Early-Life Development of the Bifidobacterial Community in the Infant Gut

Abstract

The establishment of the gut microbiota poses implications for short and long-term health. Bifidobacterium is an important taxon in early life, being one of the most abundant genera in the infant intestinal microbiota and carrying out key functions for maintaining host-homeostasis. Recent metagenomic studies have shown that different factors, such as gestational age, delivery mode, or feeding habits, affect the gut microbiota establishment at high phylogenetic levels. However, their impact on the specific bifidobacterial populations is not yet well understood. Here we studied the impact of these factors on the different Bifidobacterium species and subspecies at both the quantitative and qualitative levels. Fecal samples were taken from 85 neonates at 2, 10, 30, 90 days of life, and the relative proportions of the different bifidobacterial populations were assessed by 16S rRNA–23S rRNA internal transcribed spacer (ITS) region sequencing. Absolute levels of the main species were determined by q-PCR. Our results showed that the bifidobacterial population establishment is affected by gestational age, delivery mode, and infant feeding, as it is evidenced by qualitative and quantitative changes. These data underline the need for understanding the impact of perinatal factors on the gut microbiota also at low taxonomic levels, especially in the case of relevant microbial populations such as Bifidobacterium. The data obtained provide indications for the selection of the species best suited for the development of bifidobacteria-based products for different groups of neonates and will help to develop rational strategies for favoring a healthy early microbiota development when this process is challenged.

Effect of Intrapartum Antibiotics Prophylaxis on the Bifidobacterial Establishment within the Neonatal Gut

“…It was recently described [ 63 ] that the delivery mode affects the bifidobacterial establishment. To investigate the impact of the mother’s antibiotic administration on the gut bifidobacterial composition independently of the mode of labour, we used an ANVOCA method controlling the delivery mode as covariable.…”

“…This study analysed the effect of the IAP on the Bifidobacterium (sub)species establishment in full-term babies until three months of age. The ITS sequencing technique, which has been previously employed to assess other perinatal factors, such as gestational age, delivery and feeding mode [ 63 ], the effect of donated milk on the premature bifidobacterial community [ 66 ] or to study the vertical transmission of bifidobacteria [ 65 ], allowed us to thoroughly unveil the effect of the IAP—going a step beyond conventional studies which only used 16S sequencing information at the genus level. This technique can be used for tracking bifidobacterial (sub)species in a more accurate way than the use of other techniques.…”

“…Several studies have shown lower levels or reduced relative abundances of bifidobacteria on infant populations in different scenarios, such as prematurity, obesity, later sepsis, colics [ 19 , 59 , 60 , 61 , 62 ]. This occurs because the levels and diversity of bifidobacteria depend on different perinatal factors, as was reported in a recent publication [ 63 ]. Among them, antibiotics deeply affected the Bifidobacterium genus, which could disrupt the crosstalk with the immune system [ 44 ].…”

“…However, this has provided limited knowledge on the impact of IAP at lower taxonomical levels. To overcome this limitation, developing next-generation techniques, such as the sequencing of the Internally Transcribed Spacer (ITS) within the rRNA locus [ 64 ], was useful as marker of Bifidobacterium species, as it has been demonstrated in studies focused on the vertical transmission of bifidobacteria [ 65 ], the effect of using donor and own-mother’s milk on the premature bifidobacterial community [ 66 ] or the impact of several perinatal factors on the establishment of Bifidobacterium species in premature and full-term babies [ 63 ].…”

Neurotransmitter Profiles Are Altered in the Gut and Brain of Mice Mono-Associated with Bifidobacterium dentium

“…During this early developmental period, the gut microbiota is dominated by the genus Bifidobacterium (phylum Actinobacteria) [32][33][34][35][36][37][38]. Bifidobacteria species dominant in human infants include B. longum, B. longum subspecies infantis, B. breve, B. bifidum, B. catenulatum, B. adolescentis, B. angulatum, B. animalis, and B. dentium [39][40][41][42][43]. These early-life Bifidobacteria have been shown by several groups to beneficially modulate the gut-brain axis.…”