Sampling methods and techniques : a study of legionella isolated from freshwater habitats

Abstract

In this study Legionella was studied by two different methods, the indirect culturing method and the direct fluorescent analysis (DFA). The indirect culturing method was used to isolate the legionellae from the sample while the DF A method to count the actual number of Legionella in the sample. Legionella was isolated from four different samples. The samples from which isolation occurred were called Legionella-positive samples. The most common habitats from which Legionella was isolated were cooling towers and water tanks. 20% of the water tanks/tap water and 60% of the cooling towers were Legionella-positive samples. The species, most commonly found in the isolates was Legionella pneumophila serogroup 1. Other factors that were found to affect the growth of Legionella were incubation and sedimentation.