Bioinformatics tools and databases for whole genome sequence analysis of Mycobacterium tuberculosis

Tuberculosis (TB) is an infectious disease of global public health importance caused by Mycobacterium tuberculosis complex (MTC) in which M. tuberculosis (Mtb) is the major causative agent. Recent advancements in genomic technologies such as next generation sequencing have enabled high throughput cost-effective generation of whole genome sequence information from Mtb clinical isolates, providing new insights into the evolution, genomic diversity and transmission of the Mtb bacteria, including molecular mechanisms of antibiotic resistance. The large volume of sequencing data generated however necessitated effective and efficient management, storage, analysis and visualization of the data and results through development of novel and customized bioinformatics software tools and databases. In this review, we aim to provide a comprehensive survey of the current freely available bioinformatics software tools and publicly accessible databases for genomic analysis of Mtb for identifying disease transmission in molecular epidemiology and in rapid determination of the antibiotic profiles of clinical isolates for prompt and optimal patient treatment.     

TB-Lineage: an online tool for classification and analysis of strains of Mycobacterium tuberculosis complex

This paper formulates a set of rules to classify genotypes of the Mycobacterium tuberculosis complex (MTBC) into major lineages using spoligotypes and MIRU-VNTR results. The rules synthesize prior literature that characterizes lineages by spacer deletions and variations in the number of repeats seen at locus MIRU24 (alias VNTR2687). A tool that efficiently and accurately implements this rule base is now freely available at http://tbinsight.cs.rpi.edu/run_tb_lineage.html. When MIRU24 data is not available, the system utilizes predictions made by a Naïve Bayes classifier based on spoligotype data. This website also provides a tool to generate spoligoforests in order to visualize the genetic diversity and relatedness of genotypes and their associated lineages. A detailed analysis of the application of these tools on a dataset collected by the CDC consisting of 3198 distinct spoligotypes and 5430 distinct MIRU-VNTR types from 37,066 clinical isolates is presented. The tools were also tested on four other independent datasets. The accuracy of automated classification using both spoligotypes and MIRU24 is >99%, and using spoligotypes alone is >95%. This online rule-based classification technique in conjunction with genotype visualization provides a practical tool that supports surveillance of TB transmission trends and molecular epidemiological studies.     

344株结核分枝杆菌的基因分型研究

目的研究间隔区寡核苷酸序列基因分型技术、结核分枝杆菌散在分布重复单位(MIRU),以及多位点串联重复序列(VNTR)在河南省结核病分枝杆菌基因分型中的应用,了解河南省局部地区MIRU-VNTR基因型种类与分布,以及北京家族基因型在河南省的分布特征。方法应用2007年在河南省的嵩县、新密县、扶沟县、中牟县等4个县及南阳市的结核病防治机构实验室分离培养的344株结核分枝杆菌,设计引物,应用PCR和琼脂糖凝胶电泳技术及间隔区寡核苷酸分型技术对结核分枝杆菌进行VNTR分型检测分析,基因分型聚类分析采用Bio-Numerics软件。结果对344株结核分枝杆菌临床分离株的间隔区寡核苷酸分型结果显示,有299株为北京家族基因型,占86.9%;12个MIRU位点检测结果显示明显的基因多态性;经基因聚类分析,可分5个基因群(Ⅰ~Ⅴ群),292个基因型,Ⅰ~Ⅴ群分别占5.1%、67.8%、21.9%、1.4%、2.8%。结论河南省结核分枝杆菌MIRUs基因存在明显的多态性,存在≥5个MIRU型,主要流行型为Ⅱ型;北京家族基因型占主导地位,北京家族基因型与耐药无明显相关性。     

绍兴地区结核分枝杆菌临床分离株Rep-PCR基因分型研究

目的 应用Diversilab系统对结核分枝杆菌进行基因分型,初步探讨绍兴市定点诊治医院结核患者的分型及特征.方法 对医院的100例结核患者临床分离株应用以重复序列PCR (Rep-PCR)为原理的Diversilab基因分型系统进行分型.结果 共91例结核患者的临床分离株获得了基因分型的结果,分型显示了高度的多态性,可分5个基因群(Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ群),分别为Ⅰ群占34.1％、Ⅱ群占3.3％、Ⅲ群占29.7％、Ⅳ群占29.7％、Ⅴ群占3.3％,以Ⅰ、Ⅲ、Ⅳ群为主,不同类型的病例与基因群之间存在统计学上的关联性.结论 医院结核病就诊患者存在主要的基因群,初步建立了绍兴地区结核病就诊患者的基因分型库,为今后医院感染的控制及绍兴市结核病控制提供了积极的意义.     

Molecular epidemiology of bovine tuberculosis. I. Mycobacterium bovis genotyping

The lack of a typing system for Mycobacterium bovis has, until recently, been an impediment to undertaking sophisticated epidemiological studies to assist in the control and eradication of tuberculosis in domestic animals. Molecular biology techniques for mycobacteria have been in development since the mid-1980s, leading to the availability of a number of genetic typing systems for M. bovis. The authors summarise the available techniques, identify those which are most useful at present and those which might prove useful in the future. The present recommendation is to use spoligotyping analysis for rapid, large scale screening of M. bovis isolates, and to use restriction fragment length polymorphism analysis using the polymorphic guanine and cytosine-rich repeat sequences probe where greater differentiation of isolates is required. In the future, systematic analysis of the genome sequence of M. bovis will allow the development of improved techniques that combine good discrimination with ease of use.     

Quality assessment of Mycobacterium tuberculosis genotyping in a large laboratory network

Quality assessment exercises were conducted to evaluate the reproducibility of IS6110 DNA fingerprinting performed by eight laboratories in the National Tuberculosis Genotyping and Surveillance Network. Three panels, each with 8 to 16 isolates, were typed at all laboratories, resulting in 280 images. When the pattern obtained by the majority for each isolate was used as the standard, exact matches were obtained for 73% of patterns; 90% and 97% of patterns matched within one- and two-band differences, respectively. A second approach involved retyping of randomly selected isolates at the Centers for Disease Control and Prevention. Retyping was done for 8-19 isolates per laboratory (76 total). Paired images matched exactly for 54% of isolates and within one and two band differences, 78% and 93%, respectively. We evaluated reasons for mismatching. We also evaluated the reproducibility of spoligotyping using a test panel of 13 isolates; a discrepancy of 1 in 91 results was noted.     

Impact of genotyping of Mycobacterium tuberculosis on public health practice in Massachusetts

Massachusetts was one of seven sentinel surveillance sites in the National Tuberculosis Genotyping and Surveillance Network. From 1996 through 2000, isolates from new patients with tuberculosis (TB) underwent genotyping. We describe the impact that genotyping had on public health practice in Massachusetts and some limitations of the technique. Through genotyping, we explored the dynamics of TB outbreaks, investigated laboratory cross-contamination, and identified Mycobacterium tuberculosis strains, transmission sites, and accurate epidemiologic links. Genotyping should be used with epidemiologic follow-up to identify how resources can best be allocated to investigate genotypic findings.     

河南省结核菌分离株26位点MIRU-VNTR和Spoligotyping分子分型及耐药分析

目的 探讨河南省结核杆菌的遗传多样性。方法 使用26位点（经典24位点和其他2位点）的分支杆菌散在重复单元中数目可变串联重复序列（mycobacterium interspersed repetitive unit-variable number tandem repeat,MIRU-VNTR）和间隔区寡核苷酸分型（spoligotyping）对来自2015年期间河南省不同地区的668株结核杆菌分离株进行分型分析。对结核菌spoligotype类型和耐药表型的相关性进行分析。结果 Spoligotyping分析表明668株结核杆菌被分到10个不同的基因簇中。北京家族基因型是河南地区结核杆菌中的优势菌株。北京家族基因型菌株对四种一线药全耐药以及耐多药菌株比例明显高于非北京型菌株。668株结核杆菌通过26位点VNTR被分为567个不同的基因型。26个位点中15个位点具有高度或适中的分辨能力。10个分辨能力最强位点的组合分辨力能与26位点相当。结论 北京家族是河南省最流行的结核杆菌基因型。10位点VNTR和spoligotyping相结合可有效地用于河南省结核杆菌进化遗传学研究。     

福建省结核分枝杆菌多位点可变数目串联重复序列基因分型研究

目的 了解福建省结核分枝杆菌的多位点可变数目串联重复序列基因分型(MLVA)的特征.方法 选择15个可变数目串联重复位点(VNTR),检测福建省30个耐药监测点临床分离的结核菌株,结果使用BioNumerics (Version 4.5)软件进行聚类分析.结果 313株结核菌被分为9个基因群(Ⅰ～Ⅸ),分别包含220、9、48、2、1、3、10、10、10株菌,以Ⅰ群为主(70.3％,220/313);Ⅰ群菌株异烟肼、链霉素、乙胺丁醇和耐多药的耐药率与其他基因群的差异无统计学意义(P＞0.05),但利福平(RFP)耐药率为33.2％(73/220),明显高于其他群菌株RFP的耐药率20.4％(19/93),差异有统计学意义(P＜0.05).结论 福建省结核分枝杆菌菌株存在明显的基因多态性,以Ⅰ群菌株为主,并与RFP耐药性具有相关性,应加强此类菌株流行的监测.     

安徽东部地区结核分枝杆菌基因分型及耐药情况的初步分析

目的 了解安徽东部地区结核分枝杆菌基因分型及耐药情况,为本地区肺结核的防治提供依据.方法 对从临床收集的80例结核菌株进行培养,分别通过可变数目串联重复序列分型技术、药敏实验对菌株进行分型、耐药情况分析.结果 单耐药菌株占25.00％,多耐药菌株占23.75％.单耐药菌株以利福平和对氨基水杨酸占多数,分别为28.75％和22.50％;多耐药菌株以对异烟肼和利福平耐药最多,占52.63％.初治病人和复治病人对吡嗪酰胺耐药差异有统计学意义(P =0.032),对其他药物的耐药差异均无统计学意义(均有P＞0.05).15个基因位点均呈现等位基因多态性,QUB11a位点多态性最高为0.85,Mtub31位点仅为0.11.80株菌株可分为33个基因型,仅有16例患者的分离株为单一基因型,其余菌株可归入14个簇.结论 本地区结核分支杆菌的耐药率较高,基因分型复杂.     

不同可变数目串联重复序列组合对中国流行结核分枝杆菌分辨力的评价研究

目的 在规范化的结核分枝杆菌（Mycobacterium tuberculosis,MTB）可变数目串联重复序列（variable number of tandem repeats,VNTR）基因分型的基础上,构建我国31个省（自治区、直辖市）VNTR数据库,每个省优化一套VNTR位点组合,为我国结核病预防控制策略的制定提供科学依据。方法 对2007－2008年全国结核病耐药性基线调查的4 116株MTB15位点VNTR（15-VNTR）基因分型。汉高指数（Hunter-Gaston Index,HGI）分析每个位点的分辨率。依据谱系流行特征,以分辨率高和稳定性强为原则,为各省设计一套VNTR优化组合（12-VNTR、10-VNTR、8-VNTR和5-VNTR）,采用HGI和成簇率进行评价。结果 完成了涵盖率为96.36%（3 966/4 116）MTB完整15-VNTR图谱。发现QUB11b、MIRU26等7个高分辨率位点;QUB26、MIRU16、Mtub21、QUB11b在部分地区遗传稳定性差。内蒙古自治区、重庆市、黑龙江省的最优组合为10-VNTR,其他各省的最佳组合为8-VNTR。结论 VNTR数据库的建立将推动全国范围MTB传染源的追踪;各省优化VNTR组合的推出有助于当地结核病疫情的监测和群体遗传学的研究。     

IS6110限制性片段多态性分析标准方法的建立及其在结核分枝杆菌分子分型中的应用

目的 建立IS6110限制性片段多态性分析(IS6110-RFLP)标准方法 并评价该方法 的分型能力.方法 采用核酸提取、PCR、限制性内切酶分析、Southern杂交、琼脂糖凝胶电泳等技术,结合Gel-Pro analyzer 3.1和BioNumeries(Version 5.0)软件,对78株结核分枝杆菌插入序列IS6110-RFLP进行分析.结果 确定标准化的IS6110-RFLP技术,包括核酸提取、PCR、限制性内切酶分析、Southern杂交、琼脂糖凝胶电泳等实验步骤及标化参数的相关数据分析软件的使用;采用该技术,将78株结核分枝杆菌分为75个不同的基因型,分别归属于11个基因簇,其中有52株归属于同一个基因簇,占菌株总数的66.7%(52/78).结论 建立标准化的IS6110-RFLP技术方案,该方法 具有很强的基因分型和株水平鉴定能力,可用于结核病的病原学监测.     

结核分枝杆菌毒素-抗毒素伴侣系统基因多态性初步研究

目的 研究结核分枝杆菌毒素-抗毒素伴侣(TAC)系统中higA、higB和Rv1957在结核分枝杆菌及其不同亚型菌株中的基因多态性,并探讨其生理意义。方法 选取183株结核分枝杆菌临床菌株,经间隔区寡核苷酸方法进行基因分型,同时分析TAC系统基因higA、higB和Rv1957的PCR扩增及序列,利用I-Mutant 2.0软件预测非同义突变对蛋白结构和功能的影响。结果 183株中138株(75.41%)属北京家族,45株(24.59%)属非北京家族。共149株菌(81.42%)的TAC系统发生突变,包括2种同义突变和6种非同义突变:同义突变发生于higA基因,仅见于北京家族菌株;3个基因均可见非同义突变,其中2种非同义突变仅见于非北京家族菌株,其余4种突变仅见于北京家族菌株。6种非同义突变中有4种突变可能影响蛋白的功能。位于higA基因的CAC121CAT突变位点在单耐链霉素和单耐利福平菌株中的突变频率高于敏感株,且差异有统计学意义(P<0.05)。结论 结核分枝杆菌中的TAC系统具有一定的基因多态性,其中北京家族呈现更高的多态性水平,可能更有利于适应不同的宿主环境。     

Transmission of tuberculosis in Gironde: epidemiologic investigation by genomic analysis of Mycobacterium tuberculosis

BACKGROUND: Over the past few years, epidemiologic surveys of tuberculosis have been strengthened by new biologic technology, in particularly using RFLP (Restriction Fragment Length Polymorphism). This technique, which identifies Mycobacterium tuberculosis patterns, has allowed to study thoroughly tuberculosis bacilli transmission and pathogenesis. First applied on tuberculosis epidemics in at risk groups, RFLP has now an interest in the epidemiologic molecular survey of urbans populations. The aim of this study is to identify, in a French department, the proportion of clustering cases of tuberculosis, suspected of recent contamination. METHODS: An active surveillance of tuberculosis allows to record systematically the cases of tuberculosis-disease in Gironde. All M. tuberculosis isolates from the patients reported in this surveillance system were processed through IS6110 based RFLP analysis. Patients were interviewed face to face before this analysis, using a standardised data collection instrument. RESULTS: 102 patients were included in 1997; the RFLP analysis of all available strains identifies a high degree of polymorphism with 71 unique patterns; twelve groups with clustering patterns were found, grouping two (nine clusters), three (two clusters) and seven patients (one cluster) each. Those cases suspected of recent transmission were younger (age<60 years) and lived in poorer conditions. Epidemiologic links were confirmed in only 35% of the 31 patients clustered. CONCLUSION: This community survey analysis has allowed to identify at risk groups for tuberculosis transmission and to strengthen tuberculosis control in Gironde.     

Spoligotyping of Mycobacterium tuberculosis complex isolates using hydrogel oligonucleotide microarrays

Mycobacterium tuberculosis remains a leading cause of morbidity and mortality worldwide. This circumstance underscores the relevance of population studies of tuberculosis for transmission dynamics control. In this study, we describe a conversion of the spoligotyping of M. tuberculosis complex isolates on a platform of custom designed hydrogel microarrays (biochips). An algorithm of automated data processing and interpretation of hybridization results using online database was proposed. In total, the 445 samples were tested. Initially, 97 samples representing multiple species of M. tuberculosis complex and nontuberculous mycobacteria were used for protocol optimization and cut-off settings. The developed assay was further evaluated on the out-group of the 348 mycobacterial samples. Results showed high concordance with the conventional membrane-based spoligotyping method. Diagnostic sensitivity and diagnostic specificity of the spoligo–biochip assay were 99.1% and 100%, respectively. The analytical sensitivity was determined to be 500 genomic equivalents of mycobacterial DNA. The high sensitivity and specificity, ease of operation procedures, and the automatic processing of measured data make the developed assay a useful tool for the rapid and accurate genotyping of M. tuberculosis.     

Characterization of Mycobacterium orygis as M. tuberculosis complex subspecies

The oryx bacilli are Mycobacterium tuberculosis complex organisms for which phylogenetic position and host range are unsettled. We characterized 22 isolates by molecular methods and propose elevation to subspecies status as M. orygis. M. orygis is a causative agent of tuberculosis in animals and humans from Africa and South Asia.