Isolation of Bordetella pertussis in blood culture from a patient with multiple myeloma.

Bordetella pertussis is a fastidious aerobic, Gram-negative coccobacillus that causes the classical disease of whooping cough. We present a 63 years old man with multiple myeloma who was admitted to the medical department with cough, hoarseness and fever. Bronchopneumonia was suspected and two courses of beta-lactam antibiotics had beneficial effect on his clinical condition, but his respiratory symptoms persisted. Eventually, B. pertussis grew in an aerobic blood culture. Delayed treatment with clarithromycin had little or no effect on his cough. To our knowledge this is the third reported case of B. pertussis bacteraemia. All three patients have been immunocompromized. Growth in blood culture may be slow, and prolonged incubation (at least 6 days) of the blood culture bottles and subculture to a special culture medium is necessary for isolation of B. pertussis.