[A molecular epidemiological analysis of several outbreaks of tuberculosis in public saunas. A problem of tuberculosis among homeless people in the metropolitan area].

There were several outbreaks of pulmonary tuberculosis among employees and customers of public saunas in Shijuku, a large office, shopping and amusement quarter in Tokyo. Twenty four patients with pulmonary tuberculosis were found between March 1994 and November 1996. Restriction fragment length polymorphism analysis of DNA derived from Mycobacterium tuberculosis isolated from eighteen patients with positive cultures was used to analyze the transmission route. The DNA probe was derived from the insertion sequence IS6110. There were 14 different DNA patterns of the M. tuberculosis isolated from 18 patients. Of 14 patterns, three patterns were shared by 2 patients, patients and 3 patients, respectively. The remaining 11 patterns were observed in 11 patients, thus one pattern for each patient. These data suggest that the infection of M. tuberculosis resulted from different origins. The saunas in amusement areas like Shinjuku have been used as hotels. Many customers from different places are using the saunas for overnight stay, and in particular homeless people have been using the saunas as their "home". The sauna can be a place where groups of people with high risk for tuberculosis congregate and the potential for an outbreak of tuberculosis can occur.