Inflammation feeds E. coli

Tina Hesman Saey, Science News
Published 7 February 2013
http://www.sciencenews.org/view/generic/id/348117/description/Inflammation_feeds_E_coli

Summary
A new study shows that inflamed intestines produce compounds that nourish E. coli and other disease related bacteria. A small amount of E. coli is present in everyone's intestines, but people with inflammatory bowel diseases such as ulcerative cloitis have a higher composition of it. The study shows that inflammation, a process the body uses to kill microbes, may "feed" the harmful bacteria, such as E. coli, causing more inflammation in the gut. During inflammation, chemicals are produced that can break DNA and destroy bacteria. But in experiments done on mice, scientists have discovered that the chemicals reacting with each other can produce nitrates and other compounds that some bacteria use as fuel. E. coli normally make up about 0.1% of bacteria in the gut, but E. coli in an inflamed colon can grow to make up about 10% of the microbes in the intestine. To find out how this happens, scientists injected a chemical into mice to inflame their bowels. They found that the inflamed bowels produce nitrate, which most bacteria in the gut cannot consume. However, E. coli and its close relatives can. They have enzymes that break down nitrates and other chemicals for energy. The E. coli have a huge competitive advantage over other microbes because of their ability to use the nitrates, which helps them out compete other bacteria during inflammation. The experiment also showed that mice with normal colons and mice that had an enzyme that produces nitric oxide, the precursor to nitrate, blocked, did not have an overgrowth of E. coli. The results of the experiment suggest that removing inflammation generated nitrate or blocking E. coli's ability to use it could limit its growth in intestines. Unfortunately, nitric oxide has important functions throughout the body, such as regulating blood vessel dilation, so blocking the enzyme that produces it may not be a good way to treat bowel diseases. Scientists are working on potential treatments that would prevent E. coli and related bacteria from using nitrate, while keeping a stable microbial mix in the intestines.

Connection
This article connects to the microbes unit because E. coli is a type of bacteria, and bacteria are microbes. We also did a lab testing E. coli growth.