Clinical Trials Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 28, 2017; 23(48): 8591-8596
Published online Dec 28, 2017. doi: 10.3748/wjg.v23.i48.8591
Association between acute pancreatitis and small intestinal bacterial overgrowth assessed by hydrogen breath test
Mei Zhang, Hong-Ming Zhu, Fang He, Bang-Yi Li, Xiao-Cui Li
Mei Zhang, Hong-Ming Zhu, Fang He, Bang-Yi Li, Xiao-Cui Li, Department of Gastroenterology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
Author contributions: Zhang M designed the research; Zhu HM and He F performed the research; Li BY and Li XC analyzed the data; Zhang M wrote the paper.
Supported by Wu Jieping Medical Foundation, No. 320.6750.12120.
Institutional review board statement: The study was reviewed and approved by the Department of Gastroenterology of Xuanwu Hospital, Capital Medical University.
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: None of the authors has a conflict of interest to disclose.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Mei Zhang, MD, Professor, Chief Physician, Department of Gastroenterology, Xuanwu Hospital, Capital Medical University No. 45, Changchun Street, Xicheng District, Beijing 100053, China. zhang2955@sina.com
Telephone: +86-10-83198438 Fax: +86-10-83198438
Received: November 28, 2017
Peer-review started: November 28, 2017
First decision: December 6, 2017
Revised: December 12, 2017
Accepted: December 13, 2017
Article in press: December 13, 2017
Published online: December 28, 2017
Processing time: 29 Days and 6.1 Hours
ARTICLE HIGHLIGHTS
Research background

Current clinical and animal studies have shown that gut bacterial overgrowth and translocation is the main reason of pancreatic secondary infection. Small intestinal bacterial overgrowth (SIBO) is related to various disorders, including irritable bowel syndrome, non-alcoholic fatty liver disease, inflammatory bowel disease, and pancreatitis. Many experimental animal studies have shown that SIBO can affect the severity and progression of AP. Previous studies have shown that the pathogenic bacteria leading to pancreatic infection are similar to the opportunist species that overgrow in the small intestine, suggesting that SIBO plays a pivotal role in pancreatic infection. A recent study suggested that prophylactic total colectomy in patients with AP induces SIBO involving both Gram-negative bacilli (Escherichia coli, Proteus spp.) and anaerobic bacteria. We performed the present study to investigate the incidence of SIBO in AP with different severity grades and explore the correlation between SIBO and complications of AP.

Research motivation

Clinical studies have revealed that in SAP patients with intestinal flora disorders, gut barrier dysfunction has a significant impact on the disease occurrence, development, and prognosis. The research on SIBO in AP is mostly confined to animal experiments. The traditional method of diagnosing SIBO is to take small intestinal fluid for bacterial culture, but it is difficult to achieve in clinical patients. In this study, a portable hydrogen expiratory detector was used to detect the patients’ expired hydrogen concentration to diagnose SIBO. In the early stages of AP disease, monitoring gut microbiota and timely treatment can improve the prognosis.

Research objectives

How to protect the integrity of the intestinal mucosal barrier, maintain its function, adjust the intestinal flora disorders, and reduce and prevent bacterial translocation of the intestine has become the key to control the development of SAP and reduce complications. We performed the present study to investigate the incidence of SIBO in AP with different severity grades and explore the correlation between SIBO and complications of AP.

Research methods

Hydrogen breath test principle: After taking lactulose, it reaches the colon and is fermented and decomposed by bacteria to produce hydrogen, causing a peak of hydrogen content in the colon. If there is SIBO, lactulose is fermented by overgrowing bacteria to produce hydrogen before entering the colon. Thus, a peak of hydrogen concentration in the small intestine peak occurs. Expiratory changes in hydrogen concentration can reflect the growth of bacteria in the small intestine. Different from the traditional monitoring methods, in this study, a portable hydrogen expiratory detector was used to detect the patients’ expired hydrogen concentration to diagnose SIBO.

Research results

It was found that there were differences in the positive rates of SIBO in AP with different severity grades. Of the 27 patients with SAP, seven (25.92%) had SIBO. Of the 86 patients with MSAP, 22 (25.58%) had SIBO. Of the 95 patients with MAP, eight (8.42%) had SIBO. There were significant differences in these rates of SIBO positivity among patients with AP of different severities. Patients with more severe pancreatitis had higher positive rate of SIBO. SIBO occurred mainly within 72 h of onset. Patients with SIBO are more prone to organ failure complications. How to take timely and effective measures to deal with SIBO is a problem to be solved.

Research conclusions

In the present study, patients with MSAP and SAP were more susceptible to SIBO than patients with MAP. SIBO occurred mainly in the early stage of AP and was related to organ failure. How to intervene in the presence of SIBO in patients with SAP in the early stage will be of guiding significance to reduce early organ failure and late infectious complications.

Research perspectives

Which method can be used to effectively prevent or treat small intestinal bacterial overgrowth in patients with AP, while monitoring the intestinal mucosal barrier, is the future research direction.