Association of specific microbiota taxa in the amniotic fluid at birth with severe acute and longer-term outcomes of very preterm infants: a prospective observational study.

Background: Dysbiotic microbial colonization predisposes to severe outcomes of prematurity, including mortality and severe morbidities like necrotizing enterocolitis (NEC), late-onset infection (LOI) and bronchopulmonary dysplasia (BPD). Here, we studied the variations in the bacterial signatures in the amniotic fluid (AF) of very preterm deliveries < 32 weeks with severe acute and longer-term outcomes within a prospective cohort study.

Methods: One hundred twenty-six AF samples were available for 16S rRNA gene metabarcoding to describe bacterial community structure and diversity in connection to intraventricular haemorrhage (IVH), LOI, focal intestinal perforation (FIP), NEC, retinopathy of prematurity (ROP) and the 2-year cognitive (MDI) and motor (PDI) outcome.

Results: Diversity and overall bacterial community composition did not differ between the studied outcomes. But disparities in sequences assigned to single bacterial taxa were observed for the acute outcomes LOI and ROP and the longer-term impairments of MDI and PDI. Enrichments associated with a poor acute outcome were particularly detected in the Escherichia-Shigella cluster, while the predominance of Ureaplasma and Enterococcus species was associated with unrestricted acute and longer-term outcomes. Analysis for FIP did not reach any significance. IVH and NEC constituted rare events, prohibiting the analyses.

Conclusions: Our data provide evidence that microbiota patterns at birth might allow the early identification of infants at risk for the severe outcomes of prematurity and argue against morbidity-specific associations. The data support the early origins hypothesis and relevant contribution of prenatal factors. The partly existing disparities between acute and longer-term outcomes might be traced back to the relevant impact of the diverse longitudinal exposures and socioeconomic factors.