[Non-tuberculous mycobacteriosis. What has been coming out].

Diagnosis of non-tuberculous mycobacteriosis is relatively easy, because of recent technological advances (HRCT, MGIT, PCR, DDH etc). Although many reports of this disease have been published, there are many problems to resolve. (1) Prevalence of non-tuberculous mycobacteriosis: Shigeki SATO (Department of Medical Oncology and Immunology, Nagoya City University Graduate School of Medical Sciences) Questionnaire surveys to determine the prevalence of nontuberculous mycobacterial (NTM) disease were carried out in 2001, 2007, and 2009. The NTM disease rate was estimated at 5.9/100,000, confirming that Japan has one of the world's highest NTM disease rates. Examination of the proportions of M. avium and M. intracellulare disease in Japan by region revealed that the M. avium/M. intracellulare disease ratio increased in different regions since past reports. In the 2007 survey, the M. avium disease rate had increased over the 2001 level. M. kansasii had a high disease rate in the Kinki and Kanto regions. Disease rates tended to be high in regions that have a metropolis. However, the disease rate was low in Aichi Prefecture, so that the presence in a region of a metropolis is probably not of itself a factor causing a high disease rate. The distributions of the bacteria causing NTM thus vary among different countries and regions. (2) Polyclonal infection of Mycobacterium avium using variable numbers of tandem repeats (VNTR) analysis: Tomoshige MATSUMOTO (Department of Clinical Research and Development, Center for Infectious Diseases, Osaka Prefectural Hospital Organization, Osaka Prefectural Medical Center for Respiratory and Allergic Diseases) Mycobacterium avium complex (MAC) is refractory to therapy, containing rifampicin (RFP), ethambutol (EB), and clarithromycin (CAM). It was widely accepted that therapeutic difficulties of pulmonary MAC treatment was caused by highly resistance to antibiotics or repeated re-infection from environment. Variable number of tandem repeats (VNTR) analysis of MAC is available. So, we studied the MAC-VNTR of clinical isolates from 29 patients with pulmonary MAC, refractory to the therapy. Compared the clinical isolates before with after each therapy, clinical isolates derived from the all except one patient showed the same VNTR patterns, before and after. According to MAC-VNTR analysis of the clinical isolates we studied, frequency of polyclonal infection was low (1/29). We concluded that the highly resistance to antibiotics or the repeated same VNTR type infection from environment made refractory pulmonary MAC. (3) An approach to identify susceptibility genes in patients with non-HIV-related pulmonary Mycobaterium avium complex (MAC) infection: Naoto KEICHO (Department of Respiratory Diseases, Research Institute, National Center for Global Health and Medicine) Mycobacterium avium complex causes human pulmonary disease. Th1 T cells play a role in protective immunity from mycobacterial infection. Genetic defect of Interferon-gamma/ Interleukin-12 axis is known to cause familial non-tuberculous mycobacterial infection. On the other hand, non-mendelian type of genetic abnormalities such as polymorphisms of HLA, CFTR and SLC11A1 (NRAMP1) genes has also been investigated as disease susceptibility genes. Recently our group has reported disease association with MHC-class I related chain-A molecule (MICA), comparing 300 sporadic cases with 300 healthy controls. (4) Genetic feature of Mycobacterium avium complex: Taku NAKAGAWA, Kenji OGAWA (Department of Pulmonary Medicine, National Hospital Organization Higashinagoya National Hospital) The bacterial factors contributing to the pathogenesis of M. avium complex infection and diversity of disease progression remain unclear. MATR-VNTR typing is inexpensive and easy to perform and has an excellent discriminatory power compared with MIRU-VNTR and IS1245-RFLP typing. MATR-VNTR typing revealed that M. avium isolates from HIV-positive patients are analogous to the isolates from pig enterically-transmitted rather than those from HIV-negative patients with pulmonary diseases. M. avium comprises four subspecies. We performed genetic analysis by using Insertion Sequence (IS) for 114 clinical isolates of M. avium. All clinical isolates were identified as M. avium subsp. hominissuis by sequence analysis of hsp65. PCR detection rate of IS901 was about 70%, while detection rate in Europe and America was 0-8%. Compared with the original IS901, 60 point mutations were found in the sequence of the insertion sequence detected from all PCR-positive clinical isolates. This new insertion sequence was designated ISMav6. It became clear that M. avium strains in Japan are distinct from strains in Western countries in terms of the prevalence of ISMav6. We conducted genetic analysis for M. avium isolates collected from 11 hospitals all over Japan, but MATR-VNTR typing failed to show that distinct clusters correlate with disease progression or region. Genetic typing for M. intracellulare using VNTR has not yet been developed. We identified VNTR loci in the genome of M. intracellulare ATCC1395 and applied them as a molecular epidemiological tool to clinical isolates. (5) Infection source of pulmonary Mycobactrium avium complex (MAC) disease: Yukiko NISHIUCHI (Toneyama Institute for Tuberculosis Research Osaka City University Medical School), Ryoji MAEKURA (National Hospital Organization Toneyama National Hospital) Pulmonary MAC disease is characterized as the polyclonal infection and the recurrence, which suggest the presence of polyclonal niche of MAC in environment surrounding patients. We revealed that MAC was recovered from bathrooms but not from other sites of residences. The bathtub inlet was the niche with polyclonal colonization of MAC in the bathrooms of MAC patients. The identical/related genotypic profiles with isolates from patients were revealed by pulsed field gel electrophoresis. These results implied that the residential bathroom might be one of the infectious sources of pulmonary MAC disease.