The contamination of pipe-borne water is a major source of concern in the Lagos metropolis as it can lead to disease outbreak. Drinking water is exposed to contamination by microorganisms at every stage of its movement through the distribution systems. Six bacteria species were isolated from University of Lagos, Akoka; Yaba College of Technology, Yaba; Federal College of Education, Akoka; Johnson Bus Stop, Ladilak; and Teslim Nosiru Street, Ilaje, Bariga. The samples were isolated by plating out on nutrient agar and the representative isolates were subjected to morphological tests and biochemical tests which include gram staining and the Analytical Profile Index (API) test. The purity index (OD 260/280) of the extracted DNA was found to be 1.45 – 2.04. Extracted DNA samples were amplified using the PCR technique. Three primers were used for PCR amplification- S gene, RAPD 1 and RAPD 2. The viable count ranged from 2.0cfu/ml in the Teslim Nosiru Street sample to 1.00cfu/ml in the Yaba College of Technology sample. The isolates were identified as Bacillus polymyxa, Bacillus alvei, Bacillus mycoides, Pasteurella aerogenes, Pasteurella pneumotropica and Staphylococcus aureus. The three primers used generated a total of 128 bands including 104 polymorphic loci. On average one PCR primer produced 4.6 bands for each isolate. Statistical analyses were done using the NTSYS software version 2.02j to generate UPGMA dendrograms. The result showed a similarity coefficient of 0.66 among B. polymyxa, B. alvei and B. mycoides. There was a high similarity coefficient of 0.72 between P. pneumotropica and S. aureus. To prevent disease outbreaks, the pipes in which these water flows should be thoroughly flushed and damaged pipes should be replaced. A routine testing should be done regularly to ensure that the water has not been contaminated. The use of RAPD-PCR molecular technique has enhanced the identification and characterization of the microorganisms isolated from pipe-borne water.
Key Words :Lagos, API, UPGMA, Dendrograms and RAPD-PCR.