ABSTRACT
There is increasing concern about Chlamydia trachomatis infection during pregnancy, because of reports of increased maternal, fetal, and
neonatal risks. Amniotic fluid is known to possess antibacterial activity and has
recently been shown to inhibit formation of chlamydial inclusions in McCoy cell culture.
To further characterize the antichlamydial factor, we investigated the effect of filtering
the fluid (0.45 μm pores) prior to incubation. Amniotic fluid was obtained from 12
women at term gestation, either by amniocentesis, or at cesarean section. Chlamydial
inclusion formation was studied in McCoy cell cultures, and Escherichia coli growth was studied by a platecount method. Filtered amniotic fluid had significantly
less inhibitory activity against chlamydial inclusion formation than nonfiltered fluid
did. Both filtered and nonfiltered amniotic fluid were equally effective in inhibiting
E. coli colony growth. These data suggest that the chlamydial inhibitor in amniotic
fluid does not pass through 0.45 μm pores and is larger than the bacterial inhibitor
that was reported to be a peptide of low molecular weight.
