Small Intestinal Bacterial Overgrowth

2021 ◽  
pp. 567-584
Author(s):  
David Avelar Rodriguez ◽  
Paul MacDaragh Ryan ◽  
Eamonn Martin Mary Quigley
2016 ◽  
Vol 25 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Andrea Fialho ◽  
Andre Fialho ◽  
Prashanthi Thota ◽  
Arthur J. McCullough ◽  
Bo Shen

Background: Changes in gut bacteria play a role in type 2 diabetes mellitus (DM) and hepatic steatosis. There is a lack of studies evaluating the frequency and risk factors for non-alcoholic fatty liver disease (NAFLD) in patients tested for small intestinal bacterial overgrowth (SIBO). Aim: To evaluate the frequency of NAFLD and associated risk factors in patients tested for SIBO. Methods: In this case-control study, 372 eligible patients submitted to glucose hydrogen/methane breath test for SIBO who also had an abdominal imaging study were included. Patients were divided into SIBO-positive and SIBO-negative groups. Clinical, demographic and laboratory variables were evaluated in addition to the presence of NAFLD on abdominal imaging. Results: Of the 372 eligible patients, 141 (37.9%) were tested positive for SIBO (study group) and 231 (62.1%) were negative for it (control group). NAFLD occurred in 45.4% (64/141) of the study group compared to 17.3% (40/231) of the control group (p<0.001). Patients in the study group were found to have higher rates of elevated aspartate aminotransferase (AST) (20.6% vs. 11.3%; p=0.034) and alanine aminotransferase (ALT) levels (56.0% vs. 40.7%; p= 0.039), type 2 diabetes (23.4% vs. 13.9%; p=0.041), hypertension (54.6% vs. 40.3%; p=0.046) and metabolic syndrome (78.0% vs. 60.2%; p=0.020). In the multivariate analysis, SIBO (odds ratio [OR]: 1.95; 95% confidence interval [CI]: 1.14-3.31; p=0.014), type 2 DM (OR: 3.04; 95%CI: 1.57-5.90; p=0.001) and obesity (OR: 3.58; 95%CI: 1.70-7.54; p=0.001) remained associated with NAFLD.Conclusion: Patients with SIBO have an increased risk for hepatic steatosis and may benefit from aggressive control of the risk factors for NAFLD including metabolic syndrome. Abbreviations: ALT: alanine aminotransferase; AST: aspartate aminotransferase; BMI: body mass index; CTE: computed tomography enterography; DM: diabetes mellitus; ETOH: ethanol; IL: interleukin; LPS: lipopolysaccharide; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; PPI: proton pump inhibitor; SIBO: small intestinal bacterial overgrowth; TLR-4: toll-like receptor 4; TMAO: trimethylamine-N-oxide (TMAO); TNF-α: tumor necrosis factor alpha.


2017 ◽  
Vol 08 (01) ◽  
pp. 12-16
Author(s):  
Ioana Gabriela Moraru ◽  
Dan Lucian Dumitraşcu

Abstract Background and Aim: Small intestinal bacterial overgrowth (SIBO) is associated with gastrointestinal pathology and colonoscopy. This endoscopic investigation could cause changes in gut flora including the occurrence of SIBO. We looked in this study for the effect of colonoscopy (preparation and intubation) on the occurrence of SIBO. Materials and Methods: Prospective study including thirty patients with irritable bowel syndrome (IBS) diagnosed according to Rome III criteria. Two groups were designed: Twenty IBS patients that performed colonoscopy (G1) and ten IBS patients (G2) not referred to colonoscopy. All patients have been tested for the presence of SIBO using glucose hydrogen breath tests (GHBT) at the beginning of the study, on day 1. G1 patients have also been tested before colonoscopy (day 2) and 1 week after (day 9). G2 patients performed GHBT on day 1 and on day 9. Results: The peak value of expired H2 was assessed, and the mean value was calculated. There were no significant statistical differences between the mean H2 values in the 2 groups of patients on day 1. The mean level of H2 significantly decreased after preparing for colonoscopy in G1 patients (P < 0.0001). There were no significant statistical differences between the mean levels of H2 on day 2 versus day 9 in G1 patients (P = 0.176). The mean level of H2 1 week after performing colonoscopy (7.65 ppm) is higher than that obtained after preparing for it (6.3 ppm), but no statistical significance. Patients from G2 showed no statistical differences between the mean levels of H2 on day 1 versus day 9 (P = 0.6132). Patients in G1 had a significantly lower mean H2 level versus G2 patients on day 9. Conclusions: Colonoscopy does not produce SIBO. Preparing for colonoscopy influences the level of expired H2, it reduces the number of intestinal bacteria, probably trough a mechanic effect or by inflating air during the procedure. Performing GHBT too soon after colonoscopy might result in false negative results of GHBT.


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