Prevalence of small intestine bacterial overgrowth in patients with gastrointestinal symptoms

Carolina Piedade MARTINS, Caio Henrique Amorim CHAVES, Maurício Gustavo Bravim de CASTRO, Isabel Cristina GOMES3 and Maria do Carmo Friche PASSOS

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 (H2) breath test has been used, utilizing glucose or lactulose as substrate, which is able to determine, in the exhaled air, the H2 concentration produced from the intestinal bacterial metabolism. However, due to a number of individuals presenting a methanogenic microbiota, which does not produce H2, the testing on devices capable of detecting, concurrently, the concentration of exhaled H2 and methane (CH4) 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 H2 or H2 and CH4 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 H2 test (100 patients) and of exhaled H2 and CH4 (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 H2 test and in the test of exhaled H2 and CH4 (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. Conclusion – 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 H2 and CH4) to improve the sensitivity and hence the accuracy of small intestine bacterial overgrowth diagnosis in daily medical practice.

HEADINGS – Bacterial growth. Small intestine. Breath tests. Hydrogen. Methane.

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Maurício Gustavo Bravim de Castro – CRM MG: 29.496

Cirurgião do aparelho digestivo do Hospital Lifecenter (2002 – 2017)

Formado em medicina pela UFMG (1995)

Residência de cirurgia geral e do trauma pelo Hospital Felício Rocho e Hospital João XXIII da Fundação Hospitalar da Estado de Minas Gerais (1998)

Membro titular do Colégio Brasileiro de Cirurgia Digestiva (CBCD)

Membro efetivo da Federação Brasileira de Gastroenterologia (FBG)

Membro do conselho consultivo da Sociedade Brasileira de Motilidade Digestiva e Neurogastroenterologia (SBMDN)

Diretor técnico do CEMAD – Centro de Motilidade do Aparelho Digestivo – Belo Horizonte