The secret weapon of E. Coli for causing the worst possible infection

Two scientists at the University of Virginia Medical School revealed how E. coli look for the most oxygen-free crevices in your colon to cause the worst infection possible.

The new discovery shows how well the foodborne pathogen knows where and when to start colonizing the colon before you get sick. By recognizing the low level of oxygen in the large intestine, the dangerous bacterium gives itself the best chance of getting a robust, punitive infection for the host.

"Bacterial pathogens usually colonize a specific tissue in the host," said researcher Melissa Kendall of the Department of Microbiology, Immunology and Cancer Biology of the UVA. "Therefore, as part of their infection strategies, bacterial pathogens intervene precisely in the deployment of proteins and toxins in these host-specific colonization niches, which allows them to save energy, to avoid detection by our immune system and to cause the disease.

"By knowing how pathogenic bacteria detect where they are in the body, we may someday be able to E. coli, as well as other pathogens, knowing where it is in a human host and allowing it to cross the body without causing infection. "

A Bacterial Goldilocks

E. coli lives naturally in both of us, and most strains do not hurt us. However, many strains can cause cramps, diarrhea, vomiting, or even kidney failure and death. Children are particularly at risk. As such, E. coli epidemics appear periodically in the news. In July, for example, residents of several states were sick E. coli related to minced bison meat.

Kendall and Elizabeth M. Melson, graduate student, provided important insights on E. coli infections build up in the body. The researchers described a process used by bacteria to detect low levels of oxygen in the large intestine and then produce proteins that allow E. coli bind to the host cells and establish the infection.

In reality, oxygen diffuses into the intestines from the intestinal tissue and, in the small intestine, the rate of intoxication is higher than in the fat. E. coli waits specifically until he has reached the oxygen-deficient large bowel before hitting.

E. coliThe vital asset of the is a small form of RNA that activates particular genes when oxygen levels are low enough, reveal the researchers. It is at this point that the infection really installs. Through this natural detection process, bacteria can establish an infection and start making harmful Shiga toxins.

The researchers believe that other bacterial pathogens, such as Shigella and Salmonellaprobably use a similar control mechanism, although additional efforts are needed to establish it.

"If scientists can understand how to block the detection of oxygen, we may be able to prevent E. coli Kendall said, "This could be an effective strategy to limit the infection, and because we are not targeting growth or survival, E. coli may not develop drug resistance, she just does not know where she is. "

Kendall and Melson published their findings in the scientific journal PNAS.