title: Study of porcine postweaning diarrhea involving K88(-) hemolytic Escherichia coli.
abstract: The onset of fecal shedding, serogroup involvement, and association of hemolytic Escherichia coli with the postweaning diarrhea syndrome were studied in swine. The only E coli O antigen, detected by slide agglutination with the antisera used, was O157; K antigens were not detected. The ligated intestinal loop test (LILT) was used for enterotoxigenicity testing. All O157 serogroup isolates (n = 9) were hemolytic, and 89% (8 of 9) were LILT positive. Of all hemolytic isolates tested, 59% (10 of 17) were LILT positive. Twenty-seven nonhemolytic isolates were tested for enterotoxigenicity; of these, 45% (12) were LILT positive. The onset of postweaning diarrhea coincided with the modal onset of hemolytic E coli shedding at postweaning day 7. At postweaning day 7, hemolytic E coli shedding was concurrently associated with diarrhea (P less than 0.0005), whereas later during the postweaning period, this was not the situation.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; D004927:Escherichia coli Infections / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005260:Female; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology*; D014886:Weaning