title: Intestinal microbiota and allergic diseases: A systematic review.
abstract: Evidence suggests that possible imbalances in intestinal microbiota composition may be implicated in the occurrence of allergic diseases. Although several studies published until 2006 indicated a correlation between microbiota composition and allergic symptoms, it has not been possible to distinguish protective microorganisms from those associated with increased risk of allergic diseases. Therefore, the objective of this study was to review the studies published since 2007 that address the intestinal microbiota in allergic diseases. Twenty-one studies were identified after excluding those that performed a clinical intervention before stool collection. In the early microbiota of children who later developed allergies, lower bacterial diversity was observed, with a predominance of Firmicutes; a higher count of Bacteroidaceae; a higher prevalence of the anaerobic bacteria Bacteroides fragilis, Escherichia coli, Clostridium difficile, Bifidobacterium catenulatum, Bifidobacterium bifidum, and Bifidobacterium longum; and a lower prevalence of Bifidobacterium adolescentis, B. bifidum, and Lactobacillus. In the microbiota of allergic children whose intestinal microbiota was assessed at the onset of allergic symptoms, there was a higher count of Bacteroides; a lower count of Akkermansia muciniphila, Faecalibacterium prausnitzii, and Clostridium; a higher prevalence of B. adolescentis; a lower prevalence of B. catenulatum and Staphylococcus aureus; and a lower bacterial diversity.
authors.affiliation: Division of Pediatric Gastroenterology, Department of Pediatrics, Federal University of São Paulo/UNIFESP, São Paulo, Brazil; Biological and Health Sciences Department, University Center UNIFIEO, Osasco, São Paulo, Brazil.
authors.forename: L C F L
authors.initials: LC
authors.lastname: Melli
authors.affiliation: Biological and Health Sciences Department, University Center UNIFIEO, Osasco, São Paulo, Brazil.
authors.forename: M S
authors.initials: MS
authors.lastname: do Carmo-Rodrigues
authors.affiliation: Division of Pediatric Gastroenterology, Department of Pediatrics, Federal University of São Paulo/UNIFESP, São Paulo, Brazil; Biological and Health Sciences Department, University Center UNIFIEO, Osasco, São Paulo, Brazil.
authors.forename: H B
authors.initials: HB
authors.lastname: Araújo-Filho
authors.affiliation: Division of Allergy, Clinical Immunology and Rheumatology, Department of Pediatrics, Federal University of São Paulo/UNIFESP, São Paulo, Brazil.
authors.forename: D
authors.initials: D
authors.lastname: Solé
authors.affiliation: Division of Pediatric Gastroenterology, Department of Pediatrics, Federal University of São Paulo/UNIFESP, São Paulo, Brazil. Electronic address: ligiamelli@gmail.com.
authors.forename: M B
authors.initials: MB
authors.lastname: de Morais
mesh_terms: D000818:Animals; D001438:Bacteroidaceae; D044822:Biodiversity; D002648:Child; D000068536:Bacillota; D000069196:Gastrointestinal Microbiome; D006801:Humans; D006967:Hypersensitivity / Q000178:diet therapy / Q000382:microbiology*; D007422:Intestines / Q000276:immunology / Q000382:microbiology*; D019936:Probiotics / Q000627:therapeutic use
keywords: Allergy; Asthma; Bacteria; Eczema; Intestine; Microbiota; Rhinitis