Hazards from Legionela

Environmental ecology The Legionella family (Legionellaceae) is a group of bacteria found in a wide and diverse range of environmental niches, but in particular in fresh water. In the natural environment they are heterotrophs, organisms that feed on complex organic molecules such as amino acids. To source these organic nutrients they have developed a range of different strategies. All of these strategies depend on deriving their nutrients from other organisms in either natural or anthropogenic water systems. As a result they are always part of a complex community in the environment and not easy to isolate as pure cultures in the laboratory. Another important ecological feature is that they have a general growth range of between 20 and 45 °C, but survive at both higher and lower temperatures, though 55 °C is widely regarded as the upper limit for survival (Fields et al., 2002; WHO, 2007, Chs. 1, 2).