Prenatal diagnosis of congenital listeriosis.

A case of congenital listeriosis presenting with premature labor at 24 weeks' gestation is described. Listeria monocytogenes were isolated from the amniotic fluid, which also had an increased concentration of IgA. The significance of amniotic fluid Ig levels and their potential value in the diagnosis of intrauterine infections as an adjunct to the isolation of the infectious agent is discussed.