Expression of type 1 pili by Escherichia coli strains of high and low virulence in the intestinal tract of gnotobiotic turkeys
Dominick, M.A.; Schmerr, M.J.; Jensen, A.E.
American Journal of Veterinary Research 46(1): 270-275
1985
ISSN/ISBN: 0002-9645 PMID: 2857545 Document Number: 252888
Highly virulent (strain 1) and weakly virulent (strain 3) E. coli were examined by immunofluorescent and electron microscopy. 3-week-old gnotobiotic turkeys were killed after 1, 2, 5, 8 or 12 days. Unpiliated forms of strains 1 and 3 were more numerous than piliated forms in caecal and colonic contents examined by negative staining electron microscopy. A piliated form of strain 1 was seen in intestinal contents and was more numerous in caecal contents than in colonic contents. The mucus blanket of the caecum and colon contained large numbers of bacteria, although rarely intimately associated with the intestinal epithelium. Immunofluorescent staining indicated large numbers of piliated forms of strains 1 and 3 within the mucus blanket of the caecum and colon after 2, 5, 8 and 12 days. Piliated bacteria were infrequently seen in the ileal mucus blanket. Serum antibody titres to type 1 pili increased greatly by 5 days and persisted in turkeys inoculated with strain 1. In contrast, antibody titres in turkeys exposed to strain 3 increased gradually and varied greatly. Type 1 pili may not be important for adherence of pathogenic E. coli to intestinal epithelium of turkeys.