ABSTRACT
We evaluate the performance of Xpert MTB/RIF for the diagnosis of extrapulmonary tuberculosis (EPTB) in China. The performance of Xpert was evaluated compared to the composite reference standard (CRS), drug susceptibility testing (DST), and imaging examination. The overall sensitivity and specificity of Xpert were 64.1% (195/304) and 100% (24/24), respectively, using CRS as the gold standard. The sensitivity was significantly higher than that of culture for pus (P<0.05). The proportion of EPTB-positive cases diagnosed by imaging was two times more than that diagnosed using Xpert; however, 6 out of 19 cases may have been overdiagnosed by imaging. Compared to phenotypic DST, the sensitivity and specificity of Xpert were 80% (12/15) and 100% (75/75), respectively. Considering its high sensitivity and specificity, Xpert MTB/RIF may be used as a rapid initial test for EPTB diagnosis, and may also support a quicker decision on the treatment regimen. The combination of imaging and Xpert testing could provide high efficiency and accurate diagnosis of suspected EPTB.
Subject(s)
Humans , Bacterial Proteins , Genetics , Metabolism , China , DNA-Directed RNA Polymerases , Genetics , Metabolism , Diagnostic Tests, Routine , Methods , Drug Resistance, Bacterial , Microbial Sensitivity Tests , Mycobacterium tuberculosis , Genetics , Metabolism , Retrospective Studies , Rifampin , Pharmacology , Sensitivity and Specificity , Sputum , Tuberculosis , Tuberculosis, Pulmonary , Diagnosis , MicrobiologyABSTRACT
<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>
Subject(s)
Humans , Antitubercular Agents , Pharmacology , China , Genotype , Mycobacterium tuberculosis , Classification , Genetics , Phenotype , Rifampin , Pharmacology , Tuberculosis , Drug Therapy , Tuberculosis, Multidrug-Resistant , GeneticsABSTRACT
<p><b>OBJECTIVE</b>To study the mechanism of prophylactic effects of nasal tolerance with a dual analogue (Lys262-Ala207) on experimental autoimmune myasthenia gravis (EAMG).</p><p><b>METHODS</b>Clinical and immunological changes were observed in Lewis rats administered with dual analogue Lys262-Ala207 nasally, to compare the effects between the rats with predetermined dosage of Lys262-Ala207 and control peptides at two different time points, before the day (Group A or C) or on the day (Group B or D) of immunization with acetylcholine receptor (AChR) in complete Freud's adjuvant for 10 consecutive days. The clinical scores was evaluated for 50 days post immunization. Numbers of MNC expressing IFN-gamma, IL-4 or IL-10 and CD4+ and/or CD25+ from lymph nodes were enumerated by flow cytometry. Proliferative response, expressed as stimulation index (SI), was suppressed in response to antigen-specific stimulation in the rats receiving dual analogue, as compared with the rats receiving saline buffer only.</p><p><b>RESULTS</b>Group A and group B of Lewis rats developed EAMG with reduced severity, as compared to the control groups. Number of cells synthesizing IFN-gamma, IL-4 or IL-10 decreased, whereas numbers of CD4+CD25+ cells increased in group A and B than those in the control groups. Proliferative response was suppressed in response to antigen-specific stimulations in the rats receiving dual analogue Lys262-Ala207.</p><p><b>CONCLUSIONS</b>Nasal administration with a dual analogue Lys262-Ala207 at two different time points, before the day and on the day of immunization, could delay symptoms of muscular weakness in EAMG rats, which was associated with suppression of immune function in AChR antigen-specific T cells and lay a scientific foundation for treatment of human MG with nasal dual analogue.</p>