The experimental infection of the amniotic sac of sheep

The amniotic sac of 10 ewes was catheterised at 90–105 days of gestation. In eight ewes a suspension of a β-haemolytic strain of Staphylococcus aureus containing between 3.1 × 10⁸ and 4.4 × 10⁹ colony-forming units was infused 7–16 days after surgery. Two of the ewes were not infused with the test inoculum because fungi were identified in samples of amniotic fluid 13 days after catheterisation.Where possible, daily samples of fluid were withdrawn before abortion occurred (five ewes), hysterotomy was performed (two ewes), and death of the ewe (one ewe). In six of the ewes which were infused with the test organism a partial and temporary inhibition of bacterial multiplication occurred, ranging from 3 to 13 days after inoculation; this was followed by a phase of rapid multiplication and foetal death. It would appear that the amniotic fluid of sheep has a similar inhibitory effect as that previously identified in humans.