During convalescence stage, the patient presents with prolonged cough. Laboratory diagnosis: Specimen: Saline nasal wash (Preferred specimen) Nasopharyngeal swab or cough droplets on cough plate Smear: Small, non-motile, capsulated, gram-negative cocobacilli singly or in pair, and may show bipolar staining. Culture: Inoculate the primary specimen on Bordet-Gengue agar medium and incubate for 2-6 days at 37 oc in a moist aerobic atmosphere which produces small, raised, shiny, mucoid colonies.
. No growth on blood agar . Oxidase positive . Most of them are catalase positive Serology: Direct fluorescent antibody test is most helpful, in identifying B. pertussis after culture on solid media. Treatment: Erythromycin Adminstration of erythromycin during the catarrrhal stage of disease promotes elimination of the organism and limits rate of transmission. Treatment after the onset of paroxysmal stage does not alter the clinical course of the disease.