for each. Meanwhile, seven isolates were resistant to four antibiotics (41.2%; CI: 35.5 – 46.9%), and eight isolates were resistant to three antibiotics (41.1%, CI: 35.4 – 46.9%). In addition, 30.9% (17/55) of the isolated E. coli organisms were found to be resistant to three or more classes of antibiotics primarily; Ampicillin, Streptomycin, Tetracycline, Cefotaxime, Nalidixic Acid, Norfloxacin and Ciprofloxacin. The study revealed that E. coli contamination was highly possible, and it is recommended that water should be boiled and or treated with chlorine before use at the household level.