Dye-containing buffered charcoal-yeast extract medium for differentiation of members of the family Legionellaceae

Abstract
The addition of 0.001% bromocresol purple and 0.001% bromothymol blue to buffered charcoal-yeast extract agar allowed differentiation between members of the family Legionellaceae. On this medium, Legionella pneumophila grew as relatively flat, pale green colonies; Tatlockia micdadei (Pittsburgh pneumonia agent) produced blue-gray colonies. Fluoribacter spp. (atypical Legionella-like organisms) developed glistening colonies which were brighter green than those of L. pneumophila.