Editor: Michael Wagner
Introduction of a boost of Legionella pneumophila into a stagnant-water model by heat treatment
Article first published online: 12 JUL 2006
FEMS Microbiology Ecology
Volume 58, Issue 3, pages 583–592, December 2006
How to Cite
Vervaeren, H., Temmerman, R., Devos, L., Boon, N. and Verstraete, W. (2006), Introduction of a boost of Legionella pneumophila into a stagnant-water model by heat treatment. FEMS Microbiology Ecology, 58: 583–592. doi: 10.1111/j.1574-6941.2006.00181.x
- Issue published online: 12 JUL 2006
- Article first published online: 12 JUL 2006
- Received 9 November 2005; revised 8 May 2006; accepted 9 May 2006.First published online 12 July 2006.
- Legionella pneumophila;
- heat treatment;
- community shifts;
- stagnant water;
- real-time PCR
An environmentally representative stagnant-water model was developed to monitor the growth dynamics of Legionella pneumophila. This model was evaluated for three distinct water treatments: untreated tap water, heat-treated tap water, and heat-treated tap water supplemented with Pseudomonas putida, a known biofilm-forming bacterium. Bringing heat-treated tap water after subsequent cooling into contact with a densely formed untreated biofilm was found to promote the number of L. pneumophila by 4 log units within the biofilm, while the use of untreated water only sustained the L. pneumophila levels. Subsequent colonization of the water phase by L. pneumophila was noticed in the heat-treated stagnant-water models, with concentrations as high as 1 × 1010 mip gene copies L−1 stagnant water. Denaturing gradient gel electrophoresis in combination with clustering analysis of the prokaryotic community in the water phase and in the biofilm phase suggests that the different water treatments induced different communities. Moreover, boosts of L. pneumophila arising from heat treatment of water were accompanied by shifts to a more diverse eukaryotic community. Stimulated growth of L. pneumophila after heating of the water may explain the rapid recolonization of L. pneumophila in water systems. These results highlight the need for additional or alternative measures to heat treatment of water in order to prevent or abate potential outbreaks of L. pneumophila.