Molecular Detection of Enteropathogenic Escherichia coli in Urban Canals of Colombo, Sri Lanka

Enteropathogenic Escherichia coli is a major diarrheagenic pathogen. However, its significance is often overlooked unless there is an outbreak. Previous studies predominantly focused on freshwater systems rather than contaminated water bodies, which are primary sources of pathogenic Escherichia coli. Hence, the present study aims at detecting the presence of Enteropathogenic Escherichia coli in polluted water canals in Colombo, Sri Lanka. Water samples were collected from the Hamilton, Wellawatte, Dehiwala, and Norris canals within Colombo. Pure Escherichia coli isolates were obtained by culturing membrane-filtered samples on MacConkey agar, followed by Luria-Bertani broth. DNA was extracted using a modified boiling cell technique. Molecular identification was performed by amplifying two key virulence genes (eaeA and bfpA). The obtained results indicate the presence of Enteropathogenic Escherichia coli in the Hamilton, Wellawatte and Dehiwala canals. Isolates obtained from the Hamilton and Wellawatte canals were of typical pathotypes, which were positive for both eaeA and bfpA genes. Atypical pathotypes were detected only in the Dehiwala Canal, which were positive only for the eaeA gene. Despite yielding Escherichia coli colonies on the agar, isolates obtained from the Norris Canal were negative for both the tested genes. In conclusion, the results indicate microbial contamination of the Colombo Canals. The findings of this study prompt the need for continuous canal water monitoring and implementation of effective remediation measures to mitigate the evident microbial contamination. This is especially important in Colombo, considering that some communities continue to rely on these waterways despite the health risks associated with untreated water contamination.