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Applying Live Cell Imaging and Cryo-Electron Tomography to Resolve Spatiotemporal Features of the Legionella pneumophila Dot/Icm Secretion System
Published on: March 10, 2020
Counting Legionella cells within single amoeba host cells.
Helen Y Buse1, Nicholas J Ashbolt
1National Exposure Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Cincinnati, Ohio, USA. buse.helen@epa.gov
Applied and Environmental Microbiology
|January 10, 2012
Summary
This study quantifies Legionella pneumophila bacteria within amoeba hosts. Maximum bacterial counts were 1,348 in Acanthamoeba polyphaga and 385 in Naegleria fowleri, impacting water systems.
Area of Science:
- Microbiology
- Environmental Science
- Public Health
Background:
- Legionella pneumophila is a significant waterborne pathogen.
- Amoebae are known hosts for L. pneumophila in engineered water systems.
- Quantifying intracellular bacteria is crucial for understanding transmission.
Purpose of the Study:
- To quantify the number of culturable Legionella pneumophila within individual amoeba hosts.
- To determine the maximum L. pneumophila load in Acanthamoeba polyphaga and Naegleria fowleri.
- To assess the potential for amoeba-hosted L. pneumophila release into water systems.
Main Methods:
- Co-culture of L. pneumophila with Acanthamoeba polyphaga and Naegleria fowleri.
- Enumeration of culturable L. pneumophila using CFU counts per trophozoite.
- Statistical analysis of bacterial loads.
Main Results:
- Maximum culturable L. pneumophila counts were 1,348 CFU/trophozoite in A. polyphaga.
- Maximum culturable L. pneumophila counts were 385 CFU/trophozoite in N. fowleri.
- Mean counts were 329 CFU/trophozoite for A. polyphaga and 44 CFU/trophozoite for N. fowleri.
Conclusions:
- Amoebae can host substantial numbers of Legionella pneumophila.
- These findings highlight the role of amoebae in L. pneumophila proliferation and potential release.
- Understanding intracellular bacterial loads is vital for water system risk assessment.
