Investigation on the treatment of infection due to Mycobacterium Kansasii

Mycobacterium kansasii infection responds well to antituberculous drugs, and in the initial phase of treatment, many patients with M. kansasii infection are regarded as tuberculosis. This study was carried out to know whether the regimen of chemotherapy be continued or changed after the confirmation of diagnosis as M. kansasii infection. The treatment result of 107 cases with M. kansasii infection of the lung encountered at Fukujuji Hospital was compared with that of pulmonary tuberculosis. Sputum culture of all patients treated with drug regimens containing RFP converted to negative within 3 months after starting chemotherapy, while sputum culture of many patients treated with regimens not containing RFP converted to negative 4 months or later after the start of chemotherapy. Hence, the effectiveness of RFP in treating M. kansasii infection was confirmed. Among 65 patients with no relapse during a follow-up period of at least one year after the completion of chemotherapy, 58 patients (89.2%) were treated with drug regimens containing INH and RFP, and the treatment of 40 patients (61.5%) was finished within 12 months. Among three patients deteriorated during chemotherapy or relapsed within one year after the completion of chemotherapy, two patients were treated with drug regimens containing RFP and one of them had serious complications. The chemotherapy regimen for tuberculosis is considered to be sufficient for the initial treatment of pulmonary disease caused by M. kansasii.