Detection of Bordetella pertussis by polymerase chain reaction and culture in the nasopharynx of erythromycin-treated infants with pertussis

Pediatr Infect Dis J. 1996 Jan;15(1):54-7. doi: 10.1097/00006454-199601000-00012.


Background: Pertussis is a highly contagious respiratory disease and the most serious effects occur in young infants. Recently it has been shown that rapid and highly specific PCR can be a useful diagnostic tool for detection of pertussis infection. To our knowledge there are no previous studies concerning the disappearance of Bordetella pertussis DNA from the nasopharynx during antimicrobial treatment.

Methods: We studied prospectively how rapidly live B. pertussis organisms and DNA of these bacteria disappear from the nasopharynx during erythromycin therapy in unvaccinated infants. Eighty-five nasopharyngeal swabs obtained from nine erythromycin-treated infants with pertussis on consecutive days during hospitalization were tested by PCR and culture. The PCR products were further analyzed by Southern hybridization.

Results: On the fourth day of treatment 56% of the samples were positive by culture and 89% by PCR, whereas after 7 days the rates were 0 and 56%, respectively. In seven of nine patients PCR remained positive for 1 to 7 days longer than culture. The follow-up study also showed the semiquantitative nature of the PCR assay. The intensity of the PCR products in agarose gel usually weakened with time during erythromycin therapy.

Conclusions: The results of this study show that PCR assay can achieve the specific diagnosis of pertussis infection in a large proportion of infants even when antimicrobial treatment has killed the organisms and culture is no longer positive.

Publication types

  • Clinical Trial
  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriological Techniques*
  • Base Sequence
  • Blotting, Southern
  • Bordetella pertussis / drug effects
  • Bordetella pertussis / genetics
  • Bordetella pertussis / isolation & purification*
  • DNA, Bacterial / analysis
  • Erythromycin / therapeutic use*
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Molecular Sequence Data
  • Nasopharynx / microbiology*
  • Polymerase Chain Reaction*
  • Prospective Studies
  • Whooping Cough / diagnosis*
  • Whooping Cough / drug therapy
  • Whooping Cough / microbiology


  • DNA, Bacterial
  • Erythromycin