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Objective@#To establish the domestic matrix assisted laser desorption/ionisation time of flight mass spectrometry database for identification of clinical mycobacteria and evaluate its accuracy with foreign counterpart. @*Methods@#The establishment of "Chinese Pathogenic Mycobacteria Mass Spectrometry Database" : nineteen American type culture collection strains from 19 species and 183 "standardized" isolates from 42 species were selected and extracted by modified ultrasonic extraction method for spectral acquisition and database establishment based on microTyper MS. Each extract was dropped onto 12 spots and tested twice to generate 24 spectrum, then at least 20 qualified spectrum according to the standard were selected. Subsequently they were composed into one main spectra (MSP) by setting peak number maximum, peak frequency minimum and mass tolerance. Verification of database: Totally 305 mycobacteria from different regions were used for comparison of accuracy and spectral features between microTyper MS based on domestic database and imported MALDI TOF MS base on Mycobacteria Library 3.0 database. @*Results@#The database composed of 202 stains from 42 species was constructed, with an average of 4.8 in each species. The top ten were M. Kansasii(16), M. intracellulare(16), M. gordonae(16), M. fortuitum(16), M. avium(16), M. abscessus(16), M. tuberculosis(15), M. marseillense(11), M. arupense(10), M. yongongens(8). A total of 305 isolates were confirmed belonging to 22 species by sequencing. The accuracy based on this database was 99.67% (304/305), which was better than the Mycobacteria Library 3.0 database (χ2=4.06, P<0.05). @*Conclusion@#The construction of the "Chinese Pathogenic Mycobacteria Mass Spectrometry Database" meets the requirement of routine clinical application and was more accurate than its counterpart in terms of domestic comment strains.(Chin J Lab Med, 2018, 41: 519-526)
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Objective To investigate the incidence of drug resistance among new and retreatment TB patients from special hospital.Methods Totally 500 smear positive TB patients from June 2013 to December 2014 in Beijing Chest Hospital were enrolled.Phenotypic susceptibilities to cultured isolates were analyzed in 15 anti tuberculosis drugs by MGIT 960,include Isoniazid (INH),Rifampicin (RFP),Streptomycin (STR),Ethambuto (EMB),Kanamycin (Km),Amikacin (Am),Capreomycin (Cm),Ofloxacin (Ofx),Levofloxacin (Lfx),Moxifloxacin (Mfx),Paza-aminosalicylate (PAS),Protionamide (Pto),Linezolid (Lzd),Ethionamide (Eto),Pyrazinamide (PZA).Results A total of 500 TB cases were enrolled.71 samples among these were NTM infection and 12 samples were contaminted.The rest of 417 of cases infected with Mycobacteriuma,and the rate of drug resistance was 47.2％ (192/417) and the MDR rate was 28.2％ (120/417).The retreatment was significantly higher than that of the new in any drug resistance rate and MDR rate (P =0.000).100 of the retreatment isolates and 50 of the new isolates with Mycobacteriuma were selected to do the drug susceptibility test in 11 subsequent anti tuberculosis drugs (include:PZA,Am,Km,Cm,Ofx,Lfx,Mfx,PAS,Pto,Lzd,Eto).Five cases were contaminated,and in the rest of the cases,48 was the new and 97was the retreatment.The rate of the drug resistance to PZA,Am,Km,Cm,Ofx,Lfx,Mfx for the retreatment were significantly higher than the new (P ＜ 0.05).The rate of drug resistance to PAS,Pto,Lzd and Eto for the new and reteartment were no markedly differential in statistics.Conclusion This study further confirmed the rate of drug resistance in retreatment cases is higher,and the management of tuberculosis patients should be further strengthened.
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Objective To evaluate the resistance of multidrug-resistant Mycobacterium tuberculosis ( M. tb) strains to bedaquiline ( BDQ) and to analyze the relationships between their genotypes and BDQ-re-sistant phenotypes in order to provide a scientific basis for rational use of BDQ for the treatment of multidrug-resistant tuberculosis ( MDR-TB) in clinical practice. Methods A total of 387 clinical M. tb strains, inclu-ding 100 pan-susceptible strains and 287 strains isolated from patients with MDR ( MDR-TB strains) , were enrolled in this study. Of the 287 MDR-TB strains, 77 strains were collected in Chongqing in 2015 and the other strains were collected in a national drug-resistant tuberculosis survey conducted in China during 2007 to 2008. Minimum inhibitory concentrations (MIC) of BDQ against those strains were detected. Genotypes of those strains were analyzed by Spoligotyping. Differences in the resistant rates against BDQ between Beijing genotype and non-Beijng genotype MDR-TB strains were comparatively analyzed. Results MIC50 and MIC90 of BDQ against the 287 MDR-TB strains were 0. 03 μg/ml and 0. 25 μg/ml, respectively. Nineteen out of the 287 MDR-TB strains (6. 6%) were resistant to BDQ. Based on the Spoligotyping, 195 strains were clas-sified into Beijing genotype, and the other 92 strains belonged to non-Beijing genotype. Statistical analysis revealed that the BDQ-resistant rate in Being genotype strains (4. 6%, 9/195) was lower than that in non-Beijing genotype strains (10. 9%, 10/92, χ2=3. 955, P=0. 047). In addition, the MIC50 and MIC90 of BDQ against pan-susceptible strains were 0. 03 μg/ml and 0. 12 μg/ml, respectively. Sixty-three pan-sus-ceptible strains belonged to Beijing genotype and the other 37 strains belonged to non-Beijing genotype. None of the pan-susceptible strains was resistant to BDQ. Conclusion This study indicates that BDQ showed stronger in vitro antibacterial activity against the MDR-TB strains isolated in China. A correlation between non-Beijing genotype and BDQ resistance is observed in those MDR strains. MDR strains of Beijing genotype are more susceptible to BDQ than those of non-Beijing genotype.
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Objective To study the genotypes of representative Mycobacterium tuberculosis (M.tuberculosis) strains from China with spacer oligonucleotide typing (spoligotyping),and to investigate the prevalence of different genotypes TB in China,and analyse the relationship between genotype and drug resistance.Methods 4017 clinical isolates were collected by Chinese Center for Disease Control and Prevention from 2007 to 2008 in 31 provinces in China according to sampling principle of epidemiology.Drug susceptibility testing was performed using proportion method,and spoligotyping was chosen to carry out genotyping of these M.tuberculosis.In addition,chi-square test was used to compare the differences among the detection rate of different genotypes.Results Among the 4017 M.tuberculosis isolates,2500 ( 62.2％ ) isolates belonged to Beijing genotype.The percentage of Beijing genotypes in the northern of China was higher than that in the southern of China ( 76.5％ vs.53.2％,x2 =219.69,P ＜ 0.05 ),while T1 genotypes were more common in the southern China,compared with that in northern China ( 13.3％ vs.4.3％,x2 =219.69,P ＜ 0.05 ).The differences were statistically significant.The proportions of Rifampinresistant (21.7％ vs.21.7％ ),Ofloxacin-resistant (4.9％ vs.2.4％ ) and Multidrug-resistant ( 11.3％vs.7.4％ ) isolates among Beijing genotype strains were significantly higher than those among non-Beijing strains (x2 =22.10,14.42 and 14.83,respectively,P ＜ 0.05 ).Conclusions Beijing genotype was still predominant epidemic genotypes.The percentage of Beijing genotype showed difference between distinct areas,and the percentage of Beijing genotypes in northern China was higher than that in southern China.Beijing genotype strains reveal correlation with Rifampin-resistance,Ofloxacin-resistance and Multidrug-resistance.
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Objective To evaluate the usefulness of mycolic acid for identification of Mycobacterium species using SMIS. Methods One hundred and eighteen clinical Mycobacterium isolates collected from Beijing Tuberculosis and Thoracic Tumor Research Institute through whole year of 2007 were analyzed. The 118 isolates contain 25 isolates of Mycobacterium tuberculosis and 93 non tuberculosis Mycobacterium identified by PNB method. Mycolic acid analysis using SMIS is evaluated for identification of a broad range of Mycobacteria in comparison with 16S rDNA , 16-23S rDNA ITS sequencing to measure the concordance rate and agreement, and verify the concordance rate and agreement among results of mycolic acid, sequencing and PNB in identifying Mycobacterium tuberculosis and non tuberculosis Mycobacterium. Results The concordance rate between mycolic acid method analysis and DNA sequencing is 92% ( 108/118), of which concordance rate in Mycobacterium tuberculosis complex and non tuberculosis Mycobacterium are 95% (35/37) and 90% (73/81) respectively, agreement of both is great( agreement Kappa value is 0. 96). Through retrospective analysis, the concordance of results between SMIS and PNB method analysis is 90% (106/118)and agreement is well( agreement Kappa value is 0. 73 ), the concordance of results between sequencing and PNB method analysis is also 90% ( 106/118 ) and agreement is well (agreement Kappa value is 0. 74 ),despite the identification results of 11 isolates by PNB method are discordant. Conclusion Mycolic acid analysis by SMIS enables rapid identification of a broad range of clinical Mycobacterium species, which could play an important role in polyphasic identification of Mycobacterium species.
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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 determine whether regulatory T cells(Tr)are increased in patients with tuberculosis and whether they are associated with its immunopathology.Meantime,to investigate the possibility of tuberculosis(TB)as a model for studying Tr functions.Methods The lymphocyte subsets were isolated from peripheral blood mononuclear cells by sorting with flow cytometry.Total cellular RNA was extracted and RT-PCR was performed to detect the Foxp3 mRNA in purified CD3+CIM+T cells,CD3+CD8+T cells and non-CD3+CD4+CD8+T cells.Using FACS analysis.we further investigated the distribution of Foxp3+ population in CD4+ CD25+T cells.Finally,we compared the percentage of CD4+CD25highFoxp3+T cells present in 51 active patients with tuberculosis and 40 uninfected healthy control subjects by FACS.The detection of Tr infiltration of Foxp3+ cells were performed with immunohistochemistry(IHC)method on tuberculosis pathological sections.Results Foxp3 was specific expressed in CD3+CD4+T cells,either in tuberculosis patients or healthy control subjects.Foxp3+ T cells took about 85%fraction of CD4+ CD25highpopulation.We used CD4+CD25high Foxp3+as a detective markers for Tr in the FACS analysis.The results showed that patients with active TB had a 4.4 fold higher percentage within the CD4+T cells in peripheral blood compared to healthy control group(modian,1.01%vs 0.23%,P<0.01).Much higher frequency of Tr were found along with T cells infiltration at the tuberculosis pathological tissues.A few individuals that we can followed indicated the expanded Tr was declined after curative treatment with operation.Conclusion Tr cells are increased in tuberculosis patients and closely correlate with its immunopathology.Tuberculosis should be a valuable model for Tr functional study.
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ObJective To locate the cysteine-rich domains(CRD) of murine 4-1BB binding to its natural ligand. Methods A serial soluble extracellular CRDs of routine 4-1BB and 4-1BBL fusion proteins was constructed and prepared. The binding of purified 4-1BB-Igs to 4-1BBL and 4-1BB monoclonal antibody were tested using ELISA assay and Western blot analysis. Blocking experiment with 4-1BBL and 4-1BB mon-oclonal antibody was performed by ELISA assay. Results All truncated overlapped proteins containing ex-tracellular CRD Ⅱ of murine 4-1BB were able to bind to 4-1BBL by ELISA assay, excepting the CRD Ⅰ do-main alone. A 4-1BB monoclonal antibody proved to block the interaction of 4-1BB and 4-1BBI, was also able to bind to CRD Ⅱ. Conclusion Murine 4-1BBL whose specificity was mapped to CRD Ⅱ of 4-1BB ex-tracellular region with a possible conformational structure.