12-14: Biocide Treatments for Controlling Amoeba Amplified Legionella in

There is an expanding body of evidence that highly prevalent free-living amoebae increase both the numbers and virulence of water based, human-pathogenic, amoeba-resisting microorganisms such as Legionella. We have focused on controlling amoeba-amplified forms of Legionella by various biocide regimes commonly used in water treatment and provide proof for a hypothesis that explains the inability of conventional treatments in controlling these hardy and relevant forms. Our studies demonstrate a need to revisit current biocide dosing practices in order to meet the new guidelines for Legionella control in industrial water systems. This paper will discuss, with supporting data, some feasible alternatives that provide adequate control of amoeba-fed Legionella in cooling towers by employing a combination of US EPA approved organic biocides.