Growth of Legionella in water systems

Growth of Legionella in water systems

Between July 18 and September 13, 2012, Québec City (QcC) experienced one of the largest North American outbreaks of Legionnaires’ disease (LD) of the last decade, with 182 cases including 13 fatalities (1, 2).Legionella pneumophila (Lp) is a water-borne pathogen and most LD outbreaks are due to the contamination of water-cooling towers, which aerosolize the bacterium and enable its transmission to the human lungs (3). Hot water distribution systems are usually linked with sporadic cases, but can also lead to outbreaks in nosocomial settings (3). Growth of Lp in water systems is crucial for causing disease and the general bacterial contamination of the system is the main factor correlating with the presence of Lp (4). The influence of the microbiome on the presence and growth of Lp in water systems has not been investigated yet. Moreover, the specific reason why certain strains are more often isolated than others is unknown, but it is certainly due to difference in genetic content.

We propose a research program that will address the current knowledge gap linking the genetic factors carried by successful Lp strains and the microbiome of water systems. We have put together a team of internationally known experts on Legionella, genomics, metagenomics, and water systems to carry forward this program. Our research program will generate knowledge that will help inform public health policies, such as the identification of specific microbial strains and genetic markers associated with Legionnaires’ disease outbreaks.


Jacques Corbeil

CHUdeQc/Université Laval

Sébastien Faucher

Université de Montréal