Introduction: Probiotics may reduce the prevalence of necrotizing enterocolitis in early preterm infants and are increasingly used in Neonatal Intensive Care Units (NICU). The long-term impact of probiotics on the preterm gut remains unclear. We hypothesized that a probiotic containing four Bifidobacterium strains would colonize the hospitalized preterm infant gut.
Methods: Stool was collected every other day from hospitalized preterm infants enrolled in the Baby & Pre-Mi study, as well as at term, 6 weeks, 12 weeks, and 5 months corrected age (CA). A policy change introduced probiotics to the study NICU, resulting in probiotic exposure for 8 infants (PT-P). 14 infants without exposure to this probiotic (PT-C) and a cohort of healthy, unexposed full-term infants from the Baby & Mi study (FT-C), were used as comparator groups. Microbial community profiling was completed through amplification of the v3 region of the 16S rRNA gene and subsequent DNA sequencing with the Illumina platform. Amplicon sequence variants (ASVs) were inferred from trimmed data using the DADA2 pipeline.
Results: Four Bifidobacterium ASVs were found to be highly abundant in PT-P infants compared to PT-C infants following probiotic supplementation. The relative abundance of these suspected probiotic ASVs was significantly higher at term in PT-P infants and remained elevated to 5 months CA. No significant differences in the abundance of these ASVs were detected between groups at 5 months. At term, the gut microbiome of PT-P infants more closely resembled the gut microbiome of 10-day old FT-C infants than PT-C infants at term. The gut microbiota of both preterm groups converged with the term-born gut microbiomes by 6 weeks CA.
Conclusion: Suspected probiotic strains of bacteria may persist up to 5 months post-supplementation and potentially colonize the preterm infant gut. Further research is needed to understand their impact on the gut microbiome and infant health.
Marilia Carvalho– Research Coordinator, Department of Pediatrics, McMaster University
Sara Dizzell– Research Assistant, Department of Medicine, McMaster University
Stephanie Kim– Undergraduate Student, Department of Pediatrics, McMaster University
Elizabeth Gunn– Clinical Research Coordinator, Department of Pediatrics, McMaster University, Centre for Metabolism, Obesity and Diabetes Research
Eileen Hutton– Professor Emeritus, Department of Obstetrics & Gynecology, McMaster University, Co-Principal Investigators of the Baby & Mi Study
Katherine Morrison– Associate Professor, Department of Pediatrics, McMaster University, Centre for Metabolism, Obesity and Diabetes Research, Co-Principal Investigators of the Baby & Mi Study
Jennifer Stearns– Assistant Professor, Department of Medicine, McMaster University