Lactobacillus rodentium Origin
Lactobacillus rodentium is an organism that was isolated from the gastrointestinal tract of wild rodents. It is a Gram-negative enteric bacterium. Its cognate host is mice, and causes transmissible murine colonic hyperplasia. It is responsible for high mortality in suckling mice. Although Lactobacillus rodentium causes disease primarily in mice, it has also been reported to cause disease in other rodents, with a high rate of fatality. So far, no reports of Lactobacillus rodentium being pathogenic to humans have been found.
Lactobacillus rodentium structure
The Lactobacillus rodentium cells are Gram-positive, oxidase- and catalase-negative. Cell morphology is similar to that of most species of lactobacilli, with regular, long rods with length of 2.1–8.6 mm and width of 0.8–1.2 mm. They occur occasionally in pairs and mostly singly. The cells grow best on M.R.S. agar and in anaerobic TPY broth. However, the cells also grow under microaerophilic conditions. Colonies on M.R.S. agar are cream in color under anaerobic conditions after 72 h. They are regularly disc-shaped and rigid. The edges of the colonies are blunt, regular, and sharply defined in the profile. Colony size ranges from 0.46 to 0.68 mm in diameter. The colonies grow at a pH of 5–9.5 and temperature of 15–46°C. These are susceptible to penicillin-derived antibiotics, cephalosporines, chemotherapeutic mupirocines and macrolides. These are resistant to chemotherapeutic metronidazole, aminoglycosides, sulfonamides, and fluoroquinolones.
Lactobacillus rodentium Function
Lactobacillus rodentium is a murine mucosal pathogen. It is used as a model to distinguish between the cellular and molecular pathogenesis of infection with two clinically significant gastrointestinal pathogens, enterohemorrhagic E. coli (EHEC) and enteropathogenic Escherichia coli. The bacterial infection provides an effective model to study different aspects of host–pathogen interaction in the gut, including intestinal inflammatory responses during mucosal healing, bacteria-induced colitis, and epithelial repair. Lactobacillus rodentium belongs to the attaching and effacing (A/E) family of bacterial pathogens; these are characterized by effacement of the brush border microvilli, intimate adherence to host intestinal epithelial cells, and reorganization of the host actin cytoskeleton. Beneath the adherent bacteria called A/E lesions, the bacteria form pedestal-like extensions of epithelial cells. Lactobacillus rodentium is the only known A/E pathogen to naturally infect mice. Therefore it is a valuable model for the study of pathogenesis of the clinically important pathogens: EPEC, a leading cause of infantile diarrhea in developing countries; and EHEC, which is highly prevalent in developed countries and is responsible for kidney failure.
Effects of Lactobacillus rodentium
Lactobacillus rodentium is an extracellular enteric mouse-specific pathogen. It is used to model infections in case of Escherichia coli causing inflammatory bowel disease. The bacterium injects type III secretion system effectors into intestinal epithelial cells (IECs), thereby targeting inflammatory, cell survival, and metabolic pathways and establishing infection. The IECs respond by rapidly shifting bioenergetics to aerobic glycolysis, while the host responds to infection by activating adaptive and innate immune signaling, required for clearance, which leads to oxygenation of the epithelium. It leads to a decline of obligate anaerobes and an instant expansion of mucosal-associated commensal Enterobacteriaceae. Moreover, infected IECs reprogram intracellular metabolic pathways, characterized by import and efflux, simultaneous activation of cholesterol biogenesis, leading to increased fecal and serum cholesterol levels. Lactobacillus rodentium has been proved to be a useful in vivo model for studying the pathogenesis of gastrointestinal pathogens and secretory diarrheal diseases. It has been studied for therapeutic approaches and preventive/mucosal vaccinations.