title: PREVALENCE OF SMALL INTESTINE BACTERIAL OVERGROWTH IN PATIENTS WITH GASTROINTESTINAL SYMPTOMS.
abstract: BACKGROUND
  Small intestine bacterial overgrowth is a heterogeneous syndrome characterized by an increase in the number and/or the presence of atypical microbiota in the small intestine. The symptoms of small intestine bacterial overgrowth are unspecific, encompassing abdominal pain/distension, diarrhea and flatulence. Due to the increased cost and complexity for carrying out the jejunal aspirate, the gold standard for diagnosis of the syndrome, routinely the hydrogen (H 2 ) breath test has been used, utilizing glucose or lactulose as substrate, which is able to determine, in the exhaled air, the H 2 concentration produced from the intestinal bacterial metabolism. However, due to a number of individuals presenting a methanogenic microbiota, which does not produce H 2 , the testing on devices capable of detecting, concurrently, the concentration of exhaled H 2 and methane (CH 4 ) is justified.
  
  
  OBJECTIVE
  This study aimed to determine the prevalence of small intestine bacterial overgrowth in patients with digestive symptoms, through a comparative analysis of breath tests of H 2 or H 2 and CH 4 associated, using glucose as substrate .
  
  
  METHODS
  A total of 200 patients of both sexes without age limitation were evaluated, being directed to a Breath Test Laboratory for performing the H 2 test (100 patients) and of exhaled H 2 and CH 4 (100 patients) due to gastrointestinal complaints, most of them patients with gastrointestinal functional disorders.
  
  
  RESULTS
  The results indicated a significant prevalence of small intestine bacterial overgrowth in the H 2 test and in the test of exhaled H 2 and CH 4 (56% and 64% respectively) in patients with gastrointestinal symptoms, and higher prevalence in females. It found further that methane gas was alone responsible for positivity in 18% of patients.
  
  
  CONCLUSIONS
  The data found in this study is consistent with the findings of the current literature and underscores the need for using devices capable of capturing the two gases (exhaled H 2 and CH 4 ) to improve the sensitivity and hence the accuracy of small intestine bacterial overgrowth diagnosis in daily medical practice.
authors.affiliation: Programa de Graduação, Faculdade de Ciências Médicas de Minas Gerais, MG, Brazil.
authors.forename: Carolina Piedade
authors.initials: CP
authors.lastname: Martins
authors.affiliation: Programa de Graduação, Faculdade de Ciências Médicas de Minas Gerais, MG, Brazil.
authors.forename: Caio Henrique Amorim
authors.initials: CHA
authors.lastname: Chaves
authors.affiliation: Clínica CEMAD, Belo Horizonte, MG, Brazil.
authors.forename: Maurício Gustavo Bravim de
authors.initials: MGB
authors.lastname: Castro
authors.affiliation: Programa de Pós-Graduação, Faculdade de Ciências Médicas de Minas Gerais, e da Faculdade de Medicina da Universidade Federal de Minas Gerais, MG, Brazil.
authors.forename: Isabel Cristina
authors.initials: IC
authors.lastname: Gomes
authors.affiliation: Programa de Pós-Graduação, Faculdade de Ciências Médicas de Minas Gerais, e da Faculdade de Medicina da Universidade Federal de Minas Gerais, MG, Brazil.
authors.forename: Maria do Carmo Friche
authors.initials: MDCF
authors.lastname: Passos
mesh_terms: D001765:Blind Loop Syndrome / Q000175:diagnosis*; D001944:Breath Tests / Q000379:methods*; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D007421:Intestine, Small / Q000382:microbiology*; D008297:Male; D012189:Retrospective Studies