A number of strains of E. coli have been linked to diarrhea, but this is the first time that enteroaggregative E. coli has been linked to the illness in the United States. One of the most important aspects of the new study was the use of genetic technology to look for the presence of specific patterns of E. coli DNA. This in turn led to the identification of genes associated with diarrhea.
Other tests that look for E. coli infections are based on the use of tissue culture cells, which is not always a reliable way to identify specific strains of E. coli, according to Mitchell B. Cohen, M.D., a professor of pediatrics at Cincinnati Children's who led the research team.
Once confirmed in follow-up studies, the new research could eventually lead to the availability of testing for enteroaggregative E. coli, he said.
"The lack of having a test is, in part, why medical professionals have never really before linked enteroaggregative E. coli to diarrhea in children in the United States," Dr. Cohen said. "The identification of a different etiology allows us to focus on the question of whether diarrhea caused by viruses or bacteria should be treated differently. The strength of the study is that we can now look at these children and decide if we should develop therapies to target bacterial or viral infections."
Mary A. Staat, M.D, M.P.H., an associate professor of infectious diseases and study co-author, will present the results of the study on May 2 in San Francisco at the annual meeting of the Pediatric Academic Societies.
E. coli is a foodborne pathogen and a bacterium that normally resides in the lower intestine. There are hundreds of strains of E. coli and most are harmless, but some strains can cause illness, such as gastroenteritis and traveler's diarrhea. A strain of E. coli that is present in undercooked hamburger meat has been linked to bloody diarrhea and kidney failure.
The new study focused on 684 children, less than five years of age, who were treated at Cincinnati Children's emergency department for acute gastroenteritis. Researchers examined six different strains of E. coli and compared the results with those of 555 healthy children. They found that nearly 10 percent of children treated in the emergency department for gastroenteritis tested positive for enteroaggregative E. coli.
In the study, researchers reported that the visible signs of an enteroaggregative E. coli infection, such as vomiting and diarrhea, were virtually indistinguishable from other pathogens that cause diarrhea. For example, the visible signs of rotavirus, which was identified in 20 percent of the children in the study, are identical to that of an E. coli infection.
"Very frequently when children have diarrhea, medical professionals suggest they have viral diarrhea, and while that is a possibility, we can't be certain unless we test for the presence of other pathogens, such as E. coli," he said.
While diarrhea in children is a significant cause of illness in the United States, it is a significant cause of illness and death in children in developing countries where malnutrition and frequent infection has reached pandemic proportions.
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