Data from: Trends and determinants of gastric bacterial colonization of preterm neonates in a NICU setting

Background: Newborn gastrointestinal (GI) tract is considered sterile but
rapidly acquires a diverse microbiota from its intimate environment. Early
acquisition of a bacterial species in the upper GI tract may play a role
in establishing the colonic microbiota. There is paucity of molecular data
on the upper GI tract microbiota in preterm neonates. Methods: Gastric
aspirates from 22 neonates with an average gestational age 27.7 weeks
(±2.8), weighing 973.2 grams (±297.9) admitted to a neonatal intensive
care unit were collected prospectively from weeks 1-4 of life. All samples
were evaluated for microbiota using 16S rRNA-based Denaturing Gradient Gel
Electrophoresis. Bacterial species colonization and its association with
maternal and neonatal demographics, and neonatal clinical characteristics
were analyzed. Results: Bacteroides spp. was the predominant species in
all four weeks. Bifidobacterium spp. colonization was significantly higher
in exclusively breast milk fed compared to partially breast milk (PBM) fed
neonates in first (p = 0.03) and third (p = 0.03) week of life. Anaerobic
bacteria colonization decreased from first through fourth week of life (p
= 0.03). Aerobic bacteria colonization was highly dynamic throughout the
four week period. Premature rupture of membrane (p = 0.05) and birth
outside of study hospital (p = 0.006) influenced the acquisition of
bacteria in the first week of life. Birth weight was positively correlated
with total number of bacterial species (p = 0.002) and anaerobes (p =
0.004) in PBM-fed neonates during the fourth week of life. H. pylori and
Ureaplasma were not detected in any of our samples. Conclusion: Gastric
bacterial colonization in preterm neonates is unstable during early weeks
of life. Delayed oral feeding and use of antibiotics may be responsible
for paucity of bacterial species. Monitoring of the gastric microbiota and
concurrent examination of stool microbiota may yield important information
on the utility of gastric signature patterns for predicting colon
microbiota that may drive GI and immune dysfunctions.