Maternal antenatal treatments influence initial oral microbial acquisition in preterm infants

Objective: The purpose of this study was to analyze the association of maternal antenatal therapy on initial preterm infant oral microbial acquisition of gut metabolically important bacteria: Firmicutes, Bacteroidetes, Lactobacillus, Bifidobacterium, and Bacteroides species.

Study design: Infant oral samples were collected prefeeding at 24 hours and analyzed using group-specific primers by real-time 16S rRNA quantitative polymerase chain reaction with analysis of variance and logistic regression to evaluate effect of antenatal exposure.

Results: Sixty-five infants < 34 weeks' gestational age (GA) were evaluated; mean GA was 28.6 ± 2.6 (standard deviation) weeks. Infants unexposed to antenatal treatment (n = 5) acquired < 1% Firmicutes, which was composed of 100% Lactobacillus species with no detectable Bifidobacterium, Bacteroidetes, or Bacteroides species. Infants exposed to antibiotics (n = 7), acquired fivefold less total bacterial density (TBD) with 45% Firmicutes 1.3% Lactobacillus species, 23.5% Bacteroidetes and rare Bacteroides. Compared with unexposed infants, steroids (n = 26) or steroid and antibiotics (n = 27) exposure led to an eightfold increase in TBD with < 1% Lactobacillus species and Bacteroides species 100% and 30%, respectively (p < 0.04). Bifidobacterium was undetectable in all groups.

Conclusion: Preterm infant exposure to routine maternal antenatal treatments influence early oral microbial acquisition during the primary hours related to establishment of gut commensal bacteria.