The intestinal mucus architecture affects Salmonella Typhimurium infection patterns
A layer of viscous mucus lines the intestinal tract and protects the host tissue from bacterial infection. In a recent publication in "Cell Reports", the Hardt lab describes how the pathogen Salmonella Typhimurium interacts with the intestinal mucus and finds its way across this protective barrier.
The Hardt lab developed a live-microscopy approach to visualize Salmonella Typhimurium swimming on top and within the mucus layer in the large intestine. Using this technique, they could demonstrate that the mucus layer physically excludes non-motile bacteria. They further report that motile bacteria can swim along the mucus surface in search of sites permissive for infection and that motility is required for traversal of the mucus to infect the underlying tissue. However, only a small fraction of the bacterial population reaches this site. Together, these findings highlight the importance of bacterial motility during Salmonella Typhimurium infection. Extending the investigation to other segments of the gut, the Hardt lab showed that the mucus layer in the mouse cecum is not continuous. Gaps in the cecum mucus allow Salmonella Typhimurium to reach the intestinal tissue more easily, which explains why the cecum is the main site of infection in the mouse infection model.
Link to the paper in external page Cell Reports.