Characterization of Salmonella typhi from Shallow Well Water in Sogomo, Eldoret- Kenya and its Antimicrobial Sensitivity to Moringa oleifera Seed Extract

Abstract

Salmonella typhi is a gram negative, rod-shaped bacterium that cause typhoid fever disease, a significant cause of human mortality especially in the developing countries. This illness occurs after ingestion of Salmonella typhi bacteria in contaminated water or food. This study aimed to isolate and identify Salmonella typhi from shallow well waters and assess its sensitivity to Moringa oleifera seed extract. Twelve wells were sampled randomly, and samples collected. 10mls of each sample were measured and put in twelve different sterile test tubes. Dilutions were done serially by diluting 1 ml of each sample in tubes having 9mls of distilled water. This was labelled 10-1 dilution. Further dilutions were done to dilution factor of 10-3. Inoculation was done in Salmonella Shigella agar (SSA) and incubation done at 35 C for 24 hours. Re-inoculation was done in SSA by streaking to obtain pure isolates. These pure isolates were confirmed by biochemical tests (catalase, methyl red and Triple Sugar Iron tests). Anti-microbial sensitivity test was performed using Moringa oleifera seed extract and ofloxacin and norfloxacin drugs of antibiotic disc were used as positive and negative controls respectively. Poor method of human waste disposal, condition of sewage systems and inaccurate water treatment methods associate to well water contamination by Salmonella typhi and thus transmission. Results showed that 3 out of 12 water samples tested positive for Salmonella typhi. This gave a rate of 25% contamination of shallow wells in Sogomo by this bacterium. The bacterium was sensitive to Moringa oleifera seed extract, with sensitivity increasing with higher extract concentrations. The results of the measurements of zones of inhibition were represented using graphs. The study highlights the need for public health education among the residents of Sogomo on proper sewage management, waste disposal and water treatment to prevent contamination.