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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #125952
Title: EARLY EPITHELIAL INVASION BY SALMONELLA ENTERICA SEROVAR TYPHIMURIUM DT104 IN THE SWINE ILEUM

Author
item MEYERHOLZ, D - IOWA STATE UNIVERSITY
item STABEL, THOMAS
item ACKERMANN, M - IOWA STATE UNIVERSITY
item CARLSON, STEVEN
item JONES, B - UNIVERSITY OF IOWA
item POHLENZ, J - INSTITUT FUR PATHOLOGIE

Submitted to: Veterinary Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2002
Publication Date: 11/1/2002
Citation: MEYERHOLZ, D.K., STABEL, T.J., ACKERMANN, M.R., CARLSON, S.A., JONES, B.D., POHLENZ,J. EARLY EPITHELIAL INVASION BY SALMONELLA ENTERICA SEROVAR TYPHIMURIUM DT104 IN THE SWINE ILEUM. VETERINARY PATHOLOGY. 2002. V. 39. P. 712-720.

Interpretive Summary: Salmonella species of bacteria are a serious worldwide problem causing swine disease estimated to cost $100 million annually in the United States. Salmonella bacteria also are important human pathogens and are of great concern in food safety. The study was performed to document the early invasion of Salmonella serovar Typhimurium in the intestine of pigs. Sections of intestine, called loops, were surgically prepared in young pigs and inoculated with Salmonella for 0 to 60 minutes. Loops were harvested and prepared for both scanning and transmission electron microscopy (SEM and TEM, respectively). Preferential bacterial adherence to various cell types of the intestine was observed by 5 to 10 minutes after inoculation. Our results suggest that early Salmonella serovar Typhimurium invasion is non cell-specific in swine and reduces support for the concept of specific cell-invasion portals. In addition, SEM and TEM revealed a specific affinity of Salmonella serovar Typhimurium to cells that were in the normal process of dying or being extruded. These data suggest that Salmonella serovar Typhimurium may utilize sites of cell extrusion as an additional mechanism of invasion. Information gained from this pig model will be useful in the study of human salmonellosis. In addition, our ability to understand and reduce Salmonella transmission in the pig will affect the pork industry's ability to maintain a safe national food chain and compete for new international markets.

Technical Abstract: Salmonella enterica serovar Typhimurium is an important intestinal pathogen in swine. The study was performed to document the early cellular invasion of Salmonella serovar Typhimurium in the swine ileum. Ileal gut loops were surgically prepared in 4- to 5-week-old pigs and inoculated for 0 to 60 minutes. Loops were harvested and prepared for both scanning and transmission electron microscopy (SEM and TEM, respectively). Preferential bacterial adherence to M cells was seen at 5 minutes and by 10 minutes bacterial invasion of the apical membrane was seen in M cells, goblet cells, and enterocytes. This multicellular invasion was observed throughout the course of infection. Our results suggest that early Salmonella serovar Typhimurium invasion is noncell-specific in swine and reduces support for the concept of specific cell-invasion portals. In addition, SEM revealed a specific affinity of Salmonella serovar Typhimurium to sites of cell extrusion. Using TEM, bacteria in these areas were around and in the crevices formed by the extruding cell and the adjacent cells, and in the cytoplasm immediately beneath an extruding cell. The combination of SEM and TEM data suggests Salmonella serovar Typhimurium may utilize sites of cell extrusion as an additional mechanism of invasion.