Comparative bacteriological analysis of stored borehole water sources in Oyo town, Oyo State, Nigeria

Water contamination is one of the leading causes of deaths and diseases worldwide, accounting for the deaths of more than 14,000 people daily, majority being children under 5 years old, therefore periodic monitoring of municipal water supplies are necessary. Comparative bacteriological analyses of twenty five samples of stored borehole water from five hostels in a tertiary institution in Oyo, Oyo State, was carried out using standard microbiological methods between March and April, 2018 to determine their bacteriological content. The hostels were: University Female Hostel (UFH), Diocese of Lagos West Hostel (DLW), Joseph Adetiloye Hostel (JAH), Diocese of Lagos Hostel (LAG) and Peter Jasper Akinola Hostel (IBD). A total of thirteen (13) different bacteria genera were isolated and identified as: Aeromonas (17%); Escherichia (4%); Staphylococcus (9%); Pseudomonas (9%); Lactobacillus (13%); Corynebacterium (27%); Micrococcus (6%); Streptococcus (3%); Serratia (4%); Klebsiella (1%); Citrobacter (3%); Shigella (3%); and Salmonella (1%). The total viable count ranged from 5.0×103 cfu/mL (IBD) to 1.23×105 cfu/mL (DLW). Total coliform bacteria counts of the stored water ranged from 0 to 28 MPN/100 mL. The bacteria load and presence of coliforms and pathogenic organisms raised grave concerns as WHO permissible limits for total viable count and coliforms are 100 cfu/mL and 0 MPN/100 mL, respectively. The organisms isolated are of public health significance as ingestion of water contaminated by them could result in gastroenteritis, especially Escherichia that indicates possible fecal contamination.   Key words: Bacteriological investigations, pathogens, groundwater, water quality, Oyo.