Real-time PCR assay targeting IS481 of Bordetella pertussis and molecular basis for detecting Bordetella holmesii

Detection of Bordetella holmesii by a real-time PCR assay targeting IS481 o f Bordetella pertussis is reported. Sequencing of IS481-specific PCR produc ts from B. pertussis and B. holmesii isolates revealed sequence homology. R estriction fragment length polymorphism demonstrated a low copy number of I S481-like sequences in B. holmesii. These results, and culture of B. holmes ii from patients with cough, suggest that the specificity and predictive va lue of IS481-based PCR assays for pertussis may be compromised.