Association between submerged aquatic vegetation and elevated levels of Escherichia coli and potential bacterial pathogens in freshwater lakes

Prince P. Mathai, Hannah M. Dunn, Paolo Magnone, Qian Zhang, Satoshi Ishii, Chan Lan Chun, Michael J. Sadowsky

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Fecal indicator bacteria such as Escherichia coli have been reported to persist and potentially grow in a wide variety of secondary habitats, such as water, beach sand, sediment, periphyton and some algae. However, little is known about their association with submerged macrophytes and how this may influence water quality. In this study, we examined the association of E. coli and potential bacterial pathogens with Eurasian watermilfoil (EWM), an invasive, submerged, macrophyte that has spread across thousands of lakes in North America. EWM samples were collected from 10 lakes in Minnesota, once a month, for six consecutive months from early summer to late fall. Microbiota associated with EWM were examined using membrane filtration, quantitative PCR targeting various bacterial pathogens and host-associated marker genes, and high-throughput DNA sequencing. E. coli densities were generally elevated on EWM samples, and peaked during warmer months. Moreover, our results showed that EWM could serve as a temporal source for transmission of microbiota to the water column. Several potential pathogenic groups, including Aeromonas, Enterobacteriaceae, and Clostridium were present in significantly greater relative abundance on EWM than in water, and waterfowl was predicted to be the major source of fecal contamination. These findings have water quality implications with respect to the potential for submerged macrophytes to harbor and disperse E. coli and other bacterial pathogens in a large number of waterbodies.

Original languageEnglish (US)
Pages (from-to)319-324
Number of pages6
JournalScience of the Total Environment
StatePublished - Mar 20 2019

Bibliographical note

Funding Information:
Funding for this study was provided by the Minnesota Aquatic Invasive Species Research Center , through the Minnesota Environment and Natural Resources Trust Fund, as recommended by the Legislative-Citizen Commission on Minnesota Resources.

Publisher Copyright:
© 2018 Elsevier B.V.

Copyright 2019 Elsevier B.V., All rights reserved.


  • DNA sequence
  • Escherichia coli
  • Eurasian watermilfoil
  • Fecal indicator bacteria
  • Pathogens
  • Submerged macrophytes
  • Waterfowl


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