The species and load of gastric bacteria at birth correlate with inflammation severity in very preterm infants

The relationship between the causative bacteria of intrauterine infections and complications in preterm infants remains unclear. We investigated whether the bacterial species and load of intrauterine infections directly affect the short-term outcomes and inflammation in the uterus and infants. Very preterm infants (≤30 weeks) were analyzed. For the analysis of intrauterine infection, bacteria in the neonatal gastric fluid at birth were identified, and the bacterial load was measured by quantitative polymerase chain reaction (PCR). The first PCR primer was a bacterial universal primer; the second PCR primers were specific for Ureaplasma, Mycoplasma, and bacteria other than Ureaplasma and Mycoplasma, respectively. We investigated the effects of bacterial species and load on the stage of histological chorioamnionitis (hCAM), obstetric and neonatal complications, and responses to intrauterine inflammation, like cord blood interleukin-6 (IL-6), neonatal leukocyte, neutrophils, C-reactive protein, and IgM. We examined 41 preterm infants with a mean gestational age of 26.7 weeks and mean birth weight of 933.6 g. The presence of bacteria in gastric fluid was identified in 23 infants (56%). Ureaplasma and/or Mycoplasma induced leukocytosis and neutrophilia in very preterm infants. Early-onset sepsis was significantly more common in the group with bacteria in gastric fluid. Bacterial load in gastric fluid was significantly associated with the stage of hCAM, the presence of funisitis, and level of IL-6 and neutrophils. The species and load of bacteria in gastric fluid significantly correlated with the intensity of inflammation in the uterus and preterm infants.