Comparative Whole-genome Sequencing Research Articles

Comparison of whole genome sequences of Streptococcus equi subsp. equi from an outbreak in Texas with isolates from within the region, Kentucky, USA, and other countries

Strangles, caused by Streptococcus equi subspecies equi (S. equi) is an infectious disease of horses with worldwide distribution, but there are limited data available regarding strain variation using whole genome sequencing among and within outbreaks in the United States (US), and how US isolates compare with S. equi isolated globally. To address this knowledge-gap, we compared the whole genomes of 54 S. equi isolates from Texas and Kentucky and those of 230 publicly available sequences of S. equi isolates collected from other countries. Our results show that despite minimal variation among isolates within an outbreak some mutations do occur among individual outbreak isolates. Some S. equi strains from the US are closely related to S. equi isolates from other countries, likely reflecting international dissemination of isolates. Collectively, these data improve our understanding of phenotypic and genotypic variation of isolates within an outbreak, and the international distribution of S. equi. We also identify a novel variant of the S. equi M-protein, and observed cases of strangles that were caused by the modified-live vaccine but that were not recognized as vaccine-associated at the time of clinical sample submission.

A Genome-Wide Association Analysis in Noriker Horses Identifies a SNP Associated With Roan Coat Color

The roan coat color in horses is characterized by dispersed white hair and dark points. This phenotype segregates in a broad range of horse breeds, while the underlying genetic background is still unknown. Previous studies mapped the roan locus to the KIT gene on equine chromosome 3 (ECA3). However, this association could not be validated across different horse breeds. Performing a genome-wide association analysis (GWAS) in Noriker horses, we identified a single nucleotide polymorphism (SNP) (ECA3:g.79,543.439 A > G) in the intron 17 of the KIT gene. The G -allele of the top associated SNP was present in other roan horses, namely Quarter Horse, Murgese, Slovenian, and Belgian draught horse, while it was absent in a panel of 15 breeds, including 657 non-roan horses. In further 379 gray Lipizzan horses, eight animals exhibited a heterozygous genotype (A/G). Comparative whole-genome sequence analysis of the KIT region revealed two deletions in the downstream region (ECA3:79,533,217_79,533,224delTCGTCTTC; ECA3:79,533,282_79,533,285delTTCT) and a 3 bp deletion combined with 17 bp insertion in intron 20 of KIT (ECA3:79,588,128_79,588,130delinsTTATCTCTATAGTAGTT). Within the Noriker sample, these loci were in complete linkage disequilibrium (LD) with the identified top SNP. Based upon pedigree information and historical records, we were able to trace back the genetic origin of roan coat color to a baroque gene pool. Furthermore, our data suggest allelic heterogeneity and the existence of additional roan alleles in ponies and breeds related to the English Thoroughbred. In order to study the roan phenotype segregating in those breeds, further association and verification studies are required.

Serratia vespertilionis (García-Fraile et al. 2015) is a later heterotypic synonym of Serratia ficaria (Grimont et al. 1981).

A previous 16S rRNA gene sequence comparison had demonstrated that the type strains of Serratia vespertilionis and Serratia ficaria shared 99.5 % sequence similarity. Despite the 56.2 % homology by DNA-DNA hybridization previously found between these strains, the results of an in silico whole-genome sequence comparison and a new DNA-DNA hybridization study have clearly demonstrated that the genomes of the type strain of S. vespertilionis deposited in different Culture Collections (52T=CECT 8595T=DSM 28727T) and the type strain of S. ficaria (culture DSM 4569T), cannot support such a species differentiation. Tests for substrate utilization redone on the deposited cultures of these strains has also shown very few differences between the type strains of both species. Based on these results, and since the name S. ficaria was validly published earlier, S. vespertilionis should be considered as a later heterotypic synonym of S. ficaria, in application of the priority rule. The type strain of the species S. ficaria is strain 4024T=DSM 4569T=NCTC 12148T=ATCC 33105T=CIP 79.23T=ICPB 4050T.

An Ancient and Eroded Social Supergene Is Widespread across Formica Ants.

Supergenes, clusters of tightly linked genes, play a key role in the evolution of complex adaptive variation [1, 2]. Although supergenes have been identified in many species, we lack an understanding of their origin, evolution, and persistence [3]. Here, we uncover 20-40 Ma of evolutionary history of a supergene associated with polymorphic social organization in Formica ants [4]. We show that five Formica species exhibit homologous divergent haplotypes spanning 11 Mbp on chromosome 3. Despite the supergene's size, only 142 single nucleotide polymorphisms (SNPs) consistently distinguish alternative supergene haplotypes across all five species. These conserved trans-species SNPs are localized in a small number of disjunct clusters distributed across the supergene. This unexpected pattern of divergence indicates that the Formica supergene does not follow standard models of sex chromosome evolution, in which distinct evolutionary strata reflectan expanding region of suppressed recombination [5]. We propose an alternative "eroded strata model" in which clusters of conserved trans-species SNPs represent functionally important areas maintained by selection in the face of rare recombination between ancestral haplotypes. The comparison of whole-genome sequences across 10 additional Formica species reveals that the most conserved region of the supergene contains a transcription factor essential for motor neuron development in Drosophila [6]. The discovery that a very small portion of this large and ancient supergene harbors conserved trans-species SNPs linked to colony social organization suggests that the ancestral haplotypes have been eroded by recombination, with selection preserving differentiation at one or a few genes generating alternative social organization.

Comparison of Whole-Genome Sequences of COVID-19 Strains in Wuhan-China, USA and Spain to Determine Source of Epidemic

Background: The World Health Organization declared the SARS-CoV-2 outbreak a global public health emergency from Wuhan/China to others countries. Methodology: Genetic analyses of sixty eight complete genomes of SARS-CoV-2 (38 reference strain from China, 24 strain from USA and 7 strains from Spain and others from Japan and Korea) were performed. By the Bio Edit software a multiple alignment of the COVID-19 sequences was performed for each of America (24 strains) and China (38 strains) separately, also, multiple alignments were made with 68 sequences of strains of the virus from each of America, China and Spain. The mutation in complete genome of virus was detected. Phylogeny tree representative strains from China, USA, Spain and Japan with two MERS strains one from KSA and one from Korea as comparable. Results: The result shown that 31.6% had point mutations in Chinese strains, 73.9% in USA and 71.4 mutant strains in Spain. Most of the mutation occurred ORF1ab, OFR7a, S gene and ORF6a respectively in China, USA and Spain strains. Conclusion: The conclusion shown that there is a high genetic identity between the selected strains of virus in China-Wuhan and those that spread in America and Spain, which indicates that the epidemic center is coming from China. These observations provided evidence of the genetic diversity and rapid evolution of this novel coronavirus.

The Campylobacter jejuni Type VI Secretion System Enhances the Oxidative Stress Response and Host Colonization.

The role of the Type VI secretion system (T6SS) in Campylobacter jejuni is poorly understood despite an increasing prevalence of the T6SS in recent C. jejuni isolates in humans and chickens. The T6SS is a contractile secretion machinery capable of delivering effectors that can play a role in host colonization and niche establishment. During host colonization, C. jejuni is exposed to oxidative stress in the host gastrointestinal tract, and in other bacteria the T6SS has been linked with the oxidative stress response. In this study, comparisons of whole genome sequences of a novel human isolate 488 with previously sequenced strains revealed a single highly conserved T6SS cluster shared between strains isolated from humans and chickens. The presence of a functional T6SS in the 488 wild-type strain is indicated by expression of T6SS genes and secretion of the effector TssD. Increased expression of oxidative stress response genes katA, sodB, and ahpC, and increased oxidative stress resistance in 488 wild-type strain suggest T6SS is associated with oxidative stress response. The role of the T6SS in interactions with host cells is explored using in vitro and in vivo models, and the presence of the T6SS is shown to increase C. jejuni cytotoxicity in the Galleria mellonella infection model. In biologically relevant models, the T6SS enhances C. jejuni interactions with and invasion of chicken primary intestinal cells and enhances the ability of C. jejuni to colonize chickens. This study demonstrates that the C. jejuni T6SS provides defense against oxidative stress and enhances host colonization, and highlights the importance of the T6SS during in vivo survival of T6SS-positive C. jejuni strains.

Bezlotoxumab for prevention of Clostridium difficile infection recurrence: Distinguishing relapse from reinfection with whole genome sequencing

BackgroundBezlotoxumab has been shown to prevent Clostridium difficile infection recurrence (rCDI) in high-risk patients. MethodsWe used whole genome sequencing to estimate the impact of bezlotoxumab on same-strain relapse or new-strain reinfection in MODIFY I/II trials. Reinfection with a new strain and relapse with the same strain were differentiated by the comparison of ribotype (RT) and pair-wise single-nucleotide whole genome sequencing (WGS) variations (PWSNV). Relapse was assigned if the baseline RT and the RT isolated during rCDI were the same, and if PWSNVs were ≤ 2. Reinfection was assigned if the baseline RT and the RT isolated during rCDI were different, or if the RT was the same but PWSNVs were > 10. Unknown status was assigned if the RT was the same but PWSNVs were 3–10. Results259 rCDI events were evaluable (50 [19.3%] reinfection; 198 [76.4%] relapse). The proportion of relapses was higher for ribotype 027 (84.5%) compared with other ribotypes (74.1%). Cumulative incidence of relapse was significantly lower for bezlotoxumab versus no bezlotoxumab (p < 0.0001), with a non-significant trend towards reduction for reinfection (p = 0.14). ConclusionBezlotoxumab treatment significantly reduced the rate of CDI relapse versus a regimen without bezlotoxumab. (NCT01241552/NCT01513239).

TAC1, an unclassified bacteriophage of the family Myoviridae infecting Acinetobacter baumannii with a large burst size and a short latent period.

Bacteriophage TAC1 was isolated using a clinical isolate of Acinetobacter baumannii as the host. It showed stability over wide pH and temperature range and has exhibited in vitro antibacterial activity when applied at an MOI of 1. It demonstrated a broad intraspecies host range and infected 66% of the isolates tested. It has produced 454 virions from a single bacterium with a short latent period of 15 minutes. TAC1 has a linear dsDNA genome with a length of 101.77kb and 37.5% GC content. The genome encodes 161 proteins and 13 putative tRNAs. Whole-genome sequence comparisons using BLASTn and phylogenetic analysis showed that TAC1 is related to unclassified bacteriophages of the family Myoviridae.

Genomic Analysis of Therapy-Related Myeloid Neoplasms and Tracking of the Founder Clone By Circulating Tumor DNA

Introduction: Therapy-related myeloid neoplasms (t-MNs) are among late complications of chemotherapy and/or radiotherapy. So far, the genetic landscape of t-MNs is not yet defined as there has been few reports for their comprehensive genomic analysis. Recently, in the field of hematological malignancies, accumulating evidence supported that tumor derived fragmentary DNA in serum, known as circulating tumor DNA (ctDNA), has the potential to serve as an alternative for conventional bone marrow (BM) analysis (Nakamura and Yokoyama et al, Blood 2019). However, no studies are available to support the utility of ctDNA to evaluate the clonal kinetics in t-MNs. In the present study, by using retrospective tracking of driver mutations in BM or available serum samples, we tried to elucidate when the founder clones had appeared and how they had evolved pre-, during, and post-cytotoxic chemotherapy for prior hematological malignancies. Methods: We retrospectively collected tumor samples, including BM, tumor-rich peripheral blood (PB), or alternatively, serum samples, at diagnosis and before diagnosis from 15 t-MNs patients in our hospital. We subjected tumor DNA and control buccal swab DNA to comparative whole-exome sequencing (WES, n=13) and/or whole-genome sequencing (WGS, n=2). After identifying somatic driver mutations, we designed droplet digital PCR (ddPCR) assays for each mutation identified. Results: All 15 patients had a history of primary hematological malignancies (malignant lymphoma, n=9; acute leukemia, n=4; multiple myeloma, n=2) and had received prior chemotherapy and/or radiotherapy with or without autologous stem cell transplantation (ASCT). The median age at presentation of t-MNs was 53 years (range, 6-74), and the median latent period between prior malignancy and t-MNs was 45 months (range, 10-161). Conventional cytogenetic analysis revealed high incidence of complex karyotype (38.4%) and MLL rearrangement (30.7%). WES and/or WGS revealed that 93.3% (n=14/15) of the cases contained at least one putative driver mutation in 17 genes (median of 1 mutation per patient [range 1-4]). We found the most frequent mutations in TP53 and epigenetic modifier gene (KMT2D/KDM6A/ASXL1/ASXL2), mutated in 33% of the samples, followed by signal transduction proteins (MPL/BRAF/FLT3-TKD/KRAS, 26.7%). Together, the spectrums of driver mutations and cytogenetic alterations in our cohort were consistent with previous reports in t-MNs. Most importantly, we could trace back mutant clone using BM and/or serum before diagnosis of t-MNs in 7 patients. Particularly, in UPN-5 who developed MDS-EB1 after ASCT for lymphoma, ETV6 p.E153fs, a putative founder mutation of t-MNs, was applied to liquid biopsy to trace back. ETV6 ctDNA could be detected as early as 7 months prior to the development of MDS with variant allele frequency (VAF) of 0.06% (blue arrowhead in figure 1A). Most intriguingly, the proportion of ETV6 ctDNA varied with or without G-CSF administration during the clinical course; VAF increase from 0 to 47.0% on G-CSF and decrease from 47.0 to 1.2% off G-CSF. In UPN-10 who had been clinically diagnosed as t-MNs (MDS-EB2) after intensive chemotherapy for prior AML, not otherwise specified with normal karyotype, WGS identified 4 driver mutations in BM at diagnosis of t-MNs. Then, 4 driver mutations, WT1 p.A365fs, MLL rearrangement, inv(3), and del(20q) were all applied to combined analysis of ctDNA and BM as well. Unexpectedly, we could find the presence of the founder clone, inv(3), with high allele burden in BM at initial diagnosis of AML-NOS with normal karyotype (red arrowhead in figure 1B). On the contrary, we could not detect other 3 gene alterations until 4 months before diagnosis of t-MNs. Conclusions: These findings would contribute to outline the genetic landscape of t-MNs, and especially suggest the role of cytokine-related selective pressures after chemotherapy and of the potential pre-t-MNs conditions in the pathogenesis of t-MNs. Figure 1: Serial mutation and cytogenetic status of BM and/or ctDNA in two patients with t-MNs (UPN-5 and -10, in figure 1A and in 1B, respectively). Shaded areas indicate the period of cytotoxic chemotherapies. Abbreviations: M, months; VAF, variant allele frequency. Disclosures Nagamura-Inoue: AMED: Research Funding. Uchimaru:Daiichi Sankyo Co., Ltd..: Research Funding. Tojo:Torii Pharmaceutical: Research Funding; AMED: Research Funding.

100,000 genomes project: Integrating whole genome sequencing (WGS) data into clinical practice

Abstract Background The 100,000 Genomes Project aims to improve cancer care for NHS patients in the UK through personalised medicine. Our target is to return WGS results to clinicians in a clinically meaningful timescale to facilitate diagnosis and treatment choices for patients, and in parallel to provide a research platform of genomic data linked to longitudinal clinical data. Methods We present here an overview of clinical utility for reported outcomes. To date, bioinformatics reports for WGS, with links to potentially relevant therapies and UK clinical trials, have been produced for more than 14,000 cancer patients in the UK Currently our bioinformatics analysis of WGS includes clinical interpretation of somatic small variants, somatic structural and copy number variants (SV/CNV), germline pertinent findings, mutational burden and signatures. To iteratively develop a high-quality bioinformatics pipeline and to monitor clinical utility of returned results, we are collecting feedback via the 100,000 Genomes Project Interpretation Portal from NHS Molecular Tumour Boards. These data suggest that WGS has the potential to affect patient management. Future applications will include the utilisation of pangenomic markers to better stratify patients within the context of a clinical study. Results WGS has the ability to replace multiple standard of care tests as it has the potential to detect all types of variants (SV/CNV/SNV/indels) as well as emerging pangenome biomarkers in a single test. In this study we use samples submitted as part of the 100,000 Genomes Project to investigate the feasibility of WGS as an alternative to conventional testing. Overall comparison of WGS with the results of NGS panels (96 patients, 156 clinically-relevant SNVs), high-depth exome sequencing (10 patients, 3150 SNVs, 140 indels), cytogenetic FISH tests (70 patients, 259 SVs, 100 CNVs), immunohistochemistry tests for Mismatch Repair Deficiency (265 patients) and HER2 status (154 patients) demonstrated Positive Percentage Agreement > 90% and False Positive Rate Conclusions Further work is required to validate fully all aspects of the WGS analysis pipeline but these results indicate that WGS can reliably detect clinically relevant biomarkers in the genomes of cancer patients. Legal entity responsible for the study Genomics England. Funding Genomics England. Disclosure All authors have declared no conflicts of interest.

Comparison of Whole-Genome Sequences of Legionella pneumophila in Tap Water and in Clinical Strains, Flint, Michigan, USA, 2016.

During the water crisis in Flint, Michigan, USA (2014–2015), 2 outbreaks of Legionnaires’ disease occurred in Genesee County, Michigan. We compared whole-genome sequences of 10 clinical Legionella pneumophila isolates submitted to a laboratory in Genesee County during the second outbreak with 103 water isolates collected the following year. We documented a genetically diverse range of L. pneumophila strains across clinical and water isolates. Isolates belonging to 1 clade (3 clinical isolates, 3 water isolates from a Flint hospital, 1 water isolate from a Flint residence, and the reference Paris strain) had a high degree of similarity (2–1,062 single-nucleotide polymorphisms), all L. pneumophila sequence type 1, serogroup 1. Serogroup 6 isolates belonging to sequence type 2518 were widespread in Flint hospital water samples but bore no resemblance to available clinical isolates. L. pneumophila strains in Flint tap water after the outbreaks were diverse and similar to some disease-causing strains.

Comparison of whole-genome sequencing and pulsed field gel electrophoresis for characterizing relationships in Mannheimia haemolytica

It has long been presumed that cattle developing BRD tend to become sick from their own native strains of Mannheimia haemolytica. Previous work by others has demonstrated that the diversity of Mannheimia haemolytica, as evaluated by PFGE, within a pen of cattle remains high during BRD outbreaks. Prior to the development of whole genome sequencing (WGS), pulsed field gel electrophoresis (PFGE) had been considered the gold standard for characterizing outbreaks of bacterial disease. Recently, many studies from the human literature have raised question regarding the accuracy of PFGE as WGS has become more widely implemented. Studies investigating Acinetobacter baumanii, Clostridium difficile, and vancomycin resistant Enterococci outbreaks in hospitals have shown WGS to have superior discernment and more accurately classify strains when compared to PFGE. Considering the superiority of WGS in characterizing outbreaks in all of these species, if may be that relationships inferred in Mannheimia haemolytica based on PFGE could be inaccurate. It is therefore our goal to compare the discernment ability of PFGE and WGS for Mannheimia haemolytica isolates collected from beef cattle.

A Comparative Whole Genome Sequence Analysis Leads to Identification of Repeat-Associated Evolutionarily Conserved miRNAs in Bombyx mori (Lepidoptera: Bombycidae)

MicroRNAs (miRNAs) are evolutionarily conserved small noncoding RNAs, which play important regulatory roles in various biological processes. In this study, we have developed a computational approach for detecting conserved miRNAs based on comparison of whole genome sequences of closely related species by considering various key features of experimentally validated miRNAs. By applying this approach, we have identified 34 new miRNAs from Bombyx mori (L.), which are also conserved in Drosophila melanogaster (Diptera: Drosophilidae) and Anopheles gambiae (Diptera: Culicidae). Most of these miRNAs were associated with repeat region of the genome. We did an expression analysis of the 34 newly predicted miRNAs and found that 30 of these miRNAs are expressing in different tissues of B. mori. Besides, we have also predicted the putative targets of these miRNAs in B. mori based on several known characteristic features of miRNA::mRNA duplexes and found that these targets include diverse range of functions, suggesting multiple layers of gene regulation of various important biological processes.

DNA copy number imbalances in primary cutaneous lymphomas.

Cutaneous lymphomas (CL) represent a clinically defined group of extranodal non-Hodgkin lymphomas harbouring heterogeneous and incompletely delineated molecular aberrations. Over the past decades, molecular studies have identified several chromosomal aberrations, but the interpretation of individual genomic studies can be challenging. With a comprehensive meta-analysis, we aim to delineate genomic alterations for different types of CL and propose a more accurate classification in line with their various pathogenicity. We searched PubMed and ISI Web of Knowledge for publications from 1996 to 2016 reporting the investigation of CL for genome-wide copy number alterations, by means of comparative genomic hybridization techniques and whole-genome sequencing and whole-exome sequencing. We then extracted and remapped the available copy number variation (CNV) data from these publications with the same pipeline and performed clustering and visualisation to aggregate samples of similar CNV profiles. For 449 samples from 22 publications, CNV data were accessible for sample based meta-analysis. Our findings illustrate structural and numerical chromosomal imbalance patterns. Most frequent CNAs were linked to oncogenes or tumour suppressor genes with important roles in the course of the disease. Summary profiles for genomic imbalances, generated from case-specific data, identified complex genomic imbalances, which could discriminate between different subtypes of CL and promise a more accurate classification. The collected data presented in this study are publicly available through the 'Progenetix' online repository.

Reclassification of Paenibacillus thermophilus Zhou et al. 2013 as a later heterotypic synonym of Paenibacillus macerans (Schardinger 1905) Ash et al. 1994.

The taxonomic status of Paenibacillus thermophilus was analyzed using genomic and phenotypic approaches. The results of RNA polymerase beta subunit gene sequence comparisons indicated that two type strains of P. thermophilus (DSM 24746T and JCM 17693T) and Paenibacillus macerans ATCC 8244T shared 100 % sequence similarity. By whole-genome sequence comparison, their average nucleotide identity values were over 99.3 %. Investigation of substrate utilization, enzyme activities and cellular fatty acid patterns displayed no striking differences between P. thermophilus JCM 17693T and P. macerans JCM 2500T. On the basis of these results, we propose that the name Paenibacillus thermophilus is a later heterotypic synonym of Paenibacillus macerans.

Molecular characterization of a novel citrivirus from citrus using next-generation sequencing.

A novel positive-strand RNA virus infecting citrus with the tentative name "citrus leaf blotch virus 2" (CLBV-2), was identified in the present work. The complete genome sequence of CLBV-2 comprises 8,697 nucleotides (nt) excluding a poly(A) tail and three open reading frames (ORFs), showing the highest nucleotide sequence identity with the Actinidia strain (JN983456) of citrus leaf blotch virus (CLBV). The putative movement protein (ORF2), coat protein (ORF3), and 3' untranslated region (UTR) shared high sequence similarity with those of the extant CLBV isolates. In contrast, only low sequence similarity was observed in the 5' UTR and putative replicase polyprotein (ORF1) regions. The distant phylogenetic relationship between CLBV-2 and CLBV was deduced based on whole-genome nucleotide and whole-ORF1 amino acid sequence comparisons. Sequence comparisons suggest that CLBV-2 acquired an ORF2-ORF3-3' UTR region homologous to CLBV by recombination with of an unknown citrivirus. In view of the fact that this genomic recombination event appears to have occurred between members of different species in the genus Citrivirus, we propose that CLBV-2 should be considered a member of a distinct species.

Mitochondrial ribosomal proteins involved in tellurite resistance in yeast Saccharomyces cerevisiae

A considerable body of evidence links together mitochondrial dysfunctions, toxic action of metalloid oxyanions, and system and neurodegenerative disorders. In this study we have used the model yeast Saccharomyces cerevisiae to investigate the genetic determinants associated with tellurite resistance/sensitivity. Nitrosoguanidine-induced K2TeO3-resistant mutants were isolated, and one of these mutants, named Sc57-Te5R, was characterized. Both random spore analysis and tetrad analysis and growth of heterozygous (TeS/Te5R) diploid from Sc57-Te5R mutant revealed that nuclear and recessive mutation(s) was responsible for the resistance. To get insight into the mechanisms responsible for K2TeO3-resistance, RNA microarray analyses were performed with K2TeO3-treated and untreated Sc57-Te5R cells. A total of 372 differentially expressed loci were identified corresponding to 6.37% of the S. cerevisiae transcriptome. Of these, 288 transcripts were up-regulated upon K2TeO3 treatment. About half of up-regulated transcripts were associated with the following molecular functions: oxidoreductase activity, structural constituent of cell wall, transporter activity. Comparative whole-genome sequencing allowed us to identify nucleotide variants distinguishing Sc57-Te5R from parental strain Sc57. We detected 15 CDS-inactivating mutations, and found that 3 of them affected genes coding mitochondrial ribosomal proteins (MRPL44 and NAM9) and mitochondrial ribosomal biogenesis (GEP3) pointing out to alteration of mitochondrial ribosome as main determinant of tellurite resistance.

Clinical Manifestations and Bacterial Genomic Analysis of Group A Streptococcus Strains That Cause Pediatric Toxic Shock Syndrome.

We report here 18 cases of pediatric group A streptococcal toxic shock syndrome, associated clinical findings, and bacterial molecular genetic characteristics discovered through whole-genome sequencing. This comparative whole-genome sequencing revealed unique gene content (speK) and polymorphisms (dpiB) in emm87 group A Streptococcus, the relative contributions of which, in combination with the host response, in the development of streptococcal toxic shock syndrome remain to be elucidated.

Whole-genome sequence analysis of the Mycobacterium avium complex and proposal of the transfer of Mycobacterium yongonense to Mycobacterium intracellulare subsp. yongonense subsp. nov.

Bacterial whole-genome sequences contain informative features of their evolutionary pathways. Comparison of whole-genome sequences have become the method of choice for classification of prokaryotes, thus allowing the identification of bacteria from an evolutionary perspective, and providing data to resolve some current controversies. Currently, controversy exists about the assignment of members of the Mycobacterium avium complex, as is for the cases of Mycobacterium yongonense and 'Mycobacterium indicus pranii'. These two mycobacteria, closely related to Mycobacterium intracellulare on the basis of standard phenotypic and single gene-sequences comparisons, were not considered a member of such species on the basis on some particular differences displayed by a single strain. Whole-genome sequence comparison procedures, namely the average nucleotide identity and the genome distance, showed that those two mycobacteria should be considered members of the species M. intracellulare. The results were confirmed with other whole-genome comparison supplementary methods. According to the data provided, Mycobacterium yongonense and 'Mycobacterium indicus pranii' should be considered and renamed and included as members of M. intracellulare. This study highlights the problems caused when a novel species is accepted on the basis of a single strain, as was the case for M. yongonense. Based mainly on whole-genome sequence analysis, we conclude that M. yongonense should be reclassified as a subspecies of Mycobacterium intracellulareas Mycobacterium intracellularesubsp. yongonense and 'Mycobacterium indicus pranii' classified in the same subspecies as the type strain of Mycobacterium intracellulare and classified as Mycobacterium intracellularesubsp. intracellulare.

Comparative Genomics Shows That Mycobacterium ulcerans Migration and Expansion Preceded the Rise of Buruli Ulcer in Southeastern Australia.

Since 2000, cases of the neglected tropical disease Buruli ulcer, caused by infection with Mycobacterium ulcerans, have increased 100-fold around Melbourne (population 4.4 million), the capital of Victoria, in temperate southeastern Australia. The reasons for this increase are unclear. Here, we used whole-genome sequence comparisons of 178 M. ulcerans isolates obtained primarily from human clinical specimens, spanning 70 years, to model the population dynamics of this pathogen from this region. Using phylogeographic and advanced Bayesian phylogenetic approaches, we found that there has been a migration of the pathogen from the east end of the state, beginning in the 1980s, 300 km west to the major human population center around Melbourne. This move was then followed by a significant increase in M. ulcerans population size. These analyses inform our thinking around Buruli ulcer transmission and control, indicating that M. ulcerans is introduced to a new environment and then expands, rather than it being from the awakening of a quiescent pathogen reservoir.IMPORTANCE Buruli ulcer is a destructive skin and soft tissue infection caused by Mycobacterium ulcerans and is characterized by progressive skin ulceration, which can lead to permanent disfigurement and long-term disability. Despite the majority of disease burden occurring in regions of West and central Africa, Buruli ulcer is also becoming increasingly common in southeastern Australia. Major impediments to controlling disease spread are incomplete understandings of the environmental reservoirs and modes of transmission of M. ulcerans The significance of our research is that we used genomics to assess the population structure of this pathogen at the Australian continental scale. We have then reconstructed a historical bacterial spread and modeled demographic dynamics to reveal bacterial population expansion across southeastern Australia. These findings provide explanations for the observed epidemiological trends with Buruli ulcer and suggest possible management to control disease spread.