Mycobacterium malmoense Infections in the United States, January 1993 through June 1995

Mycobacterium malmoense is a nontuberculous mycobacterium rarely encountered in the United States. However, isolations of M. malmoense from 73 patients (11 in 1992, 35 in 1993, and 27 in 1994) were reported to the Centers for Disease Control and Prevention. We contacted state mycobacteriology laboratories and health care providers of patients whose M. malmoense isolations were reported from January 1993 through June 1995. To assign disease status for these patients, we used the criteria of the American Thoracic Society. Of 60 evaluable patients with disease status, only six (10%) had disease due to M. malmoense (five adults with pulmonary disease and one child with cervical lymphadenitis). We conclude that the number of patients with disease due to M. malmoense remains low. Increased isolation of this species may be due to the increased use of more sensitive and specific laboratory methods. For surveillance purposes, multiple M. malmoense isolates and age of younger than 10 years appear to be the best predictors for M. malmoense disease.