To thrive or not to thrive: Gut microbiota studies in preterm infants

Abstract

Introduction
One of the most important factors of health is ensuring a preterm infant meets growth and development milestones however challenging this may be. Preterm infant health is closely linked to the gut microbiome, therefore this research investigated gut microbiota development including bacterial profile, bacterial load, and correlation to Z score (weight gain). In addition, the archaeal community of stool samples were investigated for the first time in the preterm population.
Methods
DNA extracted from stool was used to sequence the V4 region of the 16S rRNA gene for community analysis. Bacterial and archaeal profiles were assessed using 16S rRNA MiSeq Illumina Next Generation Sequencing (NGS) applied to preterm infant stool samples in Chapter 3 and 5. Bacterial loads of Enterococcal and Bifidobacterium, as well as Archaea were assessed using 16S rRNA gene qPCR applied to preterm infant stool samples in Chapter 4 and 5.
Results
Preterm infants with positive Z scores had greater bacterial α-diversity. There was a tentative correlation between relative abundance of Staphylococcus and Z score at DOL 20-30. Bifidobacterial abundance and load was greater in caesarean born preterm infants as opposed to vaginally delivered in healthy preterm infants. Our findings are the first to indicate a significant increase of Methanobacterium and unclassified Archaea at the OTU level, in healthy preterm infants.
Discussion
The findings compliment previous observations of a positive correlation between Z score and bacterial relative abundance. Significant differences in archaea (at the operational taxonomic unit level) between healthy and diseased preterm infants highlight the importance of early-life microbiome studies to understand how differences in colonisation may contribute to the development of health and disease. The findings provide an important account of preterm infant colonisation within the gut microbiome by bacteria and archaea.

Date of Award	31 Jul 2022
Original language	English
Awarding Institution	Teesside University
Supervisor	Gillian Taylor (Supervisor) & Caroline Orr (Supervisor)