Year: 2019
Type: dissertation
Study design: Observational Study
Abstract: Preterm infants are especially vulnerable to dysbiosis since their early gut microbiota is less abundant and diverse. When the first microbial colonizers reach infants’ gut remains an open question. It is assumed that maternal microbiota can influence the infants’ gut colonization, making it a critical player in the offspring’s immune and endocrine systems, as well as in metabolic health. Infant feeding has been reported as a major factor influencing the gut microbiota. Thus, studying the preterm infant gut microbiota is a research priority to complement nutritional neonatal care. Objective: The aim of this study was to evaluate the influence of different types of infant-feeding on the gut microbiota preterm infants. In addition, it was evaluated the preterm infants’ meconium colonization and the influence of vertical microbiota transmission. Methodology: The FEEDMI Trial is an observational longitudinal study that included very preterm infants (≤ 32 weeks of gestational age), hospitalized in the neonatal intensive care unit of Maternidade Dr. Alfredo da Costa. A total of four meconium and fecal samples from preterm infants were collected. Mothers were also asked to collect their fecal samples. Bacterial DNA present was extracted from samples and specific bacterial groups were quantified by RT-PCR. Results: In total, 453 fecal samples were processed from 117 preterm infants and their mothers. 88% of meconium samples were colonized. Proteobacteria and Firmicutes were the most abundant phyla during the first 26th postnatal days of infants. Meconium microbiota of preterm infants born between 28 and 32 weeks gestation showed stronger correlations with their mothers’ microbiota, as well as infants born by cesarean. Maternal factors significantly influenced the offspring’s microbiota, specially the pre-gestational body mass index. Mode of delivery had a limited impact on infants’ meconium with C-section promoting a greater amount of E. coli. Infant feeding takes time to influence the gut microbiota of preterm infants. When adjusted for gestational age, antibiotherapy and maternal diet, mothers’ own milk (MOM) promoted a healthier gut microbiota with higher levels of total bacteria and Bifidobacterium compared to donor human milk (DHM) and formula. Nevertheless, these differences were lower in DHM than formula fed infants. It was also observed lower levels of Firmicutes in infants fed with formula after adjusting for the same factors. Conclusions: The findings of this thesis suggest that infants’ meconium may have bacterial DNA prior to birth and maternal factors may have a central role in this process. Furthermore, this thesis highlights the importance of human milk on gut microbiota composition of infants prematurely-delivered with MOM promoting higher levels of total bacteria and Bifidobacterium, which may be translated in future healthier outcomes.
Author: Juliana Morais
Language: English
Topic: Infant Nutrition and Health
Subfield: Nutrition and Dietetics
Field: Nursing
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2997816543