Clostridium difficile infected mouse caecum

The anaerobe Clostridium difficile is a major cause of antibiotic-associated diarrheal disease. This scanning electron micrograph was produced as part of a research project investigating the effects of deleting invasion-associated genes on the ability of this pathogen to colonise and cause disease. This image illustrates how effectively C. difficile can bounce back after antibiotic treatment, locating them within the relatively oxygen-poor environment of a crypt extending below the luminal surface of the mouse caecum. The specialised cells surrounding the crypt are microfold (M) cells associated with the Peyer’s patch. These cells are able to sample antigen in the lumen and deliver it by endocytosis to immune dendritic cells and lymphocytes. The crypt diameter at the widest point is 20µm.