What is the optimal specimen type for recovering Bordetella pertussis?

• A. Anterior nares swab
• B. Blood
• C. Expectorated sputum
• D. Nasopharyngeal swab

Answer: (D)

Bordetella pertussis primarily colonizes the nasopharynx, so the specimen that yields the highest chance of detection comes from the nasopharyngeal region. A nasopharyngeal swab (or nasopharyngeal aspirate) reaches the site where the bacteria persist and provides the best sensitivity for both culture and molecular tests. Anterior nares swabs sample the front of the nose and have a much lower yield for pertussis. Blood does not contain the organism in active pertussis infection, so it’s not useful for detection. Expectorated sputum tends to be contaminated with oropharyngeal flora and usually has a lower bacterial load for pertussis, making it less reliable. Therefore, the nasopharyngeal specimen is the optimal choice for recovering Bordetella pertussis.