Comparison of Two Molecular Assays For Detecting Smear Negative Pulmonary Tuberculosis / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To compare the performance of MTBDRplus V2 and Xpert MTB/RIF for detecting smear negative pulmonary tuberculosis (PTB).</p><p><b>METHODS</b>Clinical PTB suspects were enrolled consecutively in Anhui Chest Hospital and Xi'an Chest Hospital from January to December in 2014. The sputum samples of smear negative PTB suspects were collected and decontaminated. The sediment was used to conduct MTBDRplus V2, Xpert MTB/RIF and drug susceptibility test (DST). All the samples with discrepant drug susceptibility result between molecular methods and phenotypic method were confirmed by DNA sequencing.</p><p><b>RESULTS</b>A total of 1973 cases were enrolled in this study. The detection rates of Mycobacterium tuberculosis complex (MTBC) by MTBDRplus V2 and Xpert MTB/RIF were 27.67% and 27.98%, respectively. When setting MGIT culture result as a gold standard, the sensitivity and specificity of MTBDRplus V2 were 86.74% and 93.84%, and the sensitivity and specificity of Xpert MTB/RIF were 86.55% and 93.43%, respectively. For the detection of the resistance to rifampin, the sensitivity and specificity of MTBDRplus V2 were 94.34% and 96.62%, and the sensitivity and specificity of Xpert MTB/RIF were 88.68% and 95.96%, respectively. For the detection of the resistance to isoniazid, the sensitivity and specificity of MTBDRplus V2 were 77.38% and 98.02%, respectively.</p><p><b>CONCLUSION</b>MTBDRplus V2 and Xpert MTB/RIF can be used to detect MTBC in smear negative samples with satisfactory performance.</p>

Multicenter Evaluation of the Molecular Line Probe Assay for Multidrug Resistant Mycobacterium Tuberculosis Detection in China / 生物医学与环境科学（英文）

In order to evaluate the performance of a molecular Hain line probe assay (Hain LPA) for rapid detection of rifampicin and isoniazid resistance of Mycobacterium tuberculosis in China, 1612 smear positive patients were consecutively enrolled in this study. Smear positive sputum specimens were collected for Hain LPA and conventional drug susceptibility testing (DST). The sensitivity and specificity of Hain LPA were analyzed by using conventional DST as golden reference. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for rifampicin resistance detection were 88.33%, 97.66%, 81.54%, and 98.62%, respectively. The sensitivity, specificity, PPV and NPV for isoniazid resistance detection were 80.25%, 98.07%, 87.25%, and 96.78%, respectively. These findings suggested that Hain LPA can be an effective method worthy of broader use in China.

The feasibility of sputum transportation system in China: effect of sputum storage on the mycobacterial detection / 生物医学与环境科学（英文）

Sputum transportation from county-level to prefecture-level is an ideal strategy to cover the shortage of the laboratory capability in the resource-poor setting. Here, we firstly evaluated the feasibility of sputum transportation system in China by analyzing the culture and molecular diagnosis results from 1982 smear-positive patients with different delay in processing for culture. In this study, the total contamination rate was 2.32% and the total smear positive/culture negative (S+/C-) rate was 7.57%. We found that sputum specimens refrigerated for no more than 7 d before mycobacterial detection did not affect culture significantly. In addition, the invalid result rates among 0-3 d, 3-7 d, and 7+ d group were 3.63%, 3.14%, and 12.48%, respectively. Statistic analysis revealed that molecular diagnostic results while the invalid result rate of genechip for the specimen with more than 7 d delay was significantly higher (P<0.001). The refrigerators equipped in county laboratories, transport at low temperature and frequent transport services once a week will ensure the feasibility of sputum transportation system in China.

Relationship between Beijing genotypes of Mycobacterium tuberculosis and drug-resistant phenotypes / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the distribution of the Beijing genotypes of Mycobacterium tuberculosis (M. tuberculosis) and the relationships between Beijing genotype strains and drug-resistant phenotypes in China.</p><p><b>METHODS</b>Clinical isolates were collected during a 9-month research period from April to December in 2008 in six geographic regions of China. One isolate that had been biochemically confirmed to be a member of the M. tuberculosis complex was collected from each patient. The demographic data of the patients (eg. sex, age, and history of tuberculosis) as well as the drug resistance patterns and sources of the clinical isolates were collected. Drug susceptibility testing was performed using proportion method. Beijing genotypes of M. tuberculosis were identified by spacer oligonucleotide typing or insertion of IS6110 in the genomic dnaA-dnaN locus.</p><p><b>RESULTS</b>Among the 410 M. tuberculosis clinical isolates, 67.1% (275/410) isolates were Beijing genotypes of M. tuberculosis. Significantly larger proportions of tuberculosis patients were infected with Beijing genotypes in the northeastern regions of China than that of in the central-western regions (chi2 = 20.50, P = 0.000). No significant associations were found either between Beijing genotype strains and patients' age, sex, or treatment history. Multidrug-resistant isolates and rifampin-resistant isolates were more common among Beijing genotype strains than among non-Beijing strains (P = 0.002, P = 0.005).</p><p><b>CONCLUSIONS</b>About two third of the clinical isolates of M. tuberculosis in China are Beijing genotypes. Beijing genotype strains are not correlated with patients' age, sex, treatment history. People living in the northeastern regions of China are more susceptible to Beijing genotypes than those living in the central-western of China. Beijing genotype strains tend to be rifampin-resistant or multidrug-resistant.</p>