Objective: To evaluate the serological diagnostic value of Mycobacterium (M.) tuberculosis four new antigens Rv0432, Rv0674, Rv1566c and Rv1547. Methods:Rv0432, Rv0674, Rv1566c and Rv1547 were amplified from M. tuberculosis strain H37Rv genomic DNA by using PCR, among which Rv1547 was divided into two segments for amplification (Rv1547-1 and Rv1547-2). The segments were cloned into expression vector PET-32a while the recombinant proteins were purified by affinity chromatography. Serums were incubated with BL21 (DE3) proteins. Antibodies IgG against M. tuberculosis were tested with 151 serum samples (41 healthy people and 110 TB patients) by using ELISA. The diagnostic efficiency of antigens was analyzed by means of receiver operating characteristic curve. Difference of the objective proteins in TB patients and healthy controls was compared by t-test. Results: Recombinant antigens Rv0432, Rv0674, Rv1566c, Rv1547-1 and Rv1547-2 were successfully expressed and purified. Results from ELISA showed that the sensitivity, specificity, positive predictive value, negative predictive value, Youden index and area under the curve of Rv0432, Rv0674, Rv1566c, Rv1547-1 and Rv1547-2, as 43.64%-92.73%, 80.49%-92.68%, 0.92-0.94, 0.38-0.80, 0.363-0.732 and 0.649-0.915. All the objective proteins showed significantly higher antibody levels in TB patients, when compared to the healthy controls (P<0.000 1). Conclusion: The newly identified antigens Rv0432, Rv0674, Rv1566c, Rv1547-1 and Rv1547-2 all performed well when being used for TB serological diagnosis, thus were expected to be new candidate antigens used for TB diagnosis.
Antigens, Bacterial/genetics* ; Cloning, Molecular ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunoglobulin G ; Mycobacterium tuberculosis/metabolism* ; Polymerase Chain Reaction ; ROC Curve ; Recombinant Proteins ; Sensitivity and Specificity ; Serologic Tests/methods* ; Tuberculosis/genetics*

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.
Bacterial Proteins ; genetics ; metabolism ; China ; DNA-Directed RNA Polymerases ; genetics ; metabolism ; Diagnostic Tests, Routine ; instrumentation ; methods ; Drug Resistance, Bacterial ; Humans ; Microbial Sensitivity Tests ; Mycobacterium tuberculosis ; drug effects ; genetics ; isolation & purification ; metabolism ; Retrospective Studies ; Rifampin ; pharmacology ; Sensitivity and Specificity ; Sputum ; Tuberculosis ; Tuberculosis, Pulmonary ; diagnosis ; microbiology

The AdvanSure tuberculosis/non-tuberculous mycobacterium (TB/NTM) PCR (LG Life Science, Korea) and COBAS TaqMan Mycobacterium tuberculosis (MTB) PCR (Roche Diagnostics, USA) are commonly used in clinical microbiology laboratories. We aimed to evaluate these two commercial real-time PCR assays for detection of MTB in a large set of clinical samples over a two-year period. AdvanSure TB/NTM PCR and COBAS TaqMan MTB PCR were performed on 9,119 (75.2%) and 3,010 (24.8%) of 12,129 (9,728 respiratory and 2,401 non-respiratory) MTB specimens, with 361 (4.0%) and 102 (3.4%) acid-fast bacilli (AFB)-positive results, respectively. In MTB culture, 788 (6.5%) MTB and 514 (4.2%) NTM were identified. The total sensitivity and specificity of the AdvanSure assay were 67.8% (95% confidence interval [CI], 63.9-71.6) and 98.3% (95% CI, 98.0-98.6), while those of the COBAS TaqMan assay were 67.2% (95% CI, 60.0-73.8) and 98.4% (95% CI, 97.9-98.9), respectively. The sensitivities and specificities of the AdvanSure and COBAS TaqMan assays for AFB-positive and AFB-negative samples were comparable. Furthermore, the AdvanSure assay showed fewer invalid results compared with the COBAS TaqMan assay (5.0 vs. 20.4 invalid results/1,000 tests, P<0.001). AdvanSure assay represents a comparable yet more reliable method than COBAS TaqMan for the identification of mycobacteria in routine clinical microbiology.
DNA, Bacterial/genetics/metabolism ; Humans ; Mycobacterium tuberculosis/*genetics/isolation & purification ; Reagent Kits, Diagnostic ; Real-Time Polymerase Chain Reaction ; Republic of Korea ; Sensitivity and Specificity ; Tuberculosis, Pulmonary/diagnosis

Identification and validation of a new target is one of the most important steps for new antituberculosis (TB) drug discovery. Researches have shown that Mycobacterium tuberculosis (Mtb) encodes 20 CYP450 enzymes which play important roles in the synthesis and metabolism of lipid, cholesterol utilization, and the electron transport of respiratory chain in Mtb. With the critical roles within the organism as well as the protein structures of six Mtb CYP450 enzymes being clarified, some of them have been highlighted as potential anti-tuberculosis targets. In this paper, the phylogenetic analysis, the structural features, and the enzymatic functions of Mtb CYPs, as well as the mechanism of interactions with selective inhibitors such as azole antifungal agents for the CYPs have been reviewed and summarized. The druggability of the CYPs has also been analyzed for their further utility as targets in high throughput screening and rational design of more selective inhibitors.
Antitubercular Agents ; chemistry ; pharmacology ; Azoles ; chemistry ; pharmacology ; Cytochrome P-450 Enzyme Inhibitors ; chemistry ; pharmacology ; Cytochrome P-450 Enzyme System ; genetics ; metabolism ; Drug Delivery Systems ; methods ; Drug Discovery ; Humans ; Mycobacterium tuberculosis ; drug effects ; enzymology ; genetics ; Phylogeny ; Tuberculosis ; drug therapy ; microbiology

To obtain a vaccine to defend from dormancy Mycobacterium tuberculosis, we constructed the recombinant Bacilli Calmette-Guérin (BCG) vaccine with Rv3133c encoding dormancy-correlated transcriptional regulatory protein DosR in Mycobacterium tuberculosis as a target gene, and evaluated its immunogenicity in BALB/c mice. In this study, we constructed the recombinant plasmids of rpMV361-Rv3133c using gene colon technology. We then transformed BCG strains with above-mentioned plasmids to obtain recombinant vaccine of rBCG-Rv3133c. We used the rBCG strains successfully constructed to vaccinate in BALB/c mice. 30d and 180d after immunization, the specific antibody titers were determined to investigate humoral responses induced by recombinant vaccine. We detected changes of splenocyte subsets of CD4+T, CD8+ T cells and cytokine of IFN-gamma secreted by splenocytes for evaluation of cellular immune responses. The results showed that the rBCG-Rv3133c was able to induce higher levels of antibody titer, stronger proliferative responses and higher IFN-gamma production comparing with BCG vaccine. The results also suggested that this recombinant vaccine was a more efficacious tuberculosis vaccine for further study.
Animals ; Antibodies, Bacterial ; blood ; Antigens, Bacterial ; genetics ; immunology ; BCG Vaccine ; immunology ; Bacterial Proteins ; genetics ; immunology ; Escherichia coli ; genetics ; metabolism ; Interferon-gamma ; immunology ; Mice ; Mice, Inbred BALB C ; Mycobacterium tuberculosis ; immunology ; Protein Kinases ; genetics ; immunology ; Recombinant Proteins ; immunology ; T-Lymphocyte Subsets ; immunology ; Tuberculosis ; prevention & control ; Vaccination ; Vaccines, Synthetic ; immunology

PURPOSE: Guinea pig is one of the most suitable animal models for Mycobacterium tuberculosis (M. tb) infection since it shows similarities to pulmonary infection in humans. Although guinea pig shows hematogenous spread of M. tb infection into the whole body, immunological studies have mainly focused on granulomatous tissues in lungs and spleens. In order to investigate the time-course of disease pathogenesis and immunological profiles in each infected organ, we performed the following approaches with guinea pigs experimentally infected with M. tb over a 22-week post-infection period. MATERIALS AND METHODS: We examined body weight changes, M. tb growth curve, cytokine gene expression (IFN-gamma and TNF-alpha), and histopathology in liver, spleen, lungs and lymph nodes of infected guinea pigs. RESULTS: The body weights of infected guinea pigs did not increase as much as uninfected ones and the number of M. tb bacilli in their organs increased except bronchotracheal lymph node during the experimental period. The gene expression of IFN-gamma and TNF-alpha was induced between 3 and 6 weeks of infection; however, kinetic profiles of cytokine gene expression showed heterogeneity among organs over the study period. Histophathologically granulomatous lesions were developed in all four organs of infected guinea pigs. CONCLUSION: Although IFN-gamma and TNF-alpha gene expression profiles showed heterogeneity, the granuloma formation was clearly observed in every organ regardless of whether the number of bacilli increased or decreased. However, this protective immunity was accompanied with severe tissue damage in all four organs, which may lead to the death of guinea pigs.
Animals ; Body Weight ; *Disease Progression ; Female ; Gene Expression ; Gene Expression Regulation ; Guinea Pigs ; Interferon-gamma/genetics/*metabolism ; Kinetics ; Liver/metabolism/pathology ; Lung/metabolism/pathology ; Lymph Nodes/metabolism/pathology ; Mycobacterium tuberculosis ; Spleen/metabolism/pathology ; Tuberculosis/*genetics/pathology ; Tumor Necrosis Factor-alpha/genetics/*metabolism

Recent studies show that the vector of recombinant Bacillus Calmette-Guérin (rBCG) has a series of advantages. With exogenous gene and vaccine in one inoculation, it can obtain strong and persistent immune response at one time so that BCG is considered as a kind of ideal vector for live recombinant vaccine. This review outlines the application of rBCG vaccine and its vector in infectious diseases caused by bacteria, viruses, other microorganisms and parasites.
AIDS Vaccines ; genetics ; immunology ; Antigens, Bacterial ; genetics ; immunology ; BCG Vaccine ; genetics ; immunology ; metabolism ; Communicable Disease Control ; methods ; Genetic Vectors ; genetics ; HIV Infections ; prevention & control ; HIV-1 ; Mycobacterium tuberculosis ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Tuberculosis ; prevention & control ; Vaccines, Synthetic ; immunology

OBJECTIVETo assess the response in THP-1 treated with Rv3671c protein in Mycobacterium tuberculosis (M.tuberculosis).

METHODSThe gene encoding Rv3671c protein of M.tuberculosis was cloned into pET-28a vector and then expressed in Escherichia coli. The Rv3671c was purified with Ni-NTA affinity and ion exchange chromatography. The detection of protein concentration was by Lowry method.THP-1 cell was stimulated with Rv3671c protein and cells were analyzed by Hochest staining under fluorescence microscopy to assay cell death (apoptosis and necrosis). TNF-α and IL-1β were detected by ELISA at each stimulating time.

RESULTSThe Rv3671c protein of M.tuberculosis was successfully expressed in Escherichia coli. The purity of recombinant Rv3671c protein was 95%, and the protein concentration was up to 0.4 mg/ml. The nucleus of THP-1 was isolated and necrosis-like under fluorescence when cells were stimulated by Rv3671c protein. The levels of TNF-α and IL-1β in supernatant were 19 000 and 16 500 pg/ml respectively, and were significantly higher than control cells with the levels of 2100 and 3800 pg/ml separately.

CONCLUSIONThe necrosis of THP-1 cells could be stimulated by Rv3671c protein of M.tuberculosis and it was probably associated with high cytokines TNF-α and IL-1β levels.

Bacterial Proteins ; pharmacology ; Cell Death ; Cell Line ; Humans ; Interleukin-1beta ; metabolism ; Macrophages ; cytology ; metabolism ; Mycobacterium tuberculosis ; genetics ; Tumor Necrosis Factor-alpha ; metabolism

BACKGROUND: A peptide nucleic acid (PNA) probe-based real-time PCR (PNAqPCR(TM) TB/NTM detection kit; PANAGENE, Korea) assay has been recently developed for the simultaneous detection of Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM) in clinical specimens. The study was aimed at evaluation of the performance of PNA probe-based real-time PCR in respiratory specimens. METHODS: To evaluate potential cross-reactivity, the extracted DNA specimens from Mycobacterium species and non-mycobacterial species were tested using PNA probe-based real-time PCR assay. A total of 531 respiratory specimens (482 sputum specimens and 49 bronchoalveolar washing fluid specimens) were collected from 230 patients in July and August, 2011. All specimens were analyzed for the detection of mycobacteria by direct smear examination, mycobacterial culture, and PNA probe-based real-time PCR assay. RESULTS: In cross-reactivity tests, no false-positive or false-negative results were evident. When the culture method was used as the gold standard test for comparison, PNA probe-based real-time PCR assay for detection of MTBC had a sensitivity and specificity of 96.7% (58/60) and 99.6% (469/471), respectively. Assuming the combination of culture and clinical diagnosis as the standard, the sensitivity and specificity of the new real-time PCR assay for detection of MTBC were 90.6% (58/64) and 99.6% (465/467), respectively. The new real-time PCR for the detection of NTM had a sensitivity and specificity of 69.0% (29/42) and 100% (489/489), respectively. CONCLUSIONS: The new real-time PCR assay may be useful for the detection of MTBC in respiratory specimens and for discrimination of NTM from MTBC.
Bronchoalveolar Lavage Fluid/microbiology ; DNA Probes/chemistry/metabolism ; DNA, Bacterial/*analysis ; Humans ; Molecular Typing/*methods ; Mycobacterium tuberculosis/*genetics/isolation & purification ; Nontuberculous Mycobacteria/*genetics/isolation & purification ; Nucleic Acid Hybridization ; Peptide Nucleic Acids/chemistry/*metabolism ; *Real-Time Polymerase Chain Reaction ; Respiratory System/*microbiology ; Sputum/microbiology

OBJECTIVETuberculosis remains one of the most serious infectious diseases in the world. In this study, a scheme of Mycobacterium tuberculosis (M. tuberculosis) multilocus sequence analysis (MLSA) was established for the phylogenetic and epidemiology analysis.

METHODSTo establish the scheme of M. tuberculosis MLSA, the genome of H37Rv, CCDC5079 and CCDC5180 were compared, and some variable genes were chosen to be the MLSA typing scheme. 44 M. tuberculosis clinical isolates were typed by MLSA, IS6110-RFLP, and soligotyping, to evaluate the MLSA methods.

RESULTSAfter comparison of the genome, seven high discrimination gene loci (recX, rpsL, rmlC, rpmG1, mprA, gcvH, ideR) were chosen to be the MLSA typing scheme finally. 11 variable SNP sites of those seven genes were found among the 44 M. tuberculosis isolate strains and 11 sequence types (STs) were identified. Based on the Hunter-Gaston Index (HGI), MLSA typing was not as good for discrimination at the strain level as IS6110-RFLP, but the HGI was much better than that of spoligotyping. In addition, the MEGA analysis result of MLSA data was similar to spoligotyping/PGG lineage, showing a strong phylogenetic signal in the modern strains of M. tuberculosis. The MLSA data analysis by eBURST revealed that 4 sequence types (ST) came into a main cluster, showing the major clonal complexes in those 44 strains.

CONCLUSIONMLSA genotyping not only can be used for molecular typing, but also is an ideal method for the phylogenetic analysis for M. tuberculosis.

Chromosome Mapping ; Chromosomes, Bacterial ; Gene Expression Regulation, Bacterial ; Genome, Bacterial ; Genotype ; Multilocus Sequence Typing ; methods ; Mycobacterium tuberculosis ; genetics ; metabolism