scholarly journals Virulence and antibiotic resistance plasticity of Arcobacter butzleri: insights on the genomic diversity of an emerging human pathogen

2019 ◽  
Author(s):  
Joana Isidro ◽  
Susana Ferreira ◽  
Miguel Pinto ◽  
Fernanda Domingues ◽  
Mónica Oleastro ◽  
...  

AbstractArcobacter butzleri is a food and waterborne bacteria and an emerging human pathogen, frequently displaying a multidrug resistant character. Still, no comprehensive genome-scale comparative analysis has been performed so far, which has limited our knowledge on A. butzleri diversification and pathogenicity. Here, we performed a deep genome analysis of A. butzleri focused on decoding its core- and pan-genome diversity and specific genetic traits underlying its pathogenic potential and diverse ecology. In total, 49 A. butzleri strains (collected from human, animal, food and environmental sources) were screened.A. butzleri (genome size 2.07-2.58 Mbp) revealed a large open pan-genome with 7474 genes (about 50% being singletons) and a small core-genome with 1165 genes. The core-genome is highly diverse (≥55% of the core genes presenting at least 40/49 alleles), being enriched with genes associated with housekeeping functions. In contrast, the accessory genome presented a high proportion of loci with an unknown function, also being particularly overrepresented by genes associated with defence mechanisms. A. butzleri revealed a plastic virulome (including newly identified determinants), marked by the differential presence of multiple adaptation-related virulence factors, such as the urease cluster ureD(AB)CEFG (phenotypically confirmed), the hypervariable hemagglutinin-encoding hecA, a putative type I secretion system (T1SS) harboring another agglutinin potentially related to adherence and a novel VirB/D4 T4SS likely linked to interbacterial competition and cytotoxicity. In addition, A. butzleri harbors a large repertoire of efflux pumps (EPs) (ten “core” and nine differentially present) and other antibiotic resistant determinants. We provide the first description of a genetic determinant of macrolides resistance in A. butzleri, by associating the inactivation of a TetR repressor (likely regulating an EP) with erythromycin resistance. Fluoroquinolones resistance correlated with the Thr-85-Ile substitution in GyrA and ampicillin resistance was linked to an OXA-15-like β-lactamase. Remarkably, by decoding the polymorphism pattern of the porin- and adhesin-encoding main antigen PorA, this study strongly supports that this pathogen is able to exchange porA as a whole and/or hypervariable epitope-encoding regions separately, leading to a multitude of chimeric PorA presentations that can impact pathogen-host interaction during infection. Ultimately, our unprecedented screening of short sequence repeats detected potential phase-variable genes related to adaptation and host/environment interaction, such as lipopolysaccharide modification and motility/chemotaxis, suggesting that phase variation likely modulate A. butzleri key adaptive functions.In summary, this study constitutes a turning point on A. butzleri comparative genomics revealing that this human gastrointestinal pathogen is equipped with vast virulence and antibiotic resistance arsenals, which, coupled with its remarkable core- and pan-genome diversity, opens a multitude of phenotypic fingerprints for environmental/host adaptation and pathogenicity.IMPACT STATEMENTDiarrhoeal diseases are the most common cause of human illness caused by foodborne hazards, but the surveillance of diarrhoeal diseases is biased towards the most commonly searched infectious agents (namely Campylobacter jejuni and C. coli). In fact, other less studied pathogens are frequently found as the etiological agent when refined non-selective culture conditions are applied. A hallmark example is the diarrhoeal-causing Arcobacter butzleri which, despite being also associated with extra-intestinal diseases, such as bacteremia in humans and mastitis in animals, and displaying high rates of antibiotic resistance, has not yet been profoundly investigated regarding its epidemiology, diversity and pathogenicity. To overcome the general lack of knowledge on A. butzleri comparative genomics, we provide the first comprehensive genome-scale analysis of A. butzleri focused on exploring the intraspecies virulome content and diversity, resistance determinants, as well as how this pathogen shapes its genome towards ecological adaptation and host invasion. The unveiled scenario of A. butzleri rampant diversity and plasticity reinforces the pathogenic potential of this food and waterborne hazard, while opening multiple research lines that will certainly contribute to the future development of more robust species-oriented diagnostics and molecular surveillance of A. butzleri.DATA SUMMARYA. butzleri raw sequence reads generated in the present study were deposited in the European Nucleotide Archive (ENA) (BioProject PRJEB34441). The assembled contigs (.fasta and .gbk files), the nucleotide sequences of the predicted transcripts (CDS, rRNA, tRNA, tmRNA, misc_RNA) (.ffn files) and the respective amino acid sequences of the translated CDS sequences (.faa files) are available at http://doi.org/10.5281/zenodo.3434222. Detailed ENA accession numbers, as well as the draft genome statistics are described in Table S1.

Marine Drugs ◽  
2019 ◽  
Vol 17 (12) ◽  
pp. 661 ◽  
Author(s):  
Nadezhda Chernysheva ◽  
Evgeniya Bystritskaya ◽  
Anna Stenkova ◽  
Ilya Golovkin ◽  
Olga Nedashkovskaya ◽  
...  

We obtained two novel draft genomes of type Zobellia strains with estimated genome sizes of 5.14 Mb for Z. amurskyensis KMM 3526Т and 5.16 Mb for Z. laminariae KMM 3676Т. Comparative genomic analysis has been carried out between obtained and known genomes of Zobellia representatives. The pan-genome of Zobellia genus is composed of 4853 orthologous clusters and the core genome was estimated at 2963 clusters. The genus CAZome was represented by 775 GHs classified into 62 families, 297 GTs of 16 families, 100 PLs of 13 families, 112 CEs of 13 families, 186 CBMs of 18 families and 42 AAs of six families. A closer inspection of the carbohydrate-active enzyme (CAZyme) genomic repertoires revealed members of new putative subfamilies of GH16 and GH117, which can be biotechnologically promising for production of oligosaccharides and rare monomers with different bioactivities. We analyzed AA3s, among them putative FAD-dependent glycoside oxidoreductases (FAD-GOs) being of particular interest as promising biocatalysts for glycoside deglycosylation in food and pharmaceutical industries.


2020 ◽  
Vol 14 ◽  
pp. 117793222093806
Author(s):  
Sávio Souza Costa ◽  
Luís Carlos Guimarães ◽  
Artur Silva ◽  
Siomar Castro Soares ◽  
Rafael Azevedo Baraúna

Pan-genome is defined as the set of orthologous and unique genes of a specific group of organisms. The pan-genome is composed by the core genome, accessory genome, and species- or strain-specific genes. The pan-genome is considered open or closed based on the alpha value of the Heap law. In an open pan-genome, the number of gene families will continuously increase with the addition of new genomes to the analysis, while in a closed pan-genome, the number of gene families will not increase considerably. The first step of a pan-genome analysis is the homogenization of genome annotation. The same software should be used to annotate genomes, such as GeneMark or RAST. Subsequently, several software are used to calculate the pan-genome such as BPGA, GET_HOMOLOGUES, PGAP, among others. This review presents all these initial steps for those who want to perform a pan-genome analysis, explaining key concepts of the area. Furthermore, we present the pan-genomic analysis of 9 bacterial species. These are the species with the highest number of genomes deposited in GenBank. We also show the influence of the identity and coverage parameters on the prediction of orthologous and paralogous genes. Finally, we cite the perspectives of several research areas where pan-genome analysis can be used to answer important issues.


2017 ◽  
Author(s):  
Andries J van Tonder ◽  
James E Bray ◽  
Keith A Jolley ◽  
Sigríður J Quirk ◽  
Gunnsteinn Haraldsson ◽  
...  

AbstractBackgroundUnderstanding the structure of a bacterial population is essential in order to understand bacterial evolution, or which genetic lineages cause disease, or the consequences of perturbations to the bacterial population. Estimating the core genome, the genes common to all or nearly all strains of a species, is an essential component of such analyses. The size and composition of the core genome varies by dataset, but our hypothesis was that variation between different collections of the same bacterial species should be minimal. To test this, the genome sequences of 3,121 pneumococci recovered from healthy individuals in Reykjavik (Iceland), Southampton (United Kingdom), Boston (USA) and Maela (Thailand) were analysed.ResultsThe analyses revealed a ‘supercore’ genome (genes shared by all 3,121 pneumococci) of only 303 genes, although 461 additional core genes were shared by pneumococci from Reykjavik, Southampton and Boston. Overall, the size and composition of the core genomes and pan-genomes among pneumococci recovered in Reykjavik, Southampton and Boston were very similar, but pneumococci from Maela were distinctly different. Inspection of the pan-genome of Maela pneumococci revealed several >25 Kb sequence regions that were homologous to genomic regions found in other bacterial species.ConclusionsSome subsets of the global pneumococcal population are highly heterogeneous and thus our hypothesis was rejected. This is an essential point of consideration before generalising the findings from a single dataset to the wider pneumococcal population.


Author(s):  
Gaurav Agarwal ◽  
Ronald D. Gitaitis ◽  
Bhabesh Dutta

Pantoea stewartii subsp. indologenes (Psi) is a causative agent of leafspot of foxtail millet and pearl millet; however, novel strains were recently identified that are pathogenic on onion. Our recent host range evaluation study identified two pathovars; P. stewartii subsp. indologenes pv. cepacicola pv. nov. and P. stewartii subsp. indologenes pv. setariae pv. nov. that are pathogenic on onion and millets or on millets only, respectively. In the current study we developed a pan-genome using the whole genome sequencing of newly identified/classified Psi strains from both pathovars [pv. cepacicola (n= 4) and pv. setariae (n=13)]. The full spectrum of the pan-genome contained 7,030 genes. Among these, 3,546 (present in genomes of all 17 strains) were the core genes that were a subset of 3,682 soft-core genes (present in ≥16 strains). The accessory genome included 1,308 shell genes and 2,040 cloud genes (present in ≤ 2 strains). The pan-genome showed a clear liner progression with >6,000 genes, suggesting the pan-genome of Psi is open. Comparative phylogenetic analysis showed differences in phylogenetic clustering of Pantoea spp. using PAVs/wgMLST approach in comparison to core genome SNP-based phylogeny. Further, we conducted a horizontal gene transfer (HGT) study including four other Pantoea species namely, P. stewartii subsp. stewartii LMG 2715T, P. ananatis LMG 2665T, P. agglomerans LMG L15, and P. allii LMG 24248T. A total of 317 HGT events among four Pantoea species were identified with most gene transfers observed between Psi pv. cepacicola and Psi pv. setariae. Pan-GWAS analysis predicted a total of 154 genes including seven cluster of genes associated with the pathogenicity phenotype on onion. One of the clusters contain 11 genes with known functions and are found to be chromosomally located.


2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Kirsi Aaltonen ◽  
Ravi Kant ◽  
Marjut Eklund ◽  
Mirja Raunio-Saarnisto ◽  
Lars Paulin ◽  
...  

Streptococcus halichoeri is an emerging pathogen with a variety of host species and zoonotic potential. It has been isolated from grey seals and other marine mammals as well as from human infections. Beginning in 2010, two concurrent epidemics were identified in Finland, in fur animals and domestic dogs, respectively. The fur animals suffered from a new disease fur animal epidemic necrotic pyoderma (FENP) and the dogs presented with ear infections with poor treatment response. S. halichoeri was isolated in both studies, albeit among other pathogens, indicating a possible role in the disease etiologies. The aim was to find a possible common origin of the fur animal and dog isolates and study the virulence factors to assess pathogenic potential. Isolates from seal, human, dogs, and fur animals were obtained for comparison. The whole genomes were sequenced from 20 different strains using the Illumina MiSeq platform and annotated using an automatic annotation pipeline RAST. The core and pangenomes were formed by comparing the genomes against each other in an all-against-all comparison. A phylogenetic tree was constructed using the genes of the core genome. Virulence factors were assessed using the Virulence Factor Database (VFDB) concentrating on the previously confirmed streptococcal factors. A core genome was formed which encompassed approximately half of the genes in Streptococcus halichoeri. The resulting core was nearly saturated and would not change significantly by adding more genomes. The remaining genes formed the pangenome which was highly variable and would still evolve after additional genomes. The results highlight the great adaptability of this bacterium possibly explaining the ease at which it switches hosts and environments. Virulence factors were also analyzed and were found primarily in the core genome. They represented many classes and functions, but the largest single category was adhesins which again supports the marine origin of this species.


2016 ◽  
Vol 7 ◽  
Author(s):  
Jongoh Shin ◽  
Yoseb Song ◽  
Yujin Jeong ◽  
Byung-Kwan Cho

2014 ◽  
Vol 5 ◽  
Author(s):  
Jacqueline Z.-M. Chan ◽  
Andrew D. Millard ◽  
Nicholas H. Mann ◽  
Hendrik Schäfer

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Yoann Le Breton ◽  
Ashton T. Belew ◽  
Kayla M. Valdes ◽  
Emrul Islam ◽  
Patrick Curry ◽  
...  

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Arya Suresh ◽  
Sabiha Shaik ◽  
Ramani Baddam ◽  
Amit Ranjan ◽  
Shamsul Qumar ◽  
...  

ABSTRACT The genotoxin colibactin is a secondary metabolite produced by the polyketide synthase (pks) island harbored by extraintestinal pathogenic E. coli (ExPEC) and other members of the Enterobacteriaceae that has been increasingly reported to have critical implications in human health. The present study entails a high-throughput whole-genome comparison and phylogenetic analysis of such pathogenic E. coli isolates to gain insights into the patterns of distribution, horizontal transmission, and evolution of the island. For the current study, 23 pks-positive ExPEC genomes were newly sequenced, and their virulome and resistome profiles indicated a preponderance of virulence encoding genes and a reduced number of genes for antimicrobial resistance. In addition, 4,090 E. coli genomes from the public domain were also analyzed for large-scale screening for pks-positive genomes, out of which a total of 530 pks-positive genomes were studied to understand the subtype-based distribution pattern(s). The pks island showed a significant association with the B2 phylogroup (82.2%) and a high prevalence in sequence type 73 (ST73; n = 179) and ST95 (n = 110) and the O6:H1 (n = 110) serotype. Maximum-likelihood (ML) phylogeny of the core genome and intergenic regions (IGRs) of the ST95 model data set, which was selected because it had both pks-positive and pks-negative genomes, displayed clustering in relation to their carriage of the pks island. Prevalence patterns of genes encoding RM systems in the pks-positive and pks-negative genomes were also analyzed to determine their potential role in pks island acquisition and the maintenance capability of the genomes. Further, the maximum-likelihood phylogeny based on the core genome and pks island sequences from 247 genomes with an intact pks island demonstrated horizontal gene transfer of the island across sequence types and serotypes, with few exceptions. This study vitally contributes to understanding of the lineages and subtypes that have a higher propensity to harbor the pks island-encoded genotoxin with possible clinical implications. IMPORTANCE Extraintestinal pathologies caused by highly virulent strains of E. coli amount to clinical implications with high morbidity and mortality rates. Pathogenic E. coli strains are evolving with the horizontal acquisition of mobile genetic elements, including pathogenicity islands such as the pks island, which produces the genotoxin colibactin, resulting in severe clinical outcomes, including colorectal cancer progression. The current study encompasses high-throughput comparative genomics and phylogenetic analyses to address the questions pertaining to the acquisition and evolution pattern of the genomic island in different E. coli subtypes. It is crucial to gain insights into the distribution, transfer, and maintenance of pathogenic islands, as they harbor multiple virulence genes involved in pathogenesis and clinical implications of the infection.


2020 ◽  
Vol 21 (9) ◽  
pp. 3393
Author(s):  
Mengmeng Wang ◽  
Han Zhu ◽  
Zhijian Kong ◽  
Tuo Li ◽  
Lei Ma ◽  
...  

The genus Geobacillus is abundant in ecological diversity and is also well-known as an authoritative source for producing various thermostable enzymes. Although it is clear now that Geobacillus evolved from Bacillus, relatively little knowledge has been obtained regarding its evolutionary mechanism, which might also contribute to its ecological diversity and biotechnology potential. Here, a statistical comparison of thirty-two Geobacillus genomes was performed with a specific focus on pan- and core genomes. The pan-genome of this set of Geobacillus strains contained 14,913 genes, and the core genome contained 940 genes. The Clusters of Orthologous Groups (COG) and Carbohydrate-Active Enzymes (CAZymes) analysis revealed that the Geobacillus strains had huge potential industrial application in composting for agricultural waste management. Detailed comparative analyses showed that basic functional classes and housekeeping genes were conserved in the core genome, while genes associated with environmental interaction or energy metabolism were more enriched in the pan-genome. Therefore, the evolution of Geobacillus seems to be guided by environmental parameters. In addition, horizontal gene transfer (HGT) events among different Geobacillus species were detected. Altogether, pan-genome analysis was a useful method for detecting the evolutionary mechanism, and Geobacillus’ evolution was directed by the environment and HGT events.


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