Intramembranous localization of bacteria in beta-hemolytic group B streptococcal chorioamnionitis.

An unusual pathologic finding consisting of large colonies of bacteria, localized immediately beneath the epithelial layer of the amnion, has been observed in association with an example of group B beta-hemolytic streptococcal chorioamnionitis. Postpartum endometritis as well as neonatal sepsis and meningitis occurred. Histologic examination of the umbilical cord and placenta revealed routine features of intraamniotic inflammation, but the membranes were characterized by the presence of unusual darkly staining deposits of material immediately beneath the amniotic epithelium. Subsequent special stains revealed these to be colonies of gram-positive cocci. We have been unable to find a previous description of this observation in association with streptococcal or with other types of chorioamnionitis.