[A tuberculosis outbreak in a mental hospital]

We experienced a tuberculosis outbreak in a mental hospital and discussed preventive measures for nosocomial tuberculosis infection.

There are 18 mental hospitals within the administrative area of Hachioji public health center (PHC). A Total of 18 pulmonary tuberculosis cases were diagnosed in one of these hospitals between December 1995 and November 1998. They were all inpatients and two of them had history of tuberculosis. Fifty-two persons became candidates for isoniazid (INH) chemoprophylaxis as a consequence of the first extraordinary health examination. Chest radiographs of the inpatients had not been taken regularly in this hospital. Our recognition of the tuberculosis outbreak was delayed by omission of not only the case notification from the doctor who had diagnosed tuberculosis but the information from the PHC that had received the application of public subsidy for medical treatment. All cultured bacilli from 8 patients were susceptible to INH, rifampicin, streptomycin and ethambutol. Restriction fragment length polymorphism (RFLP) analysis of 4 strains, which we could have obtained, demonstrated an identical pattern.

To prevent tuberculosis outbreaks in mental hospitals, we should consider these problems as follows; 1) Physical conditions of inpatients should be observed carefully and suitable physical checkups on inpatients with tuberculosis symptoms should be carried out by mental hospitals. 2) The doctor who had diagnosed a patient as having tuberculosis must send the case notification to the nearest PHC. 3) The PHC that received the information should investigate the case carefully and notify all related PHC's. 4) Extraordinary health examinations should be done appropriately by leadership of the PHC. 5) RFLP analysis of the tubercle bacilli is very useful to probe the source and route of infection. 6) Criteria for chemoprophylaxis for more than middle-aged persons should be established.