Attachment of bacteria to intestinal epithelial cells in diarrhea caused by Escherichia coli strain RDEC-1 in the rabbit: stages and role of capsule.
RDEC-1 is a strain of Escherichia coli that, in rabbits, attaches to intestinal mucosal epithelial cells bereft of microvillar borders and causes diarrhea by an unknown mechanism. The stages of attachment of RDEC-1 bacteria to mucosal epithelial cells were examined using high-voltage electron microscopy of thick (0.5-micrometers) sections of ileum and cecum of rabbits with diarrhea. The tissues were stained with ruthenium red or antisera to strain RDEC-1 OK antigens. Micrographs, including stereopairs, demonstrated several stages of bacterial attachment. Bacteria were attached to the glycocalyxes of epithelial cell microvilli and to pedestal-like extrusions of the surfaces of epithelial cells lacking microvilli. Structures consistent with bacterial pili were rarely visualized. Attachment to microvilli appeared to be a result of the interaction of polysaccharides of the microvillar glycocalyx and the K antigen of the bacterial capsule.
D000818:Animals; D001287:Attachment Sites, Microbiological; D003967:Diarrhea / Q000276:immunology* / Q000473:pathology; D000939:Epitopes; D004926:Escherichia coli / Q000276:immunology / Q000648:ultrastructure; D004927:Escherichia coli Infections / Q000276:immunology* / Q000473:pathology; D010861:Fimbriae, Bacterial; D007413:Intestinal Mucosa / Q000276:immunology* / Q000648:ultrastructure; D008242:Lysogeny; D008871:Microvilli / Q000276:immunology / Q000648:ultrastructure; D011135:Polysaccharides, Bacterial / Q000276:immunology; D011817:Rabbits
D000939:Epitopes; D011135:Polysaccharides, Bacterial