This study aims to investigate the relation between
vaginal microbiota and exposition to intra-amniotic inflammation
(IAI). We conducted a prospective cohort study in women with
preterm labor <34 weeks who had undergone amniocentesis to
rule out IAI. Vaginal samples were collected after
amniocentesis. Women with IAI included those with positive
amniotic fluid (AF) for a microorganism identified by specific
culture media and Sanger sequencing 16S ribosomal RNA gene
and/or high AF interleukin (IL)-6 levels. Vaginal microbiota was
characterized by 16S ribosomal RNA gene amplicon sequencing.
Specific quantitative PCR targeted to Lactobacillus spp. was
also performed. Regression models were used to evaluate
associations between vaginal microbiota and exposition to IAI.
Concerning our results, 64 women were included. We observed an
inverse association between AF IL-6 levels and load of
Lactobacillus spp. Depletion in Lactobacillus spp. load was
significantly associated with an early gestational age at
delivery and a short latency to delivery. Microbial-diversity
was found to be a risk factor for the subsequent occurrence of
clinical chorioamnionitis. To the contrary, higher Lactobacillus
spp. load had a protective role. In conclusion, the study
identifies reduced bacterial load of Lactobacillus spp. in women
exposed to IAI and found microbial-diversity and Lactobacillus
spp. depletion to be associated with a worse perinatal outcome