Minireviews
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Aug 6, 2022; 10(22): 7653-7664
Published online Aug 6, 2022. doi: 10.12998/wjcc.v10.i22.7653
Update on gut microbiota in gastrointestinal diseases
Atsushi Nishida, Kyohei Nishino, Masashi Ohno, Keitaro Sakai, Yuji Owaki, Yoshika Noda, Hirotsugu Imaeda
Atsushi Nishida, Kyohei Nishino, Masashi Ohno, Keitaro Sakai, Yuji Owaki, Yoshika Noda, Hirotsugu Imaeda, Department of Gastroenterology and Hepatology, Nagahama City Hospital, Nagahama 526-8580, Japan
Author contributions: Nishida A wrote the paper; Nishino K, Masashi O, Sakai K, Owaki Y, Noda Y, and Imaeda H contributed critical revision of the manuscript.
Conflict-of-interest statement: No conflict of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Atsushi Nishida, MD, PhD, Chief Doctor, Department of Gastroenterology and Hepatology, Nagahama City Hospital, 313 Oinuicho, Nagahama 526-8580, Japan. atsuda@belle.shiga-med.ac.jp
Received: February 8, 2022
Peer-review started: February 8, 2022
First decision: April 5, 2022
Revised: April 20, 2022
Accepted: June 22, 2022
Article in press: June 22, 2022
Published online: August 6, 2022
Processing time: 163 Days and 8.3 Hours
Abstract

The human gut is a complex microbial ecosystem comprising approximately 100 trillion microbes collectively known as the “gut microbiota”. At a rough estimate, the human gut microbiome contains almost 3.3 million genes, which are about 150 times more than the total human genes present in the human genome. The vast amount of genetic information produces various enzymes and physiologically active substances. Thus, the gut microbiota contributes to the maintenance of host health; however, when healthy microbial composition is perturbed, a condition termed “dysbiosis”, the altered gut microbiota can trigger the development of various gastrointestinal diseases. The gut microbiota has consequently become an extremely important research area in gastroenterology. It is also expected that the results of research into the gut microbiota will be applied to the prevention and treatment of human gastrointestinal diseases. A randomized controlled trial conducted by a Dutch research group in 2013 showed the positive effect of fecal microbiota transplantation (FMT) on recurrent Clostridioides difficile infection (CDI). These findings have led to the development of treatments targeting the gut microbiota, such as probiotics and FMT for inflammatory bowel diseases (IBD) and other diseases. This review focuses on the association of the gut microbiota with human gastrointestinal diseases, including CDI, IBD, and irritable bowel syndrome. We also summarize the therapeutic options for targeting the altered gut microbiota, such as probiotics and FMT.

Keywords: Inflammatory bowel disease; Clostridioides difficile (Clostridium) infection; Irritable bowel syndrome; Probiotics; Fecal microbiota transplantation

Core Tip: In this review, we discuss the gut microbiota in human gastrointestinal diseases, including Clostridioides difficile infection, inflammatory bowel disease, and irritable bowel syndrome. We review the role of the gut microbiota in human gastrointestinal diseases and the therapeutic options for manipulating it.