INHIBITION OF GROWTH OF LEGIONELLA SPECIES BY HETEROTROPHIC PLATE-COUNT BACTERIA ISOLATED FROM CHLORINATED DRINKING-WATER

The ability of heterotrophic plate count bacterial strains isolated from chlorinated drinking water on low-nutrient media to inhibit the growth of Legionella species was examined. Between 16% and 32% of these strains were able to inhibit the growth of Legionella species when tested on buffered charcoal yeast extract agar. The exact proportion of inhibiting strains varied with the individual Legionella species. Two strains that inhibited the growth of several Legionella species could also stimulate the growth of the same species when both the test strain and the Legionella species were grown on buffered charcoal yeast extract agar that lacked the essential amino acid l-cysteine. © 1990 Springer-Verlag New York Inc.