Microbiology All are true about bordetella pertussis except A a)Most common cause is B. petrussis B It may occur in children and young adult after vaccination C Bacteria culture from nasopharyngeal swab is the definitive diagnosis D Presence of antibodies in serum is diagnostic of the disease 💡 Explanation All are true about bordetella pertussis except ✓ Correct Answer: D. Presence of antibodies in serum is diagnostic of the disease