Activity and characterization of a low molecular fraction present in human amniotic fluid with broad spectrum antibacterial activity.

The isolation of a low molecular weight fraction from amniotic fluid with broad spectrum antimicrobial activity is reported. This fraction consists of a family of peptides whose bactericidal activity is zinc dependent and can be inhibited by phosphate. Peptides are present in early gestation in low concentration increasing in amount from about 28 weeks gestation when antimicrobial activity becomes detectable in whole amniotic fluid. A simple bacteriological assay for this material is described. Its relation to the occurrence of perinatal infection is discussed.