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Objective:To preliminarily evaluate the immunogenicity and efficacy of two novel tuberculosis vaccine candidates (a fusion multicomponent protein EPDPA015f and a mixed multicomponent protein EPDPA015m) and to provide a new antigen combination for the development of tuberculosis vaccines.Methods:Recombinant plasmids for the expression of EPDPA015f and EPDPA015m proteins were constructed. Six-week-old BALB/c mice were immunized with EPDPA015f or EPDPA015m in combination with aluminium adjuvant (50 μg/mouse) for three times with an interval of 10 d. The mice were sacrificed 10 d after the last immunization to collect blood and spleen samples. Serum antibody titers and cytokine levels were measured by ELISA, Luminex technique and enzyme-linked immunospot assay (ELISPOT). Mycobacterial growth inhibition assay (MGIA) was used to detect the ability of mouse splenocytes to inhibit the growth of Mtb in vitro. One-way analysis of variance and t-test were used for statistical analysis. Results:Both EPDPA015f and EPDPA015m could induce the production of various cytokines and IgG antibodies at a high level. The levels of cytokines related to Th1 (IL-2, TNF-α, IFN-γ), Th2 (IL-4, IL-6, IL-10) and Th17 (IL-17) as well as other proinflammatory cytokines (GM-CSF, IL-12) were higher in the EPDPA015f group than in the adjuvant group ( P<0.05). The titer of IgG antibody induced by EPDPA015f was as high as 1∶4×10 6. The results of MGIA showed that the numbers of Mtb (lgCFU) in the PBS, adjuvant, EPDPA015f and EPDPA015m groups were 3.46±0.11, 3.51±0.06, 2.98±0.09 and 3.19±0.08, respectively. The number of colonies in the EPDPA015f group was the least as compared with that in the other three groups ( P<0.001, P<0.001, P<0.01). Conclusions:The vaccine candidate EPDPA015f could elicit more comprehensive and high-level cellular and humoral immune responses, and exhibited superior in vitro inhibitory activity against the growth of Mtb. EPDPA015f had the potential to be used as a preventive vaccine or a booster vaccine
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Objective@#To examine the association between the cross-resistance to ethionamide (Eto) and isoniazid (INH) and mutations of drug resistant genes in Mycobacterium tuberculosis (MTB), so as to provide the evidence for clinical diagnosis and treatment for multidrug-resistant (MDR) tuberculosis.@*Methods@#Totally 126 MTB clinical isolates were selected, including 88 MDR-MTB clinical isolates and 38 INH- and rifampicin (RFP)-sensitive isolates. The resistance to INH and Eto was tested in MTB clinical isolates using the drug susceptibility test, and the mutations in the spacer region of INH and Eto resistance-related katG, inhA, ethA, mshA, ndh, spacer region of oxyR-ahpC and inhA promoter were detected using PCR assay. The phenotypic resistance served as a gold standard, and the sensitivity, specificity and accuracy of gene mutation tests were calculated for detection of MTB clinical isolates cross-resistant to INH and Eto.@*Results@#Of the 126 MTB clinical isolates, there were 37 isolates cross-resistant to INH and Eto (29.37%), 51 isolates with resistance to INH and susceptibility to Eto (40.48%), 4 isolates with susceptibility to INH and resistance to Eto (3.17%) and 34 isolates with susceptibility to INH and Eto (26.98%). Among the 41 Eto-resistant MTB clinical isolates, there were 37 isolates with resistance to INH (90.24%). There were 64 MTB clinical isolates detected with katG mutations (50.79%), 4 isolates with mutation in the spacer region of oxyR-ahpC (3.17%), 2 isolates with inhA mutations (1.59%), and these isolates were all resistant to INH. There were 11 MTB clinical isolates detected with mutation in the inhA promoter (8.73%) and one isolate with ndh mutation, and all these isolates were cross-resistant to INH and Eto. There were 23 MTB clinical isolates detected with ethA mutations (18.25%) and 40 isolates with mshA mutations (31.75%), in which Eto-susceptible and -resistant isolates were detected. The diagnostic sensitivity, specificity and accuracy of inhA promoter tests for detection of cross-resistance to INH and Eto were 29.73% (95%CI: 16.44%-47.17%), 100.00% (95%CI: 87.36%-100.00%) and 63.38% (95%CI: 51.76%-73.63%) in MTB clinical isolates.@*Conclusions@#The prevalence of INH resistance is high in Eto-resistant MTB clinical isolates. Mutation in the inhA promoter region correlates with the cross-resistance to INH and Eto in MTB clinical isolates, and detection of mutation in the inhA promoter may be feasible to detect the cross-resistance to INH and Eto in MTB clinical isolates.
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Objective:To evaluate the humoral and cellular immunoreactivity of recombinant Mycobacterium tuberculosis ( M. tuberculosis) PstS1 and HspX protein antigens in order to provide reference for immunodiagnosis of tuberculosis and screening of candidates for vaccine antigens. Methods:Purified recombinant M. tuberculosis PstS1 and HspX proteins were obtained using molecular cloning expression and Ni 2+ affinity chromatography. Blood samples and epidemiological data of healthy individuals and patients with M. tuberculosis infection were collected. Specific IgG antibodies and IFN-γ-producing antigen-specific T cells were respectively detected by enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immunospot assay (ELISPOT) with the recombinant proteins used as antigens. The humoral and cellular immunoreactivity of the recombinant PstS1 and HspX proteins were assessed with statistical analysis of data. Results:Both the recombinant PstS1 and HspX proteins could induce the secretion of IFN-γ by more specific effector T cells in patient with M. tuberculosis infection, and the differences between the infection and healthy control groups were statistically significant ( P<0.05). The specificity and sensitivity of the recombinant PstS1 and HspX as the diagnostic antigens of ELISPOT were 92.11% (35/38) and 65.96% (31/47), and 68.42% (26/38) and 91.49% (43/47), respectively. The two proteins also possessed some humoral immunoreactivity, but statistically significant difference was only observed in the HspX-specific antibody level between the two groups ( P<0.05). Conclusions:Both the recombinant PstS1 and HspX proteins had good cellular immunoreactivity and were the immunodominant antigens of cellular immunity. They performed well in cellular immunodiagnosis and were good potential candidate antigens for anti-tuberculosis vaccines.
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Objective To establish and evaluate a multiplex PCR method for rapid identification of Mycobacterium species in order to provide an approach for rapid diagnosis of pathogens causing tuberculo-sis. Methods Four genes including 16S rRNA, Rv0577, RD9 and mtbk_20680 were selected to establish the multiplex PCR method. Specific primers were designed and the reaction system and conditions were opti-mized. The sensitivity and specificity of the multiplex PCR method were evaluated through identifying Myco-bacterium africanum (M. africanum), Mycobacterium bovis (M. bovis), M. bovis BCG, seven common non-tuberculosis Mycobacterium (NTM), seven reference species of common respiratory bacteria and 93 clinical strains of Mycobacterium tuberculosis (MTB) isolated from patients with tuberculosis in Gansu Province of China. Results The fragments of 16S rRNA, Rv0577, RD9 and mtbk_20680 genes were 543 bp, 786 bp, 369 bp and 231 bp in length, respectively. MTB strains of the Beijing genotype were positive for all of the four genes, while the non-Beijing genotype strains were negative for mtbk_20680. M. africanum, M. bovis and M. bovis BCG strains were negative for 16S rRNA and Rv0577. NTM strains only carried 16S rRNA and none of four genes were detected in the seven species of respiratory bacteria. Among the 93 clinical MTB strains, 80 (86. 02％ ) belonged to the Beijing genotype and the other 13 (13. 98％ ) were non-Beijing gen-otype strains. The specificity of the multiplex PCR method was 100％ . Conclusions The established multi-plex PCR method could accurately distinguish Mycobacterium, Mycobacterium tuberculosis complex (MTBC), NTM, MTB, and Beijing and non-Beijing genotype MTB with high sensitivity and specificity.
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Objective@#To establish and evaluate a multiplex PCR method for rapid identification of Mycobacterium species in order to provide an approach for rapid diagnosis of pathogens causing tuberculosis.@*Methods@#Four genes including 16S rRNA, Rv0577, RD9 and mtbk_20680 were selected to establish the multiplex PCR method. Specific primers were designed and the reaction system and conditions were optimized. The sensitivity and specificity of the multiplex PCR method were evaluated through identifying Mycobacterium africanum (M.africanum), Mycobacterium bovis (M.bovis), M. bovis BCG, seven common non-tuberculosis Mycobacterium (NTM), seven reference species of common respiratory bacteria and 93 clinical strains of Mycobacterium tuberculosis (MTB) isolated from patients with tuberculosis in Gansu Province of China.@*Results@#The fragments of 16S rRNA, Rv0577, RD9 and mtbk_20680 genes were 543 bp, 786 bp, 369 bp and 231 bp in length, respectively. MTB strains of the Beijing genotype were positive for all of the four genes, while the non-Beijing genotype strains were negative for mtbk_20680. M. africanum, M. bovis and M. bovis BCG strains were negative for 16S rRNA and Rv0577. NTM strains only carried 16S rRNA and none of four genes were detected in the seven species of respiratory bacteria. Among the 93 clinical MTB strains, 80 (86.02%) belonged to the Beijing genotype and the other 13 (13.98%) were non-Beijing genotype strains. The specificity of the multiplex PCR method was 100%.@*Conclusions@#The established multiplex PCR method could accurately distinguish Mycobacterium, Mycobacterium tuberculosis complex (MTBC), NTM, MTB, and Beijing and non-Beijing genotype MTB with high sensitivity and specificity.
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Objective@#Autoregressive integrated moving average (ARIMA) model was used to predict the incidence of tuberculosis in China from 2018 to 2019, providing references for the prevention and control of pulmonary tuberculosis.@*Methods@#The monthly incidence data of tuberculosis in China were collected from January 2005 to December 2017. R 3.4.4 software was used to establish the ARIMA model, based on the monthly incidence data of tuberculosis from January 2005 to June 2017. Both predicted and actual data from July to December 2017 were compared to verify the effectiveness of this model, and the number of tuberculosis cases in 2018-2019 also predicted.@*Results@#From 2005 to 2017, a total of 13 022 675 cases of tuberculosis were reported, the number of pulmonary tuberculosis patients in 2017 was 33.68% lower than that in 2005, and the seasonal character was obvious, with the incidence in winter and spring was higher than that in other seasons. According to the incidence data from 2005 to 2017, we established the model of ARIMA (0,1,2)(0,1,0)12. The relative error between the predicted and actual values of July to December 2017 fitted by the model ranged from 1.67% to 6.80%, and the predicted number of patients in 2018 and 2019 were 789 509 and 760 165 respectively.@*Conclusion@#The ARIMA (0, 1, 2)(0, 1, 0)12 model well predicted the incidence of tuberculosis, thus can be used for short-term prediction and dynamic analysis of tuberculosis in China, with good application value.
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Objective To evaluate the antigenicity of two proteins of Mycobacteium tuberculosis (M. tuberculosis), Dnak(Rv0350) and MPT83(Rv2873), in order to provide a scientific basis for immuno-logical diagnosis of tuberculosis and research on vaccines. Methods The two antigen proteins, Dnak (Rv0350) and MPT83(Rv2873), were cloned, expressed and purified using the methods of genetic recom-bination and protein purification technology. Blood samples were collected from subjects including tuberculo-sis patients ( TB) , non-tuberculosis patients with other pulmonary diseases ( non-TB) and healthy volunteers (HV). To analyze the immunological properties of the recombinant Dnak (Rv0350) and MPT83 (Rv2873) proteins, they were used as antigens to detect humoral and cellular immunity in the subjects with enzyme linked immunosorbent assay ( ELISA ) and effector T cell enzyme-linked immunospot assay ( ELISPOT ) . Results The recombinant and purified Dnak (Rv0350) and MPT83 (Rv2873) proteins of M. tuberculosis were successfully obtained and used as antigens in the detection of humoral and cellular immunity in the sub-jects. Specific antibodies ( IgG) in the serum samples of 135 TB, 56 non-TB and 94 HV were tested with ELISA. The results showed that the sensitivity, specificity and accuracy of Dnak ( Rv0350 ) protein were 77. 80％ (105/135), 56. 70％ (85/150) and 66. 67％ (190/285). Similarly, the sensitivity, specificity and accuracy of MPT83 (Rv2873) protein were 76. 30％ (103/135), 43. 30％ (65/150) and 58. 95％(168/285). Cellular immunity was tested with the levels of IFN-γproduced by effector T lymphocytes after stimulating peripheral blood monouclear cells ( PBMC) collected form subjects of 59 TB, 65 non-TB and 64 HV with Dnak (Rv0350) and MPT83 (Rv2873) protein antigens. The results showed that the sensitivity, specificity and accuracy of Dnak (Rv0350) and MPT83 (Rv2873) proteins were 66. 10％ (39/59), 62. 79％ (81/129) and 63. 83％ (120/188), and 47. 46％ (28/59), 79. 84％ (103/129) and 69. 68％(131/188), respectively. Conclusions M. tuberculosis Dnak (Rv0350) and MPT83 (Rv2873) proteins have good antigenicity and could stimulate T cells to produce stronger immune responses. The two proteins used in combination might have promising potential in the research of immunodiagnosis of tuberculosis and the development of new anti-tuberculosis vaccines.
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Objective To investigate the cross-reactive immune responses to Mycobacterium vac-cae (M. vaccae), Mycobacterium tuberculosis (M. tuberculosis, H37Rv) and Mycobacterium bovis Bacillus Calmette-Guerin ( BCG) for providing reference for the development of new vaccines with M. vaccae. Meth-ods M. vaccae (ATCC95051), M. tuberculosis (H37Rv) and BCG (China strain) were cultured on L-J solid media and harvested. Total bacterial protein antigens prepared by ultrasonic disruption were used to im-munize BALB/c mice. IgG antibodies in serum samples were detected with enzyme-linked immunosorbent assay ( ELISA) to evaluate humoral immune responses. Cellular immunity was assessed by detecting various cytokines with cytokine release assay ( CRA) . Results The mice that were respectively immunized with the three mycobacterial antigens could produce high titers of antibodies ( IgG) and high levels of IFN-γand IL-2, but low levels of IL-4 and IL-10. Results of the cross reactivity tests showed that ATCC95051, H37Rv and BCG were able to cross-react with the immunized mice, and all of them induced high levels of IFN-γ, IL-2 and IgG antibodies. Conclusions The three Mycobacteria mainly elicited Th1 immune responses. There were cross-reactive immune responses to M. vaccae, M. tuberculosis and BCG, which might provide ref-erence for using M. vaccae in the development of new anti-tuberculous vaccines.
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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.
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Humanos , Antígenos Bacterianos/genética , Clonación Molecular , Ensayo de Inmunoadsorción Enzimática , Inmunoglobulina G , Mycobacterium tuberculosis/metabolismo , Reacción en Cadena de la Polimerasa , Curva ROC , Proteínas Recombinantes , Sensibilidad y Especificidad , Pruebas Serológicas/métodos , Tuberculosis/genéticaRESUMEN
Objective: To understand the etiological characteristics and drug susceptibility of Mycobacterium thermoresistibile and Mycobacterium elephantis isolated from a cow with mastitis and provide evidence for the prevention and control of infectious mastitis in cows. Methods: The milk sample was collected from a cow with mastitis, which was pretreated with 4% NaOH and inoculated with L-J medium for Mycobacterium isolation. The positive cultures were initially identified by acid-fast staining and multi-loci PCR, then Mycobacterium species was identified by the multiple loci sequence analysis (MLSA) with 16S rRNA, hsp65, ITS and SodA genes. The drug sensitivity of the isolates to 27 antibiotics was tested by alamar blue assay. Results: Two anti-acid stain positive strains were isolated from the milk of a cow with mastitis, which were identified as non-tuberculosis mycobacterium by multi-loci PCR, and multi-loci nucleic acid sequence analysis indicated that one strain was Mycobacterium thermoresistibile and another one was Mycobacterium elephantis. The results of the drug susceptibility test showed that the two strains were resistant to most antibiotics, including rifampicin and isoniazid, but they were sensitive to amikacin, moxifloxacin, levofloxacin, ethambutol, streptomycin, tobramycin, ciprofloxacin and linezolid. Conclusions:Mycobacterium thermoresistibile and Mycobacterium elephantis were isolated in a cow with mastitis and the drug susceptibility spectrum of the pathogens were unique. The results of the study can be used as reference for the prevention and control the infection in cows.
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Animales , Bovinos , Femenino , Humanos , Antibacterianos/farmacología , Antituberculosos/farmacología , Farmacorresistencia Bacteriana , Mastitis Bovina/microbiología , Pruebas de Sensibilidad Microbiana , Leche/microbiología , Mycobacterium/aislamiento & purificación , Infecciones por Mycobacterium/veterinaria , Mycobacterium tuberculosis/efectos de los fármacos , Micobacterias no Tuberculosas/aislamiento & purificación , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S/genéticaRESUMEN
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).Condnsion 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.
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Objective To understand the etiological characteristics and drug susceptibility of Mycobacterium thermoresistibile and Mycobacterium elephantis isolated from a cow with mastitis and provide evidence for the prevention and control of infectious mastitis in cows.Methods The milk sample was collected from a cow with mastitis,which was pretreated with 4％ NaOH and inoculated with L-J medium for Mycobacterium isolation.The positive cultures were initially identified by acid-fast staining and multi-loci PCR,then Mycobacterium species was identified by the multiple loci sequence analysis (MLSA) with 16S rRNA,hsp65,ITS and SodA genes.The drug sensitivity of the isolates to 27 antibiotics was tested by alamar blue assay.Results Two anti-acid stain positive strains were isolated from the milk of a cow with mastitis,which were identified as non-tuberculosis mycobacterium by multi-loci PCR,and multi-loci nucleic acid sequence analysis indicated that one strain was Mycobacterium thermoresistibile and another one was Mycobacterium elephantis.The results of the drug susceptibility test showed that the two strains were resistant to most antibiotics,including rifampicin and isoniazid,but they were sensitive to amikacin,moxifloxacin,levofloxacin,ethambutol,streptomycin,tobramycin,ciprofloxacin and linezolid.Conclusions Mycobacterium thermoresistibile and Mycobacterium elephantis were isolated in a cow with mastitis and the drug susceptibility spectrum of the pathogens were unique.The results of the study can be used as reference for the prevention and control the infection in cows.
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Investigations on the genetic diversity of Mycobacterium tuberculosis in China have shown that Beijing genotype strains play a dominant role. To study the association between the M. tuberculosis Beijing genotype and the drug-resistance phenotype, 1286 M. tuberculosis clinical isolates together with epidemiological and clinical information of patients were collected from the center for tuberculosis (TB) prevention and control or TB hospitals in Beijing municipality and nine provinces or autonomous regions in China. Drug resistance testing was conducted on all the isolates to the four first-line anti-TB drugs (isoniazid, rifampicin, streptomycin, and ethambutol). A total of 585 strains were found to be resistant to at least one of the four anti-TB drugs. The Beijing family strains consisted of 499 (53.20%) drug-sensitive strains and 439 (46.80%) drug-resistant strains, whereas the non-Beijing family strains comprised 202 (58.05%) drug-sensitive strains and 146 (41.95%) drug-resistant strains. No significant difference was observed in prevalence (χ= 2.41, P > 0.05) between the drug-resistant and drugsensitive strains among the Beijing family strains. Analysis of monoresistance, multidrug-resistant TB, and geographic distribution of drug resistance did not find any relationships between the M. tuberculosis Beijing genotype and drug-resistance phenotype in China. Results confirmed that the Beijing genotype, the predominant M. tuberculosis genotype in China, was not associated with drug resistance.
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Humanos , Antituberculosos , Usos Terapéuticos , China , Epidemiología , Farmacorresistencia Bacteriana Múltiple , Variación Genética , Genotipo , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis , Genética , Fenotipo , Tuberculosis Resistente a Múltiples Medicamentos , Quimioterapia , EpidemiologíaRESUMEN
<p><b>OBJECTIVE</b>To investigate the polymorphisms of the coding gene and the human T cell epitopes of antigen GlnA1, Mpt70, LppX, GroES and LpqH on Mycobacterium tuberculosis complex (MTBC) strains in thirteen provinces of China.</p><p><b>METHODS</b>A total of 173 clinical MTBC isolates from thirteen provinces were selected to test the gene sequences of the five antigens, using PCR and DNA sequencing methods. Sequences were compared and sliced by BioEdit, and the variations of the human and nonhuman T cell epitopes were analyzed. The rates on synonymous mutation (dS), non-synonymous mutation (dN) and dN/dS values were calculated by Mega 6.0 software.</p><p><b>RESULTS</b>Among the 173 strains, there were two non-synonymous mutations in the non-epitope region of glnA1, one non-synonymous mutations in epitope domain of mpt70, one non-synonymous mutation and one synonymous mutation in the epitope domain of lpqH; while groES showed no mutation. lppX had five non-synonymous mutations and one synonymous mutation in the epitope domain. Nine strains presented higher polymorphism at the same gene locus of position 152 in lppX. And seven of the fifteen epitopes contained in lppX were altered and the dN/dS value of this gene was 0.19.</p><p><b>CONCLUSIONS</b>Data from the human T cell epitope domains of MTBC antigens Mpt70, LppX and LpqH contained epitope diversity, indicated that these antigens may have involved in diversifying the selection to evade the host immunity. GlnA1 had the polymorphism in epitope domain, which might have little influence on the immuno-response. While GroES seemed relatively conservative, it could play an important role on identification, diagnosis and the development of potential Mycobacterium tuberculosis vaccine.</p>
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Humanos , Antígenos Bacterianos , Genética , Proteínas Bacterianas , Genética , China , Epítopos de Linfocito T , Genética , Mycobacterium tuberculosis , Genética , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Análisis de Secuencia de ADNRESUMEN
Objective To investigate the single nucleotide polymorphism (SNP) of toxinantitoxin-chaperone (TAC) system of Mycobacterium (M.) tuberculosis with different genotypes and its biological significance.Methods A total of 183 clinical M.tuberculosis isolates were collected for spoligotyping.The sequences of higA,higB and Rv1957 were obtained by using PCR and DNA sequencing.The sequences were compared for possible mutations.Functional consequences of nonsynonymous SNPs were predicted by using I-Mutant 2.0 servers.Results Among the 183 M.tuberculosis isolates,138(75.41％) belonged to the Beijing family,while 45(24.59％) belonged to the non-Beijing family.A total of 149(81.42％) isolates showed polymorphisms in the TAC system.We discovered 6 nonsynonymous SNPs and 2 synonymous SNPs.All the synonymous mutations occurred in higA gene,while nonsynonymous SNPs were found in the higA,higB and Rv1957 genes either.All the synonymous mutations and 4 nonsynonymous SNPs were restricted to the Beijing family strains and only 2 nonsynonymous SNPs were observed in the non-Beijing family strains.Of the 6 nonsynonymous SNPs studied,4 were predicted to have ability to affect the stability of respective protein.Conclusion The SNPs in the coding sequences of TAC system in clinical isolates can be relatively high and the Beijing family strains are with higher polymorphism,which might benefit to adapt to different host environment.
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<p><b>OBJECTIVE</b>To investigate the variable number tandem repeats (VNTR) genetic polymorphisms, genotyping and distribution pattern of clinical Mycobacterium (M.) tuberculosis isolates from Qinghai province.</p><p><b>METHODS</b>The clinical M. tuberculosis strains isolated from the patients with tuberculosis and related background data were collected from Qinghai Provincial Center for Disease Control and Prevention from 2009 to 2012. Genotyping was conducted by using multiple locus VNTR analysis (MLVA). Genomic DNA was extracted and 15 VNTR loci were amplified with PCR and the PCR products were detected with gel electrophoresis. The VNTR diversity and clusters of genotyping were analyzed with BioNumerics (Version 5.0).</p><p><b>RESULTS</b>A total of 251 clinical M. tuberculosis isolates were analyzed with 15 VNTR loci showing that there were great genetic diversity in these isolates. Six of the 15 VNTR loci, showed that the Hunter-Gaston index (HGI) were higher than 0.6, in which the highest resolution was MIRU26. The clusters of genotyping showed that these isolates could be categorized into four gene clusters and 238 genotypes. The four gene clusters accounted for 4.9%, 91.9%, 1.6% and 1.6% of the clinical isolates, respectively.</p><p><b>CONCLUSION</b>The results showed that there is great variety of VNTR genetic polymorphisms in clinical M. tuberculosis isolates in Qinghai province.</p>