Mycobacterium shottsii is a dysgonic, nonpigmented mycobacterium originally isolated from diseased striped bass (Morone saxatilis) in the Chesapeake Bay, USA. Genomic analysis reveals that M. shottsii is a Mycobacterium ulcerans/Mycobacterium marinum clade (MuMC) member, but unlike the superficially similar M. pseudoshottsii, also isolated from striped bass, it is not an M. ulcerans ecovar, instead belonging to a transitional group of strains basal to proposed “Aronson” and “M” lineages. Although phylogenetically distinct from the human pathogen M. ulcerans, the M. shottsii genome shows parallel but nonhomologous genomic degeneration, including massive accumulation of pseudogenes accompanied by proliferation of unique insertion sequences (ISMysh01, ISMysh03), large-scale deletions, and genomic reorganization relative to typical M. marinum strains. Coupled with its observed ecological characteristics and loss of chromogenicity, the genomic structure of M. shottsii is suggestive of evolution toward a state of obligate pathogenicity, as observed for other Mycobacterium spp., including M. ulcerans, M. tuberculosis, and M. leprae.
Original Publication Citation
Gauthier, D. T., Doss, J. H., LaGatta, M., Gupta, T., Karls, R. K., & Quinn, F. D. (2022). Genomic degeneration and reduction in the fish pathogen Mycobacterium shottsii. Microbiology Spectrum, 10(3), 1-13, Article e01158-21. https://doi.org/10.1128/spectrum.01158-21
Gauthier, David T.; Doss, Janis H.; LaGatta, M.; Gupta, T.; Karls, R.K.; and Quinn, F. D., "Genomic Degeneration and Reduction in the Fish Pathogen Mycobacterium shottsi" (2022). Biological Sciences Faculty Publications. 486.