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 of Bordetella pertussis is reported. Sequencing of IS481-specific PCR products from B. pertussis and B. holmesii isolates revealed sequence homology. Restriction fragment length polymorphism demonstrated a low copy number of IS481-like sequences in B. holmesii. These results, and culture of B. holmesii from patients with cough, suggest that the specificity and predictive value of IS481-based PCR assays for pertussis may be compromised.