Persistent Bordetella bronchiseptica pneumonia in an immunocompetent infant and genetic comparison of clinical isolates with kennel cough vaccine strains.

An infant who experienced recurrent episodes of respiratory failure received a diagnosis of pertussis on the basis of immunofluorescence testing, but culture revealed macrolide-resistant Bordetella bronchiseptica. Genetic analysis demonstrated that the child was not infected with a kennel cough vaccine strain, although the family's dog had recently been vaccinated. The infection cleared with imipenem therapy.