Oxygen-Sensing Mechanism Based on Small RNA (sRNA) Is Key to E. coli Locating Region of Colon in Which to Set Up Most Threatening Infections; Discovery May Ultimately Enable Avoidance of These Food-Borne Infections

A pair of University of Virginia (UVA) School of Medicine scientists has revealed how E. coli seeks out the most oxygen-free crevices of the colon to cause the worst infection possible. The discovery could one day let doctors prevent the infection by allowing E. coli to pass harmlessly through the body. The new discovery shows just how the food-borne pathogen knows where and when to begin colonizing the colon on its way to making you sick. By recognizing the low-oxygen environment of the large intestine, the dangerous bacterium gives itself the best odds of establishing a robust infection - one that is punishing for the host. "Bacterial pathogens typically colonize a specific tissue in the host. Therefore, as part of their infection strategies, bacterial pathogens precisely time deployment of proteins and toxins to these specific colonization niches in the human host. This allows the pathogens to save energy and avoid detection by our immune systems and ultimately cause disease," said researcher Melissa Kendall (left in photo), PhD, of UVA's Department of Microbiology, Immunology, and Cancer Biology. "By knowing how bacterial pathogens sense where they are in the body, we may one day be able to prevent E. coli, as well as other pathogens, from knowing where it is inside a human host and allow it (the E. coli) to pass through the body without causing an infection." The UVA research was published in the July 9, 2019 issue of PNAS. The article is titled “The sRNA DicF Integrates Oxygen Sensing to Enhance Enterohemorrhagic Escherichia coli Virulence via Distinctive RNA Control Mechanisms.” E. coli naturally lives in our colons, and most strains do us no harm. But there are several strains that can cause cramps, diarrhea, vomiting, even kidney failure and death. Children are at particular risk.
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