Microbiological quality of water samples obtained from water sources in Ishaka, Uganda

This study aimed to evaluate the microbiological quality of water sources in Ishaka division, Bushenyi district.

Water from taps, wells and springs were sampled for the cross-sectional investigation. The enumeration and identification of microbes (Escherichia coli, Salmonella, Shigella, Proteus, Staphylococcus aureus and total coliforms) in water samples were carried out using a variety of methods. Escherichia coli was enumerated using the membrane filtration method; Salmonella, Shigella and Proteus using a two-step enrichment method; Staphylococcus aureus using the surface spread method and total coliforms using the most probable number technique. Mannitol salt agar was used for enumeration of Staphylococcus Aureus and violet red bile agar was used for enumeration of total coliforms and Escherichia coli; xylose lysine deoxycholate agar was used for both Salmonella spp. and Shigella spp. API-20E was used to phenotypically identify the Enterobacteriaceae contaminants in water. These included Escherichia coli, Proteus mirabilis, Proteus vulgaris, Salmonella spp. and Staphylococcus aureus.

Escherichia coli counts in the water from springs and wells ranged from 0 to 314 cfu/mL (p = 0.173) and 0 to 3 cfu/mL (p = 0.269), respectively, while tap water had no incidence of Escherichia coli. Highest level of bacterial contamination in water sources, beyond acceptable WHO (0 cfu/100 mL) limits for drinking water, was reported: Proteus spp., 34 (54.8%), followed by total coliforms, 24 (38.7%), Shigella spp., 22 (35.5%) and least were Salmonella spp. (8.1%) and Staphylococcus aureus spp. (8.1%).

It is therefore concluded that spring and well community water sources in Ishaka division, Uganda, are significantly contaminated with pathogenic bacteria and thus unsafe for drinking without adequate water treatment (disinfection and filtration).