Clinical studies on lung disease due to atypical mycobacteria in our hospital during the past 13 years

Abstract

Among the patients with pulmonary diseases admitted to our hospital during a 13-year period from 1977 to 1989, clinical examinations and laboratory data on admission and the following clinical courses of 102 cases where atypical mycobacteria had been identified three times or more in sputum cultures at the time of hospitalization were investigated. 1. The ratio of the number of cases positive for atypical mycobacteria to those positive for acidfast bacilli in sputum cultures tested on admission was fairly constant, 6.0 to 7.8% every year since 1981. In the cases associated with positive sputum cultures for atypical mycobacteria, M. avium complex was observed in 84% of the cases: M. kansasii, M. fortuitum and M. chelonae were found in 13, 2 and 1 cases, respectively, since 1984. 2. A total of 102 cases studied consisted of 66 male and 36 female patients; the mean age was 61.9 years. 3. Sputa became negative on culture in 19 (86.4%) out of 22 cases of primary infection. In all primary infection cases, roentgenographic findings did not worsen and prognosis was extremely good. In secondary infection cases, sputum cultures became negative in 25 (83.3%) out of 30 cases expectorating a small quantity of mycobacteria on admission, where x-ray findings worsened in only one case. In contrast, in 47 cases expectorating a large quantity of the bacilli at the time of admission, negative sputum cultures were attained in only 14 cases (29.8%) and x-ray findings worsened in 10 cases, and their prognosis were poor. 4. In general, sputum cultures turned negative within 3 months after admission. If sputum cultures remained positive thereafter, it was found very difficult to stop expectoration of the bacilli in these patients, and hence their prognosis are supposed to be greatly affected by the bacteriologic findings in early stages of the disease.