Research on Escherichia coli described by P. Nart and colleagues

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According to a study from Scotland, "Recent research has established that the terminal rectum is the predominant colonization site of enterohemorrhagic Escherichia coli O157:H7 in cattle. The main aim of the present work was to investigate pathological changes and associated immune responses at this site in animals colonized with E. coli O157:H7."

"Tissue and gastrointestinal samples from a total of 22 weaned Holstein-cross calves challenged with E. coli O157:H7 were analyzed for bacterial colonization and pathology. Five unexposed age-matched calves were used as comparative negative controls. E. coli O157:H7 bacteria induced histopathological alterations of the rectal mucosa with enterocyte remodeling. This was often associated with removal of the colonized epithelial layer. Immunogold labeling and transmission electron microscopy (TEM) showed E. coli O157 bacteria on pedestals, as part of attaching and effacing lesions. These pathological changes induced a local infiltration of neutrophils that was quantified as larger in infected animals. Rectal mucosal immunoglobulin A responses were detected against the E. coli O157:H7 antigen," wrote P. Nart and colleagues (see also Escherichia Coli).

The researchers concluded: "This work presents evidence that E. coli O157:H7 is not a commensal bacteria in the bovine host and that the mucosal damage produced by E. coli O157:H7 colonization of the terminal rectum induces a quantifiable innate immune response and production of specific mucosal antibodies."

Nart and colleagues published their study in Infection and Immunity (Responses of Cattle to Gastrointestinal Colonization by Escherichia coli O157:H7. Infection and Immunity, 2008;76(11):5366-5372).

For more information, contact J.C. Low, Animal Health Group, Sir Stephen Watson Bldg, Bush Estate, Penicuik EH26 0PH, Midlothian, Scotland.

Publisher contact information for the journal Infection and Immunity is: American Society Microbiology, 1752 N St. NW, Washington, DC 20036-2904, USA.

Keywords: Scotland, Escherichia coli, Gastroenterology, Infectious Disease, Pathology.

This article was prepared by FDA Law Weekly editors from staff and other reports.


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