Buffered Charcoal Yeast Extract (BCYE Agar) medium is used for the isolation, cultivation and maintenance of Legionellaspp. from environmental and clinical specimens. Yeast Extract provides essential nutrients like amino acids, peptides, and vitamins. ACES Buffer maintains a proper pH for this species. α-Ketoglutarate stimulates bacterial growth. Charcoal absorbs toxic metabolic products and modifies the surface tension of the medium. The medium is supplemented with L-Cysteine HCl and Ferric Pyrophosphate to satisfy specific nutritional requirements of Legionella. Agar is the gelifying agent.