Goldfish, Carassius auratus, a novel animal model for the study of Mycobacterium marinum pathogenesis.

We have developed an animal model for studying mycobacterial pathogenesis using Mycobacterium marinum and the goldfish, Carassius auratus. Goldfish are injected intraperitoneally with doses between 10(2) and 10(9) CFU of M. marinum organisms. Depending on the dose of M. marinum organisms administered, an acute or chronic disease is produced. The acute disease is characterized by systemic mycobacterial infection, severe peritonitis, tissue necrosis, and a short median survival time. The chronic disease is characterized by granuloma formation in all organs and survival of animals to the end point of the experiment (56 days). Colony counts in organ homogenates showed recovery of mycobacteria from a high percentage of inoculated animals. We believe this well-characterized animal model will be useful for studying mycobacterial pathogenesis.