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New Research Links Irritable Bowel Syndrome to Reduced Bacterial Diversity

Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder that affects the large intestine. It is characterized by symptoms such as abdominal pain, bloating, constipation, and diarrhea.

According to a team of Korean researchers, individuals with Irritable Bowel Syndrome (IBS) have a decreased diversity of bacteria in their intestines compared to healthy individuals. This is the first study to establish a clear connection between IBS and a reduction in gut microbiota diversity. The findings were published in the American Society for Microbiology’s journal Microbiology Spectrum.

Normally, “More than 10,000 speciesA species is a group of living organisms that share a set of common characteristics and are able to breed and produce fertile offspring. The concept of a species is important in biology as it is used to classify and organize the diversity of life. There are different ways to define a species, but the most widely accepted one is the biological species concept, which defines a species as a group of organisms that can interbreed and produce viable offspring in nature. This definition is widely used in evolutionary biology and ecology to identify and classify living organisms.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>species of microorganism live in the human intestine,” said corresponding author Jung Ok Shim, M.D., Ph.D., professor of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Korea University College of Medicine, Seoul. Disruption of the microbiome of the human gastrointestinal tract can trigger IBS. Typically, IBS causes bloating, diarrhea, and stomach pain or cramps.

Previous studies of gut bacteria in patients with IBS have been controversial, with inconsistent results, due to small sample size and lack of consistent analytical methods used among these studies, said Shim. The investigators combined their own dataset with 9 published, shared datasets, encompassing 576 IBS patients and 487 healthy controls, analyzing them with a “unified data processing and analytical method.”

The researchers found that the gut bacterial community is less diverse in IBS patients than in healthy people, said Shim. Additionally, the abundance of 21 bacterial species differed between IBS patients and healthy controls. However, the findings were not statistically significant in the pediatric cohort due to a small sample size.

The investigators proved that the disturbed gut bacterial community “is associated with IBS, though this does not mean that the relationship is causal,” said Shim. “Functional studies are needed to prove whether the change in gut micro-organisms contributes to the development of IBS.”

Even though IBS is a common disorder, its pathogenesis remains unknown, and as yet there is no effective treatment strategy. “Based on the epidemiological studies of IBS patients, altered gut microbiota was proposed as one of the possible causes of IBS,” the researchers write. “Acute bacterial gastroenteritis can cause chronic, asymptomatic, low-grade intestinal wall inflammation sufficient to alter neuromuscular and epithelial cell function.”

“Gut Bacterial Dysbiosis in Irritable Bowel Syndrome: a Case-Control Study and a Cross-Cohort Analysis Using Publicly Available Data Sets” by Gun-Ha Kim, Kihyun Lee and Jung Ok Shim, 18 January 2023, Microbiology Spectrum.
DOI: 10.1128/spectrum.02125-22

Source: SciTechDaily