Translocating Mycobacterium ulcerans: an experimental model.
Mycobacterium ulcerans is a non-tuberculous environmental mycobacterium responsible for extensive cutaneous and subcutaneous ulcers in mammals, named Buruli ulcer in patients. M. ulcerans has been seldom detected in the feces of mammals but not in patients, nevertheless the detection and isolation of M. ulcerans in animal feces does not feet with the current epidemiological schemes for the disease. Here using an experimental model in which rats were fed with 109 colony-forming units of M. ulcerans, we detected M. ulcerans in feces of challenged rats for two weeks and along their digestive tract for 10 days. M. ulcerans was further detected in the lymphatic system including cervical and axillary lymph nodes and the spleen, but not in any other tissue including the healthy and breached skin, 10 days post-challenge. These observations indicate that in some herbivorous mammals, M. ulcerans contamination by the digestive route may precede translocation and limited infection of the lymphatic tissues without systemic infection. These herbivorous mammals may be sources of M. ulcerans for exposed populations but are unlikely reservoirs for the pathogen.