BORDETELLA-PERTUSSIS DIAGNOSED BY POLYMERASE CHAIN-REACTION

The object of this work was to test the polymerase chain reaction (PCR ) for demonstration of Bordetella pertussis (BP) in nasopharyngeal sec retions. The method was applied to patients with recently diagnosed pe rtussis, as verified by BP culture. In order to test the sensitivity a nd specificity of PCR for the diagnosis of BP, we used known concentra tions of BP, Bordetella parapertussis and Bordetella bronchiseptica in aqueous solutions. PCR was furthermore carried out on species of bact eria that might be isolated from the nasopharynx. The applicability of PCR to patient specimens was tested in 25 patients in whose nasophary ngeal secretions BP had been demonstrated after 4-7 days of culture. T he detection limit of PCR in aqueous solution was 1-2 BP bacteria per reaction tube. PCR was 100% specific for BP, showing no response with other Bordetella species or other bacteria known to colonize the nasop harynx. Of 25 patient specimens, 16 were PCR-positive 4-7 days after t he positive primary culture had been established; only 5 out of 13 pat ient specimens were positive by repeated conventional nasopharyngeal c ulture at that time. We conclude that PCR is a possible alternative to culture for the demonstration of BP, as PCR is considerably faster th an culture and might be more sensitive.