Enrichment medium for the isolation of Bordetella

The development of a specimen collection and transport medium outfit for the rapid laboratory diagnosis of whoping cough is described. The transport medium consisted of a semisolid agar containing charcoal, cephalexin, and defibrinated horse blood. It was also found to be an excellent enrichment medium for the selective isolation of Bordetella pertussis and B. parapertussis from scantily populated specimens. The investigation of 3,237 specimens that yielded 1,419 positive isolates of Bordetella, including 86 B. parapertussis, during a 20-month period is presented. A total of 3,076 specimens were processed in the laboratory by using the enrichment medium in addition to the routine procedure. Of these specimens, 757 were submitted in our medium, from which 137 (18%) were positive. Of the 567 specimens received in Amies transport medium, 290 (51%) positive cultures were obtained by the enrichment method only and not by primary culture.