Factors affecting growth of Legionella pneumophila in liquid media.

The growth in liquid media of Legionella pneumophila serogroups 1-6 was monitored turbidimetrically and factors affecting growth rate were studied. The presence of inhibitors, use of detoxifying agents and the method of broth preparation each had significant effects on cultivation. Cysteine was essential for growth; the optimal concentration was 100 micrograms/ml, but supplemental iron had no demonstrable effect.