Importance of culture in laboratory diagnosis of Bordetella pertussis infections.

Nasopharyngeal secretions from 223 patients were examined for the presence of Bordetella pertussis and B. parapertussis by culturing on Regan-Lowe agar (J. Regan and F. Lowe, J. Clin. Microbiol. 6:303-309, 1977) and by direct fluorescent-antibody testing. B. pertussis was found in 38 patients; B. parapertussis was recovered from 2. Culturing was more sensitive (38 of 38 patients) than direct fluorescent-antibody testing (26 of 38 patients) for the detection of B. pertussis. Overgrowth by other organisms (7 of 223 patients) was uncommon. The patients with B. pertussis infections were generally less than 1 year old, had received no or one immunization, and had coughing spells but infrequently had whooping cough. Accurate diagnosis of B. pertussis infections should include culturing.