Adhesion of Enteropathogenic Escherichia Coli to Pig Intestinal Brush Borders: The Existence of Two Pig Phenotypes

Abstract

PLATES XXVIII AND XXIX NEONATAL diarrhoea in piglets follows the proliferation of certain strains of Escherichia coli in the small intestine (Smith and Jones, 1963). These enteropathogenic strains synthesise enterotoxins which produce diarrhoea and dehydration that frequently result in the death of the piglets (Kohler, 1968;Smith and Gyles, 1970;Smith and Linggood, 1971). The rapid proliferation of E. coli in the small intestine appears to be attributable to the ability of the bacteria to attach themselves to the intestinal epithelium (Arbuckle, 1970; Drees and Wader, 1970a and b; Bertschinger, Moon and Whipp, 1972) and thereby avoid removal from the small intestine by peristalsis (Dixon, 1960). Sojka (1965) noted that the majority of E. coli strains isolated from cases of neonatal piglet diarrhoea possess a surface antigen designated K88, and it has been shown that this antigen is an essential virulence determinant (Smith and Linggood, 1971 ;Jones and Rutter, 1972) apparently because it enabled K88-positive E. coli to attach to the intestinal lining (Jones and Rutter, 1972).To investigate the interaction between the host mucosal surface and K88-positive E. coli a convenient test system is essential. The K88 antigen agglutinates guinea-pig red cells (Stirm et al., 1967;Jones and Rutter, 1974), and attempts to study the chemical aspects of adhesion by means of this reaction have been reported (Gibbons, Jones and Sellwood, 1975). It would have been preferable to use a natural intestinal receptor, but the technique involving adhesion of E. coli to disks of intestinal tissue (Jones and Rutter, 1972) is laborious. This paper describes a simple in-vitro technique that demonstrates adhesion of K88-positive E. coli to brush borders from pig intestinal cells; a survey of pigs in respect of the ability of their brush borders to adhere to E. coli is also described. MATERIALS AND METHODS

Estimating transmission parameters of F4+ E. coli for F4-receptor-positive and -negative piglets: one-to-one transmission experiment

“…The method was essentially that of Sellwood et al [7]. Mucosal scrapings were put in PBS containing 0 .…”

“…This adhesion site is a genetically inherited dominant characteristic and its presence can be shown by in vitro adhesion assays [7,8]. Based on this test, pigs can be classified as F4R-positive (F4R+, adhesive brush borders) or F4R-negative (F4Rx, non-adhesive brush borders).…”

Transmission of F4+ E. coli in groups of early weaned piglets

“…On day 19 piglets were weighed, euthanized, bled and necropsied. A 5-10 cm jejunal sample was taken for determination of the F4R status by brush border adhesion assay (BBA) [10].…”

“…Epithelial brush borders were prepared to determine the F4R status of the piglets modified after Sellwood et al [10]. Mucosal scrapings were placed in PBS containing 0 .…”

“…It was shown that F4+ E. coli do not adhere to the small intestine of all piglets, some piglets do not express the adherence site, F4 receptor (F4R) [10]. The adherence strategy of F4+ E. coli and the differences in expression of the receptor offers opportunities to prevent F4+ E. coli infections for example by F4-based oral vaccines [3,4] and genetic selection for F4Rx piglets [11].…”