Legionella pneumophila: An Environmental Organism and Accidental Pathogen

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Author(s) Mariam Mekkour | El Khalil Ben Driss | Jalila Tai | Nozha Cohen
Pages 187-196
Volume 2
Issue 2
Date February, 2013
Keywords Biofilms, environmental exposure, Legionella pneumophila, legionnaireís disease, water microbiology, water supply.

Ecological studies on Legionella spp. are essential to better understand their sources in the natural environments, the mechanism of their entry into man-made water systems and the factors enabling their survival and growth in aquatic habitats. The Legionella pneumophila specie is the principal etiologic agent of legionnairesídisease, a form of lobar pneumonia. Ubiquitous in aquatic environments, the gram-negative Legionella organism is a facultative, intracellular parasite of protozoa. This bacteria exhibits peculiar and multiple strategies to adapt to stressful environment conditions which normally impair other germ survival. These strategies include the ability to enter in a viable but non-cultivable state, to multiply intracellularly within a variety of protozoa, such as amoebae, to survive as free organisms within biofilms and to be enhanced/ inhibited by the presence of other aquatic bacteria. The infection with Legionella pneumophila ranks among the most common causes of severe pneumonia in the community setting. There are no clinical features unique to Legionnairesí disease. The availability of a good diagnostic constitutes the basis for the early recognition and treatment of the individual patient as well as for effective measures for prevention against Legionnaires diseases. This review summarizes the available information regarding the ecology and points out important areas which require further study. Lastly, new perspectives in controlling Legionella pneumophila contamination can arise from investigations from our laboratory in measures to prevent the contamination of water intended for human consumption and prevent the infection by Legionnairesí diseases.

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