The respiratory pathology in infants with sudden unexpected deaths in whom respiratory specimens were initially PCR-positive or PCR-negative for Bordetella pertussis.

BACKGROUND: In a previous controlled study, we investigated the relationship between Bordetella pertussis infections and sudden unexpected deaths among German infants (sudden infant death syndrome, SIDS). In this present study, we investigated further the respiratory pathology in a subset of infants in the original study. METHODS: Originally, there were 234 infants with SIDS and, of these, 12 had either a nasopharyngeal swab (NPS) or a tracheal swab specimen (TS) that was positive for B. pertussis by polymerase chain reaction (PCR). Here, tissue specimens from eight infants who were originally PCR-positive were compared with tissue specimens from seven infants in whom the original PCR studies were negative. RESULTS: The histopathologic diagnoses were as follows: 14 of 15 had pulmonary edema and the remaining case had early diffuse alveolar damage. Although 14 of 15 cases had some histologic or clinical evidence suggesting respiratory tract infection, the features were more consistent with a viral etiology, and in none were the findings typical of respiratory disease attributable to B. pertussis. CONCLUSIONS: The findings in this present investigation do not support a direct role of B. pertussis at the site of infection (ciliated epithelium) in the causation of SIDS. The clinical aspects of this study were carried out in the 1990s when pertussis was widespread in Germany. Therefore, the original finding of some PCR-positive cases is not surprising. The possibility that B. pertussis infection could still be a factor in some SIDS cases, e.g., by a systemic release of toxins, cannot be definitely ruled out.