Effect of type 2 diabetes mellitus on the clinical severity and treatment outcome in patients with pulmonary tuberculosis: a potential role in the emergence of multidrug-resistance.

BACKGROUND/PURPOSE: A globally increasing trend of type 2 diabetes mellitus (DM), the rising prevalence of tuberculosis (TB) in many countries, and the emergence of multidrug-resistant TB (MDR-TB) in recent years pose a serious challenge for TB control. METHODS: We investigated pulmonary tuberculosis patients with and without type 2 DM (DMTB and TB, respectively) treated at the Chest Hospital, Taiwan, between November 2004 and October 2005. RESULTS: One hundred and ninety-two new patients (60 DMTB, 132 TB) were regularly treated for a full course (≥ 6 months) and prospectively followed for more than 1 year. The DMTB patients had more severe infections (far-advanced: 45.0%vs. 22.7%, p < 0.01), higher mycobacterial loads (sputum smear: 2.9 ± 1.3(+)vs. 1.9 ± 1.7(+), p < 0.01), higher treatment failure rates (17%vs. 2%, p < 0.01), and longer delayed clearance of mycobacteria than did the TB patients (2.5 ± 3.0 months vs. 1.6 ± 1.4 months, p < 0.01). After one year, three DMTB patients and one TB patient had MDR-TB (5.0%vs. 0.8%, p = 0.056). Bacterial genotyping revealed that the proportion of mycobacterial strains was not significantly different in DMTB and TB patients (Beijing strain: 46.7%vs. 40.6%, Non-Beijing strain: 53.3%vs. 59.4%, p = 0.632). CONCLUSION: DMTB patients have more severe TB infections, which require longer treatment and are more likely to develop MDR-TB than are patients with TB alone.

Transmission of Mycobacterium tuberculosis in a family proved by genotyping.

BACKGROUND/PURPOSE: Molecular genetic methods have been applied in various epidemiologic studies including investigations of disease acquisition by contact. This report describes the use of various molecular genetic methods in tracing possible household transmission of tuberculosis by contact. METHODS: Four Mycobacterium tuberculosis strains, each from four members of a family, were first isolated and identified in the clinical laboratory of the Chest Hospital and were submitted to the National Reference Laboratory of Mycobacteriology for further confirmation and genotyping. In this study, IS6110 restriction fragment length polymorphism (RFLP), spacer oligonucleotide typing (spoligotyping) and mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTR), and rpoB gene sequencing were used for genotyping. RESULTS: All four strains were found to have identical spoligotypes, MIRU-VNTR patterns, and similar IS6110 RFLP profiles. The results of the drug susceptibility test and of rpoB sequencing showed that all four strains were rifampicin resistant. CONCLUSION: Household transmission through close contact was thus proved by genotyping. We conclude that all four family members were infected with the same lineage of M. tuberculosis.