Social and Environmental Exposures and the Developing Gut of Newborns With Congenital Heart Disease

BACKGROUND: Dysbiotic gut microbiomes are linked to morbidity, mortality, and poor outcomes, so it is critical to understand their influencing factors. OBJECTIVES: To investigate the impact of nosocomial and socioecological factors on the gut microbiome in newborns with congenital heart disease (CHD). METHODS: This was a secondary analysis of a prospective cohort of newborns with CHD matched to healthy newborns by age, sex, and race and ethnicity. Data on feeding type and routes and disease-related factors were collected from electronic medical records. Stool samples were collected at 3 perioperative time points. Gut microbiome diversity and abundance were analyzed using QIIME 2. RESULTS: Newborns with CHD (n = 41) showed higher alpha diversity (P = .007) and dissimilar beta diversity (P = .001) versus controls (n = 40). Beta diversity was dissimilar between those receiving human milk versus formula (P = .05), between those receiving fortified versus nonfortified human milk (P = .04), and between those receiving naso-orogastric tube feeds versus other routes (P = .02). Newborns with CHD fed only human milk had higher relative abundance of Haemophilus (P = .04), those with longer duration of aortic cross-clamping had lower relative abundance of Streptococcus (P = .10), and those of higher socioeconomic deprivation had higher relative abundance of Enterococcus (P = .03). CONCLUSIONS: Feeding tubes, formula exposure, aortic cross-clamp, and socioeconomic status were associated with altered gut microbiome diversity. Further study is needed to determine the causal relationships leading to gut microbial dysbiosis in newborns in the cardiac intensive care unit.