Abstract:

The microorganisms living in the cooling towers water can affect both human health through inhalation of aerosolized water as well as industrial processes. In order to analyse such man-made water systems, microbiological tests that can give results in a short time are needed. In this study, the presence of heterotrophic bacteria, Legionella bacteria and free - living amoeba, FLA, including Acanthamoeba, in cooling-tower water and biofilm samples were investigated using two different methods, fluorescent in situ hybridization (FISH), and culture. For this, a total of 40 water and biofilm samples were taken from 16 different cooling towers in Istanbul. FISH and culture analysis have revealed that the number of heterotrophic bacteria within the water and the biofilm samples was above the threshold values (>105 cell. mL-1), generally. Despite Acanthamoeba were present in all cooling tower specimens, Legionella pneumophila serogroup 1 were only detected in the biofilm of one cooling tower. According to the results of this study, both methods are recommended to be used in conjunction. Due to the the large biodiversity of FLA such as Hartmanella sp. and Naeglaria sp, there is a need for new studies utilizing FISH method for sensitive, reliable results in a short period of time.

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