Abstract
Mycobacterium marinum is a fish pathogen that has become a powerful and well-established model that has accelerated our understanding of the mechanisms of mycobacterial disease. M. marinum is a versatile surrogate for understanding the closely related human pathogen M. tuberculosis, which causes tuberculosis in humans. M. marinum has defined key mechanisms of pathogenesis, both shared with M. tuberculosis and unique to this species. In this review, we discuss the discovery of M. marinum as an occasional human pathogen, the shared aspects of pathogenesis with M. tuberculosis, and how M. marinum has been exploited as a model to define the molecular mechanisms of mycobacterial pathogenesis across several phases of infection.