Causative agent of Johne's disease, or paratuberculosis, a chronic severe intestinal infection.. Mycobacterium avium subsp. paratuberculosis K-10 strain:k10

Mycobacterium avium subsp. paratuberculosis. This organism is a slowly growing species, with doubling times of around 22-24 hours. One of the important diagnostic features of this bacterium is that its growth in laboratory settings depends on the presence of mycobactin J, a natural siderophore. This bacterium is not common in the environment, and is predominantly found as an intracellular parasite. It causes a chronic granulomatous enteritis termed Johne's disease or paratuberculosis. The desease affects domestic and free-ranging ruminants, but has also been reported in primates, rabbits, stoats and foxes. The usually fatal disease is characterized by weight loss and diarrhea, after a long pre-clinical phase. Treatment is ineffective and economically impracticable. Paratuberculosis in domestic livestock entails significant economic losses in the dairy industry totaling $1.5 billion annually. Several reports suggest a role for this organism in the etiology of Crohn's disease, a severe inflammatory bowel disease in humans. Mycobacterium avium subsp. paratuberculosis strain K-10. This strain was isolated from a dairy herd in Wisconsin in the 1970's by investigators from the USDA National Animal Disease Center. It is an extensively studied low passage clinical strain and is amenable to genetic manipulation.