Whole genome sequencing (WGS)

全基因组测序 ( WGS )
  • 文章类型: Journal Article
    萎缩芽孢杆菌HAB-5是一种植物生长促进根际细菌(PGPR),具有多种生物技术特征,例如促进植物生长,在根际定居,从事生物防治活动。在这项研究中,我们使用PacificBiosciences(PacBio;UnitedStates)的单分子实时(SMRT)测序平台对B.atrophaeusHAB-5进行了全基因组测序,其具有环状染色体,总长度为4,083,597bp,G+C含量为44.21%。与其他菌株的比较基因组分析。解淀粉芽孢杆菌DSM7、萎缩芽孢杆菌SRCM101359、变形杆菌FZB42、变形杆菌HAB-2和枯草芽孢杆菌168表明,这些菌株共有2,465个CDS,而599个CDS是萎缩芽孢杆菌HAB-5株独有的。萎缩芽孢杆菌HAB-5基因组中的许多基因簇与抗微生物脂肽和多肽的产生相关。这些基因簇包含编码三个NRP的不同酶,两个Transat-Pks,一种萜烯,一种羊毛硫肽,一个T3PKS,一个Ripp,和一个硫肽。除了可能产生IAA的基因(trpA,trpB,trpC,trpD,trpE,trps,ywkB,MiaA,andnadE),有可能产生挥发性化学物质的基因(acoA,acoB,acoR,acuB,和acuC)。此外,HAB-5含有与铁运输相关的基因(fbpA,fetB,FeuC,feub,FeuA,和fecD),硫代谢(cysC,sat,cysK,cysS,andsulP),磷溶解(ispH,pstA,pstC,pstS,pstB,gltP,和phoH),和固氮(类似于nif3,gltP,gltX,glnR,glnA,nadR,nirB,nird,美国国家航空航天局,narl,narh,narJ,和纳克)。总之,这项研究提供了一个全面的基因组分析B.abrophaeusHAB-5,精确定位的基因和基因组区域相关的抗菌特性的菌株。这些发现提高了我们对枯萎病芽孢杆菌抗菌特性的遗传基础的认识,并暗示HAB-5可以采用各种商业生物农药和生物肥料作为替代策略来增加农业产量和管理各种植物病害。
    Bacillus atrophaeus HAB-5 is a plant growth-promoting rhizobacterium (PGPR) that exhibits several biotechnological traits, such as enhancing plant growth, colonizing the rhizosphere, and engaging in biocontrol activities. In this study, we conducted whole-genome sequencing of B. atrophaeus HAB-5 using the single-molecule real-time (SMRT) sequencing platform by Pacific Biosciences (PacBio; United States), which has a circular chromosome with a total length of 4,083,597 bp and a G + C content of 44.21%. The comparative genomic analysis of B. atrophaeus HAB-5 with other strains, Bacillus amyloliquefaciens DSM7, B. atrophaeus SRCM101359, Bacillus velezensis FZB42, B. velezensis HAB-2, and Bacillus subtilis 168, revealed that these strains share 2,465 CDSs, while 599 CDSs are exclusive to the B. atrophaeus HAB-5 strain. Many gene clusters in the B. atrophaeus HAB-5 genome are associated with the production of antimicrobial lipopeptides and polypeptides. These gene clusters comprise distinct enzymes that encode three NRPs, two Transat-Pks, one terpene, one lanthipeptide, one T3PKS, one Ripp, and one thiopeptide. In addition to the likely IAA-producing genes (trpA, trpB, trpC, trpD, trpE, trpS, ywkB, miaA, and nadE), there are probable genes that produce volatile chemicals (acoA, acoB, acoR, acuB, and acuC). Moreover, HAB-5 contained genes linked to iron transportation (fbpA, fetB, feuC, feuB, feuA, and fecD), sulfur metabolism (cysC, sat, cysK, cysS, and sulP), phosphorus solubilization (ispH, pstA, pstC, pstS, pstB, gltP, and phoH), and nitrogen fixation (nif3-like, gltP, gltX, glnR, glnA, nadR, nirB, nirD, nasD, narl, narH, narJ, and nark). In conclusion, this study provides a comprehensive genomic analysis of B. atrophaeus HAB-5, pinpointing the genes and genomic regions linked to the antimicrobial properties of the strain. These findings advance our knowledge of the genetic basis of the antimicrobial properties of B. atrophaeus and imply that HAB-5 may employ a variety of commercial biopesticides and biofertilizers as a substitute strategy to increase agricultural output and manage a variety of plant diseases.
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  • 文章类型: Journal Article
    结核病(TB),主要由结核分枝杆菌(Mtb)引起,仍然是一个严重的公共卫生问题。越来越多的证据支持选择性进化是影响Mtb表型的基因组决定因素的重要力量。有必要进一步了解Mtb的选择性进化并鉴定可能驱动Mtb表型的正选择基因。
    本研究主要集中于使用全基因组测序(WGS)对来自中国南疆的807Mtb菌株的阳性选择。PAML软件用于鉴定在807Mtb菌株中处于阳性选择下的基因和位点。
    谱系2(62.70%)菌株是该地区的优势菌株,其次是谱系3(19.45%)和谱系4(17.84%)菌株。47个基因中有239个密码子处于正选择状态,这些基因主要与转录功能相关,防御机制,和细胞壁/膜/包膜生物发生。八个基因中有28个密码子(43个突变)(gyrA,rpoB,rpoc,katG,pncA,embb,GID,和cut1)在多药耐药(MDR)菌株而非药物敏感(DS)菌株中的阳性选择下,其中27个突变是耐药基因座,9个突变为非耐药位点,但在耐药基因中,2个突变是代偿性突变,cut1耐药基因未知,有5个突变。在L3菌株的阳性选择下,在Rv0336中存在密码子,但在L2和L4菌株中没有。T细胞和B细胞的表位都是高度保守的,特别是在T细胞表位中。
    这项研究揭示了Mtb的持续选择性进化。我们发现了一些特殊的基因和位点处于正选择状态,这可能有助于MDR和L3菌株的优势。有必要进一步研究这些突变,以了解其对表型的影响,为开发新的结核病干预措施提供更多有用的信息。
    UNASSIGNED: Tuberculosis (TB), mainly caused by Mycobacterium tuberculosis (Mtb), remains a serious public health problem. Increasing evidence supports that selective evolution is an important force affecting genomic determinants of Mtb phenotypes. It is necessary to further understand the Mtb selective evolution and identify the positively selected genes that probably drive the phenotype of Mtb.
    UNASSIGNED: This study mainly focused on the positive selection of 807 Mtb strains from Southern Xinjiang of China using whole genome sequencing (WGS). PAML software was used for identifying the genes and sites under positive selection in 807 Mtb strains.
    UNASSIGNED: Lineage 2 (62.70%) strains were the dominant strains in this area, followed by lineage 3 (19.45%) and lineage 4 (17.84%) strains. There were 239 codons in 47 genes under positive selection, and the genes were majorly associated with the functions of transcription, defense mechanisms, and cell wall/membrane/envelope biogenesis. There were 28 codons (43 mutations) in eight genes (gyrA, rpoB, rpoC, katG, pncA, embB, gid, and cut1) under positive selection in multi-drug resistance (MDR) strains but not in drug-susceptible (DS) strains, in which 27 mutations were drug-resistant loci, 9 mutations were non-drug-resistant loci but were in drug-resistant genes, 2 mutations were compensatory mutations, and 5 mutations were in unknown drug-resistant gene of cut1. There was a codon in Rv0336 under positive selection in L3 strains but not in L2 and L4 strains. The epitopes of T and B cells were both hyper-conserved, particularly in the T-cell epitopes.
    UNASSIGNED: This study revealed the ongoing selective evolution of Mtb. We found some special genes and sites under positive selection which may contribute to the advantage of MDR and L3 strains. It is necessary to further study these mutations to understand their impact on phenotypes for providing more useful information to develop new TB interventions.
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  • 文章类型: Journal Article
    本研究的目的是探讨中国某医院耐碳青霉烯类抗碳青霉烯类鸟氨酸盐(CR-ROR)的分子特征和耐药机制。收集三株CR-ROR菌株,并通过基质辅助激光解吸/电离飞行时间质谱(MALDI-TOF-MS)Vitek-MS和数字DDH分析进行细菌鉴定。VITEK2紧凑型系统和Kirby-Bauer(K-B)圆盘扩散用于抗菌药物敏感性测试。使用Illumina平台NovaSeq测序仪进行全基因组测序。采用Arbricate软件对3株CR-ROR菌株的耐药基因进行预测。通过基因组SNPs构建系统进化树,研究3株CR-ROR菌株的亲缘关系。在本研究中收集了三个CR-ROR(WF1357、WF2441和WF3367)菌株。从神经外科分离出两个菌株(WF1357和WF2441),其中1例分离自肺科(WF3367)。所有菌株都具有多个抗生素抗性基因。两株(WF1357,WF2441)携带blaNDM-1基因,其中一个菌株(WF3367)携带blaKPC-2基因。三种CR-ROR对包括碳青霉烯类在内的不同抗菌剂具有耐药性。本研究中收集的三个CR-ROR菌株和从NCBI下载的51个CR-ROR菌株基因组,分为六个进化组(A-F)。在这项研究中,发现三株CR-ROR菌株对抗菌剂具有较高的耐药性,并携带多个抗生素抗性基因。携带多个抗菌耐药基因的CR-ROR菌株需要严格的监测以避免多药耐药菌株的传播。
    Aim of this study was to explore molecular characteristics and resistance mechanisms of carbapenem-resistant Raoultella ornithinolytica (CR-ROR) isolated from patients in a hospital in China. Three CR-ROR strains were collected and bacterial identification was done by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) Vitek-MS and by digital DDH analysis. VITEK 2 compact system and Kirby-Bauer (K-B) disk diffusion were used for antimicrobial susceptibility testing. Whole genome sequencing was carried out using the Illumina platform NovaSeq sequencer. Abricate software was used for the prediction of antibiotic resistance genes of three CR-ROR strains. The phylogenetic tree was constructed through genome SNPs to investigate the genetic relationship of three CR-ROR strains. Three CR-ROR (WF1357, WF2441, and WF3367) strains were collected in this study. Two strains were isolated from neurosurgery (WF1357 and WF2441), and one was isolated from pulmonology department (WF3367). All strains harboured multiple antibiotic resistance genes. Two strains (WF1357, WF2441) carried the blaNDM-1 gene, one of the strains (WF3367) carried the blaKPC-2 gene. Three CR-RORs were resistant to different antimicrobial agents including carbapenems. The three CR-ROR strains collected in this study and 51 CR-ROR strain genomes downloaded from NCBI, were divided into six evolutionary groups (A-F). In this study, three CR-ROR strains were found to have a higher level of resistance to antibacterial agents and carried multiple antibiotic resistance genes. The CR-ROR strains carrying multiple antibacterial resistant genes require the stringent monitoring to avoid the spread of multidrug-resistant bacterial strains.
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  • 文章类型: Journal Article
    端粒是保护染色体末端的结构。然而,仍然缺乏一种可扩展且具有成本效益的方法来研究大型项目中的染色体臂水平(ChArm)端粒(Telos),阻碍了对癌症和其他疾病的高分辨率端粒的深入研究。这里,ChArmTelo,第一个分析人类和其他动物物种染色体臂水平端粒的计算工具箱,使用10X链接读取和类似技术,是presented。ChArmTelo目前由两种算法组成,TeloEM和TeloKnow,用于臂水平端粒长度(TL)分析。通过对来自人类和动物的近400个全基因组测序样本(WGS)中的染色体臂水平端粒长度(chArmTLs)的综合分析,证明了该算法。包括健康和癌症样本。值得注意的是,通过使用最新的完整端粒到端粒参考基因组(CHM13v2),与HG38相比,如图所示。ChArmTelo揭示了人群特异性chArmTL差异和chArmTL的肝癌特征,并且DNA复制起点破坏可能通过影响TL而导致癌症。重要的是,ChArmTelo可以很容易地应用于数以万计的癌症和健康样本与已发表的WGS数据。
    Telomeres are structures protecting chromosome ends. However, a scalable and cost-effective method to investigate chromosome arm-level (ChArm) telomeres (Telos) in large-scale projects is still lacking, hindering intensive investigation of high-resolution telomeres across cancers and other diseases. Here, ChArmTelo, the first computational toolbox to analyze telomeres at chromosome arm level in human and other animal species, using 10X linked-read and similar technologies, is presented. ChArmTelo currently consists of two algorithms, TeloEM and TeloKnow, for arm-level telomere length (TL) analysis. The algorithms are demonstrated by comprehensive analysis of chromosome arm-level telomere lengths (chArmTLs) in nearly 400 whole genome sequencing samples (WGS) from human populations and animals, including healthy and cancer samples. Notably, considerable performance improvement contributed by using the latest complete telomere-to-telomere reference genome (CHM13v2), compared to hg38, is shown. ChArmTelo reveals population-specific chArmTL differences and liver cancer signatures of chArmTLs and that DNA replication origin disruption may contribute to cancer by affecting TLs. Importantly, ChArmTelo can be readily applied to tens of thousands of cancer and healthy samples with published WGS data.
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  • 文章类型: Journal Article
    智力障碍(ID)是一种常见的神经发育障碍,其特征是适应性行为和认知能力显着受损。高通量测序方法揭示了25-50%的ID患者的遗传病因,而在<5%的病例中检测到遗传基因突变。这里,我们调查了一个汉族家庭中非综合征性ID的遗传原因。对诊断为ID的同卵双胞胎姐妹进行全基因组测序,他们各自的孩子,以及他们无症状的父母.过滤了罕见变异的数据,并使用计算机预测工具建立致病等位基因。通过Sanger测序验证候选突变。计算机建模用于评估突变对候选编码基因编码的蛋白质的影响。ZBTB18基因c.1323C>G(p。His441Gln)被鉴定。该变体以常染色体显性模式与受影响的个体共分离,在无症状的家庭成员中未检测到。分子研究表明,p.His441Gln取代会破坏第二个锌指内的锌结合,并破坏ZBTB18结合DNA的能力。这是关于ID的遗传ZBTB18突变的第一份报告。本研究进一步验证了WGS对ID的准确分子诊断。
    Intellectual disability (ID) is a common neurodevelopmental disorder characterized by significantly impaired adaptive behavior and cognitive capacity. High throughput sequencing approaches have revealed the genetic etiologies for 25-50% of ID patients, while inherited genetic mutations were detected in <5% cases. Here, we investigated the genetic cause for non-syndromic ID in a Han Chinese family. Whole genome sequencing was performed on identical twin sisters diagnosed with ID, their respective children, and their asymptomatic parents. Data was filtered for rare variants, and in silico prediction tools were used to establish pathogenic alleles. Candidate mutations were validated by Sanger sequencing. In silico modeling was used to evaluate the mutation\'s effects on the protein encoded by a candidate coding gene. A novel heterozygous variant in the ZBTB18 gene c.1323C>G (p.His441Gln) was identified. This variant co-segregated with affected individuals in an autosomal dominant pattern and was not detected in asymptomatic family members. Molecular studies reveal that a p.His441Gln substitution disrupts zinc binding within the second zinc finger and disrupts the capacity for ZBTB18 to bind DNA. This is the first report of an inherited ZBTB18 mutation for ID. This study further validates WGS for the accurate molecular diagnosis of ID.
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  • 文章类型: Case Reports
    泛菌(P.anthophila)是一种革兰氏阴性细菌,最初从印度的凤仙花中分离出来。嗜花菌的特征是致病性低,目前还没有这种生物引起人类感染的报道。我们报告了一名73岁的男性膀胱癌手术后由嗜花性疟原虫引起的第一例尿路感染。
    从尿液中获得的细菌分离物被命名为UI705,并通过MALDI-TOF质谱鉴定为嗜花性疟原虫。进行基因组测序和分析以进一步表征临床分离物的发病机理。
    据我们所知,这是我国首例人类感染嗜花性疟原虫的报道。嗜花性疟原虫UI705的基因组序列草案为其毒力因子的后续研究提供了基础资源,抗生素耐药性,宿主-病原体相互作用,和泛菌属的比较基因组学。
    Pantoea anthophila (P. anthophila) is a Gram-negative bacterium initially isolated from Impatiens balsamina in India. P. anthophila has been characterized with low pathogenicity, and no human infections caused by this organism have been reported yet. We report the first case of urinary tract infection caused by P. anthophila in a 73-year-old man after bladder cancer surgery.
    The bacterial isolate gained from urine was named UI705 and identified as P. anthophila by MALDI-TOF mass spectrometry. The genome sequencing and analysis were performed to further characterize the pathogenesis of the clinical isolate.
    To the best of our knowledge, this is the first report of human infection caused by P. anthophila in China. The draft genome sequence of P. anthophila UI705 provides a fundamental resource for subsequent investigation of its virulence factors, antibiotic resistance, host-pathogen interactions, and comparative genomics of genus Pantoea.
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  • 文章类型: Journal Article
    苜蓿已被选为基因功能研究的豆科植物模型之一。为了阐明植物基因组中存在的大量基因的功能,遗传突变资源是非常有用和必要的工具。快中子(FN)诱变可有效诱导不同物种基因组中的缺失突变。通过这种方法,我们已经在M.truncatula中产生了大量的突变资源。该突变体资源已用于使用正向遗传学方法筛选不同的突变体。我们已经分离并鉴定了大量的共生固氮(SNF)缺乏突变体。这里,我们描述了用于表征M.truncatula共生突变体的详细程序。近年来,全基因组测序已被用于加快和扩大突变体的缺失鉴定。使用此方法,我们已经成功地分离出SNF缺陷突变体FN007,并确定它在3号染色体上有一个大的片段缺失。通过尾PCR扩增和测序确认突变体中的因果缺失。我们的结果说明了全基因组测序分析在表征FN诱导的缺失突变体中的实用性,可用于M.truncatula的基因发现和功能研究。有望在很大程度上提高我们对豆科植物共生固氮的分子机制的理解。
    Medicago truncatula has been selected as one of the model legume species for gene functional studies. To elucidate the functions of the very large number of genes present in plant genomes, genetic mutant resources are very useful and necessary tools. Fast Neutron (FN) mutagenesis is effective in inducing deletion mutations in genomes of diverse species. Through this method, we have generated a large mutant resource in M. truncatula. This mutant resources have been used to screen for different mutant using a forward genetics methods. We have isolated and identified a large amount of symbiotic nitrogen fixation (SNF) deficiency mutants. Here, we describe the detail procedures that are being used to characterize symbiotic mutants in M. truncatula. In recent years, whole genome sequencing has been used to speed up and scale up the deletion identification in the mutant. Using this method, we have successfully isolated a SNF defective mutant FN007 and identified that it has a large segment deletion on chromosome 3. The causal deletion in the mutant was confirmed by tail PCR amplication and sequencing. Our results illustrate the utility of whole genome sequencing analysis in the characterization of FN induced deletion mutants for gene discovery and functional studies in the M. truncatula. It is expected to improve our understanding of molecular mechanisms underlying symbiotic nitrogen fixation in legume plants to a great extent.
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  • 文章类型: Journal Article
    产气克雷伯菌是一种常见的感染性细菌,对人类健康构成威胁。然而,关于人口结构的数据有限,遗传多样性,和产气克雷伯菌的致病性,尤其是与男性发生性关系的男性(MSM)。本研究旨在阐明序列类型(STs),克隆复合物(CC),抗性基因,和流行菌株的毒力因子。多位点序列分型用于描述产气K.使用毒力因子数据库和综合抗生素抗性数据库来评估毒力和抗性谱。在这项研究中,对广州HIV自愿咨询门诊收集的鼻拭子标本进行了下一代测序,中国,2019年4月至8月。鉴定结果表明,从911名参与者中收集了总共258株产气K.我们发现分离株对呋喃妥因的抗性最强(89.53%,231/258)和氨苄青霉素(89.15%,230/258),其次是亚胺培南(24.81%,64/258)和头孢噻肟(18.22%,47/258)。耐碳青霉烯K.aerogenes中最常见的STs是ST4、ST93和ST14。人口至少有14个CC,包括本研究中发现的几个新的(CC11-CC16)。耐药基因的主要机制是抗生素外排。基于铁载体生产基因irp和ybt的存在,我们根据毒力谱确定了两个簇。在A组中,CC3和CC4携带编码毒素的clb操纵子。MSM携带的三种主要ST型菌株需要加强监测。主要克隆群CC4具有大量的毒素基因,它在MSM中传播。需要注意防止该克隆组在该群体中进一步传播。总之,我们的研究结果可能为开发治疗MSM的新治疗和监测策略奠定基础.
    Klebsiella aerogenes is a common infectious bacterium that poses a threat to human health. Nevertheless, there are limited data on the population structure, genetic diversity, and pathogenicity of K. aerogenes, especially among men who have sex with men (MSM). The present study aimed to clarify the sequence types (STs), clonal complexes (CCs), resistance genes, and virulence factors of popular strains. Multilocus sequence typing was used to describe the population structure of K. aerogenes. The Virulence Factor Database and Comprehensive Antibiotic Resistance Database were used to assess the virulence and resistance profiles. In this study, next-generation sequencing was performed on nasal swabs specimens collected in an HIV Voluntary Counseling Testing outpatient department in Guangzhou, China, from April to August 2019. The identification results showed that a total of 258 K. aerogenes isolates were collected from 911 participants. We found that the isolates were most resistant to furantoin (89.53%, 231/258) and ampicillin (89.15%, 230/258), followed by imipenem (24.81%, 64/258) and cefotaxime (18.22%, 47/258). The most common STs in carbapenem-resistant K. aerogenes were ST4, ST93, and ST14. The population has at least 14 CCs, including several novel ones identified in this study (CC11-CC16). The main mechanism of drug resistance genes was antibiotic efflux. Based on the presence of the iron carrier production genes irp and ybt, we identified two clusters according to virulence profiles. In cluster A, CC3 and CC4 carry the clb operator encoding the toxin. Increased monitoring is needed for the three main ST type strains carried by MSM. The main clone group CC4 has a large number of toxin genes, and it spreads among MSM. Caution is needed to prevent further spread of this clone group in this population. In sum, our results may provide a foundation for the development of new therapeutic and surveillance strategies for treating MSM.
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  • 文章类型: Journal Article
    识别癌症患者的种系致病变异对于治疗计划至关重要,遗传咨询,和卫生政策制定。然而,之前对胰腺导管腺癌(PDAC)种系病因患病率的估计存在偏倚,因为它们仅基于已知PDAC候选基因的蛋白质编码区的测序数据.为了确定携带种系致病变异的PDAC患者的百分比,我们从消化健康诊所招募了住院病人,血液学和肿瘤学诊所,以及台湾一家三级医疗中心的外科诊所,用于基因组DNA的全基因组测序(WGS)分析。750个基因的虚拟基因组包括PDAC候选基因和COSMIC癌症基因普查中列出的那些。研究中的遗传变异类型包括单核苷酸替换,小型indel,结构变体,和移动元素插入(MEI)。24例PDAC患者中有8例(33.3%),我们确定了致病/可能的致病变异,包括ATM中的单核苷酸取代和小的插入缺失,BRCA1,BRCA2,POLQ,SPINK1和CASP8,以及CDC25C和USP44中的结构变体。我们确定了携带可能潜在地影响剪接的变体的其他患者。这项队列研究表明,对WGS方法产生的丰富信息的广泛分析可以揭示许多致病变异,这些变异可能被传统的基于面板或基于全外显子组测序的方法所遗漏。携带种系变体的PDAC患者的百分比可能比先前预期的高得多。
    Identification of germline pathogenic variants in cancer patients is critical for treatment planning, genetic counseling, and health policymaking. However, previous estimates of the prevalence of germline etiology of pancreatic ductal adenocarcinoma (PDAC) were biased because they were based only on sequencing data of protein-coding regions of known PDAC candidate genes. To determine the percentage of patients with PDAC carrying germline pathogenic variants, we enrolled the inpatients from the digestive health clinics, hematology and oncology clinics, and surgical clinics of a single tertiary medical center in Taiwan for whole genome sequencing (WGS) analysis of genomic DNA. The virtual gene panel of 750 genes comprised PDAC candidate genes and those listed in the COSMIC Cancer Gene Census. The genetic variant types under investigation included single nucleotide substitutions, small indels, structural variants, and mobile element insertions (MEIs). In 8 of 24 (33.3%) patients with PDAC, we identified pathogenic/likely pathogenic variants, including single nucleotide substitutions and small indels in ATM, BRCA1, BRCA2, POLQ, SPINK1 and CASP8, as well as structural variants in CDC25C and USP44. We identified additional patients carrying variants that could potentially affect splicing. This cohort study demonstrates that an extensive analysis of the abundant information yielded by the WGS approach can uncover many pathogenic variants that could be missed by traditional panel-based or whole exome sequencing-based approaches. The percentage of patients with PDAC carrying germline variants might be much higher than previously expected.
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  • 文章类型: Journal Article
    尽管酵母Cyberlindnerafabianii(C.fabianii)在人类感染中很少报道,已经记录了由这种生物引起的医院爆发。在这里,我们报告了中国一家医院泌尿科在两周内发生的假性爆发。
    北京某三级教学医院泌尿外科收治了3名患者,中国,2018年11月至12月,针对不同的医疗干预需求。在11月28日至12月5日期间,这三名患者发生了真菌尿,其中两人尿液培养多次呈阳性。rDNA内部转录间隔区(ITS)和MALDI-TOFMS的测序用于菌株鉴定。Further,rDNA非转录间隔区(NTS)区域的测序和全基因组测序方法用于暴发调查目的。
    所有培养的酵母菌株通过ITS区测序鉴定为法氏杆菌。并且与法氏梭菌型菌株CBS5640T100%相同。然而,MALDI-TOFMS系统未能正确鉴定该酵母病原体。此外,这三个成簇病例的分离株共有99.91%-100%相同的NTS区序列,这不能排除爆发的可能性。然而,全基因组测序结果显示,仅有2例C.fabianii病例与192nt的配对SNP遗传相关,而第三个病例的基因组上有超过26,000个SNP,暗示了一个不同的起源。此外,前三个病例菌株的基因组在系统发育上与从另一个患者中鉴定出的C.fabianii菌株相比,差异更大,7个月后入住同一家医院的普通外科。前三名患者中的一名最终因一般情况不佳而去世,一个是无症状的,和其他临床改善。
    总而言之,越来越多地报道由新兴和罕见的真菌物种引起的医院爆发,因此,必须提高认识。用常用的通用基因靶标进行基因分型在追踪这些生物的感染源方面可能具有有限的辨别能力。需要使用全基因组测序来确认爆发事件。
    Although the yeast Cyberlindnera fabianii (C. fabianii) has been rarely reported in human infections, nosocomial outbreaks caused by this organism have been documented. Here we report a pseudo-outbreak of C. fabianii in a urology department of a Chinese hospital over a two-week period.
    Three patients were admitted to the urology department of a tertiary teaching hospital in Beijing, China, from Nov to Dec 2018, for different medical intervention demands. During the period Nov 28 to Dec 5, funguria occurred in these three patients, and two of them had positive urine cultures multiple times. Sequencing of rDNA internal transcribed spacer (ITS) region and MALDI-TOF MS were applied for strain identification. Further, sequencing of rDNA non-transcribed spacer (NTS) region and whole genome sequencing approaches were used for outbreak investigation purpose.
    All the cultured yeast strains were identified as C. fabianii by sequencing of ITS region, and were 100% identical to the C. fabianii type strain CBS 5640T. However, the MALDI-TOF MS system failed to correctly identify this yeast pathogen. Moreover, isolates from these three clustered cases shared 99.91%-100% identical NTS region sequences, which could not rule out the possibility of an outbreak. However, whole genome sequencing results revealed that only two of the C. fabianii cases were genetically-related with a pairwise SNP of 192 nt, whilst the third case had over 26,000 SNPs on its genome, suggesting a different origin. Furthermore, the genomes of the first three case strains were phylogenetically even more diverged when compared to a C. fabianii strain identified from another patient, who was admitted to a general surgical department of the same hospital 7 months later. One of the first three patients eventually passed away due to poor general conditions, one was asymptomatic, and other clinically improved.
    In conclusion, nosocomial outbreaks caused by emerging and uncommon fungal species are increasingly being reported, hence awareness must be raised. Genotyping with commonly used universal gene targets may have limited discriminatory power in tracing the sources of infection for these organisms, requiring use of whole genome sequencing to confirm outbreak events.
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