Featured Research

from universities, journals, and other organizations

Scientists find key to growth of 'bad' bacteria in inflammatory bowel disease

Date:
February 7, 2013
Source:
University of California - Davis Health System
Summary:
Scientists have long puzzled over why "bad" bacteria such as E. coli can thrive in the guts of those with inflammatory bowel disease (IBD), causing serious diarrhea. Now researchers have discovered the answer -- one that may be the first step toward finding new and better treatments for IBD.

Sebastian E. Winter (left) and Andreas J. Bδumler have discovered why potentially harmful bacteria can thrive in inflammatory bowel disease, paving the way for the development of new and better treatments.
Credit: Image courtesy of University of California - Davis Health System

Scientists have long puzzled over why "bad" bacteria such as E. coli can thrive in the guts of those with inflammatory bowel disease (IBD), causing serious diarrhea. Now UC Davis researchers have discovered the answer -- one that may be the first step toward finding new and better treatments for IBD.

Related Articles


The researchers discovered a biological mechanism by which harmful bacteria grow, edge out beneficial bacteria and damage the gut in IBD. This new understanding, published in the Feb. 8 issue of Science, may help researchers develop new treatments for IBD with fewer side effects than current therapies.

IBD begins when "good" bacteria are mistakenly killed by the immune system, while harmful bacteria multiply -- resulting in inflammation and damage to the intestines, and chronic episodes of abdominal pain, cramping, diarrhea and other changes in bowel habits. It's estimated that IBD, which includes ulcerative colitis and Crohn's disease, affects 1.4 million people in the U.S., according to the Centers for Disease Control and Prevention.

In test-tube and animal studies, the researchers found that potentially harmful bacteria in the intestine called Enterobacteriaceae use nitrate -- a byproduct formed during the intestinal inflammation in IBD -- to grow and thrive. Enterobacteriaceae strains include certain E. coli bacteria, which can worsen the intestinal damage of IBD. Eventually, the intestines of those with IBD become overrun by harmful bacteria, and the numbers of normal good bacteria in the gut decrease.

"Much like humans use oxygen, E. coli can use nitrate as a replacement for oxygen to respire, produce energy and grow," said lead author Andreas Baumler, a professor of medical microbiology and immunology at UC Davis.

"In IBD, nitrate produced by inflammation in the gut allows E. coli to take a deep 'breath,' and beat out our beneficial microbes in the competition for nutrients," he said.

The inflammation in the intestines of those with IBD leads to the release of nitric oxide radicals that are powerful in attacking bacteria, Baumler explained. Yet these nitric oxide radicals are also very unstable, and eventually decompose into nitrate, which can be used by bacteria like E. coli to thrive and grow. By contrast, good bacteria in the gut grows through fermentation -- a much slower process.

Determining the reasons why bacteria like E. coli can edge out good bacteria in the gut is crucial for determining new ways to halt the IBD disease process, according to Baumler. Current treatments for IBD suppress the immune response through antibiotics, corticosteroids or other powerful immune-modifying drugs. But long-term side effects can limit their use and their effectiveness for IBD patients.

The UC Davis team's research indicates that targeting the molecular pathways that generate nitric oxide and nitrate, as well as other molecules that feed harmful gut bacteria, could calm down and normalize the intestinal environment in IBD, Baumler noted. They are already doing research with one candidate drug that could halt the multiple pathways by which harmful bacteria thrive in IBD.

"The idea would be to inhibit all pathways that produce molecules that can be used by bacteria such as E. coli for respiration and growth," Baumler said. "Essentially you could then smother the bacteria."

This work was supported by the California Agricultural Experiment Station and Public Health Service grants AI089078, AI076246 and AI088122 along with a scholarship from the Faculty of Medicine, Chiang Mai University, Thailand.


Story Source:

The above story is based on materials provided by University of California - Davis Health System. Note: Materials may be edited for content and length.


Journal Reference:

  1. S. E. Winter, M. G. Winter, M. N. Xavier, P. Thiennimitr, V. Poon, A. M. Keestra, R. C. Laughlin, G. Gomez, J. Wu, S. D. Lawhon, I. E. Popova, S. J. Parikh, L. G. Adams, R. M. Tsolis, V. J. Stewart, A. J. Baumler. Host-Derived Nitrate Boosts Growth of E. coli in the Inflamed Gut. Science, 2013; 339 (6120): 708 DOI: 10.1126/science.1232467

Cite This Page:

University of California - Davis Health System. "Scientists find key to growth of 'bad' bacteria in inflammatory bowel disease." ScienceDaily. ScienceDaily, 7 February 2013. <www.sciencedaily.com/releases/2013/02/130207172102.htm>.
University of California - Davis Health System. (2013, February 7). Scientists find key to growth of 'bad' bacteria in inflammatory bowel disease. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2013/02/130207172102.htm
University of California - Davis Health System. "Scientists find key to growth of 'bad' bacteria in inflammatory bowel disease." ScienceDaily. www.sciencedaily.com/releases/2013/02/130207172102.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) — In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
New Dinosaur Species Found in Museum Collection

New Dinosaur Species Found in Museum Collection

Reuters - Innovations Video Online (Nov. 27, 2014) — A British palaeontologist has discovered a new species of dinosaur while studying fossils in a Canadian museum. Pentaceratops aquilonius was related to Triceratops and lived at the end of the Cretaceous Period, around 75 million years ago. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Tryptophan Isn't Making You Sleepy On Thanksgiving

Tryptophan Isn't Making You Sleepy On Thanksgiving

Newsy (Nov. 27, 2014) — Tryptophan, a chemical found naturally in turkey meat, gets blamed for sleepiness after Thanksgiving meals. But science points to other culprits. Video provided by Newsy
Powered by NewsLook.com
Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) — The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins