Bactericidal Effect of Disinfectants Against Legionella pneumophila and Legionella bozemanii

Legionella pneumophila and L. bozemanii suspended in distilled water were exposed to 10 kinds of disinfectants recommended for inhibiting growth of organisms in cooling towers and evaporative condesers of air-coditioning systems. Sodium hypochlorite, a compound containing sodium hypochlorite and 5, 5-dimethylhydantoin, and 2, 2-dibromo-3-nitrilopropionamide were effective in destroying concentration 106 to 108 viable cells per ml. Althogh 2, 4-dibromo-5, 5-dimethylhydantoin and cyanohalogenpenylsulfone formulation did not act as rapidly as sodium hypochlorite or 2, 2-dibromo-3-nitrilopropionamide, failure to recover viable cells after 6h. to 24h.of exposure suggest that these disinfectants would also destroy the organism in water within a reasonable treatment period. Zinc pyridine thione, 2-bromo-2-nitropropane-1, 3-dial and hydragine were less effective.