Mucus Architecture and Near-Surface Swimming Affect Distinct Salmonella Typhimurium Infection Patterns along the Murine Intestinal Tract

Cell Rep. 2019 May 28;27(9):2665-2678.e3. doi: 10.1016/j.celrep.2019.04.106.


Mucus separates gut-luminal microbes from the tissue. It is unclear how pathogens like Salmonella Typhimurium (S.Tm) can overcome this obstacle. Using live microscopy, we monitored S.Tm interactions with native murine gut explants and studied how mucus affects the infection. A dense inner mucus layer covers the distal colon tissue, limiting direct tissue access. S.Tm performs near-surface swimming on this mucus layer, which allows probing for colon mucus heterogeneities, but can also entrap the bacterium in the dense inner colon mucus layer. In the cecum, dense mucus fills only the bottom of the intestinal crypts, leaving the epithelium between crypts unshielded and prone to access by motile and non-motile bacteria alike. This explains why the cecum is highly infection permissive and represents the primary site of S.Tm enterocolitis in the streptomycin mouse model. Our findings highlight the importance of mucus in intestinal defense and homeostasis.

Keywords: Salmonella typhimurium; baceterial infections; bacteria tracking; intestinal infection; intestinal mucus; live imaging; mucus layer; near-surface swimming.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cecum / immunology
  • Cecum / metabolism
  • Cecum / microbiology*
  • Colon / immunology
  • Colon / metabolism
  • Colon / microbiology*
  • DNA-Binding Proteins / physiology
  • Epithelium / immunology
  • Epithelium / metabolism
  • Epithelium / pathology*
  • Intestines / immunology
  • Intestines / microbiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mucin-2 / physiology
  • Mucus / cytology*
  • Mucus / metabolism
  • Salmonella Infections / immunology
  • Salmonella Infections / metabolism
  • Salmonella Infections / microbiology*
  • Salmonella typhimurium / pathogenicity*
  • Ubiquitin-Protein Ligases / physiology


  • DNA-Binding Proteins
  • Muc2 protein, mouse
  • Mucin-2
  • Trim27 protein, mouse
  • Ubiquitin-Protein Ligases