[Review of pulmonary Mycobacterium xenopi infection cases: 11 cases of our own and 18 other cases reported in Japan].

OBJECTIVE: To investigate clinical features of patients with pulmonary Mycobacterium xenopi infection treated at our hospital.

SUBJECTS AND METHODS: We diagnosed 11 cases of M. xenopi infection at Tokyo National Hospital between 2000 and 2008 and recorded the drug susceptibility, patient characteristics, radiographic findings, treatments given and clinical courses. Eighteen other Japanese cases from the literature were discussed along with our findings.

RESULTS AND METHODS: The cases of M. xenopi infection at our hospital consisted of 10 men and 1 woman with a mean age (+/- SD) of 55.1 +/- 19.4 years. Among the patients, 10 were smokers, 4 were heavy drinkers, and 6 had sequelae of pulmonary tuberculosis as an underlying disorder. Four patients had chronic obstructive pulmonary disease and 2 had diabetes mellitus, while there were 2 patients who had no underlying disease. All cases had radiographic opacities, predominantly found in the upper lung region, and cavernous lesions. These findings were demonstrated in both lungs in 5 patients, in the right lung only in 5 patients and in the left lung only in 1 patient. Concurrent aspergillosis was observed in 8 patients. The bacterial isolates from 7 cases were tested for drug sensitivity to levofloxacin (LVFX) and were found to be susceptible. M. xenopi disease was treated in 5 cases with INH+RFP+EB, in 2 cases with INH+RFP+Clarithromycin (CAM), and in 1 case with RFP+EB+CAM. Concurrent aspergillosis was treated with itraconazole in 2 cases. One patient underwent surgery for lung cancer. The duration of treatment was 16.4 +/- 12.8 months (range, 4-36 months). The radiographic findings were improved in 4 cases, deteriorated in 2 and unchanged in 5. M. xenopi was eradicated bacteriologically in 6 cases. The combination of radiographic and bacteriological findings indicated improvement in 3 cases, no change in 6 and deterioration in 2.

DISCUSSION: The review of our cases disclosed that medical treatment alone was not sufficient in most cases for the control of clinical M. xenopi infection as reported overseas. Although we did not use LVFX for treatment, LVFX might be recommended for the treatment since all isolates tested proved to be susceptible to LVFX.