Author
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HIGGINS, JAMES |
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Submitted to: American Society of Tropical Medicine and Hygiene
Publication Type: Abstract Only Publication Acceptance Date: 11/6/2006 Publication Date: 11/15/2006 Citation: Higgins, J.A. 2006. Molecular Ecology of Waterborne E. coli [Abstract]. 55th Annual Meeting of the American Society of Tropical Medicine and Hygiene, Atlanta, GA, November 12-16, 2006. p.183. Interpretive Summary: Technical Abstract: Escherichia coli is a common inhabitant of surface and ground waters in the developed and developing worlds. The majority of the E coli present in water are not particularly pathogenic to humans; however, there are E coli present in small proportion, that possess virulence genes that allow them to colonize the digestive tract and cause acutre and chronic diarrheal disease. People can acquire these pathogenic E coli from recreational exposure to contaminated water, ingestion of water that has not undergone sufficient purification and/or disinfection, or ingestion of foods treated with contaminated water. We have been studying the distribution of E coli in different streams representative of agricultural, forested, and urban watersheds. A triplex genotyping PCR assay, as well as multiplex PCRs for select virulence genes, as well as sequence analysis of a portion of the lac Z gene, have been employed to characterize diversity of E coli in these different stream types. We have learned that four genotypes of E coli are prevalent in streams in the metro Baltimore and Washington DC areas; many stream samples contain E coli that are potential pathogens; and even streams in relatively pristine habitats support populations of enteric bacteria. In light of these findings, we would argue that reliance on coliform counts as a part of TMDL regulations and/or impairment designations should be tempered with an awareness of dynamic nature of the bacterial ecology of freshwaters. |
