Bacterial Pathogens Associated with Tap and Well Waters in Lagos, Nigeria.

Background: The increasing cases of waterborne diseases in recent times necessitated the investigation of well and tap waters, which serve as source of drinking water in Lagos, Nigeria. Methods: A total of 180 each of well and tap water samples collected from 18 different locations in Lagos were brought to the Laboratory for bacteriological analyses. The water samples were tested using the multiple tube fermentation technique of the most probable number method. Subcultures were made from positive tubes of the presumptive test on to the appropriate solid media. Bacterial isolates were identified by standard procedures. Results: Our finding revealed that all the well waters from the locations under study were contaminated with one or more of the following bacterial pathogens Escherichia coli , Klebsiella pneumoniae , Salmonella typhi , Enterobacter aerogenes , Shigella dysenteriae , Proteus vulgaris and Pseudomonas aeruginosa , with E coli predominating. Surprisingly, one or two of these pathogens were isolated from tap water in 8/18 sample locations where pipe leakages were observed. However, no S. typhi, S. dysenteriae or P. vulgaris were isolated from any of the tap water samples. Conclusion: Our study confirmed gross contamination of well water, which is a source of drinking water in Lagos. Chlorinated tap water supply particularly in areas where pipe leakages were imminent were also contaminated with pathogens. Therefore, we suggest close and constant monitoring of various wells dug in Lagos to meet up with WHO standards, provision of adequate potable water, and prompt repair of leaking pipes as well as improvement in household hygiene to prevent the spread of waterborne diseases among people drinking that wate