Influence of blue-green algae (cyanobacteria) on survival of Legionella pneumophila in aerosols.

The fluid in which blue-green algae (cyanobacteria) (Fischerella sp.) had been grown (algal extract) was investigated for its effect on aerosols of Legionella pneumophila. The bacteria were significantly more stable when suspended in algal extract than in the tryptose-saline solution employed in previously reported experiments. The stabilizing property of the extract disappeared after dialysis, suggesting that a relatively small molecule was involved. The relationship of this observation to the epidemiology of Legionnaires disease is discussed.