Clinical and radiographic predictors in diagnosing sputum smear-negative pulmonary tuberculosis in HIV-negative patients: a cross-sectional study in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>In county-level tuberculosis (TB) dispensaries in China, the accurate diagnosis of sputum smear-negative pulmonary tuberculosis (SNPT) needs to be improved by developing and validating clinical and radiographic predictors.</p><p><b>METHODS</b>The study was conducted simultaneously in three counties per province in Chongqing Municipality and Liaoning Province in China between May 2005 and May 2006. A total of 432 new SNPT patients who are HIV-negative and more than 15 years old diagnosed by expert panels in county-level TB dispensaries were recruited. Their sputum samples were collected for culture before anti-TB treatment, and the treatment outcomes (changes of X-rays) were followed up at the end of the 6th month.</p><p><b>RESULTS</b>Of the 432 SNPT patients, sputum culture positive (9.7%) or culture negative with good changes of X-rays at the end of the 6th month (73.6%) was validated as SNPT. Four predictive variables were associated with validated SNPT in the multivariate logistic regression model: age ≤55 years old (odds ratio (OR) 5.66; 95% CI 2.69-11.91), >60 days of cough (OR 3.73; 95% CI 1.10-12.65), ≥10% of pulmonary consolidation in the lungs (OR 5.40; 95% CI 2.90-10.06), and pulmonary consolidation in the upper lobe anterior segment (OR 3.00; 95% CI 1.57-5.72). The area under the receiver operating characteristic curve of the model was 0.77 (95% CI 0.71-0.83).</p><p><b>CONCLUSION</b>Four predictors of clinical and radiological characteristics that had a good diagnostic performance of SNPT deserve to be recommended as index indicators of SNPT diagnosis in county-level TB dispensaries in China.</p>

Molecular characterization of embB306 gene in Mycobacterium tuberculosis isolates from tuberculosis patients in Chongqing municipality / 中华预防医学杂志

<p><b>OBJECTIVE</b>To understand the characteristics of embB gene mutation of Mycobacterium tuberculosis (MTB) isolates from tuberculosis patients in Chongqing, and the value of embB306 as a molecular marker used to diagnose ethambutol (EMB)-resistant MTB strains.</p><p><b>METHODS</b>Direct sequencing was used to analyze the polymorphism of embB mutation in 51 EMB-resistant MTB strains and 50 EMB-sensitive MTB strains. And diagnostic testing was used to evaluate the value of embB306 as a molecular marker of EMB -resistant MTB strains as compared with the traditional sensitivity test.</p><p><b>RESULTS</b>All 34 of 51 EMB-resistant strains (66.7%) and 3 of 51 EMB-sensitive strains (6%) had had embB306 mutation. The embB306 mutation rate in EMB-resistant strains coming from previously treated case was 87.5%, showing significantly higher than that from new cases (48.1%, P < 0.01); embB306 mutation rate was increased with the number of the resistant drugs; embB306 mutation serving as a marker to diagnose EMB-resistant MTB strains comparing with the traditional sensitivity test, had the rate of sensitivity = 66.7%, specificity = 94.0%, accuracy = 80.2% and Youden index = 60.7%.</p><p><b>CONCLUSION</b>embB306 mutation should be the main mechanism of MTB resistance to EMB in Chongqing, showing an association with the history of the treated and numbers of the resistant drugs. embB306 mutation should be a good marker to diagnose EMB-resistant MTB strains.</p>