Attaching and effacing activities of rabbit and human enteropathogenic Escherichia coli in pig and rabbit intestines

TLDR

Enteropathogenic E. coli strains isolated from humans and rabbits can attach to and efface microvilli of pig and rabbit intestinal epithelial cells, although the precise mechanisms remain unknown. The study aimed to determine whether colostrum‑deprived newborn pigs and ligated intestinal loops in pigs and rabbits could serve as models for detecting attaching‑and‑effacing EPEC and for investigating their pathogenesis. Attachment and effacement were demonstrated by light microscopy of routine histological sections and by transmission electron microscopy.

Abstract

Three strains of enteropathogenic Escherichia coli (EPEC), originally isolated from humans and previously shown to cause diarrhea in human volunteers by unknown mechanisms, and one rabbit EPEC strain were shown to attach intimately to and efface microvilli and cytoplasm from intestinal epithelial cells in both the pig and rabbit intestine. The attaching and effacing activities of these EPEC were demonstrable by light microscopic examination of routine histological sections and by transmission electron microscopy. It was suggested that intact colostrum-deprived newborn pigs and ligated intestinal loops in pigs and rabbits may be useful systems to detect EPEC that have attaching and effacing activities and for studying the pathogenesis of such infections. The lesions (attachment and effacement) produced by EPEC in these systems were multifocal, with considerable animal-to-animal variation in response to the same strain of EPEC. The EPEC strains also varied in the frequency and extent of lesion production. For example, three human EPEC strains usually caused extensive lesions in rabbit intestinal loops, whereas two other human EPEC strains usually did not produce lesions in this system.