Indira T Kudva
United States Department of Agriculture-Agricultural Research Service, USA
Title: Shiga toxin-producing Escherichia coli and recto anal junction persistence in ruminants: A study of bacterial-epithelial interactions
Biography
Biography: Indira T Kudva
Abstract
Escherichia coli O157:H7 (O157) was the first Shiga toxin-producing E. coli serotype to be associated with bloody diarrhea or
hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS) in humans. It has since been implicated in several outbreaks
in the U.S. and globally. Non-O157 STEC have not been associated with major outbreaks but still cause 64% of all STEC infections
in the U.S. Cattle are well documented ruminant reservoirs of STEC and the primary site of STEC persistence in these animals is the
rectoanal junction (RAJ). To investigate this persistence at the RAJ we have analyzed O157 adherence at a histological level, developed
a novel adherence assay using squamous epithelial cells at the RAJ, evaluated role of well characterized STEC adherence proteins,
in STEC attachment to the RAJ and explored the similarities in RAJ-STEC interactions with another ruminant animal. STEC show
distinct adherence patterns on the columnar epithelial and squamous epithelial (RSE) cells at the RAJ. The novel RSE cell adhesion
assay provides a convenient means of directly evaluating bacterial interactions with host-specific cells. We have determined that
proteins other than LEE and intimin-γ proteins are involved in STEC adherence to RSE cells. Such proteins with adhesin potential
have been shortlisted using proteomics for development of efficacious anti-adhesion modalities. We have also found that bison and
cattle RAJ share similar distribution of epithelial cell markers and O157 adheres to RSE cells from both animals in similar patterns,
supporting bison as likely ‘wildlife’ reservoirs for O157.