Excretion in feces and mucosal persistence of Salmonella ser. Typhimurium in pigs subclinically infected with Oesophagostomum spp

Objective-To determine interactions between Oesophagostomum spp and Salmonella ser. Typhimurium in pigs. Animals-30 healthy 5- to 6-week-old pigs. Procedure-Pigs were allotted to 3 groups (n = 10 pigs/group) and treated as follows: group A was given Oesophagostomum dentatum and 0 quadrispinulatum; group B was given 0 dentatum, 0 quadrispinulatum, and S Typhimurium; and group C was given STyphimurium only.

Pigs in groups A and B were trickle infected with Oesophagostomum spp 3 times weekly throughout the study. After 19 days, groups B and C were inoculated once with STyphimurium. One pig from each group was euthanatized on the day of Salmonella exposure and 2 and 4 days after Salmonella exposure. The remaining pigs were euthanatized on days 16 and 17 after Salmonella exposure.

Results-Pigs with dual infections of nematodes and bacteria (group B) excreted significantly higher amounts of S Typhimurium in feces, compared with nematode-free pigs (group C). In addition, group-B pigs excreted STyphimurium on more days than pigs in group C. SalmonellaTyphimurium was detected in the cecum and colon in the majority of pigs in group B, whereas STyphimurium was only detected in the colon in pigs in group C.

Immunohistochemical examination detected STyphimurium in 7 of 9 pigs in group B but only 2 of 9 pigs in group C. Conclusions and Clinical Relevance-Interactions between intestinal nematodes and bacteria may play an important role in the dynamics of STyphimurium infections.