Source Attribution of Salmonella and Escherichia coli Contaminating Lake Victoria fish in Kenya

Abstract

Escherichia coli and Salmonella are major contaminants of fish from Lake Victoria but the sources and possible reservoirs of these microbes have not been determined. Fish and environmental samples were collected from five locations in Kenya, along with human specimens and analysed for E. coli and Salmonella spp. E. coli was the most common isolate recovered in humans but it was lowest in freshly caught fish. Salmonella spp was recovered in soil, sundried fish, humans and domestic animals. Enterotoxigenic E. coli were detected among humans but no E. coli virulence genes were detected among fish isolates. Soil was the possible source of contamination of fish, based on closeness of Salmonella isolates recovered from soil and a 38% misclassification of E. coli isolates from fish as soil isolates. Phenotypic approaches employed in this study are promising tools for attibuting sources reponsible for fish contamination in the region.