Abstract
BACKGROUND: The presumed ascending route of group B beta-hemolytic streptococcus (GBS) infection from the colonized maternal genital tract is well accepted. This case report proposes a hematogenous, selective infection of one unruptured amniotic sac over the other ruptured amniotic sac in a twin gestation in a patient with known GBS vaginal colonization. CASE: This is a case report of GBS sepsis in twin B with intact membranes. Twin A, with 28 h of ruptured membranes, failed to show any signs of infection. The pathology of the placenta confirmed chorioamnionitis in twin B and the absence of infection in twin A. CONCLUSION: The presence of culture-positive GBS sepsis in the twin with the unruptured amniotic sac, as well as the absence of GBS infection in the twin with the ruptured sac, suggests an alternative means of infection for GBS infection, such as hematogenous transplacental transmission.