Vaccination against Lawsonia intracellularis decreases shedding of Salmonella enterica serovar Typhimurium in co-infected pigs changes the host gut microbiome

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week,  we are sharing the summary of a publication by  Dr. Fernando Leite who recently received his PhD from the University of Minnesota. The full scientific article regarding the effect of the vaccination against Lawsonia intracellularis on the shedding of Salmonella typhimurium and the host microbiome is available on open access in Nature.

Materials and Methods

A total of five treatment groups were used:

  1. challenged with S. Typhimurium alone,
  2. challenged with both S. Typhimurium and L. intracellularis,
  3. challenged with S. Typhimurium and vaccinated against L. intracellularis,
  4. challenged with both S. Typhimurium and L. intracellularis and vaccinated against L. intracellularis
  5. a non-infected control.

Results

The greatest difference in shedding level between groups was found at 7 days post-infection. At this time point, the co-challenged animals from the vaccinated group shed statistically less S. Typhimurium per gram of feces than the animals from the non-vaccinated, co-challenged group. The co-challenged vaccinated group also shed significantly less S. Typhimurium than the singly infected S. Typhimurium group.
L. intracellularis vaccination did not have a significant impact on S. Typhimurium shedding when animals were singly infected with S. Typhimurium.

Leite Ileitis vaccination salmonelle co infection

 

At 7 days post-infection, different treatment groups had significant differences in their microbiome community structure. The co-infected vaccinated group clustered apart from all other treatment groups.

Conclusion

These results indicate that vaccination against L. intracellularis impacts the microbiome and reduces shedding of S. Typhimurium in co-infected animals.

 

NHF: Enteroids as in vitro model for ileitis

Our new contribution to the National Hog Farmer was written by Dr. Talita Resende, a PhD candidate at the University of Minnesota under the supervision of Dr. Connie Gebhart. Talita’s research focuses on swine ileitis and models to better understand its pathogen: Lawsonia intracellularis. Today, she explains how she uses enteroids.

The small intestine is largely responsible for nutrient digestion and absorption in the gastrointestinal tracts of pigs, but it is also an ideal colonization site for enteric pathogens. The investigation of the interactions between host and enteric pathogens can be conducted in vivo, or in vitro, with advantages and disadvantages for each of the models. Enteroids, small intestinal organoids, represent a new in vitro approach to investigate those interactions. But why are enteroids a new approach and what are their advantages in comparison to the current models?

Enteroids are three-dimensional structures originated from embryonic stem cells, induced pluripotent cells or adult stem cells from intestinal tissue. Therefore, they present all the cell types and a structural organization similar to crypts and villi found in the small intestine. This complex structure offers ideal conditions to investigate the mechanisms by which Lawsonia intracellularis causes proliferative enteropathy – also known as ileitis – in pigs.