Comparison of polymerase chain reaction, culture, and western immunoblot serology for diagnosis of Bordetella pertussis infection.

Polymerase chain reaction (PCR) amplification of the pertussis toxin promoter region was used to detect Bordetella pertussis infection in nasopharyngeal aspirates collected from 24 infants and children infected with pertussis and 13 adult contacts during an epidemiological study. The sensitivity of this PCR assay was approximately one bacterium, and the assay was specific for B. pertussis in tests with other Bordetella species and other respiratory pathogens. The pertussis case definition required a cough with a duration of more than 21 days for infants and children and laboratory confirmation by serology as the primary detection method for infants, children, and adults. The sensitivity of PCR and culture on Bordet-Gengou agar medium was assessed with regard to the case definitions. In the group of infants and children (index cases), the sensitivities of the culture and the PCR were 54.1% (13 of 24) and 95.8% (23 of 24), respectively. In the adult group (household contacts), the sensitivities of the two methods were 15.4% (2 of 13) and 61.5% (8 of 13), respectively. PCR combined with pertussis-specific serology appears to be a useful tool for diagnosis of pertussis especially in epidemiological studies.