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<p><b>BACKGROUND</b>The Xpert MTB/RIF showed high sensitivity and specificity in previous studies carried out in different epidemiological and geographical settings and patient populations in high-burden tuberculosis (TB) countries. However, there were little data obtained by validation or demonstration study of the assay in China. In this study, the performance of Xpert MTB/RIF was investigated in two county-level laboratories in Hunan Province, China.</p><p><b>METHODS</b>Consecutive patients with suspected pulmonary tuberculosis (PTB) and suspicion for multidrug-resistant tuberculosis (MDR-TB) were enrolled. For each patient suspected to have PTB, three sputum specimens (one spot sputum, one night sputum, and one morning sputum) were collected and each sputum was tested with smear microscopy, Löwenstein-Jensen (LJ) culture, and Xpert MTB/RIF test. For comparison across subgroups and testing methods, 95% confidence intervals were calculated. All analyses were done with SPSS 16.0, and P < 0.05 was regarded as significant.</p><p><b>RESULTS</b>For case detection, the sensitivity of Xpert MTB/RIF was 100% for smear- and culture-positive TB and 88.6% for smear-negative and culture-positive TB; the overall sensitivity was 94.5% for all culture-positive patients. The specificity was 99.8%. The sensitivity of Xpert MTB/RIF assay was 22.0% in clinical TB patients and the specificity reached 100.0% in the group of patients who are infected with nontuberculous mycobacteria. For the detection of rifampin resistance, the sensitivity of MTB/RIF RIF-resistance detection was 92.9%, and the specificity was 98.7%. Of the 26 Xpert MTB/RIF-positive and RIF-resistant patients confirmed by LJ proportion tests, 20 (76.9%) patients were infected by MDR-TB.</p><p><b>CONCLUSIONS</b>The Xpert MTB/RIF assay is a highly sensitive and specific method for diagnosis of TB and RIF resistance, which will enable it to have the potential to be used in county-level laboratories and lead to the reduction of the infectious pool and improvements in TB control in China. Further evaluations in county-level laboratories for implementing the assay are still required.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Young Adult , Antibiotics, Antitubercular , Therapeutic Uses , China , Rifampin , Therapeutic Uses , Tuberculosis , Diagnosis , Drug Therapy , Tuberculosis, Multidrug-Resistant , Tuberculosis, Pulmonary , Diagnosis , Drug TherapyABSTRACT
The early and effective diagnosis is crucial to efficacious treatment of pulmonary tuberculosis, especially for smear negative cases and MDR-TB, and is one of the priorities of global tuberculosis control and prevention. The traditional methods which have been used for decades of years, show many well-known drawbacks, in terms of fast speed and time consuming. Recently, some new promising diagnostic methods emerged, which have been expected to optimize the diagnosis of tuberculosis, especially for MDR-TB.
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Objective To evaluate a rapid biochip system for the determination of muhidrugresistant tuberculosis (MDR-TB) in Mycobacterium tuberculosis isolates. MethodsA total of 1 186 clinical strains, including 800 rifampin (RFP) resistant isolates, 797 isoniozid (INH)resistant isolates, 791 MDR-TB and 380 susceptible strains, were selected from Beijing Chest Hospital, Shanghai Pulmonary Hospital and Guangzhou Chest Hospital respectively using stratified sampling method. Biochips were used to detect loci of rpoB 511 (T→C), 513 (A→C, C→A), 516 (G→T, A→T, A→G) , 526 (C→T, C→G, A→T, A→G), 531 (C→T, C→G), 533 (T→C), katG 315 ( G→C, G→A) and inhA -15 (C→T). Absolute concentration drug susceptibility test of RFP and INH were performed to serve as the gold standard to calculate susceptibility, specificity and overall concordance of biochip test. All polymerase chain reaction (PCR) products were sequenced to confirm the mutations. ResultsThe concordances between the biochip system and absolute concentration drug susceptibility test were 93.7％ ( 1 108/1 183 ) for RFP, 83. 8％(994/1 186) for INH and 82.4％ (975/1 183) for MDR-TB. Compared with absolute concentration drug susceptibility test, the biochip method displayed a sensitivity of 92. 0％ (733/797) and 77. 4％ (617/797)and a specificity of 97. 2％ (375/386) and 96. 9％ (377/389) for RIF and INH, respectively. For MDR-TB, the biochip system reached a sensitivity of 74. 6％ ( 588/788 ) and a specificity of 98.0％ ( 387/395 ).Among rpoB mutants, mutations were mostly detected at codon 531[64. 5％ (480/744)]. In stains with mutations in katG or inhA, 77.4％ ( 487/629 ) had mutation at codon 315 ( TCG ) of katG only. The sequencing results had a high concordance with that of the biochip method. There were slight differences in 5 strains, among which one strain was detected by biochip as katG 315(G→C) mutant, but was identified by sequencing as wild type, and mutation types other than those detected by the biochip were confirmed in the other 4 strains by sequencing. Conclusion This biochip system is adapted for extensive application in clinical diagnosis, as it allows fast and reliable detection of resistance to isoniazid and rifampin in tuberculosis clinical isolates.
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@#Objective To explore the restoration of motor function and the expression of calcitonin gene-related peptide(CGRP)and acetylcholine esterase(AChE)in the anterior horn motoneurons after different types of spinal cord injury.Methods 60 adult female Wistar rats were randomly assigned to 3 groups:sham group,completely transection group and contusion group.Average combined scores(ACOS)were applied to assess the motor function at various time after the surgery.The content of AChE in the anterior horn of L2-L4 was detected with Karnovsky-Roots staining and the expression of CGRP was then determined with immunohistochemistry.Results The scores of ACOS were much higher in the contusion group than in the transection group at each time point examined.The content of both AChE and CGRP significantly decreased after either type of spinal cord injury.However,their activity gradually recovered to the normal level in the contusion group,but not in the transection group.Moreover,the changes of CGRP occurred earlier than those of AChE.Conclusion There is strong relationship between the motor function recovery and the functional state of anterior horn cells.CGRP or AChE may play an important role in the functional recovery of locomotion after spinal cord injury in rats.
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@#Objective To observe the effect of the chitosan tube combined with basic fibroblast growth factor(bFGF) on inducing nerve axon regeneration of rats with peripherial nerve injury.MethodsA novel chitosan tube combined with bFGF was developed and used to suture the 10 milimeter long right sciatic nerve gap of 10 rats,single injury group(10 rats) were the control with sciatic nerve injury alone,and other 10 rats were assigned to sham group.Immunohistochemistry and electrophysiology study had been done to observe the effect of repairing.Results3 months after operations,the sciatic nerve gap were repaired by the regeneration nerve in the experiment group.And there was no evident inflammation in the defects.ConclusionThe chitosan tube combined with bFGF can induce the sciatic nerve to regenerate.
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@#Objective To explore the degeneration of motor end plates (MEP) by observing the expression of calcitonin gene-relative peptide (CGRP) and acetylcholine esterase (AChE) in the MEP after different types of spinal cord injury. Methods 60 adult female Wistar rats were randomly assigned to 3 groups: sham group, completely transection group and contusion group. The content of AChE in the MEP was detected with Karnovsky-Roots staining and the expression of CGRP was then determined with immunohistochemistry. Results The content of both AChE and CGRP significantly decreased after either type of spinal cord injury. However, their activity gradually recovered to the normal level in the contusion group, but not in the transection group. Moreover, the changes of CGRP occurred earlier than those of AChE. Conclusion The motor end plate degenerates differently after different kinds of spinal cord injury in adult rat, CGRP and AChE are related to the degeneration of MEP.