Records Links
Author Walker, R.W.; Clemente, J.C.; Peter, I.; Loos, R.J.F. file  url
openurl 
Title The prenatal gut microbiome: are we colonized with bacteria in utero? Type Journal Article
Year 2017 Publication Pediatric Obesity Abbreviated Journal Pediatr Obes  
Volume 12 Suppl 1 Issue Pages 3-17  
Keywords Animals; Bacteria; Delivery, Obstetric; Female; Fetus/*microbiology; *Gastrointestinal Microbiome; Humans; Infant; Infant, Newborn; Mothers; Pregnancy; Bacteria; foetal development; gut microbiome; pregnancy  
Abstract The colonization of the gut with microbes in early life is critical to the developing newborn immune system, metabolic function and potentially future health. Maternal microbes are transmitted to offspring during childbirth, representing a key step in the colonization of the infant gut. Studies of infant meconium suggest that bacteria are present in the foetal gut prior to birth, meaning that colonization could occur prenatally. Animal studies have shown that prenatal transmission of microbes to the foetus is possible, and physiological changes observed in pregnant mothers indicate that in utero transfer is likely in humans as well. However, direct evidence of in utero transfer of bacteria in humans is lacking. Understanding the timing and mechanisms involved in the first colonization of the human gut is critical to a comprehensive understanding of the early life gut microbiome. This review will discuss the evidence supporting in utero transmission of microbes from mother to infants. We also review sources of transferred bacteria, physiological mechanisms of transfer and modifiers of maternal microbiomes and their potential role in early life infant health. Well-designed longitudinal birth studies that account for established modifiers of the gut microbiome are challenging, but will be necessary to confirm in utero transfer and further our knowledge of the prenatal microbiome.  
Call Number Serial 2081  
Permanent link to this record
 

 
Author Dzidic, M.; Abrahamsson, T.R.; Artacho, A.; Bjorksten, B.; Collado, M.C.; Mira, A.; Jenmalm, M.C. file  url
openurl 
Title Aberrant IgA responses to the gut microbiota during infancy precede asthma and allergy development Type Journal Article
Year 2017 Publication The Journal of Allergy and Clinical Immunology Abbreviated Journal J Allergy Clin Immunol  
Volume 139 Issue 3 Pages 1017-1025.e14  
Keywords Bacteria/isolation & purification; Bacterial Load; Child; Child, Preschool; Feces/*microbiology; Female; *Gastrointestinal Microbiome; Humans; Hypersensitivity/*immunology/*microbiology; Immunoglobulin A/*immunology; Infant; Male; Allergic disease; IgA index; IgA recognition patterns; asthma; childhood; gut microbiota; microbiome composition; secretory IgA  
Abstract BACKGROUND: Although a reduced gut microbiota diversity and low mucosal total IgA levels in infancy have been associated with allergy development, IgA responses to the gut microbiota have not yet been studied. OBJECTIVE: We sought to determine the proportions of IgA coating together with the characterization of the dominant bacteria, bound to IgA or not, in infant stool samples in relation to allergy development. METHODS: A combination of flow cytometric cell sorting and deep sequencing of the 16S rDNA gene was used to characterize the bacterial recognition patterns by IgA in stool samples collected at 1 and 12 months of age from children staying healthy or having allergic symptoms up to 7 years of age. RESULTS: The children with allergic manifestations, particularly asthma, during childhood had a lower proportion of IgA bound to fecal bacteria at 12 months of age compared with healthy children. These alterations cannot be attributed to differences in IgA levels or bacterial load between the 2 groups. Moreover, the bacterial targets of early IgA responses (including coating of the Bacteroides genus), as well as IgA recognition patterns, differed between healthy children and children with allergic manifestations. Altered IgA recognition patterns in children with allergy were observed already at 1 month of age, when the IgA antibodies are predominantly maternally derived in breast-fed children. CONCLUSION: An aberrant IgA responsiveness to the gut microbiota during infancy precedes asthma and allergy development, possibly indicating an impaired mucosal barrier function in allergic children.  
Call Number Serial 1933  
Permanent link to this record