Occurrence of Legionella pneumophila in environmental samples

During the last 5 years, several outbreaks of Legionnaires’ disease have been reported throughout Europe, resulting in hundreds of infections and several deaths. Legionella pneumophila has been shown to be the most infectious agent for Legionnaires’ disease. Biofilms that are present throughout the water distribution system are probably the most important sources of Legionella-outbreaks. Although it is accepted that Legionella spp. exist in biofilms, only a limited number of studies have attempted to characterise the bacteria’s survival and interaction within these complex ecosystems. The relationship between biofilm formation and Legionella multiplication has not yet been quantified and the prevention or abatement of biofilm formation has attracted limited attention as a(n additional) control measure. Preventing the spread of Legionella by limiting biofilm formation or the association of Legionella in the biofilm requires a systematic and stringent approach to ensure the biosafety of water and materials. However such approach may be a promising control measure to lower the risk for Legionella multiplication.