CLINICAL AND RADIOLOGICAL FEATURES OF PULMONARY-DISEASE CAUSED BY RAPIDLY GROWING MYCOBACTERIA IN CANCER-PATIENTS

The role of rapidly growing mycobacteria in the pathogenesis of pulmon ary disease is being increasingly recognized; however, the clinical si gnificance of these mycobacteria in patients with underlying malignanc y has not been well studied. Over a 6-year period, 37 cancer patients with rapidly growing mycobacteria isolated from respiratory specimens were identified at our center. Mycobacterium chelonae group was isolat ed in 24 cases and Mycobacterium fortuitum in 13 cases. Of the 24 case s with cultures yielding Mycobacterium chelonae group, eight met the s tudy criteria for infection and were determined to be clinically signi ficant, whereas only one of the Mycobacterium fortuitum isolates was d etermined to represent infection. An average of two antimicrobial agen ts were used for treatment, most commonly clarithromycin, ciprofloxaci n, and trimethoprim/sulfamethoxazole. Although the isolation of rapidl y growing mycobacteria represents colonization in most cases, these ba cteria, especially the Mycobacterium chelonae group, may cause pulmona ry disease in cancer patients. The clinical and radiological findings are usually non-specific in this population, and patients with respira tory cultures yielding rapidly growing mycobacteria should be assessed carefully to distinguish infection from colonization. Effective thera py can be provided with oral regimens that include at least two antibi otics to which the organism is susceptible.