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BACKGROUND: Colistin is one of the last resort therapeutic options for treating carbapenemase-producing Enterobacterales, which are resistant to a broad range of beta-lactam antibiotics. However, the increased use of colistin in clinical and livestock farming settings in Thailand and China, has led to the inevitable emergence of colistin resistance. To better understand the rise of colistin-resistant strains in each of these settings, we characterized colistin-resistant Enterobacterales isolated from farmers, swine, and hospitalized patients in Thailand. METHODS: Enterobacterales were isolated from 149 stool samples or rectal swabs collected from farmers, pigs, and hospitalized patients in Thailand between November 2014-December 2017. Confirmed colistin-resistant isolates were sequenced. Genomic analyses included species identification, multilocus sequence typing, and detection of antimicrobial resistance determinants and plasmids. RESULTS: The overall colistin-resistant Enterobacterales colonization rate was 26.2% (n = 39/149). The plasmid-mediated colistin-resistance gene (mcr) was detected in all 25 Escherichia coli isolates and 9 of 14 (64.3%) Klebsiella spp. isolates. Five novel mcr allelic variants were also identified: mcr-2.3, mcr-3.21, mcr-3.22, mcr-3.23, and mcr-3.24, that were only detected in E. coli and Klebsiella spp. isolates from farmed pigs. CONCLUSION: Our data confirmed the presence of colistin-resistance genes in combination with extended spectrum beta-lactamase genes in bacterial isolates from farmers, swine, and patients in Thailand. Differences between the colistin-resistance mechanisms of Escherichia coli and Klebsiella pneumoniae in hospitalized patients were observed, as expected. Additionally, we identified mobile colistin-resistance mcr-1.1 genes from swine and patient isolates belonging to plasmids of the same incompatibility group. This supported the possibility that horizontal transmission of bacterial strains or plasmid-mediated colistin-resistance genes occurs between humans and swine.
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Colistina , Agricultores , Humanos , Animales , Porcinos , Colistina/farmacología , Tailandia/epidemiología , Escherichia coli , Genómica , KlebsiellaRESUMEN
DNAmix 2021 is a large-scale study conducted to evaluate the extent of consistency and variation among forensic laboratories in the interpretation of DNA mixtures, and to assess the effects of various potential sources of variability. This study utilized a multi-phasic approach designed to collect information about participating laboratories, laboratory policies, and their standard operating procedures (SOPs). It also characterizes the degree of variation in assessments of suitability and number of contributors as well as in comparisons and statistical analyses of DNA mixture profiles. This paper specifically details the study design and the data collected in the first two phases of the study: the Policies & Procedures (P&P) Questionnaire and the Casework Scenarios Questionnaire (CSQ). We report on the variation in policies and SOPs for 86 forensic laboratories-including information about their DNA workflows, systems, and type of statistics reported. We also provide details regarding various case-scenario specific decisions and the nature of mixture casework for 83 forensic laboratories. The data discussed in this article provide insight into the state of the field for forensic DNA mixture interpretation policies and SOPs at the time of the study (2021-2022).
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BACKGROUND: Infections caused by carbapenemase-producing Enterobacteriaceae (CPE) have continually grown as a global public health threat, with significant mortality rates observed across the world. We examined the clinical data from patients with CPE infections and their outcomes, concentrating on Klebsiella pneumoniae isolates. We analysed the clinical information, performed antimicrobial susceptibility testing, and conducted molecular epidemiological and genomic analyses on the isolates to identify patterns in the data. METHODS: The clinical characteristics of 33 hospitalised patients with confirmed CPE, including patient-related factors associated with the development of CPE infections, were examined. Patients were divided according to whether they were "colonised" or "infected" with CPE and by the timing and frequency of their rectal swab collections, from which 45 swabs were randomly selected for analysis. CPE isolates were purified, and antimicrobial susceptibility tests performed. Whole genome sequences of these isolates were determined and analysed to compute bacterial multilocus sequence types and plasmid replicon types, infer phylogenetic relationships, and identify antimicrobial resistance and virulence genes. RESULTS: Altogether, 88.9% (40/45) of the CPE isolates were K. pneumoniae. The most abundant carbapenemase gene family in the K. pneumoniae isolates (33/39) was blaOXA-232, with blaNDM-1 additionally identified in 19 of them. All CPE isolates carrying either blaOXA-232 or blaNDM-1 were resistant to meropenem, but only 40 from 45 were susceptible to colistin. Among the CPE-infected patients (n = 18) and CPE-colonised patients who developed CPE infections during the study (n = 3), all but one received standard colistin-based combination therapy. Phylogenetic analysis revealed the polyclonal spread of carbapenemase-producing K. pneumoniae (CPKP) within the patient population, with the following two major subclades identified: ST16 (n = 15) and ST231 (n = 14). CPKP-ST231 had the highest virulence score of 4 and was associated with primary bacteraemia. The siderophores yersiniabactin and aerobactin, considered to be important virulence factors, were only identified in the CPKP-ST231 genomes. CONCLUSIONS: This study has revealed the genomic features of colonising CPE isolates, focusing on antimicrobial resistance and virulence determinants. This type of multi-layered analysis can be further exploited in Thailand and elsewhere to modify the regimes used for empirical antibiotic treatment and improve the management strategies for CPE infections in hospitalised patients.
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Proteínas Bacterianas/aislamiento & purificación , Enterobacteriaceae Resistentes a los Carbapenémicos/genética , Farmacorresistencia Bacteriana Múltiple/genética , Infecciones por Enterobacteriaceae/genética , Klebsiella pneumoniae/aislamiento & purificación , Tipificación de Secuencias Multilocus , Secuenciación Completa del Genoma , beta-Lactamasas/aislamiento & purificación , Anciano , Anciano de 80 o más Años , Antibacterianos/farmacología , Colistina/farmacología , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Epidemiología Molecular , Filogenia , Plásmidos , Tailandia/epidemiología , Factores de Virulencia , beta-Lactamasas/genéticaRESUMEN
The human gut microbiome plays a vital role in both health and disease states and as a mediator of cognitive and physical performance. Despite major advances in our understanding of the role of gut microbes in host physiology, mechanisms underlying human-microbiome dynamics have yet to be fully elucidated. This knowledge gap represents a major hurdle to the development of targeted gut microbiome solutions influencing human health and performance outcomes. The microbiome as it relates to warfighter health and performance is of interest to the Department of Defense (DoD) with the development of interventions impacting gut microbiome resiliency among its top research priorities. While technological advancements are enabling the development of experimental model systems that facilitate mechanistic insights underpinning human health, disease, and performance, translatability to human outcomes is still questionable. This review discusses some of the drivers influencing the DoD's interest in the warfighter gut microbiome and describes current in vitro gut model systems supporting direct microbial-host interactions.
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OBJECTIVES: To investigate the genomic context of a novel resistance island (RI) in multiply antibiotic-resistant Acinetobacter baumannii clinical isolates and global isolates. METHODS: Using a combination of long and short reads generated from the Oxford Nanopore and Illumina platforms, contiguous chromosomes and plasmid sequences were determined. BLAST-based analysis was used to identify the RI insertion target. RESULTS: Genomes of four multiply antibiotic-resistant A. baumannii clinical strains, from a US hospital system, belonging to prevalent MLST ST2 (Pasteur scheme) and ST281 (Oxford scheme) clade F isolates were sequenced to completion. A class 1 integron carrying aadB (tobramycin resistance) and aadA2 (streptomycin/spectinomycin resistance) was identified. The class 1 integron was 6.8 kb, bounded by IS26 at both ends, and embedded in a new target location between an α/ß-hydrolase and a reductase. Due to its novel insertion site and unique RI composition, we suggest naming this novel RI AbGRI4. Molecular analysis of global A. baumannii isolates identified multiple AbGRI4 RI variants in non-ST2 clonal lineages, including variations in the resistance gene cassettes, integron backbone and insertion breakpoints at the hydrolase gene. CONCLUSIONS: A novel RI insertion target harbouring a class 1 integron was identified in a subgroup of ST2/ST281 clinical isolates. Variants of the RI suggested evolution and horizontal transfer of the RI across clonal lineages. Long- and short-read hybrid assembly technology completely resolved the genomic context of IS-bounded RIs, which was not possible using short reads alone.
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Infecciones por Acinetobacter , Acinetobacter baumannii , Antibacterianos , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/genética , Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple/genética , Humanos , Integrones , Islas , Tipificación de Secuencias MultilocusRESUMEN
Plazomicin was tested against 697 recently acquired carbapenem-resistant Klebsiella pneumoniae isolates from the Great Lakes region of the United States. Plazomicin MIC50 and MIC90 values were 0.25 and 1 mg/liter, respectively; 680 isolates (97.6%) were susceptible (MICs of ≤2 mg/liter), 9 (1.3%) intermediate (MICs of 4 mg/liter), and 8 (1.1%) resistant (MICs of >32 mg/liter). Resistance was associated with rmtF-, rmtB-, or armA-encoded 16S rRNA methyltransferases in all except 1 isolate.
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Antibacterianos/farmacología , Enterobacteriaceae Resistentes a los Carbapenémicos/efectos de los fármacos , Klebsiella pneumoniae/efectos de los fármacos , Metiltransferasas/genética , Sisomicina/análogos & derivados , Adulto , Anciano , Proteínas Bacterianas/metabolismo , Farmacorresistencia Bacteriana/genética , Femenino , Humanos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Sisomicina/farmacología , Estados Unidos , beta-Lactamasas/metabolismoRESUMEN
Outbreaks of infection occur more often than they are reported in most developing countries, largely due to poor diagnostic services. A Klebsiella species bacteremia outbreak in a newborn unit with high mortality was recently encountered at a location being surveilled for childhood bacteremia. These surveillance efforts offered the opportunity to determine the cause of this neonatal outbreak. In this report, we present the whole-genome sequences of New Delhi metallo-ß-lactamase (NDM-5)-containing Klebsiella quasipneumoniae subsp. similipneumoniae bloodstream isolates from a neonatal bacteremia outbreak at a tertiary hospital in Nigeria and as part of the largest collection of K. pneumoniae bloodstream isolates from children in Africa. Comparative analysis of the genetic environment surrounding the NDM-5 genes revealed nearly perfect sequence identity to blaNDM-5-bearing IncX3-type plasmids from other members of the EnterobacteriaceaeIMPORTANCE Carbapenem-resistant Klebsiella pneumoniae is of global health importance, yet there is a paucity of genome-based studies in Africa. Here we report fatal blood-borne NDM-5-producing K. quasipneumoniae subsp. similipneumoniae infections from Nigeria, Africa. New Delhi metallo-ß-lactamase (NDM)-producing Klebsiella spp. are responsible for high mortality and morbidity, with the NDM-5 variant showing elevated carbapenem resistance. The prevalence of NDM-5 in Klebsiella has been limited primarily to K. pneumoniae, with only one isolate being collected from Africa. During an outbreak of sepsis in a teaching hospital in Nigeria, five NDM-5-producing K. quasipneumoniae subsp. similipneumoniae sequence type 476 isolates were identified. Given the increased resistance profile of these strains, this study highlights the emerging threat of blaNDM-5 dissemination in hospital environments. The observation of these NDM-5-producing isolates in Africa stresses the urgency to improve monitoring and clinical practices to reduce or prevent the further spread of resistance.
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Genoma Bacteriano , Infecciones por Klebsiella/epidemiología , Klebsiella pneumoniae/enzimología , Klebsiella pneumoniae/genética , beta-Lactamasas/genética , Bacteriemia/epidemiología , Preescolar , Brotes de Enfermedades , Farmacorresistencia Bacteriana Múltiple/genética , Monitoreo Epidemiológico , Hospitalización , Humanos , Lactante , Recién Nacido , Infecciones por Klebsiella/sangre , Klebsiella pneumoniae/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Nigeria/epidemiología , Plásmidos , Secuenciación Completa del GenomaRESUMEN
SUMMARY: The JCVI pan-genome pipeline is a collection of programs to run PanOCT and tools that support and extend the capabilities of PanOCT. PanOCT (pan-genome ortholog clustering tool) is a tool for pan-genome analysis of closely related prokaryotic species or strains. The JCVI Pan-Genome Pipeline wrapper invokes command-line utilities that prepare input genomes, invoke third-party tools such as NCBI Blast+, run PanOCT, generate a consensus pan-genome, annotate features of the pan-genome, detect sets of genes of interest such as antimicrobial resistance (AMR) genes and generate figures, tables and html pages to visualize the results. The pipeline can run in a hierarchical mode, lowering the RAM and compute resources used. AVAILABILITY AND IMPLEMENTATION: Source code, demo data, and detailed documentation are freely available at https://github.com/JCVenterInstitute/PanGenomePipeline.
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Genoma Bacteriano , Genoma Microbiano , Análisis por Conglomerados , Células Procariotas , Programas InformáticosRESUMEN
Background: The predominant species in clinical Enterobacter isolates is E. hormaechei. Many articles, clinicians, and GenBank submissions misname these strains as E. cloacae. The lack of sequenced type strains or named species/subspecies for some clades in the E. cloacae complex complicate the issue. Methods: The genomes of the type strains for Enterobacter hormaechei subsp. oharae, E. hormaechei subsp. steigerwaltii, and E. xiangfangensis, and two strains from Hoffmann clusters III and IV of the E. cloacae complex were sequenced. These genomes, the E. hormaechei subsp. hormaechei type strain, and other available Enterobacter type strains were analysed in conjunction with all extant Enterobacter genomes in NCBI's RefSeq using Average Nucleotide Identity (ANI). Results: There were five recognizable subspecies of E. hormaechei: E. hormaechei subsp. hoffmannii subsp. nov., E. hormaechei subsp. xiangfangensis comb. nov., and the three previously known subspecies. One of the strains sequenced from the E. cloacae complex was not a novel E. hormaechei subspecies but rather a member of a clade of a novel species: E. roggenkampii sp. nov.. E. muelleri was determined to be a later heterotypic synonym of E. asburiae which should take precedence. Conclusion: The phylogeny of the Enterobacter genus, particularly the cloacae complex, was re-evaluated based on the type strain genome sequences and all other available Enterobacter genomes in RefSeq.
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Técnicas de Tipificación Bacteriana/métodos , Biología Computacional , Enterobacter/clasificación , Genoma Bacteriano , Enterobacter/genética , Filogenia , ARN Ribosómico 16S/genética , Especificidad de la EspecieRESUMEN
BACKGROUND: Bacterial pan-genomes, comprised of conserved and variable genes across multiple sequenced bacterial genomes, allow for identification of genomic regions that are phylogenetically discriminating or functionally important. Pan-genomes consist of large amounts of data, which can restrict researchers ability to locate and analyze these regions. Multiple software packages are available to visualize pan-genomes, but currently their ability to address these concerns are limited by using only pre-computed data sets, prioritizing core over variable gene clusters, or by not accounting for pan-chromosome positioning in the viewer. RESULTS: We introduce PanACEA (Pan-genome Atlas with Chromosome Explorer and Analyzer), which utilizes locally-computed interactive web-pages to view ordered pan-genome data. It consists of multi-tiered, hierarchical display pages that extend from pan-chromosomes to both core and variable regions to single genes. Regions and genes are functionally annotated to allow for rapid searching and visual identification of regions of interest with the option that user-supplied genomic phylogenies and metadata can be incorporated. PanACEA's memory and time requirements are within the capacities of standard laptops. The capability of PanACEA as a research tool is demonstrated by highlighting a variable region important in differentiating strains of Enterobacter hormaechei. CONCLUSIONS: PanACEA can rapidly translate the results of pan-chromosome programs into an intuitive and interactive visual representation. It will empower researchers to visually explore and identify regions of the pan-chromosome that are most biologically interesting, and to obtain publication quality images of these regions.
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Cromosomas/genética , Biología Computacional/métodos , Genómica/métodos , HumanosRESUMEN
In light of the ongoing antimicrobial resistance crisis, there is a need to understand the role of co-pathogens, commensals, and the local microbiome in modulating virulence and antibiotic resistance. To identify possible interactions that influence the expression of virulence or survival mechanisms in both the multidrug-resistant organisms (MDROs) and human host cells, unique cohorts of clinical isolates were selected for whole genome sequencing with enhanced assembly and full annotation, pairwise co-culturing, and transcriptome profiling. The MDROs were co-cultured in pairwise combinations either with: (1) another MDRO, (2) skin commensals (Staphylococcus epidermidis and Corynebacterium jeikeium), (3) the common probiotic Lactobacillus reuteri, and (4) human fibroblasts. RNA-Seq analysis showed distinct regulation of virulence and antimicrobial resistance gene responses across different combinations of MDROs, commensals, and human cells. Co-culture assays demonstrated that microbial interactions can modulate gene responses of both the target and pathogen/commensal species, and that the responses are specific to the identity of the pathogen/commensal species. In summary, bacteria have mechanisms to distinguish between friends, foe and host cells. These results provide foundational data and insight into the possibility of manipulating the local microbiome when treating complicated polymicrobial wound, intra-abdominal, or respiratory infections.
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Bacterias/crecimiento & desarrollo , Farmacorresistencia Bacteriana Múltiple , Fibroblastos/microbiología , Interacciones Huésped-Patógeno , Interacciones Microbianas , Probióticos , Bacterias/efectos de los fármacos , Células Cultivadas , Técnicas de Cocultivo , Perfilación de la Expresión Génica , Humanos , Anotación de Secuencia Molecular , Virulencia , Secuenciación Completa del GenomaRESUMEN
Motivation: The vast number of available sequenced bacterial genomes occasionally exceeds the facilities of comparative genomic methods or is dominated by a single outbreak strain, and thus a diverse and representative subset is required. Generation of the reduced subset currently requires a priori supervised clustering and sequence-only selection of medoid genomic sequences, independent of any additional genome metrics or strain attributes. Results: The Gaussian Genome Representative Selector with Prioritization (GGRaSP) R-package described below generates a reduced subset of genomes that prioritizes maintaining genomes of interest to the user as well as minimizing the loss of genetic variation. The package also allows for unsupervised clustering by modeling the genomic relationships using a Gaussian mixture model to select an appropriate cluster threshold. We demonstrate the capabilities of GGRaSP by generating a reduced list of 315 genomes from a genomic dataset of 4600 Escherichia coli genomes, prioritizing selection by type strain and by genome completeness. Availability and implementaion: GGRaSP is available at https://github.com/JCVenterInstitute/ggrasp/. Supplementary information: Supplementary data are available at Bioinformatics online.
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Genoma , Análisis por Conglomerados , Genómica/métodos , Distribución Normal , Programas InformáticosRESUMEN
The introduction of DNA fingerprinting to forensic science rapidly expanded the available evidence that could be garnered from a crime scene and used in court cases. Next generation sequencing technologies increased available genetic data that could be used as evidence by orders of magnitude, and as such, significant additional genetic information is now available for use in forensic science. This includes DNA from the bacteria that live in and on humans, known as the human microbiome. Next generation sequencing of the human microbiome demonstrates that its bacterial DNA can be used to uniquely identify an individual, provide information about their life and behavioral patterns, determine the body site where a sample came from, and estimate postmortem intervals. Bacterial samples from the environment and objects can also be leveraged to address similar questions about the individual(s) who interacted with them. However, the applications of this new field in forensic sciences raises concerns on current methods used in sample processing, including sample collection, storage, and the statistical power of published studies. These areas of human microbiome research need to be fully addressed before microbiome data can become a regularly incorporated evidence type and routine procedure of the forensic toolkit. Here, we summarize information on the current status of microbiome research as applies to the forensic field, the mathematical models used to make predictions, and the possible legal and practical difficulties that can limit the application of microbiomes in forensic science.
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Genética Forense/métodos , Secuenciación de Nucleótidos de Alto Rendimiento , Microbiota/genética , Humanos , Cambios Post Mortem , ARN Ribosómico 16S , Análisis de Secuencia de ARNRESUMEN
SUMMARY: LOCUST is a custom sequence locus typer tool for classifying microbial genomes. It provides a fully automated opportunity to customize the classification of genome-wide nucleotide variant data most relevant to biological research. AVAILABILITY AND IMPLEMENTATION: Source code, demo data, and detailed documentation are freely available at http://sourceforge.net/projects/locustyper . CONTACT: lbrinkac@jcvi.org. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
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Bacterias/clasificación , Genoma Bacteriano , Tipificación Molecular/métodos , Análisis de Secuencia de ADN/métodos , Programas Informáticos , Bacterias/genética , Genómica/métodosRESUMEN
Bordetella hinzii is known to cause respiratory disease in poultry and has been associated with a variety of infections in immunocompromised humans. In addition, there are several reports of B. hinzii infections in laboratory-raised mice. Here we sequenced and analysed the complete genome sequences of multiple B. hinzii-like isolates, obtained from vendor-supplied C57BL/6 mice in animal research facilities on different continents, and we determined their taxonomic relationship to other Bordetella species. The whole-genome based and 16S rRNA gene based phylogenies each identified two separate clades in B. hinzii, one was composed of strains isolated from poultry, humans and a rabbit whereas the other clade was restricted to isolates from mice. Distinctly different estimated DNA-DNA hybridization values, average nucleotide identity scores, gene content, metabolic profiles and host specificity all provide compelling evidence for delineation of the two species, B. hinzii - from poultry, humans and rabbit - and Bordetella pseudohinzii sp. nov. type strain 8-296-03T (=NRRL B-59942T=NCTC 13808T) that infect mice.
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Bordetella/clasificación , Ratones Endogámicos C57BL/microbiología , Filogenia , Animales , Técnicas de Tipificación Bacteriana , Composición de Base , Bordetella/genética , Bordetella/aislamiento & purificación , ADN Bacteriano/genética , Ácidos Grasos/análisis , Humanos , Ratones , Hibridación de Ácido Nucleico , Aves de Corral , ARN Ribosómico 16S/genética , Conejos , Análisis de Secuencia de ADNRESUMEN
Bacteriovorax is the halophilic genus of the obligate bacterial predators, Bdellovibrio and like organisms. The predators are known for their unique biphasic life style in which they search for and attack their prey in the free living phase; penetrate, grow, multiply and lyse the prey in the intraperiplasmic phase. Bacteriovorax isolates representing four phylogenetic clusters were selected for genomic sequencing. Only one type strain genome has been published so far from the genus Bacteriovorax. We report the genomes from non-type strains isolated from aquatic environments. Here we describe and compare the genomic features of the four strains, together with the classification and annotation.
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We provide here a comparative genome analysis of ten strains within the Pseudomonas fluorescens group including seven new genomic sequences. These strains exhibit a diverse spectrum of traits involved in biological control and other multitrophic interactions with plants, microbes, and insects. Multilocus sequence analysis placed the strains in three sub-clades, which was reinforced by high levels of synteny, size of core genomes, and relatedness of orthologous genes between strains within a sub-clade. The heterogeneity of the P. fluorescens group was reflected in the large size of its pan-genome, which makes up approximately 54% of the pan-genome of the genus as a whole, and a core genome representing only 45-52% of the genome of any individual strain. We discovered genes for traits that were not known previously in the strains, including genes for the biosynthesis of the siderophores achromobactin and pseudomonine and the antibiotic 2-hexyl-5-propyl-alkylresorcinol; novel bacteriocins; type II, III, and VI secretion systems; and insect toxins. Certain gene clusters, such as those for two type III secretion systems, are present only in specific sub-clades, suggesting vertical inheritance. Almost all of the genes associated with multitrophic interactions map to genomic regions present in only a subset of the strains or unique to a specific strain. To explore the evolutionary origin of these genes, we mapped their distributions relative to the locations of mobile genetic elements and repetitive extragenic palindromic (REP) elements in each genome. The mobile genetic elements and many strain-specific genes fall into regions devoid of REP elements (i.e., REP deserts) and regions displaying atypical tri-nucleotide composition, possibly indicating relatively recent acquisition of these loci. Collectively, the results of this study highlight the enormous heterogeneity of the P. fluorescens group and the importance of the variable genome in tailoring individual strains to their specific lifestyles and functional repertoire.
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Genoma Bacteriano , Plantas , Pseudomonas fluorescens/genética , Pseudomonas fluorescens/metabolismo , Análisis de Secuencia de ADN , Animales , Proteínas Bacterianas/genética , Toxinas Bacterianas/genética , Bacteriocinas/genética , Heterogeneidad Genética , Variación Genética , Interacciones Huésped-Patógeno/genética , Insectos/genética , Familia de Multigenes , Filogenia , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Plantas/genética , Plantas/microbiología , Secuencias Repetitivas de Ácidos Nucleicos/genética , Resorcinoles/metabolismoRESUMEN
BACKGROUND: In order to maintain genome information accurately and relevantly, original genome annotations need to be updated and evaluated regularly. Manual reannotation of genomes is important as it can significantly reduce the propagation of errors and consequently diminishes the time spent on mistaken research. For this reason, after five years from the initial submission of the Entamoeba histolytica draft genome publication, we have re-examined the original 23 Mb assembly and the annotation of the predicted genes. PRINCIPAL FINDINGS: The evaluation of the genomic sequence led to the identification of more than one hundred artifactual tandem duplications that were eliminated by re-assembling the genome. The reannotation was done using a combination of manual and automated genome analysis. The new 20 Mb assembly contains 1,496 scaffolds and 8,201 predicted genes, of which 60% are identical to the initial annotation and the remaining 40% underwent structural changes. Functional classification of 60% of the genes was modified based on recent sequence comparisons and new experimental data. We have assigned putative function to 3,788 proteins (46% of the predicted proteome) based on the annotation of predicted gene families, and have identified 58 protein families of five or more members that share no homology with known proteins and thus could be entamoeba specific. Genome analysis also revealed new features such as the presence of segmental duplications of up to 16 kb flanked by inverted repeats, and the tight association of some gene families with transposable elements. SIGNIFICANCE: This new genome annotation and analysis represents a more refined and accurate blueprint of the pathogen genome, and provides an upgraded tool as reference for the study of many important aspects of E. histolytica biology, such as genome evolution and pathogenesis.
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Entamoeba histolytica/genética , Genoma de Protozoos/genética , Proteínas Protozoarias/genética , Mapeo Cromosómico , Biología Computacional/métodos , Bases de Datos Genéticas , Duplicación de Gen , Cadenas de Markov , Conformación Proteica , Proteínas Protozoarias/química , Proteínas Protozoarias/metabolismo , Secuencias Repetitivas de Ácidos Nucleicos , Análisis de Secuencia de ADNRESUMEN
Efforts to annotate the genomes of a wide variety of model organisms are currently carried out by sequencing centers, model organism databases and academic/institutional laboratories around the world. Different annotation methods and tools have been developed over time to meet the needs of biologists faced with the task of annotating biological data. While standardized methods are essential for consistent curation within each annotation group, methods and tools can differ between groups, especially when the groups are curating different organisms. Biocurators from several institutes met at the Third International Biocuration Conference in Berlin, Germany, April 2009 and hosted the 'Best Practices in Genome Annotation: Inference from Evidence' workshop to share their strategies, pipelines, standards and tools. This article documents the material presented in the workshop.
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Generation of syntactically correct and unambiguous names for proteins is a challenging, yet vital task for functional annotation processes. Proteins are often named based on homology to known proteins, many of which have problematic names. To address the need to generate high-quality protein names, and capture our significant experience correcting protein names manually, we have developed the Protein Naming Utility (PNU, http://www.jcvi.org/pn-utility). The PNU is a web-based database for storing and applying naming rules to identify and correct syntactically incorrect protein names, or to replace synonyms with their preferred name. The PNU allows users to generate and manage collections of naming rules, optionally building upon the growing body of rules generated at the J. Craig Venter Institute (JCVI). Since communities often enforce disparate conventions for naming proteins, the PNU supports grouping rules into user-managed collections. Users can check their protein names against a selected PNU rule collection, generating both statistics and corrected names. The PNU can also be used to correct GenBank table files prior to submission to GenBank. Currently, the database features 3080 manual rules that have been entered by JCVI Bioinformatics Analysts as well as 7458 automatically imported names.