ObjectiveThis study is a pharmacogenetic clinical trial designed to clarify whether the N-acetyltransferase 2 gene (NAT2) genotype-guided dosing of isoniazid improves the tolerability and efficacy of the 6-month four-drug standard regimen for newly diagnosed pulmonary tuberculosis.MethodsIn a multicenter, parallel, randomized, and controlled trial with a PROBE design, patients were assigned to either conventional standard treatment (STD-treatment: approx. 5 mg/kg of isoniazid for all) or NAT2 genotype-guided treatment (PGx-treatment: approx. 7.5 mg/kg for patients homozygous for NAT2*4: rapid acetylators; 5 mg/kg, patients heterozygous for NAT2*4: intermediate acetylators; 2.5 mg/kg, patients without NAT2*4: slow acetylators). The primary outcome included incidences of 1) isoniazid-related liver injury (INH-DILI) during the first 8 weeks of therapy, and 2) early treatment failure as indicated by a persistent positive culture or no improvement in chest radiographs at the8th week.ResultsOne hundred and seventy-two Japanese patients (slow acetylators, 9.3 %; rapid acetylators, 53.5 %) were enrolled in this trial. In the intention-to-treat (ITT) analysis, INH-DILI occurred in 78 % of the slow acetylators in the STD-treatment, while none of the slow acetylators in the PGx-treatment experienced either INH-DILI or early treatment failure. Among the rapid acetylators, early treatment failure was observed with a significantly lower incidence rate in the PGx-treatment than in the STD-treatment (15.0 % vs. 38 %). Thus, the NAT2 genotype-guided regimen resulted in much lower incidences of unfavorable events, INH-DILI or early treatment failure, than the conventional standard regimen.ConclusionOur results clearly indicate a great potential of the NAT2 genotype-guided dosing stratification of isoniazid in chemotherapy for tuberculosis.

The tuberculin skin test for immunologic diagnosis of Mycobacterium tuberculosis infection has many limitations, including being confounded by bacillus Calmette-Guérin (BCG) vaccination or exposure to nontuberculous mycobacteria. M. tuberculosis-specific antigens that are absent from BCG and most nontuberculous mycobacteria have been identified. We examined the use of two of these antigens, CFP-10 and ESAT-6, in a whole blood IFN-gamma assay as a diagnostic test for tuberculosis in BCG-vaccinated individuals. Because of the lack of an accurate standard with which to compare new tests for M. tuberculosis infection, specificity of the whole blood IFN-gamma assay was estimated on the basis of data from people with no identified risk for M. tuberculosis exposure (216 BCG-vaccinated Japanese adults) and sensitivity was estimated on the basis of data from 118 patients with culture-confirmed M. tuberculosis infection who had received less than 1 week of treatment. Using a combination of CFP-10 and ESAT-6 responses, the specificity of the test for the low-risk group was 98.1% and the sensitivity for patients with M. tuberculosis infection was 89.0%. The results demonstrate that the whole blood IFN-gamma assay using CFP-10 and ESAT-6 was highly specific and sensitive for M. tuberculosis infection and was unaffected by BCG vaccination status.

We have investigated the efficacy of a clarithromycin-containing four-drug regimen for Mycobacterium avium complex (MAC) pulmonary disease in 46 patients without acquired immunodeficiency syndrome (AIDS). The patients were 14 males and 32 females with a mean age of 60.9 +/- 11.5 yr. Patients received 10 mg/kg/d of clarithromycin plus ethambutol, rifampin, and initial kanamycin and subsequent quinolone for 24 mo. Seven patients (15.2%) were dropped in the first 6 mo. Among 39 patients who received more than 6 mo of therapy, 28 patients (71.8%) converted their sputa to negative: 26 of 31 patients (83.9%) infected with clarithromycin-susceptible strains and two of eight patients (25.0%) with resistant or intermediate strains. The timing of sputum conversion was 3.6 +/- 1.9 mo, with a range of 2 to 9 mo. The conversion rate was significantly lower in patients who were infected with clarithromycin-resistant or intermediate strains, who had had prior therapy (55.0% versus 89.5%), or who were acid-fast bacilli (AFB) smear-positive at entry (60.7% versus 100%). The age and sex of patients, the species of pathogen (M. avium or M. intracellulare), type and extent of the disease, and the use of kanamycin did not significantly affect the conversion rate. Although the regimen was efficacious for newly treated patients, frequent adverse reactions and a low conversion rate of sputum in retreated patients are problems that remain to be solved.

In recent years, many novel nontuberculous mycobacterial species have been discovered through genetic analysis. Mycobacterium massiliense and M. bolletii have recently been identified as species separate from M. abscessus. However, little is known regarding their clinical and microbiological differences in Japan. We performed a molecular identification of stored M. abscessus clinical isolates for further identification. We compared clinical characteristics, radiological findings, microbiological findings, and treatment outcomes among patients with M. abscessus and M. massiliense lung diseases. An analysis of 102 previous isolates of M. abscessus identified 72 (71%) M. abscessus, 27 (26%) M. massiliense, and 3 (3%) M. bolletii isolates. Clinical and radiological findings were indistinguishable between the M. abscessus and M. massiliense groups. Forty-two (58%) patients with M. abscessus and 20 (74%) patients with M. massiliense infections received antimicrobial treatment. Both the M. abscessus and M. massiliense groups showed a high level of resistance to all antimicrobials, except for clarithromycin, kanamycin, and amikacin. However, resistance to clarithromycin was more frequently observed in the M. abscessus than in the M. massiliense group (16% and 4%, respectively; P ‫؍‬ 0.145). Moreover, the level of resistance to imipenem was significantly lower in M. abscessus isolates than in M. massiliense isolates (19% and 48%, respectively; P ‫؍‬ 0.007). The proportions of radiological improvement, sputum smear conversion to negativity, and negative culture conversion during the follow-up period were higher in patients with M. massiliense infections than in those with M. abscessus infections. Patients with M. massiliense infections responded more favorably to antimicrobial therapy than those with M. abscessus infections. Mycobacterium species are common causes of pulmonary infections in both humans and animals (14). Although members of the Mycobacterium tuberculosis complex cause the majority of pulmonary infections worldwide, many nontuberculous mycobacteria (NTM) can cause similar infections (13,20). In recent years, many novel NTM species have been discovered through the increased application of genetic investigation tools; detailed genetic characterizations have helped define new taxonomic groupings (17,29). Recently, two new M. abscessus-related species, M. massiliense and M. bolletii, were identified, which were previously grouped with M. abscessus (1, 3). The rate of isolation of these two species has been increasing in Japan. However, very little is known about the natural epidemiology and pathogenicity of M. massiliense and M. bolletii outside outbreak situations. One report found that the ratio of M. abscessus to all NTM is much higher in South Korea (19) than in other countries, including Japan.Here, we aimed to evaluate the epidemiology, clinical and radiological spectrum, treatments, drug susceptibility, and outcome of M. abscessus and M. massiliense lung diseases during therapy in Japan. MATERIALS AND ME...

SUMMARYThe purpose of the present study was to elucidate the role of oestrogen in the pathogenesis of Mycobacterium avium complex (MAC) pulmonary disease, which occurs most frequently in postmenopausal women. The study was carried out in a murine infectious model using ovariectomized DBA/2 female mice. Infection with MAC was established by intratracheal administration of bacilli. In some experiments, ovariectomized mice were treated with exogenous 17b -estradiol (E2). The number of bacilli in the lungs of infected mice which received ovariectomy was significantly larger than that in the lungs of sham-operated control mice, and treatment of ovariectomized mice with exogenous E2 restored the burden of bacilli to the same level as that in the sham-operated control mice. We next examined the effect of E2 in vitro using bone marrow-derived macrophages obtained from DBA/2 female mice. The macrophages showed bacteriostatic activity against MAC after treatment with interferon-gamma (IFNg) and this activity was further enhanced by the exogenous addition of E2 to the culture medium. In parallel with these findings, E2 augmented the production of reactive nitrogen intermediates (RNI) by macrophages pretreated with IFN-g and stimulated with MAC, as shown by evaluating nitrite production and inducible nitric oxide synthase mRNA expression. These findings taken together suggest that absence of endogenous oestrogen appears to be responsible for the development of MAC pulmonary disease in this mouse model and that the enhancement by E2 of anti-MAC activity of murine macrophages induced through increased RNI production may play some role in resistance to MAC infection.