Although many studies have assessed factors affecting culture conversion during tuberculosis treatment, few have looked into the effect of tobacco smoking. This study included 89 active pulmonary tuberculosis patients with positive sputum culture upon presentation and collected information regarding smoking history and culture conversion after 60 days of therapy. Current smokers had a higher risk (OR 5.6; 95%CI 1.7-18.7) of non-conversion after two months of therapy when compared to never and ex-smokers. Cavities on chest X-ray and alcohol abuse were shown to confound this association. After adjustment for cavities on the chest X-ray and alcohol abuse current smoking compared to current non-smoking remained significantly associated with culture non-conversion at 60 days of treatment (adjusted OR 6.9; 95%CI 1.8-26.7, p = 0.002) with a significant (p = 0.004) trend in adjusted OR with the number of cigarettes smoked daily to 11.6 (1.8-73.4) among those smoking more than 20 cigarettes per day. In conclusion tobacco smoking was found to delay culture conversion during treatment for pulmonary tuberculosis in a dose-dependent manner. More research is needed to elucidate the effects of smoking on tuberculosis treatment response, and of smoking cessation during tuberculosis treatment.

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In settings with a high prevalence of smear-negative PTB, the system can be useful for screening and also to aid clinical practice in expediting complementary tests for higher risk patients.

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The caves built in quartzites at the Ibitipoca Range are part of hierarquized underground drainage systems. Spelcogencsis was a two-stage process, following the sanding/piping model. In the first stage, porosity was generated by feldspar and phyllosilicates alteration and silica solution from quartz. The essential conditions for cave development were: (1) a large diference between local and regional base levels; (2) presence of rock layers specially susceptible to sanding and piping processes (fine-grained micaceous quartzite) and (3) a sequence of cycles of stability and uplift Different cave patterns and sizes can be explained by changes in one or more of the above conditionants.

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Background: Rapid molecular methods such as the line probe assay (LPA) and Xpert ® MTB/RIF assay (Xpert) have been recommended by the World Health Organization for drug-resistant tuberculosis (DR-TB) diagnosis. We conducted an interventional trial in DR-TB reference centers in Brazil to evaluate the impact of the use of LPA and Xpert.Methods: Patients with DR-TB were eligible if their drug susceptibility testing results were available to the treating physician at the time of consultation. The standard reference MGIT TM 960 was compared with Xpert (arm 1) and LPA (arm 2). Effectiveness was considered as the start of the appropriate TB regimen that matched drug susceptibility testing (DST) and the proportions of culture conversion and favorable treatment outcomes after 6 months.Results: A higher rate of empirical treatment was observed with MGIT alone than with the Xpert assay (97.0% vs. 45.0%) and LPA (98.2% vs. 67.5%). Patients started appropriate TB treatment more quickly than those in the MGIT group (median 15.0 vs. 40.5 days; p<0.01) in arm 1. Compared to the MGIT group, culture conversion after 6 months was higher for Xpert in arm 1 (90.9% vs. 79.3%, p=0.39) and LPA in arm 2 (80.0% vs. 83.0%, p=0.81). Conclusions:In the Xpert arm, there was a significant reduction in days to the start of appropriate anti-TB treatment and a trend towards greater culture conversion in the sixth month.

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