Experimental intrauterine Ureaplasma infection in sheep

Objective Prenatal Ureaplasma spp exposure is associated with preterm birth and modulates the neonatesʹ susceptibility to respiratory distress syndrome and bronchopulmonary dysplasia. We hypothesized that intra-amniotic ureaplasmas would cause lung inflammation and alter fetal lung development. Study design Pregnant ewes bearing singleton fetuses were given an intra-amniotic injection of 20 × 106 CFUs of U parvum (serovar 3) or vehicle, either 1, 3, 6, or 10 weeks before the delivery of preterm lambs at 124 days of gestation (n = 4-10 per group) for evaluation of inflammation and fetal lung maturation. Results Ureaplasmas were recovered from amniotic and fetal lung fluids after intra-amniotic injection. Body weight and umbilical arterial pH were reduced by Ureaplasma exposure for 10 weeks (P< .05). Ureaplasmas caused progressive lung inflammation and improvements in lung function that were associated with increased surfactant lipids (control, 0.13 ± 0.02 μmol/kg; 10 weeks of Ureaplasma exposure, 7.43 ± 3.0 μmol/kg; P< .001) and surfactant protein messenger RNA expression. Conclusion Long-term exposure to ureaplasmas in amniotic fluid alters ovine fetal development.