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- Mycobacterial species
- Slow grower (2-6 weeks for positive with liquid media), photochromogen.
- AFB staining may show beaded characteristics [Fig].
- DNA analysis suggests there may be 5-7 subspecies.
- Subtype I appears to be responsible for most human infection.
- M. tuberculosis and M. kansasii can occur together: cultures positive for M. kansasii should be incubated for prolonged periods to exclude M. tuberculosis, which grows slightly slower than M. kansasii.
- Reservoir appears to be water (tap water, standing water, saltwater) with likely infection via aerosol.
- No human-to-human or animal-to-human transmission (with the exception of unusual case reports)