[Establishment of new diagnostic technique and its clinical application for nontuberculous mycobacterial infections]

The clinical futures of 52 patients with pulmonary Mycobacterium avium complex infection (MAC group), 7 M. kansasii infection (MK group), and 5 M. chelonae infection (MC group) were studied. Aged female was dominant in MAC and MC group, while middleaged man was dominant in MK group. Although body mass index (BMI) was the lowest in MAC group, there was no difference between the groups in clinical sign, symptom, and laboratory data. Type III radiological finding was dominant in MAC group, while type II in MK and MC groups. Bacteriological eradication rate of causative organisms was 86% in MK group, 54% in MAC group, and 40% in MC group. However, the relation between clinical efficacy of chemotherapy, BMI, serum protein level, and cavity formation in chest radiogram was not observed. MAC was detected in clinical samples such as sputum, bronchial washing fluid, and gastric juice with 5 to 10% in frequency by Amplicor, one of commercially available PCR detection kits for mycobacteria. Furthermore 60% to 80% of the MAC positive cases were diagnosed and treated as nontuberculous mycobacteriosis. Although MAC is occasionally exist in oral cavity or clinical environment, the positive result of genetic diagnostic method such as Amplicor should be carefully considered.