Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/14/2000
Publication Date: N/A
Technical Abstract: The purpose of this study was to determine the cellular interaction and adherence of Salmonella typhimurium DT104 in the swine gut loop model. S. typhimurium DT104 was inoculated from -70 C culture to 1 ml LB broth and grown shaking at 37 C for 7 hrs. Then 10 ul was transferred to 5 ml LB and grown statically for 16 hrs at 37 C. Pigs, 4-5 weeks old, were anesthetized for the terminal surgery after being fasted 18 hrs. A midline abdominal incision was made and the ileocecal junction exteriorized. Silk suture (#2) was used to ligate the ileum starting near the ileocecal junction and the ligation process was continued proximally. Six loops (6-7 cm) were made with a 2-cm space in between each loop. S. typhimurium DT104 culture or sterile LB was injected as a 6 ml volume into each loop. The loops were replaced into the abdomen for the appropriate amount of time. Then the abdomen was reopened and the lumen of the loops injected with fixative (2.5% gluteraldehyde in 0.1 M sodium cacodylate buffer [pH 7.2]). Loops were then removed from the pig and placed into a jar of fixative. After 1-2 hrs in fixative, the tissues were cut and prepared for SEM. Examination of tissues at 45 and 60 min post- inoculation indicates that S. typhimurium DT104 preferentially adheres to M-cells of the follicle-associated epithelia (FAE) and to sites of enterocyte extrusion on the FAE or absorptive epithelia (AE). Evaluation of shorter time points are pending. In conclusion, this modified gut loop model provides an excellent method to study the early stages of bacteria-host interaction. These adherence sites may play an important role in the invasion of S. typhimurium DT104.