DIRECT-METHODS OF IDENTIFICATION OF BORDE TELLA-PERTUSSIS IN HUMAN SAMPLES

Culture on specific media such as Bordet-Gengou or Regan-Lowe agar enr iched with fresh sheep blood remains the principal method for direct i dentification of Bordetella pertussis in nasopharyngeal aspirates duri ng pertussis. However, complete identification takes usually 5 to 7 da ys, and sensitivity does not exceed 50-60 % overall because of rapid n egativation after the onset of paroxysms. Direct immunofluorescence is rapid but is not recommended because of poor sensitivity and specific ity. The polymerase chain reaction or PCR takes only 1 or 2 days and a llows theoretically the detection of only one bacteria. Different tech niques have been successfully applied to the diagnosis of pertussis in nasopharyngeal aspirates or swabs from patients and have shown greate r sensitivity than culture and excellent specificity. However, routine PCR is not yet available in every laboratory and culture remains esse ntial to analyze the effects of the future vaccination strategies on t he evolution of the circulating B. pertussis strains.