RAPID DIAGNOSIS OF PERTUSSIS IN YOUNG INFANTS - COMPARISON OF CULTURE, PCR, AND INFANTS AND MOTHERS SEROLOGY

The contribution of maternal pertussis serology comparing prepartum se rum to serum collected during the infant's disease to the diagnosis of pertussis in infants was evaluated for 28 pairs of young infants with pertussis syndrome and their mothers and was compared to those of cul ture and PCR, Infants had a nasopharyngeal aspiration tested by PCR, a nd acute and convalescent sera were collected during their disease, Mo thers had a first acute serum collected concomitantly with the infant' s acute serum, and both acute sera were compared to a prepartum serum, Sera were analyzed by immunoblotting for the detection of antipertuss is toxin (PT) antibodies, Serological evidence of pertussis in infants was assessed as either an increase in anti-PT antibody levels between the mother's prepartum and acute sera or the presence of antibodies i n the infant's acute serum and their absence in both the mother's acut e and prepartum sera. Culture and PCR sensitivity were 43 and 89%, res pectively, Most Infants (18 of 24) had no pertussis antibody detectabl e in their acute sera, confirming a delayed immune response at this ag e. A comparison of infant's and mother's serology, using prepartum ser um, rapidly confirmed the diagnosis in 57% of the cases, Although less sensitive than PCR, this serological method should be used for a rapi d diagnosis of pertussis in young infants when culture and PCR are eit her not available or negative.