[Clinical analysis of Mycobacterium abscessus pulmonary infection in our hospital]

We analyzed the clinical characteristics of pulmonary infection due to Mycobacterium abscessus.

Four cases diagnosed with M. abscessus pulmonary infection encountered at Kawasaki Medical School Hospital and affiliated hospitals over the last five years were enrolled in this study. They all satisfied the diagnostic criteria of the Japanese Society for Tuberculosis. The clinical findings in this study were also compared to those of previously reported cases in Japan.

The average age of the four cases was 56 years (one male and three females). All four cases showed underlying diseases, comprising two cases with malignancy, one with old pulmonary tuberculosis and one with collagen vascular disease receiving immunosuppressive treatment. Three cases were detected based on clinical symptoms, and one was incidentally identified during follow-up for another underlying disease. Laboratory examinations revealed mild or moderate inflammatory responses in three of the four cases, and three of the four were smear-positive for acid-fast bacilli in the clinical specimens (sputum in one and bronchial alveolar lavage fluid in two) microbiologically. The radiological examination revealed that one case showed tuberculosis resembling a cavitary lesion and three showed the small nodular and bronchiectatic type. The extent of lesions was within the unilateral lung in all cases. Concerning treatment for M. abscessus pulmonary infection, combined multi-drug chemotherapy using IPM/cs, AMK, CAM, and LVFX was carried out in three of the four cases, achieving a satisfactory clinical effect. However, one case died due to progression of the underlying disease before the initiation of treatment.

Although M. abscessus pulmonary infection was more frequent in cases with underlying disease, the early, appropriate administration of antibiotics was performed in two of the four cases correctly diagnosed using bronchoscopic procedures, resulting in clinical improvement.