Mycobacterium avium-M. intracellulare Complex による肺感染症と肺結核症における粉塵職歴所有者比率の比較

抄録

Many investigators reported that patients with lung disease due to atypical mycobacteria engaged frequently in dusty work (Reviewed by Tsukamura (Kekkaku 52: 367-372, 1977)). However, a question is raised whether the dusty work is more important in lung disease due to atypical mycobacteria than in lung tuberculosis. In relation to this question, it is desired to compare the ratio of patients engaged in dusty occupation between these two diseases. Nevertheless, such study is at present very scanty. The Research Committee of the British Thoracic and Tuberculosis Association (Tubercle 56: 295-310, 1975) and Marks (Tubercle 56: 311-313, 1975) reported that the dusty occupation especially metal grinding work was more often observed in patients with lung disease due to M. kansasii than in those with lung tuberculosis, and Shimoide (Jap. J. Chest Dis. 38: 765-773, 1977) reported that the dusty work was more frequently observed in patients with lung disease due to atypical mycobacteria than in patients with lung tuberculosis. The purpose of the present study is to compare the ratio of patients engaged in dusty work between lung disease due to Mycobacterium-avium-M. intracellulare complex (_{M. avium} complex) and lung tuberculosis. The patients with lung tuberculosis studied were restricted to those who showed _{M. tuberculosis} in their sputum at the time of hospitalization. This was due to consideration that all patients with lung disease due to M. avium complex were culture-positive and, therefore, the patients with lung tuberculosis studied as the control also should be culture-positive.
The patients with lung disease due to M. avium complex were diagnosed according to the criteria described previously (Tsukamura: Kekkaku 53: 367-376, 1978). These were 77 patients who were hospitalized in the period of 1971 to 1980. The patients with lung tuberculosis were thosse hospitalized in January 1981. Identification of M. avium complex was done by the methods previously reported (Tsukamura: Identification of mycobacteria, p.1-75, 1975, The National Chubu Hospital, Aichi 474), and that of M. tuberculosis was done by the absence of growth on Ogawa egg medium containing 0.5 mg/m/ p-nitrobenzoic acid (Tsukamura & Tsukamura: Tubercle 45: 64-65, 1964).
The dusty works shown in Table 2 were the subjects of the study. Patients who engaged in these works for more than five yeras were recorded.
The age of patients of both groups differed not significantly from each another, except the age of female patients with M. avium complex-disease was slightly higher than that of female patients with lung tuberculosis (Table 1). The ratio of patients with dusty work in patients with M. avium complex-disease was significantly higher than that in patients with culture-positive lung tuberculosis (Tables 2 and 3).
The above fact suggests that the dusty work has a more important meaning for the incidence of lung disease due to M. avium complex than for that of lung tuberculosis, and that the incidence of lung disease due to M. avium complex is predisposed by the exposure to dusts and the host condition is more important for the incidence of lung disease due to M. avium complex than for the incidence of lung tuberculosis.