Management of disease due to Mycobacterium kansasii.

Mycobacterium kansasii presents clinically in a manner most resembling tuberculosis. Diagnosis is usually not difficult; however, the significance of M kansasii isolates from some patients may be hard to determine. Usually, the presence of even one respiratory culture positive for M kansasii is sufficient to make a diagnosis, though few patients can have single respiratory culture positive for M kansasii without evidence of active disease. If not started on medication, these patients must be followed closely. Effective treatment can usually be accomplished with a rifampin-based regimen, or a rifabutin-based regimen for HIV-seropositive patients receiving antiretroviral therapy. Short course and intermittent regimens for treating M kansaii disease show promise but are not yet recommended for routine use.