Fusobacteria. An important cause of chorioamnionitis.

Prematurity is the main cause of human perinatal disease and chorioamnionitis is the main cause of prematurity. The diverse etiologic role of infection is incompletely known. Fusobacteria (FB) are herein reported to be delineated by the Warthin-Starry (WS) stain; an animal model was developed to reinforce evidence that FB cause chorioamnionitis. Isolates of these bacteria from three human placentas were inoculated into rabbits to develop antisera. Within an annual study of 297 human placentas, 138 were processed with WS stains. By WS stain, microbiologic culture, and immunofluorescent labelling of three placentas, FB were proved to cause chorioamnionitis. Sixty-two (35%) of 176 premature newborns had chorioamnionitis. Of these 62, 11 (18%) had morphologically evident FB; FB-like organisms were associated with chorioamnionitis and prematurity. Our findings support and expand clinical investigation of the amniotic infection syndrome.