keywords: BLAST, Escherichia coli, GenBank, Molecular Identification, PCR 16s rRNA
The high contamination levels in abattoir effluent is leading to the transmission of pathogens to human and diseases. Thus, detection and control of Escherichia coli (E. coli) in aquatic environments ensures that drinking and bathing water is bacteriological safe. Molecular biology has offered significant increase in detection and identification specificity of microorganisms as it can identify unique genetic properties that is encoded in genome of such organism. Polymerase chain reaction (PCR) based methods are applied most frequently to detect and identify particular bacterial species. This paper reports the use of molecular methods in the identification of E. coli isolates of River Tauga and three surrounding well waters associated with abattoir effluent inKaru, FCT, Abuja. DNA was extracted from 12 bacterial isolates from 12 samples sites in the sample area. Total genomic DNA yield and purity was between 12.0 (ng/μl) and 30.0 (ng/μl) for DNA yield and a genomic purity of between 1.9 to 2.5 (A260:A280). Bacterial 16S rRNA gene was amplified using the 16s sRNA universal primers. The amplified 16S rRNA gene sequence was compared with the sequence in NCBI sequence database using Basic Local Alignment Search Tool (BLAST) search program. All sequences queried showed >= 200 similarity indexwith E value of 0.0 and percentage similarity of sequences (btw 99.9 to 100%) with sequences deposited in the GenBank. This study has shown that molecular techniques are more reliable in the identification of bacteria than the traditional methods of identification. The results of in this study revealed a precise and definitive identification of the isolates. This showed that all the isolates were of Escherichia coli as an indicator of faecal contamination of water associated with the untreated abattoir effluent in the water samples of River Tauga and the three surrounding wells with close proximity of the wells. The presence of E. coli in well water, river water and abattoir effluent provided sufficient evidence of the possible presence of pathogenic organisms from the untreated abattoir wastewater in this study.