Association of prior nocardiosis and subsequent occurrence of nontuberculous mycobacteriosis in a defined, immunosuppressed population.

A retrospective epidemiologic and risk factor analysis demonstrated an association of prior nocardiosis to the subsequent development of nontuberculous mycobacteriosis in five cardiac allograft recipients. Strong statistical support for this association was derived from five separate analytical approaches, including comparisons with time-matched cohorts and by multivariate regression analysis. Each of the five patients in the study had had uncomplicated pulmonary nocardiosis and had been treated successfully with long-term sulfonamide therapy. Although each patient remained clinically, radiographically, and bacteriologically free of recurrent nocardial disease during an average follow-up period of approximately three years, each patient subsequently (after a mean period of greater than two years from the diagnosis of nocardiosis) developed infection due to Mycobacterium kansasii or Mycobacterium avium-intracellulare-scrofulaceum. Detailed statistical studies failed to identify factors that could account for this observation.