Clinical laboratory differentiation of Legionellaceae family members with pigment production and fluorescence on media supplemented with aromatic substrates.

A systematic study of pigment production (browning) and fluorescence (extracellular yellow-green and intracellular blue-white) by nine Legionellaceae species was performed. A total of 56 strains representing Tatlockia micdadei (Pittsburgh pneumonia agent), Legionella pneumophila, Legionella jordanis, Legionella longbeachae, Legionella oakridgensis, Legionella wadsworthii, Fluoribacter bozemanae, Fluoribacter gormanii, and Fluoribacter dumoffii could be separated on media supplemented with tyrosine plus cystine, 3,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, and 3-aminotyrosine. Parallel testing by hippurate hydrolysis and the bromocresol purple spot test enabled the identification of Legionellaceae species 24 to 72 h after primary isolation. This schema may be a practical alternative to species-specific antisera methods (slide agglutination or direct immunofluorescence) in the identification of members of the family Legionellaceae.