Genetic makeup of the most deadly strains of E. coli identified

Posted Feb 9, 2016 by Karen Graham
A group of researchers from the university of Maryland have for the first time identified the genetic makeup of a number of strains of E. coli responsible for the deaths of hundreds of thousands of people around the world every year.
E. coli magnified 10 000 times using an electron microscope.
E. coli magnified 10,000 times using an electron microscope.
The scientists, led by David Rasko, Ph.D., Associate Professor of Microbiology and Immunology at the Institute for Genome Sciences (IGS) at UM SOM and Michael Donnenberg, MD, Professor of Medicine at UM SOM, analysed the DNA of Enteropathogenic Escherichia coli (EPEC) which are the strains of the bacteria causing diarrhea.
Enteropathogenic Escherichia coli (EPEC) is a gram-negative rod-shaped bacterium that adheres to the cells on the intestinal wall, causing diarrhea. Each year in developing countries, diarrheal diseases cause the death of 760,000 children under five. Diarrhea is also the leading cause of malnutrition in children under five. Over 1.7 million cases of diarrheal disease are recorded globally each year.
Even though EPEC was the first E. coli strain to be implicated in human disease in the 1940s, it remained a complete mystery until the 1980s when major advances were made in understanding its pathogeneisis.
Dr. Rasko and his team of researchers examined some 70 genomes of strains of E.coli obtained from infected children enrolled in the Global Enterics Multi-Center study (GEMS). Some of the cases involved the death of a child, some cases involved children with symptoms of diarrhea and some cases had no symptoms. The team had a broad range of outcomes to work with.
The genetic differences were mapped, and the strains divided into categories based on genetic content and clinical outcome. Rasko suspects the increased E. coli lethality of EPEC is caused by a group of genes interacting rather than one or two genes.
"This research epitomizes what IGS is all about," says Claire M. Fraser, PhD, Director of IGS "We want to take genomics and use it in novel ways, ways that can be of practical use to clinicians around the world."
This interesting study, "Genomic diversity of EPEC associated with clinical presentations of differing severity," was published in the online journal Nature Microbiology on January 18, 2016.