Small intestinal bacterial overgrowth and non‐alcoholic fatty liver disease diagnosed by transient elastography and liver biopsy

Abstract

Background We aimed to determine if there was a higher incidence of small intestinal bacterial overgrowth (SIBO) in non‐alcoholic fatty liver disease (NAFLD) than in patients without NAFLD. Moreover, we assessed whether patients with significant fibrosis (SF) had a higher incidence of SIBO compared with patients with non‐significant or no liver fibrosis. Methods NAFLD was diagnosed in 117 patients by using Fibroscan with a controlled attenuation parameter (CAP) as well as liver biopsy (LB). SIBO was defined by esophagogastroduodenoscopy with an aspiration of the descending duodenum. Results Patients with non‐alcoholic steatohepatitis (NASH) and those with SF on LB had a significantly higher incidence of SIBO than patients without NASH and those without SF, respectively (P < .05). According to histological characteristics, there was a higher proportion of patients in the SIBO group with higher steatosis and fibrosis grade, lobular and portal inflammation, and ballooning grade (P < .001). In multivariate analysis, significant predictors associated with SF and NASH were type 2 diabetes mellitus (T2DM) and SIBO. Moreover, in multivariate analysis, significant predictors that were independently associated with SIBO were T2DM, fibrosis stage and ballooning grade (OR 8.80 (2.07‐37.37), 2.50 (1.16‐5.37) and 27.6 (6.41‐119), respectively). The most commonly isolated were gram‐negative bacteria, predominantly Escherichia coli and Klebsiella pneumoniae. Conclusion In this relatively large population of patients, we used a gold standard for both SIBO (quantitative culture of duodenum's descending part aspirate) and NAFLD (LB), and we demonstrated that NASH patients and those with SF had a higher incidence of SIBO. Moreover, significant predictors independently associated with SIBO were T2DM, fibrosis stage and ballooning grade. Although TE is a well‐investigated method for steatosis and fibrosis detection, in our study, independent predictors of SIBO were histological characteristics of NAFLD, while elastographic parameters did not reach statistical significance.

Gut‐liver axis‐mediated mechanism of liver cancer: A special focus on the role of gut microbiota

“…However, SIBO and metabolite changes seem to be frequently observed in patients with NAFLD (MAFLD)/NASH, regardless of the gut microbial species in the patient. 76 , 77 , 78 Specifically, SIBO plays an important role in NASH development and progression, given that it enhances intestinal permeability by disrupting intercellular tight junctions in the gut. 79 , 80 It also enhances the expression of TLR‐4 as well as CD14, which is a co‐receptor molecule of TLR4, in the immune cells of the liver, 81 , 82 leading to inflammatory cytokine release.…”

The Role of Insulin Resistance in Fueling NAFLD Pathogenesis: From Molecular Mechanisms to Clinical Implications

“…Consistently, the evidence has also revealed a strong association between NAFLD and small intestinal bacterial overgrowth (SIBO) [38][39][40]. Recently, Mikolasevic et al, by assessing SIBO through the esophagogastroduodenoscopy aspiration of the descending duodenum, demonstrated a higher incidence of advanced NAFLD spectra [41]. Furthermore, a previous work pointed out significantly higher serum endotoxin levels in NAFLD patients with SIBO, suggesting a key pathogenetic role [42].…”

Novel approaches to intervene gut microbiota in the treatment of chronic liver diseases

“…Therefore, HiAlc Kpn gavage plus high‐fat diet further accelerated the development of NAFLD in mice 18 . Moreover, K. pneumoniae was found to be among the most common bacteria isolated from 117 NAFLD patients with SIBO, supporting that this microbe is highly associated with the pathogenesis of NAFLD 35 …”

“…18 Moreover, K. pneumoniae was found to be among the most common bacteria isolated from 117 NAFLD patients with SIBO, supporting that this microbe is highly associated with the pathogenesis of NAFLD. 35…”