Comparison of four charcoal media for the isolation of Bordetella pertussis.

Charcoal-horse blood agar with 40 micrograms of cephalexin per ml, charcoal-horse blood agar with 3 micrograms of lincomycin per ml, charcoal agar with 3 micrograms of lincomycin per ml, and Legionella (buffered charcoal-yeast extract) agar with 3 micrograms of lincomycin per ml were compared for isolation of Bordetella pertussis. Charcoal-horse blood agar with 40 micrograms of cephalexin per ml gave the best results, with a B. pertussis recovery rate of 100%. Growth was most rapid and the mean number of colonies was highest on this agar, and growth of pharyngeal flora was completely suppressed.