The K88 Adherence System in Swine
This chapter is concerned with an important mechanism which enables enteropathogenic Escherichia coli to colonize the intestinal tract of pigs, i.e., the adhesin K88. The K88 antigen is a surface antigen of many porcine enterotoxigenic strains of E. coli. It appears under electron microscope as a filamentous structure radiating from the surface of the bacterium. Studies on the infection of piglets with K88-positive E. coli have revealed the extent of colonization that occurs. A property of the K88 antigen which is common to many E. coli is the ability to cause hemagglutination of erythrocytes. An in vitro study of the adherence of K88-positive E. coli to the epithelial cells of the small intestine revealed that these organisms were unable to attach to the brush border surface of some pigs. The role of the K88 antigen in the establishment of K88 E. coli infection in the intestinal tract of the pig is well documented.