Volume 22, Issue 2 p. 568-583
Research article

Exploring bacterial pathogen community dynamics in freshwater beach sediments: A tale of two lakes

Danielle VanMensel

Corresponding Author

Danielle VanMensel

Great Lakes Institute for Environmental Research, University of Windsor, Ontario, Canada

For correspondence. E-mail [email protected]; Tel. (+519) 253 3000 x4739Search for more papers by this author
Subba Rao Chaganti

Subba Rao Chaganti

Great Lakes Institute for Environmental Research, University of Windsor, Ontario, Canada

Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI, USA

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Ian G. Droppo

Ian G. Droppo

Environment and Climate Change Canada, Burlington, Ontario, Canada

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Christopher G. Weisener

Christopher G. Weisener

Great Lakes Institute for Environmental Research, University of Windsor, Ontario, Canada

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First published: 17 November 2019
Citations: 15

Summary

Pathogenic bacteria associated with freshwater ecosystems can pose significant health risks particularly where recreational water use is popular. Common water quality assessments involve quantifying indicator Escherichia coli within the water column but neglect to consider physical and geochemical factors and contributions from the sediment. In this study, we used high-throughput sequencing to investigate sediment microbial communities at four freshwater public beaches in southern Ontario, Canada and analysed community structure, function, and gene expression with relation to geographical characteristics. Our results indicate that beach sediments at the sediment–water interface could serve as potential sources of bacterial contamination under low-energy environments with tightly packed small sediment particles compared with high-energy environments. Further, the absence of pathogens but expression of pathogenic transcripts suggests occurrence of alternate gene acquisition. Pathogenicity at these locations included expression of Salmonella virulence factors, genes involved in pertussis, and antimicrobial resistance. Finally, we introduce a proposed universal bacterial pathogen model to consider the combined and synergistic processes used by these microbes. To our knowledge, this is the first study of its kind to investigate chemolithotrophic activity related to pathogens within bed sediment at freshwater beaches. This work helps advance current understanding of health risks in these environments.