The origin of Fusobacterium nucleatum involved in intra-amniotic infection and preterm birth

Objective. To evaluate the potential oral origin of Fusobacterium nucleatum found in amniotic fluid of women at high risk of preterm birth. Methods. A transversal study nested into a cohort study of women with preterm labor and/or preterm premature rupture of membranes was undergone. Women with the presence of F. nucleatum in the amniotic fluid and their respective partners were invited to be examined for their periodontal health after delivery, and samples of saliva and subgingival plaque were collected. For each couple, specific PCR detection of Fusobacterium species was performed on each oral sample, and the DNA sequences were compared with the one obtained from amniotic fluid. Results. Three women, all in preterm labor with intact membranes, were included. Intra-amniotic sludge was observed in all of them. A strain of F. nucleatum with 100% sequence identity with the strain detected in the amniotic fluid was found in the oral samples of one of them and of two partners. Conclusion. This study suggests that intra-amniotic F. nucleatum could originate from the patient's or the partner's oral microflora.