Abstract
A simple medium containing yeast extract, phosphate, and hemin as major components has been formulated for the study of legionellae. The medium supports the growth of a wide range of clinical and environmental isolates, with plating efficiencies comparable to those of charcoal-yeast extract agar. In addition, it does not contain activated charcoal or other components which may be associated with adverse reactions in humans. The medium is buffered and transparent; therefore, it would be suitable for genetic studies, production of biological reagents such as antigens and skin tests for human use, and antibiotic susceptibility assays.