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Lyu B, Song Q. The intricate relationship of G-Quadruplexes and bacterial pathogenicity islands. eLife 2024; 12:RP91985. [PMID: 38391174 PMCID: PMC10942614 DOI: 10.7554/elife.91985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024] Open
Abstract
The dynamic interplay between guanine-quadruplex (G4) structures and pathogenicity islands (PAIs) represents a captivating area of research with implications for understanding the molecular mechanisms underlying pathogenicity. This study conducted a comprehensive analysis of a large-scale dataset from reported 89 pathogenic strains of bacteria to investigate the potential interactions between G4 structures and PAIs. G4 structures exhibited an uneven and non-random distribution within the PAIs and were consistently conserved within the same pathogenic strains. Additionally, this investigation identified positive correlations between the number and frequency of G4 structures and the GC content across different genomic features, including the genome, promoters, genes, tRNA, and rRNA regions, indicating a potential relationship between G4 structures and the GC-associated regions of the genome. The observed differences in GC content between PAIs and the core genome further highlight the unique nature of PAIs and underlying factors, such as DNA topology. High-confidence G4 structures within regulatory regions of Escherichia coli were identified, modulating the efficiency or specificity of DNA integration events within PAIs. Collectively, these findings pave the way for future research to unravel the intricate molecular mechanisms and functional implications of G4-PAI interactions, thereby advancing our understanding of bacterial pathogenicity and the role of G4 structures in pathogenic diseases.
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Affiliation(s)
- Bo Lyu
- Division of Plant Science and Technology, University of MissouriColumbiaUnited States
| | - Qisheng Song
- Division of Plant Science and Technology, University of MissouriColumbiaUnited States
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2
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Hoppe-Elsholz G, Piña-Iturbe A, Vallejos OP, Suazo ID, Sepúlveda-Alfaro J, Pereira-Sánchez P, Martínez-Balboa Y, Catalán EA, Reyes P, Scaff V, Bassi F, Campos-Gajardo S, Avilés A, Santiviago CA, Kalergis AM, Bueno SM. SEN1990 is a predicted winged helix-turn-helix protein involved in the pathogenicity of Salmonella enterica serovar Enteritidis and the expression of the gene oafB in the SPI-17. Front Microbiol 2023; 14:1236458. [PMID: 38029095 PMCID: PMC10655114 DOI: 10.3389/fmicb.2023.1236458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/27/2023] [Indexed: 12/01/2023] Open
Abstract
Excisable genomic islands (EGIs) are horizontally acquired genetic elements that harbor an array of genes with diverse functions. ROD21 is an EGI found integrated in the chromosome of Salmonella enterica serovar Enteritidis (Salmonella ser. Enteritidis). While this island is known to be involved in the capacity of Salmonella ser. Enteritidis to cross the epithelial barrier and colonize sterile organs, the role of most ROD21 genes remains unknown, and thus, the identification of their function is fundamental to understanding the impact of this EGI on bacterium pathogenicity. Therefore, in this study, we used a bioinformatical approach to evaluate the function of ROD21-encoded genes and delve into the characterization of SEN1990, a gene encoding a putative DNA-binding protein. We characterized the predicted structure of SEN1990, finding that this protein contains a three-stranded winged helix-turn-helix (wHTH) DNA-binding domain. Additionally, we identified homologs of SEN1990 among other members of the EARL EGIs. Furthermore, we deleted SEN1990 in Salmonella ser. Enteritidis, finding no differences in the replication or maintenance of the excised ROD21, contrary to what the previous Refseq annotation of the protein suggests. High-throughput RNA sequencing was carried out to evaluate the effect of the absence of SEN1990 on the bacterium's global transcription. We found a downregulated expression of oafB, an SPI-17-encoded acetyltransferase involved in O-antigen modification, which was restored when the deletion mutant was complemented ectopically. Additionally, we found that strains lacking SEN1990 had a reduced capacity to colonize sterile organs in mice. Our findings suggest that SEN1990 encodes a wHTH domain-containing protein that modulates the transcription of oafB from the SPI-17, implying a crosstalk between these pathogenicity islands and a possible new role of ROD21 in the pathogenesis of Salmonella ser. Enteritidis.
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Affiliation(s)
- Guillermo Hoppe-Elsholz
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alejandro Piña-Iturbe
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Omar P. Vallejos
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Isidora D. Suazo
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Javiera Sepúlveda-Alfaro
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Patricia Pereira-Sánchez
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Yohana Martínez-Balboa
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Eduardo A. Catalán
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo Reyes
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Valentina Scaff
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Franco Bassi
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Sofia Campos-Gajardo
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Andrea Avilés
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Carlos A. Santiviago
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Alexis M. Kalergis
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Endocrinología, Facultad de Medicina, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M. Bueno
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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Tran SC, McClain MS, Cover TL. Role of the CagY antenna projection in Helicobacter pylori Cag type IV secretion system activity. Infect Immun 2023; 91:e0015023. [PMID: 37638724 PMCID: PMC10501215 DOI: 10.1128/iai.00150-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/07/2023] [Indexed: 08/29/2023] Open
Abstract
Helicobacter pylori strains containing the cag pathogenicity island (PAI) are associated with the development of gastric adenocarcinoma and peptic ulcer disease. The cag PAI encodes a secreted effector protein (CagA) and a type IV secretion system (Cag T4SS). Cag T4SS activity is required for the delivery of CagA and non-protein substrates into host cells. The Cag T4SS outer membrane core complex (OMCC) contains a channel-like domain formed by helix-loop-helix elements (antenna projections, AP) from 14 copies of the CagY protein (a VirB10 ortholog). Similar VirB10 antenna regions are present in T4SS OMCCs from multiple bacterial species and are predicted to span the outer membrane. In this study, we investigated the role of the CagY antenna region in Cag T4SS OMCC assembly and Cag T4SS function. An H. pylori mutant strain with deletion of the entire CagY AP (∆AP) retained the capacity to produce CagY and assemble an OMCC, but it lacked T4SS activity (CagA translocation and IL-8 induction in AGS gastric epithelial cells). In contrast, a mutant strain with Gly-Ser substitutions in the unstructured CagY AP loop retained Cag T4SS activity. Mutants containing CagY AP loops with shortened lengths were defective in CagA translocation and exhibited reduced IL-8-inducing activity compared to control strains. These data indicate that the CagY AP region is required for Cag T4SS activity and that Cag T4SS activity can be modulated by altering the length of the CagY AP unstructured loop.
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Affiliation(s)
- Sirena C. Tran
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mark S. McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Timothy L. Cover
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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Canzian F, Rizzato C, Stein A, Flores-Luna L, Camorlinga-Ponce M, Mendez-Tenorio A, Chen W, Kasamatsu E, Bravo MM, Torres J, Muñoz N, Kato I. Phylogenetic origin of Helicobacter pylori pathogenicity island and risk of stomach cancer and high-grade premalignant gastric lesions. Eur J Cancer Prev 2023; 32:301-304. [PMID: 36719829 PMCID: PMC10073236 DOI: 10.1097/cej.0000000000000779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Infection by Helicobacter pylori (Hp) has been causally linked to risk of gastric cancer (GC). The coevolution of Hp and humans shaped the risk of GC as our species left Africa and migrated to the other continents. Latin America (LatAm) is a high GC incidence region where Hp evolved uniquely in the 500 years since European colonization. Differential virulence of the Hp cagA -pathogenicity island (cagPAI) by ancestral origin has been reported. We hypothesized that Hp phylogenetic origin might play a role in determining GC risk in LatAm. We used genotypes of 50 Hp genetic variants mapping to the Hp cagPAI, studied in 1220 subjects from Venezuela, Colombia, Mexico and Paraguay, who were infected with cagA-positive Hp, including 150 GC, 177 high-grade premalignant lesions (HGPMLs) and 893 low-grade premalignant lesions. We estimated the phylogenetic origin of Hp cagPAI in all study subjects by use of the STRUCTURE software and principal component analysis (PCA) and tested whether the estimated African ancestry percentage was associated with the risk of GC or HGPML. African ancestral component estimates by STRUCTURE and PCA were highly correlated. STRUCTURE-based African origin estimate was not significantly associated with the risk of HGPML, but it was inversely associated with GC risk: the OR associated with the continuous values of African component was 0.09 (95% CI, 0.01-0.85; P = 0.035). Similar trends were observed for GC with PCA-based estimates, but the association was not statistically significant. These results suggest that Hp ancestral origin may play a role in gastric carcinogenesis.
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Affiliation(s)
- Federico Canzian
- Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Cosmeri Rizzato
- Department of Translation Research and of New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Angelika Stein
- Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Lourdes Flores-Luna
- Center for Public Health Research, National Institute of Public Health, Cuernavaca
| | - Margarita Camorlinga-Ponce
- Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatría, Instituto Mexicano del Seguro Social
| | - Alfonso Mendez-Tenorio
- Laboratorio de Biotecnología y Bioinformática Genómica, ENCB, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Wei Chen
- Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Elena Kasamatsu
- Instituto de Investigaciones en Ciencias de la Salud, National University of Asunción, Asunción, Paraguay
| | - Maria Mercedes Bravo
- Grupo de Investigación en Biología del Cáncer, Instituto Nacional de Cancerología
| | - Javier Torres
- Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatría, Instituto Mexicano del Seguro Social
| | - Nubia Muñoz
- Cancer Institute of Colombia, Bogotá, Colombia
| | - Ikuko Kato
- Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan, USA
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Robinson L, Liaw J, Omole Z, Corcionivoschi N, Hachani A, Gundogdu O. In silico investigation of the genus Campylobacter type VI secretion system reveals genetic diversity in organization and putative effectors. Microb Genom 2022; 8:mgen000898. [PMID: 36314601 PMCID: PMC9676060 DOI: 10.1099/mgen.0.000898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 09/11/2022] [Indexed: 01/25/2023] Open
Abstract
Bacterial type VI secretion systems (T6SSs) are contractile nanomachines that deliver proteinic substrates into target prokaryotic or eukaryotic cells and the surrounding milieu. The genus Campylobacter encompasses 39 recognized species and 13 subspecies, with many belonging to a group known as ‘emerging Campylobacter pathogens’. Within Campylobacter , seven species have been identified to harbour a complete T6SS cluster but have yet to be comparatively assessed. In this study, using systematic bioinformatics approaches and the T6SS-positive Campylobacter jejuni 488 strain as a reference, we explored the genus-wide prevalence, similarity and make-up of the T6SS amongst 372 publicly available ‘complete’ Campylobacter genomes. Our analyses predict that approximately one-third of Campylobacter species possess a T6SS. We also putatively report the first identification of a T6SS in four species: Campylobacter cuniculorum, Campylobacter helveticus, Campylobacter armoricus and Campylobacter ornithocola . The Campylobacter T6SSs cluster into three distinct organizations (I–III), of which two break down into further variants. Thirty T6SS-containing genomes were found to harbour more than one vgrG gene, with Campylobacter lari strain NCTC 11845 possessing five. Analysis of the C. jejuni Pathogenicity Island-1 confirmed its conservation amongst T6SS-positive C. jejuni strains, as well as highlighting its diverse genetic composition, including additional putative effector–immunity pairs (e.g. PoNe and DUF1911 domains). Effector–immunity pairs were also observed neighbouring vgrG s in several other Campylobacter species, in addition to putative genes encoding nucleases, lysozymes, ATPases and a ferric ATP-binding cassette uptake system. These observations highlight the diverse genetic make-up of the T6SS within Campylobacter and provide further evidence of its role in pathogenesis.
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Affiliation(s)
- Luca Robinson
- National Heart and Lung Institute, Imperial College London, London, UK
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Janie Liaw
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Zahra Omole
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Nicolae Corcionivoschi
- Bacteriology Branch, Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, UK
- Bioengineering of Animal Resources, University of Life Sciences – King Mihai I of Romania from Timisoara, Timisoara, Romania
| | - Abderrahman Hachani
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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Lipps SM, Samac DA. Pseudomonas viridiflava: An internal outsider of the Pseudomonas syringae species complex. Mol Plant Pathol 2022; 23:3-15. [PMID: 34463014 PMCID: PMC8659605 DOI: 10.1111/mpp.13133] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
UNLABELLED Pseudomonas viridiflava is a gram-negative pseudomonad that is phylogenetically placed within the Pseudomonas syringae species complex. P. viridiflava has a wide host range and causes a variety of symptoms in different plant parts, including stems, leaves, and blossoms. Outside of its role as a pathogen, P. viridiflava also exists as an endophyte, epiphyte, and saprophyte. Increased reports of P. viridiflava causing disease on new hosts in recent years coincide with increased research on its genetic variability, virulence, phylogenetics, and phenotypes. There is high variation in its core genome, virulence factors, and phenotypic characteristics. The main virulence factors of this pathogen include the enzyme pectate lyase and virulence genes encoded within one or two pathogenicity islands. The delineation of P. viridiflava in the P. syringae complex has been investigated using several molecular approaches. P. viridiflava comprises its own species, within the complex. While seemingly an outsider to the complex as a whole due to differences in the core genome and virulence genes, low average nucleotide identity to other of P. syringae complex members, and some phenotypic traits, it remains as part of the complex. Defining phylogenetic, phenotypic, and genomic characteristics of P. viridiflava in comparison to other P. syringae members is important to understanding this pathogen and for the development of disease resistance and management practices. TAXONOMY Kingdom Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Family Pseudomonadaceae; Genus Pseudomonas; Species Pseudomonas syringae species complex, Genomospecies 6, Phylogroup 7 and 8. MICROBIOLOGICAL PROPERTIES Gram-negative, fluorescent, aerobic, motile, rod-shaped, oxidase negative, arginine dihydrolase negative, levan production negative (or positive), potato rot positive (or negative), tobacco hypersensitivity positive. GENOME There are two complete genomes, five chromosome-level genomes, and 1,540 genomes composed of multiple scaffolds of P. viridiflava available in the National Center for Biotechnology Information Genome database. The median total length of these assemblies is 5,975,050 bp, the median number of protein coding genes is 5,208, and the median G + C content is 59.3%. DISEASE SYMPTOMS P. viridiflava causes a variety of disease symptoms, including spots, streaks, necrosis, rots, and more in above- and below-ground plant parts on at least 50 hosts. EPIDEMIOLOGY There have been several significant disease outbreaks on field and horticultural crops caused by P. viridiflava since the turn of the century. P. viridiflava has been reported as a pathogen, epiphyte, endophyte, and saprophyte. This species has been isolated from a variety of environmental sources, including asymptomatic wild plants, snow, epilithic biofilms, and icepacks.
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Affiliation(s)
- Savana M. Lipps
- Plant PathologyUniversity of Minnesota Twin CitiesSt PaulMNUSA
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7
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Robinson L, Liaw J, Omole Z, Xia D, van Vliet AHM, Corcionivoschi N, Hachani A, Gundogdu O. Corrigendum: Bioinformatic Analysis of the Campylobacter jejuni Type VI Secretion System and Effector Prediction. Front Microbiol 2021; 12:793252. [PMID: 34867930 PMCID: PMC8637873 DOI: 10.3389/fmicb.2021.793252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 10/13/2021] [Indexed: 11/24/2022] Open
Affiliation(s)
- Luca Robinson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Janie Liaw
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Zahra Omole
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Dong Xia
- Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Arnoud H M van Vliet
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Nicolae Corcionivoschi
- Bacteriology Branch, Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, United Kingdom.,Bioengineering of Animal Science Resources, Banat University of Agricultural Sciences and Veterinary Medicine - King Michael the I of Romania, Timisoara, Romania
| | - Abderrahman Hachani
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Heo T, Kang H, Choi S, Kim J. Detection of pks Island mRNAs Using Toehold Sensors in Escherichia coli. Life (Basel) 2021; 11:1280. [PMID: 34833155 DOI: 10.3390/life11111280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/15/2021] [Accepted: 11/18/2021] [Indexed: 12/14/2022] Open
Abstract
Synthetic biologists have applied biomolecular engineering approaches toward the goal of novel biological devices and have shown progress in diverse areas of medicine and biotechnology. Especially promising is the application of synthetic biological devices towards a novel class of molecular diagnostics. As an example, a de-novo-designed riboregulator called toehold switch, with its programmability and compatibility with field-deployable devices showed promising in vitro applications for viral RNA detection such as Zika and Corona viruses. However, the in vivo application of high-performance RNA sensors remains challenging due to the secondary structure of long mRNA species. Here, we introduced ‘Helper RNAs’ that can enhance the functionality of toehold switch sensors by mitigating the effect of secondary structures around a target site. By employing the helper RNAs, previously reported mCherry mRNA sensor showed improved fold-changes in vivo. To further generalize the Helper RNA approaches, we employed automatic design pipeline for toehold sensors that target the essential genes within the pks island, an important target of biomedical research in connection with colorectal cancer. The toehold switch sensors showed fold-changes upon the expression of full-length mRNAs that apparently depended sensitively on the identity of the gene as well as the predicted local structure within the target region of the mRNA. Still, the helper RNAs could improve the performance of toehold switch sensors in many instances, with up to 10-fold improvement over no helper cases. These results suggest that the helper RNA approaches can further assist the design of functional RNA devices in vivo with the aid of the streamlined automatic design software developed here. Further, our solutions for screening and stabilizing single-stranded region of mRNA may find use in other in vivo mRNA-sensing applications such as cas13 crRNA design, transcriptome engineering, and trans-cleaving ribozymes.
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Pazhani GP, Chowdhury G, Ramamurthy T. Adaptations of Vibrio parahaemolyticus to Stress During Environmental Survival, Host Colonization, and Infection. Front Microbiol 2021; 12:737299. [PMID: 34690978 PMCID: PMC8530187 DOI: 10.3389/fmicb.2021.737299] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/08/2021] [Indexed: 02/03/2023] Open
Abstract
Vibrio parahaemolyticus (Vp) is an aquatic Gram-negative bacterium that may infect humans and cause gastroenteritis and wound infections. The first pandemic of Vp associated infection was caused by the serovar O3:K6 and epidemics caused by the other serovars are increasingly reported. The two major virulence factors, thermostable direct hemolysin (TDH) and/or TDH-related hemolysin (TRH), are associated with hemolysis and cytotoxicity. Vp strains lacking tdh and/or trh are avirulent and able to colonize in the human gut and cause infection using other unknown factors. This pathogen is well adapted to survive in the environment and human host using several genetic mechanisms. The presence of prophages in Vp contributes to the emergence of pathogenic strains from the marine environment. Vp has two putative type-III and type-VI secretion systems (T3SS and T6SS, respectively) located on both the chromosomes. T3SS play a crucial role during the infection process by causing cytotoxicity and enterotoxicity. T6SS contribute to adhesion, virulence associated with interbacterial competition in the gut milieu. Due to differential expression, type III secretion system 2 (encoded on chromosome-2, T3SS2) and other genes are activated and transcribed by interaction with bile salts within the host. Chromosome-1 encoded T6SS1 has been predominantly identified in clinical isolates. Acquisition of genomic islands by horizontal gene transfer provides enhanced tolerance of Vp toward several antibiotics and heavy metals. Vp consists of evolutionarily conserved targets of GTPases and kinases. Expression of these genes is responsible for the survival of Vp in the host and biochemical changes during its survival. Advanced genomic analysis has revealed that various genes are encoded in Vp pathogenicity island that control and expression of virulence in the host. In the environment, the biofilm gene expression has been positively correlated to tolerance toward aerobic, anaerobic, and micro-aerobic conditions. The genetic similarity analysis of toxin/antitoxin systems of Escherichia coli with VP genome has shown a function that could induce a viable non-culturable state by preventing cell division. A better interpretation of the Vp virulence and other mechanisms that support its environmental fitness are important for diagnosis, treatment, prevention and spread of infections. This review identifies some of the common regulatory pathways of Vp in response to different stresses that influence its survival, gut colonization and virulence.
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Affiliation(s)
- Gururaja Perumal Pazhani
- School of Pharmaceutical Sciences, Chettinad Academy of Research and Education, Kelambakkam, India
| | - Goutam Chowdhury
- ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
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Tegtmeyer N, Harrer A, Rottner K, Backert S. Helicobacter pylori CagA Induces Cortactin Y-470 Phosphorylation-Dependent Gastric Epithelial Cell Scattering via Abl, Vav2 and Rac1 Activation. Cancers (Basel) 2021; 13:4241. [PMID: 34439396 DOI: 10.3390/cancers13164241] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/10/2021] [Accepted: 08/15/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Various microbial pathogens target the actin-binding protein cortactin to promote their own uptake, proliferation and spread, and exhibit proposed roles in human cancerogenesis. We aimed to study the molecular mechanisms of how the gastric pathogen Helicobacter pylori hijacks cortactin phosphorylation via tyrosine kinase Abl to trigger cancer-related signal transduction events. We discovered that cortactin phosphorylated at Y-470 recruits the signaling factor Vav2 to activate the small Rho GTPase Rac1, and finally, a cancer cell motility phenotype. We also demonstrate that phosphorylation of cortactin at Y-470 can be completely inhibited by the well-known Abl inhibitor imatinib. Imatinib is an established oral chemotherapy medication, employed for efficient systemic treatment of various cancers. These results reveal a comprehensive novel pathway for how precisely H. pylori manipulates host signaling in gastric disease development, and may pave the way for new opportunities of treatment of the outcome of infections with this pathogen, i.e., through using imatinib. Abstract The pathogen Helicobacter pylori is the first reported bacterial type-1 carcinogen playing a role in the development of human malignancies, including gastric adenocarcinoma. Cancer cell motility is an important process in this scenario, however, the molecular mechanisms are still not fully understood. Here, we demonstrate that H. pylori subverts the actin-binding protein cortactin through its type-IV secretion system and injected oncoprotein CagA, e.g., by inducing tyrosine phosphorylation of cortactin at Y-470, which triggers gastric epithelial cell scattering and motility. During infection of AGS cells, cortactin was discovered to undergo tyrosine dephosphorylation at residues Y-421 and Y-486, which is mediated through inactivation of Src kinase. However, H. pylori also profoundly activates tyrosine kinase Abl, which simultaneously phosphorylates cortactin at Y-470. Phosphorylated cortactin interacts with the SH2-domain of Vav2, a guanine nucleotide exchange factor for the Rho-family of GTPases. The cortactin/Vav2 complex then stimulates a previously unrecognized activation cascade including the small GTPase Rac1, to effect actin rearrangements and cell scattering. We hypothesize that injected CagA targets cortactin to locally open the gastric epithelium in order to get access to certain nutrients. This may disturb the cellular barrier functions, likely contributing to the induction of cell motility, which is important in gastric cancer development.
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Hudec C, Biessy A, Novinscak A, St-Onge R, Lamarre S, Blom J, Filion M. Comparative Genomics of Potato Common Scab-Causing Streptomyces spp. Displaying Varying Virulence. Front Microbiol 2021; 12:716522. [PMID: 34413844 PMCID: PMC8369830 DOI: 10.3389/fmicb.2021.716522] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/13/2021] [Indexed: 11/20/2022] Open
Abstract
Common scab of potato causes important economic losses worldwide following the development of necrotic lesions on tubers. In this study, the genomes of 14 prevalent scab-causing Streptomyces spp. isolated from Prince Edward Island, one of the most important Canadian potato production areas, were sequenced and annotated. Their phylogenomic affiliation was determined, their pan-genome was characterized, and pathogenic determinants involved in their virulence, ranging from weak to aggressive, were compared. 13 out of 14 strains clustered with Streptomyces scabiei, while the last strain clustered with Streptomyces acidiscabies. The toxicogenic and colonization genomic regions were compared, and while some atypical gene organizations were observed, no clear correlation with virulence was observed. The production of the phytotoxin thaxtomin A was also quantified and again, contrary to previous reports in the literature, no clear correlation was found between the amount of thaxtomin A secreted, and the virulence observed. Although no significant differences were observed when comparing the presence/absence of the main virulence factors among the strains of S. scabiei, a distinct profile was observed for S. acidiscabies. Several mutations predicted to affect the functionality of some virulence factors were identified, including one in the bldA gene that correlates with the absence of thaxtomin A production despite the presence of the corresponding biosynthetic gene cluster in S. scabiei LBUM 1485. These novel findings obtained using a large number of scab-causing Streptomyces strains are challenging some assumptions made so far on Streptomyces’ virulence and suggest that other factors, yet to be characterized, are also key contributors.
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Affiliation(s)
- Cindy Hudec
- Department of Biology, Université de Moncton, Moncton, NB, Canada
| | - Adrien Biessy
- Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC, Canada
| | - Amy Novinscak
- Agassiz Research and Development Centre, Agriculture and Agri-Food Canada, Agassiz, BC, Canada
| | - Renée St-Onge
- Department of Biology, Université de Moncton, Moncton, NB, Canada
| | - Simon Lamarre
- Department of Biology, Université de Moncton, Moncton, NB, Canada
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-Universität Giessen, Giessen, Germany
| | - Martin Filion
- Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC, Canada
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12
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El-Mahdy R, Mahmoud R, Shrief R. Characterization of E. coli Phylogroups Causing Catheter-Associated Urinary Tract Infection. Infect Drug Resist 2021; 14:3183-3193. [PMID: 34429618 PMCID: PMC8378909 DOI: 10.2147/idr.s325770] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/28/2021] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Characterization of different uropathogenic E. coli (UPEC) phylogroups is crucial to understand pathogenesis of urinary tract infection (UTI). The objective of our study was to evaluate the antibiotic resistance pattern, biofilm formation and pathogenicity islands (PAIs) of UPEC phylogroups isolated from catheter-associated UTI (CAUTI) compared to community UTI (Com-UTI). PATIENTS AND METHODS This study included 90 UPEC strains recovered from CAUTI and Com-UTI. Antimicrobial susceptibility was tested by the Kirby-Bauer method and extended spectrum beta-lactamase (ESBL) production was confirmed using the combined disk. The biofilm formation was tested using the microtiter plate assay. Main E. coli phylogroups (A, B1, B2 and D) were detected by multiplex PCR and 2 multiplex PCR detected the 8 PAIs. RESULTS Antibiotic resistance of UPEC strains showed a similar high resistance in CAUTI and Com-UTI. Isolates from CAUTI significantly produced biofilm higher than Com-UTI strains (68.9% vs 44.4%). In CAUTI and Com-UTI isolates, phylogroup A was the commonest (53.3% vs 48.9%, respectively). PAI IV536 was the most common in the strains from CAUTI (71.1%) and Com-UTI (73.3%). No significant relationship was detected between the studied characters and different phylogroups except the significant resistance to cefotaxime, ceftazidime and aztreonam among phylogroups from CAUTI isolates. CONCLUSION Increased antibiotic resistance and ESBLs were detected in UPEC strains from CAUTI and Com-UTI. The strains from CAUTI significantly produced biofilm higher than Com-UTI strains. Phylogroup A was the predominate phylogroup and PAI IV536 was the most prevalent marker in all phylogroups from both types of UTI.
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Affiliation(s)
- Rasha El-Mahdy
- Medical Microbiology and Immunology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Rasha Mahmoud
- Internal Medicine Department, Nephrology and Dialysis Unit, Mansoura University, Mansoura, Egypt
| | - Raghdaa Shrief
- Medical Microbiology and Immunology Department, Faculty of Medicine, Damietta University, Damietta, Egypt
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Sharafutdinov I, Backert S, Tegtmeyer N. The Helicobacter pylori type IV secretion system upregulates epithelial cortactin expression by a CagA- and JNK-dependent pathway. Cell Microbiol 2021; 23:e13376. [PMID: 34197673 DOI: 10.1111/cmi.13376] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 06/18/2021] [Accepted: 06/28/2021] [Indexed: 12/11/2022]
Abstract
Cortactin represents an important actin-binding factor, which controls actin-cytoskeletal remodelling in host cells. In this way, cortactin has been shown to exhibit crucial functions both for cell movement and tumour cell invasion. In addition, the cortactin gene cttn is amplified in various cancer types of humans. Helicobacter pylori is the causative agent of multiple gastric diseases and represents a significant risk factor for the development of gastric adenocarcinoma. It has been repeatedly shown that H. pylori manipulates cancer-related signal transduction events in infected gastric epithelial cells such as the phosphorylation status of cortactin. In fact, H. pylori modifies the activity of cortactin's binding partners to stimulate changes in the actin-cytoskeleton, cell adhesion and motility. Here we show that H. pylori infection of cultured AGS and Caco-2 cells for 24-48 hr leads to the overexpression of cortactin by 2-3 fold at the protein level. We demonstrate that this activity requires the integrity of the type IV secretion system (T4SS) encoded by the cag pathogenicity island (cagPAI) as well as the translocated effector protein CagA. We further show that ectopic expression of CagA is sufficient to stimulate cortactin overexpression. Furthermore, phosphorylation of CagA at the EPIYA-repeat region is not required, suggesting that this CagA activity proceeds in a phosphorylation-independent fashion. Inhibitor studies further demonstrate that the involved signalling pathway comprises the mitogen-activated protein kinase JNK (c-Jun N-terminal kinase), but not ERK1/2 or p38. Taken together, using H. pylori as a model system, this study discovered a previously unrecognised cortactin activation cascade by a microbial pathogen. We suggest that H. pylori targets cortactin to manipulate the cellular architecture and epithelial barrier functions that can impact gastric cancer development. TAKE AWAYS: Helicobacter pylori infection induces overexpression of cortactin at the protein level Cortactin upregulation requires the T4SS and effector protein CagA Ectopic expression of CagA is sufficient to stimulate cortactin overexpression Overexpression of cortactin proceeds CagA phosphorylation-independent The involved host cell signalling pathway comprises the MAP kinase JNK.
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Affiliation(s)
- Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, 91058, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, 91058, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, 91058, Germany
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Robinson L, Liaw J, Omole Z, Xia D, van Vliet AHM, Corcionivoschi N, Hachani A, Gundogdu O. Bioinformatic Analysis of the Campylobacter jejuni Type VI Secretion System and Effector Prediction. Front Microbiol 2021; 12:694824. [PMID: 34276628 PMCID: PMC8285248 DOI: 10.3389/fmicb.2021.694824] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/07/2021] [Indexed: 12/30/2022] Open
Abstract
The Type VI Secretion System (T6SS) has important roles relating to bacterial antagonism, subversion of host cells, and niche colonisation. Campylobacter jejuni is one of the leading bacterial causes of human gastroenteritis worldwide and is a commensal coloniser of birds. Although recently discovered, the T6SS biological functions and identities of its effectors are still poorly defined in C. jejuni. Here, we perform a comprehensive bioinformatic analysis of the C. jejuni T6SS by investigating the prevalence and genetic architecture of the T6SS in 513 publicly available genomes using C. jejuni 488 strain as reference. A unique and conserved T6SS cluster associated with the Campylobacter jejuni Integrated Element 3 (CJIE3) was identified in the genomes of 117 strains. Analyses of the T6SS-positive 488 strain against the T6SS-negative C. jejuni RM1221 strain and the T6SS-positive plasmid pCJDM202 carried by C. jejuni WP2-202 strain defined the “T6SS-containing CJIE3” as a pathogenicity island, thus renamed as Campylobacter jejuni Pathogenicity Island-1 (CJPI-1). Analysis of CJPI-1 revealed two canonical VgrG homologues, CJ488_0978 and CJ488_0998, harbouring distinct C-termini in a genetically variable region downstream of the T6SS operon. CJPI-1 was also found to carry a putative DinJ-YafQ Type II toxin-antitoxin (TA) module, conserved across pCJDM202 and the genomic island CJIE3, as well as several open reading frames functionally predicted to encode for nucleases, lipases, and peptidoglycan hydrolases. This comprehensive in silico study provides a framework for experimental characterisation of T6SS-related effectors and TA modules in C. jejuni.
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Affiliation(s)
- Luca Robinson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Janie Liaw
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Zahra Omole
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Dong Xia
- Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Arnoud H M van Vliet
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Nicolae Corcionivoschi
- Bacteriology Branch, Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, United Kingdom.,Bioengineering of Animal Science Resources, Banat University of Agricultural Sciences and Veterinary Medicine - King Michael the I of Romania, Timisoara, Romania
| | - Abderrahman Hachani
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Yu F, Cienfuegos-Gallet AV, Cunningham MH, Jin Y, Wang B, Kreiswirth BN, Chen L. Molecular Evolution and Adaptation of Livestock-Associated Methicillin-Resistant Staphylococcus aureus (LA-MRSA) Sequence Type 9. mSystems 2021; 6:e0049221. [PMID: 34156294 DOI: 10.1128/mSystems.00492-21] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) sequence type 9 (ST9) has emerged and disseminated in Asia. It is associated with colonization or infection in both humans and animal hosts; however, the genetic factors underpinning its adaptation to animal and human population remain to be determined. Here, we conducted a genomic analysis of 191 ST9 S. aureus genomes collected from 12 different countries, including 174 genomes retrieved from public databases and 17 sequenced in this study. In silico spa typing, staphylococcal cassette chromosome mec (SCCmec) typing, and antimicrobial resistance and virulence gene mining were conducted, and the temporal phylogenetic signal was assessed by Bayesian inference. Our results point toward a human methicillin-susceptible S. aureus (MSSA) origin of ST9 that evolved approximately 2 centuries ago. Three major genetic events occurred during ST9 host shift from human to animals: the loss of the immune evasion cluster genes (scn, chp, and sak), which were reported to contribute to virulence in human infections, the acquisition of the SaPIbov4-like element-encoding vwb gene, which is an animal-specific virulence factor responsible for the clotting of animal plasma, and the acquisition of antibiotic resistance genes, including SCCmec, quinolone resistance-determining region (QRDR) mutations, and a multidrug resistance genetic element (MDRST9). Evidence of direct transmission of animal-adapted strains to human hosts also suggest that transmission could potentially reshape the resistance and virulence genetic pool in these isolates. The rapid clonal expansion of MDR ST9 strains in mainland China and Taiwan highlights the increasing need for effective surveillance of antibiotic consumption in animal husbandry to control antimicrobial resistance spread. IMPORTANCEStaphylococcus aureus sequence type 9 (ST9) is the main LA-MRSA clone spreading in the Asian continent. It can colonize and cause mild to severe infections both in animal and humans. Previous work described its genotypic characteristics; however, the molecular history of global spread of ST9 strains remains largely unclear. We conducted a detailed analysis of genomic evolution of global ST9 strains and identified key genetic changes associated with its adaptation to specific hosts. Our results suggest that the ST9 clone originated from human-adapted strains, which lost genes related to the evasion of the immune system. The introduction of ST9 strains in animal populations was aligned with the acquisition of animal-specific virulent factors and mobile elements harboring multiple antimicrobial resistance genes, especially in isolates from mainland China and Taiwan.
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Knorr J, Sharafutdinov I, Fiedler F, Soltan Esmaeili D, Rohde M, Rottner K, Backert S, Tegtmeyer N. Cortactin Is Required for Efficient FAK, Src and Abl Tyrosine Kinase Activation and Phosphorylation of Helicobacter pylori CagA. Int J Mol Sci 2021; 22:ijms22116045. [PMID: 34205064 PMCID: PMC8199859 DOI: 10.3390/ijms22116045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 12/11/2022] Open
Abstract
Cortactin is a well-known regulatory protein of the host actin cytoskeleton and represents an attractive target of microbial pathogens like Helicobacter pylori. H. pylori manipulates cortactin's phosphorylation status by type-IV secretion-dependent injection of its virulence protein CagA. Multiple host tyrosine kinases, like FAK, Src, and Abl, are activated during infection, but the pathway(s) involved is (are) not yet fully established. Among them, Src and Abl target CagA and stimulate tyrosine phosphorylation of the latter at its EPIYA-motifs. To investigate the role of cortactin in more detail, we generated a CRISPR/Cas9 knockout of cortactin in AGS gastric epithelial cells. Surprisingly, we found that FAK, Src, and Abl kinase activities were dramatically downregulated associated with widely diminished CagA phosphorylation in cortactin knockout cells compared to the parental control. Together, we report here a yet unrecognized cortactin-dependent signaling pathway involving FAK, Src, and Abl activation, and controlling efficient phosphorylation of injected CagA during infection. Thus, the cortactin status could serve as a potential new biomarker of gastric cancer development.
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Affiliation(s)
- Jakob Knorr
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Florian Fiedler
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Delara Soltan Esmaeili
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
| | - Klemens Rottner
- Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
- Correspondence:
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Auvray F, Perrat A, Arimizu Y, Chagneau CV, Bossuet-Greif N, Massip C, Brugère H, Nougayrède JP, Hayashi T, Branchu P, Ogura Y, Oswald E. Insights into the acquisition of the pks island and production of colibactin in the Escherichia coli population. Microb Genom 2021; 7:000579. [PMID: 33961542 PMCID: PMC8209727 DOI: 10.1099/mgen.0.000579] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 04/11/2021] [Indexed: 01/19/2023] Open
Abstract
The pks island codes for the enzymes necessary for synthesis of the genotoxin colibactin, which contributes to the virulence of Escherichia coli strains and is suspected of promoting colorectal cancer. From a collection of 785 human and bovine E. coli isolates, we identified 109 strains carrying a highly conserved pks island, mostly from phylogroup B2, but also from phylogroups A, B1 and D. Different scenarios of pks acquisition were deduced from whole genome sequence and phylogenetic analysis. In the main scenario, pks was introduced and stabilized into certain sequence types (STs) of the B2 phylogroup, such as ST73 and ST95, at the asnW tRNA locus located in the vicinity of the yersiniabactin-encoding High Pathogenicity Island (HPI). In a few B2 strains, pks inserted at the asnU or asnV tRNA loci close to the HPI and occasionally was located next to the remnant of an integrative and conjugative element. In a last scenario specific to B1/A strains, pks was acquired, independently of the HPI, at a non-tRNA locus. All the pks-positive strains except 18 produced colibactin. Sixteen strains contained mutations in clbB or clbD, or a fusion of clbJ and clbK and were no longer genotoxic but most of them still produced low amounts of potentially active metabolites associated with the pks island. One strain was fully metabolically inactive without pks alteration, but colibactin production was restored by overexpressing the ClbR regulator. In conclusion, the pks island is not restricted to human pathogenic B2 strains and is more widely distributed in the E. coli population, while preserving its functionality.
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Affiliation(s)
- Frédéric Auvray
- IRSD, INSERM, Université de Toulouse, INRAE, ENVT, UPS, Toulouse, France
| | - Alexandre Perrat
- IRSD, INSERM, Université de Toulouse, INRAE, ENVT, UPS, Toulouse, France
| | - Yoko Arimizu
- Department of Bacteriology, Kyushu University, Fukuoka, Japan
| | | | | | - Clémence Massip
- IRSD, INSERM, Université de Toulouse, INRAE, ENVT, UPS, Toulouse, France
- CHU Toulouse, Hôpital Purpan, Service de Bactériologie-Hygiène, Toulouse, France
| | - Hubert Brugère
- IRSD, INSERM, Université de Toulouse, INRAE, ENVT, UPS, Toulouse, France
| | | | - Tetsuya Hayashi
- Department of Bacteriology, Kyushu University, Fukuoka, Japan
| | - Priscilla Branchu
- IRSD, INSERM, Université de Toulouse, INRAE, ENVT, UPS, Toulouse, France
| | - Yoshitoshi Ogura
- Division of Microbiology, Department of Infectious Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan
| | - Eric Oswald
- IRSD, INSERM, Université de Toulouse, INRAE, ENVT, UPS, Toulouse, France
- CHU Toulouse, Hôpital Purpan, Service de Bactériologie-Hygiène, Toulouse, France
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Travis BA, Ramsey KM, Prezioso SM, Tallo T, Wandzilak JM, Hsu A, Borgnia M, Bartesaghi A, Dove SL, Brennan RG, Schumacher MA. Structural Basis for Virulence Activation of Francisella tularensis. Mol Cell 2021; 81:139-152.e10. [PMID: 33217319 PMCID: PMC7959165 DOI: 10.1016/j.molcel.2020.10.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/25/2020] [Accepted: 10/22/2020] [Indexed: 01/25/2023]
Abstract
The bacterium Francisella tularensis (Ft) is one of the most infectious agents known. Ft virulence is controlled by a unique combination of transcription regulators: the MglA-SspA heterodimer, PigR, and the stress signal, ppGpp. MglA-SspA assembles with the σ70-associated RNAP holoenzyme (RNAPσ70), forming a virulence-specialized polymerase. These factors activate Francisella pathogenicity island (FPI) gene expression, which is required for virulence, but the mechanism is unknown. Here we report FtRNAPσ70-promoter-DNA, FtRNAPσ70-(MglA-SspA)-promoter DNA, and FtRNAPσ70-(MglA-SspA)-ppGpp-PigR-promoter DNA cryo-EM structures. Structural and genetic analyses show MglA-SspA facilitates σ70 binding to DNA to regulate virulence and virulence-enhancing genes. Our Escherichia coli RNAPσ70-homodimeric EcSspA structure suggests this is a general SspA-transcription regulation mechanism. Strikingly, our FtRNAPσ70-(MglA-SspA)-ppGpp-PigR-DNA structure reveals ppGpp binding to MglA-SspA tethers PigR to promoters. PigR in turn recruits FtRNAP αCTDs to DNA UP elements. Thus, these studies unveil a unique mechanism for Ft pathogenesis involving a virulence-specialized RNAP that employs two (MglA-SspA)-based strategies to activate virulence genes.
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Affiliation(s)
- Brady A Travis
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kathryn M Ramsey
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Cell and Molecular Biology and Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - Samantha M Prezioso
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas Tallo
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jamie M Wandzilak
- Department of Cell and Molecular Biology and Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - Allen Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Mario Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Alberto Bartesaghi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA; Department of Computer Science, Duke University, Durham, NC 27708, USA
| | - Simon L Dove
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Richard G Brennan
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA.
| | - Maria A Schumacher
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA.
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Skoog EC, Martin ME, Barrozo RM, Hansen LM, Cai LP, Lee SJ, Benoun JM, McSorley SJ, Solnick JV. Maintenance of Type IV Secretion Function During Helicobacter pylori Infection in Mice. mBio 2020; 11:e03147-20. [PMID: 33443133 DOI: 10.1128/mBio.03147-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The Helicobacter pylori type IV secretion system (T4SS) encoded on the cag pathogenicity island (cagPAI) secretes the CagA oncoprotein and other effectors into the gastric epithelium. During murine infection, T4SS function is lost in an immune-dependent manner, typically as a result of in-frame recombination in the middle repeat region of cagY, though single nucleotide polymorphisms (SNPs) in cagY or in other essential genes may also occur. Loss of T4SS function also occurs in gerbils, nonhuman primates, and humans, suggesting that it is biologically relevant and not simply an artifact of the murine model. Here, we sought to identify physiologically relevant conditions under which T4SS function is maintained in the murine model. We found that loss of H. pylori T4SS function in mice was blunted by systemic Salmonella coinfection and completely eliminated by dietary iron restriction. Both have epidemiologic parallels in humans, since H. pylori strains from individuals in developing countries, where iron deficiency and systemic infections are common, are also more often cagPAI+ than strains from developed countries. These results have implications for our fundamental understanding of the cagPAI and also provide experimental tools that permit the study of T4SS function in the murine model.IMPORTANCE The type IV secretion system (T4SS) is the major Helicobacter pylori virulence factor, though its function is lost during murine infection. Loss of function also occurs in gerbils and in humans, suggesting that it is biologically relevant, but the conditions under which T4SS regulation occurs are unknown. Here, we found that systemic coinfection with Salmonella and iron deprivation each promote retention of T4SS function. These results improve our understanding of the cag pathogenicity island (cagPAI) and provide experimental tools that permit the study of T4SS function in the murine model.
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Fischer W, Tegtmeyer N, Stingl K, Backert S. Four Chromosomal Type IV Secretion Systems in Helicobacter pylori: Composition, Structure and Function. Front Microbiol 2020; 11:1592. [PMID: 32754140 PMCID: PMC7366825 DOI: 10.3389/fmicb.2020.01592] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/18/2020] [Indexed: 12/14/2022] Open
Abstract
The pathogenic bacterium Helicobacter pylori is genetically highly diverse and a major risk factor for the development of peptic ulcer disease and gastric adenocarcinoma in humans. During evolution, H. pylori has acquired multiple type IV secretion systems (T4SSs), and then adapted for various purposes. These T4SSs represent remarkable molecular transporter machines, often associated with an extracellular pilus structure present in many bacteria, which are commonly composed of multiple structural proteins spanning the inner and outer membranes. By definition, these T4SSs exhibit central functions mediated through the contact-dependent conjugative transfer of mobile DNA elements, the contact-independent release and uptake of DNA into and from the extracellular environment as well as the secretion of effector proteins in mammalian host target cells. In recent years, numerous features on the molecular functionality of these T4SSs were disclosed. H. pylori encodes up to four T4SSs on its chromosome, namely the Cag T4SS present in the cag pathogenicity island (cagPAI), the ComB system, as well as the Tfs3 and Tfs4 T4SSs, some of which exhibit unique T4SS functions. The Cag T4SS facilitates the delivery of the CagA effector protein and pro-inflammatory signal transduction through translocated ADP-heptose and chromosomal DNA, while various structural pilus proteins can target host cell receptors such as integrins or TLR5. The ComB apparatus mediates the import of free DNA from the extracellular milieu, whereas Tfs3 may accomplish the secretion or translocation of effector protein CtkA. Both Tfs3 and Tfs4 are furthermore presumed to act as conjugative DNA transfer machineries due to the presence of tyrosine recombinases with cognate recognition sequences, conjugational relaxases, and potential origins of transfer (oriT) found within the tfs3 and tfs4 genome islands. In addition, some extrachromosomal plasmids, transposons and phages have been discovered in multiple H. pylori isolates. The genetic exchange mediated by DNA mobilization events of chromosomal genes and plasmids combined with recombination events could account for much of the genetic diversity found in H. pylori. In this review, we highlight our current knowledge on the four T4SSs and the involved mechanisms with consequences for H. pylori adaptation to the hostile environment in the human stomach.
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Affiliation(s)
- Wolfgang Fischer
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Medizinische Fakultät, LMU München, Munich, Germany
| | - Nicole Tegtmeyer
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Kerstin Stingl
- Department of Biological Safety, National Reference Laboratory for Campylobacter, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Steffen Backert
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Canzian F, Rizzato C, Obazee O, Stein A, Flores-Luna L, Camorlinga-Ponce M, Mendez-Tenorio A, Vivas J, Trujillo E, Jang H, Chen W, Kasamatsu E, Bravo MM, Torres J, Muñoz N, Kato I. Genetic polymorphisms in the cag pathogenicity island of Helicobacter pylori and risk of stomach cancer and high-grade premalignant gastric lesions. Int J Cancer 2020; 147:2437-2445. [PMID: 32363734 DOI: 10.1002/ijc.33032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/01/2020] [Accepted: 04/09/2020] [Indexed: 12/12/2022]
Abstract
Helicobacter pylori (Hp) infects the stomach of about half of the human population and is strongly associated with the risk of gastric cancer (GC) and its premalignant precursors. The cag pathogenicity island (cagPAI) is a region of the Hp genome encoding for key molecular machinery involved in the infection process. Following a sequencing study, we selected 50 genetic polymorphisms located in seven cagPAI genes and tested their associations with the risk of advanced gastric premalignant lesions and GC in 1220 subjects from various Latin American populations showing the whole spectrum of phenotypes from gastritis to GC. We found that three polymorphisms of cagA are associated with the risk of advanced gastric premalignant lesions (incomplete intestinal metaplasia [ie, Type 2 and 3] or dysplasia), and that six polymorphisms located in cagA, cagL and cagI were associated with risk of GC. When corrected for multiple testing none of the associations were statistically significant. However, scores built by integrating the individual polymorphisms were significantly associated with the risk of advanced gastric premalignant lesions and GC. These results have the potential of establishing markers for risk stratification in the general population, in view of targeting Hp eradication to high-risk population groups.
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Affiliation(s)
- Federico Canzian
- Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Cosmeri Rizzato
- Department of Translation Research and of New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Ofure Obazee
- Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Angelika Stein
- Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Lourdes Flores-Luna
- Center for Public Health Research, National Institute of Public Health, Cuernavaca, Morelos, Mexico
| | - Margarita Camorlinga-Ponce
- Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatría, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Alfonso Mendez-Tenorio
- Laboratorio de Biotecnología y Bioinformática Genómica, ENCB, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Jorge Vivas
- Cancer Control Center of the Tachira State, San Cristobal, Venezuela
| | - Esperanza Trujillo
- Grupo de Investigación en Biología del Cáncer, Instituto Nacional de Cancerología, Bogotá, Colombia
| | - Hyejong Jang
- Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Wei Chen
- Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Elena Kasamatsu
- Instituto de Investigaciones en Ciencias de la Salud, National University of Asunción, Asunción, Paraguay
| | - Maria Mercedes Bravo
- Grupo de Investigación en Biología del Cáncer, Instituto Nacional de Cancerología, Bogotá, Colombia
| | - Javier Torres
- Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatría, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Nubia Muñoz
- Cancer Institute of Colombia, Bogotá, Colombia
| | - Ikuko Kato
- Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan, USA
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Bustamante P, Vidal R. Repertoire and Diversity of Toxin - Antitoxin Systems of Crohn's Disease-Associated Adherent-Invasive Escherichia coli. New Insight of T his Emergent E. coli Pathotype. Front Microbiol 2020; 11:807. [PMID: 32477289 PMCID: PMC7232551 DOI: 10.3389/fmicb.2020.00807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 04/06/2020] [Indexed: 12/13/2022] Open
Abstract
Adherent-invasive Escherichia coli (AIEC) corresponds to an E. coli pathovar proposed as a possible agent trigger associated to Crohn's disease. It is characterized for its capacity to adhere and to invade epithelial cells, and to survive and replicate inside macrophages. Mechanisms that allow intestinal epithelium colonization, and host factors that favor AIEC persistence have been partly elucidated. However, bacterial factors involved in AIEC persistence are currently unknown. Toxin-antitoxin (TA) systems are recognized elements involved in bacterial persistence, in addition to have a role in stabilization of mobile genetic elements and stress response. The aim of this study was to elucidate the repertoire and diversity of TA systems in the reference AIEC NRG857c strain and to compare it with AIEC strains whose genomes are available at databases. In addition, toxin expression levels under in vitro stress conditions found by AIEC through the intestine and within the macrophage were measured. Our results revealed that NRG857c encodes at least 33 putative TA systems belonging to types I, II, IV, and V, distributed around all the chromosome, and some in close proximity to genomic islands. A TA toxin repertoire marker of the pathotype was not found and the repertoire of 33 TA toxin genes described here was exclusive of the reference strains, NRG857c and LF82. Most toxin genes were upregulated in the presence of bile salts and acidic pH, as well as within the macrophage. However, different transcriptional responses were detected between reference strains (NRG857c and HM605), recalling the high diversity associated to this pathotype. To our knowledge this is the first analysis of TA systems associated to AIEC and it has revealed new insight associated to this emergent E. coli pathotype.
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Affiliation(s)
- Paula Bustamante
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Roberto Vidal
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Instituto Milenio de Inmunología e Inmunoterapia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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Lee YA, Yang PY, Huang SC. Characterization, Phylogeny, and Genome Analyses of Nonpathogenic Xanthomonas campestris Strains Isolated from Brassica Seeds. Phytopathology 2020; 110:981-988. [PMID: 32167850 DOI: 10.1094/phyto-08-19-0319-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Xanthomonads were detected by using the Xan-D(CCF) medium from the brassica seeds, and their pathogenicity was determined by plant inoculation tests. It was found that some seed lots were infested with Xanthomonas campestris pv. campestris, some with X. campestris pv. raphani, and some with nonpathogenic xanthomonads. The nonpathogenic xanthomonad strains were identified as X. campestris, and the multilocus sequence analysis showed that the nonpathogenic X. campestris strains were grouped together with pathogenic X. campestris, but not with nonpathogenic strains of X. arboricola. In addition, all isolated X. campestris pv. campestris and X. campestris pv. raphani strains were positive in the hrpF-PCR, but the nonpathogenic strains were negative. It was further found that nonpathogenic X. campestris strain nE1 does not contain the entire pathogenicity island (hrp gene cluster; type III secretion system) and all type III effector protein genes based on the whole genome sequence analyses. The nonpathogenic X. campestris strain nE1 could acquire the entire pathogenicity island from the endemic X. campestris pv. campestris and X. campestris pv. raphani strains by conjugation, but type III effector genes were not cotransferred. The studies showed that the nonpathogenic X. campestris strains indeed exist on the brassica seeds, but it could be differentiated by the PCR assays on the hrp and type III effector genes. Nevertheless, the nonpathogenic X. campestris strains cannot be ignored because they may be potential gene resources to increase genetic diversity in the endemic pathogenic X. campestris pv. campestris and X. campestris pv. raphani strains.
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Affiliation(s)
- Yung-An Lee
- Department of Life Science, Fu Jen Catholic University, Xin-Zhuang District, New Taipei City, Taiwan, Republic of China
| | - Pei-Yu Yang
- Department of Life Science, Fu Jen Catholic University, Xin-Zhuang District, New Taipei City, Taiwan, Republic of China
| | - Shau-Chang Huang
- Department of Life Science, Fu Jen Catholic University, Xin-Zhuang District, New Taipei City, Taiwan, Republic of China
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Lerminiaux NA, MacKenzie KD, Cameron ADS. Salmonella Pathogenicity Island 1 (SPI-1): The Evolution and Stabilization of a Core Genomic Type Three Secretion System. Microorganisms 2020; 8:microorganisms8040576. [PMID: 32316180 PMCID: PMC7232297 DOI: 10.3390/microorganisms8040576] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/10/2020] [Accepted: 04/10/2020] [Indexed: 11/16/2022] Open
Abstract
Salmonella Pathogenicity Island 1 (SPI-1) encodes a type three secretion system (T3SS), effector proteins, and associated transcription factors that together enable invasion of epithelial cells in animal intestines. The horizontal acquisition of SPI-1 by the common ancestor of all Salmonella is considered a prime example of how gene islands potentiate the emergence of new pathogens with expanded niche ranges. However, the evolutionary history of SPI-1 has attracted little attention. Here, we apply phylogenetic comparisons across the family Enterobacteriaceae to examine the history of SPI-1, improving the resolution of its boundaries and unique architecture by identifying its composite gene modules. SPI-1 is located between the core genes fhlA and mutS, a hotspot for the gain and loss of horizontally acquired genes. Despite the plasticity of this locus, SPI-1 demonstrates stable residency of many tens of millions of years in a host genome, unlike short-lived homologous T3SS and effector islands including Escherichia ETT2, Yersinia YSA, Pantoea PSI-2, Sodalis SSR2, and Chromobacterium CPI-1. SPI-1 employs a unique series of regulatory switches, starting with the dedicated transcription factors HilC and HilD, and flowing through the central SPI-1 regulator HilA. HilA is shared with other T3SS, but HilC and HilD may have their evolutionary origins in Salmonella. The hilA, hilC, and hilD gene promoters are the most AT-rich DNA in SPI-1, placing them under tight control by the transcriptional repressor H-NS. In all Salmonella lineages, these three promoters resist amelioration towards the genomic average, ensuring strong repression by H-NS. Hence, early development of a robust and well-integrated regulatory network may explain the evolutionary stability of SPI-1 compared to T3SS gene islands in other species.
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Affiliation(s)
- Nicole A. Lerminiaux
- Department of Biology, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada; (N.A.L.); (K.D.M.)
- Institute for Microbial Systems and Society, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada
| | - Keith D. MacKenzie
- Department of Biology, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada; (N.A.L.); (K.D.M.)
- Institute for Microbial Systems and Society, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada
| | - Andrew D. S. Cameron
- Department of Biology, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada; (N.A.L.); (K.D.M.)
- Institute for Microbial Systems and Society, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada
- Correspondence:
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Banaszkiewicz S, Calland JK, Mourkas E, Sheppard SK, Pascoe B, Bania J. Genetic Diversity of Composite Enterotoxigenic Staphylococcus epidermidis Pathogenicity Islands. Genome Biol Evol 2020; 11:3498-3509. [PMID: 31769803 PMCID: PMC6931896 DOI: 10.1093/gbe/evz259] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2019] [Indexed: 02/07/2023] Open
Abstract
The only known elements encoding enterotoxins in coagulase-negative staphylococci are composite Staphylococcus epidermidis pathogenicity islands (SePIs), including SePI and S. epidermidis composite insertion (SeCI) regions. We investigated 1545 Staphylococcus spp. genomes using whole-genome MLST, and queried them for genes of staphylococcal enterotoxin family and for 29 ORFs identified in prototype SePI from S. epidermidis FRI909. Enterotoxin-encoding genes were identified in 97% of Staphylococcus aureus genomes, in one Staphylococcus argenteus genome and in nine S. epidermidis genomes. All enterotoxigenic S. epidermidis strains carried composite SePI, encoding sec and sel enterotoxin genes, and were assigned to a discrete wgMLST cluster also containing genomes with incomplete islands located in the same region as complete SePI in enterotoxigenic strains. Staphylococcus epidermidis strains without SeCI and SePI genes, and strains with complete SeCI and no SePI genes were identified but no strains were found to carry only SePI and not SeCI genes. The systematic differences between SePI and SeCI regions imply a lineage-specific pattern of inheritance and support independent acquisition of the two elements in S. epidermidis. We provided evidence of reticulate evolution of mobile elements that contain elements with different putative ancestry, including composite SePI that contains genes found in other coagulase-negative staphylococci (SeCI), as well as in S. aureus (SePI-like elements). We conclude that SePI-associated elements present in nonenterotoxigenic S. epidermidis represent a scaffold associated with acquisition of virulence-associated genes. Gene exchange between S. aureus and S. epidermidis may promote emergence of new pathogenic S. epidermidis clones.
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Affiliation(s)
- Sylwia Banaszkiewicz
- Department of Food Hygiene and Consumer Health Protection, Wrocław University of Environmental and Life Sciences, Poland
| | | | | | | | - Ben Pascoe
- The Milner Centre for Evolution, University of Bath, United Kingdom
| | - Jacek Bania
- Department of Food Hygiene and Consumer Health Protection, Wrocław University of Environmental and Life Sciences, Poland
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Zhao Y, Li G, Yao XY, Lu SG, Wang J, Shen XD, Li M. The Impact of SsPI-1 Deletion on Streptococcus suis Virulence. Pathogens 2019; 8:pathogens8040287. [PMID: 31817637 PMCID: PMC6963714 DOI: 10.3390/pathogens8040287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 01/26/2023] Open
Abstract
(1) Background: Streptococcus suis is an important zoonotic pathogen that infects pigs and can occasionally cause life-threatening systemic infections in humans. Two large-scale outbreaks of streptococcal toxic shock-like syndrome in China suggest that the pathogenicity of S. suis has been changing in recent years. Genetic analysis revealed the presence of a chromosomal pathogenicity island (PAI) designated SsPI-1 in Chinese epidemic S. suis strains. The purpose of this study is to define the role of SsPI-1 in the virulence of S. suis. (2) Methods: A SsPI-1 deletion mutant was compared to the wild-type strain regarding the ability to attach to epithelial cells, to cause host disease and mortality, and to stimulate host immune response in experimental infection of piglets. (3) Results: Deletion of SsPI-1 significantly reduces adherence of S. suis to epithelial cells and abolishes the lethality of the wild-type strain in piglets. The SsPI-1 mutant causes no significant pathological lesions and exhibits an impaired ability to induce proinflammatory cytokine production. (4) Conclusions: Deletion of the SsPI-1 PAI attenuates the virulence of this pathogen. We conclude that SsPI-1 is a critical contributor to the evolution of virulence in epidemic S. suis.
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Affiliation(s)
- Yan Zhao
- Department of Microbiology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Key Laboratory of Microbial Engineering under the Educational Committee in Chongqing, Chongqing 400038, China; (Y.Z.); (G.L.); (S.-G.L.); (J.W.)
| | - Gang Li
- Department of Microbiology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Key Laboratory of Microbial Engineering under the Educational Committee in Chongqing, Chongqing 400038, China; (Y.Z.); (G.L.); (S.-G.L.); (J.W.)
| | - Xin-Yue Yao
- Jinling Hospital Research Institute of Clinical Laboratory Medicine, Nanjing University, School of Medicine, Nanjing 210002, China;
| | - Shu-Guang Lu
- Department of Microbiology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Key Laboratory of Microbial Engineering under the Educational Committee in Chongqing, Chongqing 400038, China; (Y.Z.); (G.L.); (S.-G.L.); (J.W.)
| | - Jing Wang
- Department of Microbiology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Key Laboratory of Microbial Engineering under the Educational Committee in Chongqing, Chongqing 400038, China; (Y.Z.); (G.L.); (S.-G.L.); (J.W.)
| | - Xiao-Dong Shen
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Chongqing 400038, China
- Correspondence: (M.L.); (X.-D.S.); Tel.: +86-23-68772241 (M.L.)
| | - Ming Li
- Department of Microbiology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Key Laboratory of Microbial Engineering under the Educational Committee in Chongqing, Chongqing 400038, China; (Y.Z.); (G.L.); (S.-G.L.); (J.W.)
- Correspondence: (M.L.); (X.-D.S.); Tel.: +86-23-68772241 (M.L.)
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Ekundayo TC, Okoh AI. Pathogenomics of Virulence Traits of Plesiomonas shigelloides That Were Deemed Inconclusive by Traditional Experimental Approaches. Front Microbiol 2018; 9:3077. [PMID: 30627119 PMCID: PMC6309461 DOI: 10.3389/fmicb.2018.03077] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 11/29/2018] [Indexed: 12/31/2022] Open
Abstract
One of the major challenges of modern medicine includes the failure of conventional protocols to characterize the pathogenicity of emerging pathogens. This is particularly apparent in the case of Plesiomonas shigelloides. Although a number of infections have been linked to this microorganism, experimental evidence of its virulence factors (VFs), obtained by traditional approaches, is somewhat inconclusive. Hence, it remains unclear whether P. shigelloides is a true or opportunistic one. In the current study, four publicly available whole-genome sequences of P. shigelloides (GN7, NCTC10360, 302-73, and LS1) were profiled using bioinformatics platforms to determine the putative candidate VFs to characterize the bacterial pathogenicity. Overall, 134 unique open reading frames (ORFs) were identified that were homologous or orthologous to virulence genes identified in other pathogens. Of these, 52.24% (70/134) were jointly shared by the strains. The numbers of strain-specific virulence traits were 4 in LS1; 7 in NCTC10360; 10 in 302-73; and 15 in GN7. The pathogenicity islands (PAIs) common to all the strains accounted for 24.07% ORFs. The numbers of PAIs exclusive to each strain were 8 in 302-73; 11 in NCTC10360; 14 in GN7; and 18 in LS1. A PAI encoding Vibrio cholerae ToxR-activated gene d protein was specific to 302-73, GN7, and NCTC10360 strains. Out of 33 antibiotic multi-resistance genes identified, 16 (48.48%) genes were intrinsic to all strains. Further, 17 (22.08%) of 77 antibiotic resistance islands were found in all the strains. Out of 23 identified distinct insertion sequences, 13 were only harbored by strain LS1. The number of intact prophages identified in the strains was 1 in GN7; 2 in 302-73; and 2 in NCTC10360. Further, 1 CRISPR element was identified in LS1; 2 in NCTC10360; and 8 in 302-73. Fifteen (78.95%) of 19 secretion systems and secretion effector variants were identified in all the strains. In conclusion, certain P. shigelloides strains might possess VFs associated with gastroenteritis and extraintestinal infections. However, the role of host factors in the onset of infections should not be undermined.
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Affiliation(s)
- Temitope C. Ekundayo
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, South Africa
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
- Department of Biological Sciences, University of Medical Sciences, Ondo City, Nigeria
| | - Anthony I. Okoh
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, South Africa
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
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Zhang Y, Jiang G, Ding Y, Loria R. Genetic background affects pathogenicity island function and pathogen emergence in Streptomyces. Mol Plant Pathol 2018; 19:1733-1741. [PMID: 29316196 PMCID: PMC6638181 DOI: 10.1111/mpp.12656] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/27/2017] [Accepted: 01/05/2018] [Indexed: 05/30/2023]
Abstract
With few exceptions, thaxtomin A (ThxA), a nitrated diketopiperazine, is the pathogenicity determinant for plant-pathogenic Streptomyces species. In Streptomyces scabiei (syn. S. scabies), the ThxA biosynthetic cluster is located within a 177-kb mobile pathogenicity island (PAI), called the toxicogenic region (TR). In S. turgidiscabies, the ThxA biosynthetic cluster is located within a 674-kb pathogenicity island (PAIst). The emergence of new plant pathogens occurs in this genus, but not frequently. This raises the question of whether the mobilization of these pathogenicity regions, through mating, is widespread and whether TR and PAIst can confer plant pathogenicity. We showed that ThxA biosynthetic clusters on TR and PAIst were transferred into strains from five non-pathogenic Streptomyces species through mating with S. scabiei and S. turgidiscabies. However, not all of the transconjugants produced ThxA and exhibited the virulence phenotype, indicating that the genetic background of the recipient strains affects the functionality of the ThxA biosynthetic cluster and therefore would be expected to affect the emergence of novel pathogenic Streptomyces species. Thxs have been patented as natural herbicides, but have yet to be commercialized. Our results also demonstrated the potential of the heterologous production of ThxA as a natural and biodegradable herbicide in non-pathogenic Streptomyces species.
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Affiliation(s)
- Yucheng Zhang
- Department of Plant PathologyUniversity of FloridaGainesvilleFL32611USA
| | - Guangde Jiang
- Department of Medicinal ChemistryUniversity of FloridaGainesvilleFL32610USA
| | - Yousong Ding
- Department of Medicinal ChemistryUniversity of FloridaGainesvilleFL32610USA
| | - Rosemary Loria
- Department of Plant PathologyUniversity of FloridaGainesvilleFL32611USA
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Severin GB, Ramliden MS, Hawver LA, Wang K, Pell ME, Kieninger AK, Khataokar A, O'Hara BJ, Behrmann LV, Neiditch MB, Benning C, Waters CM, Ng WL. Direct activation of a phospholipase by cyclic GMP-AMP in El Tor Vibrio cholerae. Proc Natl Acad Sci U S A 2018; 115:E6048-55. [PMID: 29891656 DOI: 10.1073/pnas.1801233115] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Second messengers are employed by all organisms to regulate fundamental behaviors, including biofilm formation, motility, metabolism, and pathogenesis in bacteria. We have identified a phospholipase in the El Tor Vibrio cholerae biotype, responsible for the current cholera pandemic, that is directly activated by the second messenger 3′, 3′-cyclic GMP-AMP (cGAMP). Discovery of this proteinaceous bacterial cGAMP effector sheds light on the functions and basic principles of cGAMP signaling. Both this phospholipase and the cGAMP synthase are encoded within the VSP-1 pathogenicity island, unique to the El Tor biotype, and our findings assign a biochemical function to VSP-1 that may contribute to the epidemiological success of El Tor V. cholerae. Sensing and responding to environmental changes is essential for bacteria to adapt and thrive, and nucleotide-derived second messengers are central signaling systems in this process. The most recently identified bacterial cyclic dinucleotide second messenger, 3′, 3′-cyclic GMP-AMP (cGAMP), was first discovered in the El Tor biotype of Vibrio cholerae. The cGAMP synthase, DncV, is encoded on the VSP-1 pathogenicity island, which is found in all El Tor isolates that are responsible for the current seventh pandemic of cholera but not in the classical biotype. We determined that unregulated production of DncV inhibits growth in El Tor V. cholerae but has no effect on the classical biotype. This cGAMP-dependent phenotype can be suppressed by null mutations in vc0178 immediately 5′ of dncV in VSP-1. VC0178 [renamed as cGAMP-activated phospholipase in Vibrio (CapV)] is predicted to be a patatin-like phospholipase, and coexpression of capV and dncV is sufficient to induce growth inhibition in classical V. cholerae and Escherichia coli. Furthermore, cGAMP binds to CapV and directly activates its hydrolase activity in vitro. CapV activated by cGAMP in vivo degrades phospholipids in the cell membrane, releasing 16:1 and 18:1 free fatty acids. Together, we demonstrate that cGAMP activates CapV phospholipase activity to target the cell membrane and suggest that acquisition of this second messenger signaling pathway may contribute to the emergence of the El Tor biotype as the etiological agent behind the seventh cholera pandemic.
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Skoog EC, Morikis VA, Martin ME, Foster GA, Cai LP, Hansen LM, Li B, Gaddy JA, Simon SI, Solnick JV. CagY-Dependent Regulation of Type IV Secretion in Helicobacter pylori Is Associated with Alterations in Integrin Binding. mBio 2018; 9:e00717-18. [PMID: 29764950 DOI: 10.1128/mBio.00717-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Strains of Helicobacter pylori that cause ulcer or gastric cancer typically express a type IV secretion system (T4SS) encoded by the cag pathogenicity island (cagPAI). CagY is an ortholog of VirB10 that, unlike other VirB10 orthologs, has a large middle repeat region (MRR) with extensive repetitive sequence motifs, which undergo CD4+ T cell-dependent recombination during infection of mice. Recombination in the CagY MRR reduces T4SS function, diminishes the host inflammatory response, and enables the bacteria to colonize at a higher density. Since CagY is known to bind human α5β1 integrin, we tested the hypothesis that recombination in the CagY MRR regulates T4SS function by modulating binding to α5β1 integrin. Using a cell-free microfluidic assay, we found that H. pylori binding to α5β1 integrin under shear flow is dependent on the CagY MRR, but independent of the presence of the T4SS pili, which are only formed when H. pylori is in contact with host cells. Similarly, expression of CagY in the absence of other T4SS genes was necessary and sufficient for whole bacterial cell binding to α5β1 integrin. Bacteria with variant cagY alleles that reduced T4SS function showed comparable reduction in binding to α5β1 integrin, although CagY was still expressed on the bacterial surface. We speculate that cagY-dependent modulation of H. pylori T4SS function is mediated by alterations in binding to α5β1 integrin, which in turn regulates the host inflammatory response so as to maximize persistent infection.IMPORTANCE Infection with H. pylori can cause peptic ulcers and is the most important risk factor for gastric cancer, the third most common cause of cancer death worldwide. The major H. pylori virulence factor that determines whether infection causes disease or asymptomatic colonization is the type IV secretion system (T4SS), a sort of molecular syringe that injects bacterial products into gastric epithelial cells and alters host cell physiology. We previously showed that recombination in CagY, an essential T4SS component, modulates the function of the T4SS. Here we found that these recombination events produce parallel changes in specific binding to α5β1 integrin, a host cell receptor that is essential for T4SS-dependent translocation of bacterial effectors. We propose that CagY-dependent binding to α5β1 integrin acts like a molecular rheostat that alters T4SS function and modulates the host immune response to promote persistent infection.
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Yuan CW, Liu WX, Hou JL, Zhang LG, Wang GQ. Prevalence of pathogenicity island ETT2 in Escherichia coli isolated from piglets with diarrhea in northeast of China. Pol J Vet Sci 2018; 21:5-12. [PMID: 29623998 DOI: 10.24425/119016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Our aim was to investigate the prevalence of the pathogenicity island ETT2 and to examine the relationship between the ETT2 locus and other virulence factors in Escherichia coli (E. coli) isolated from piglets with diarrhea. A total of 354 E. coli strains isolated from scouring piglets were tested using PCR for the presence of the ETT2 locus. The E. coli strains were also analyzed for enterotoxins, fimbriae, non-fimbrial adhesin, Shiga toxins, pathogenicity islands, α-haemolysin (hlyA), afa8 gene cluster and autotransporter protease (sepA) genes. The results showed that 215 (60.7%) of the isolates possessed the ETT2 island. In 215 ETT2-positive E. coli strains, the virulence genes found were EAST1 (27.0%), irp2 (18.6%), paa (15.4%), STb (7.9%), LT (6.5%), ler (4.7%), hlyA (3.7%), AIDA-I (3.7%), K88 (3.7%), eae (3.3%), STa (2.8%), afaD (1.4%), afaE (1.4%), K99 (0.9%) and sepA (0.47%), respectively, and the isolates could be assigned into 25 different virulence factor patterns. In 139 ETT2-negative E. coli strains, the virulence genes detected were EAST1 (38.9%), paa (14.4%), STb (11.5%), AIDA-I (10.1%), irp2 (7.9%), sepA (2.16%), LT (0.7%), STa (0.7%), eae (0.7%), ler (0.7%), hlyA (0.7%) and K88 (0.7%), respectively, and the isolates could be classified into 13 different virulence factor patterns. Moreover, the occurrence of LT gene of ETT2-positive E. coli strains was far more than that of ETT2-negative E. coli strains.
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Affiliation(s)
- C W Yuan
- College of life and health sciences, Northeastern University, No. 89, Wenhua East Road, Shenyang, Liaoning,110011, P. R. China
| | - W X Liu
- Laboratory of Hematology, Affiliated hospital of Guangdong Medical College, No.2, Wenming East Road, Zhanjiang, 524001, P. R. China
| | - J L Hou
- College of life and health sciences, Northeastern University, No. 89, Wenhua East Road, Shenyang, Liaoning,110011, P. R. China
| | - L G Zhang
- Center for Animal Disease Emergency of Liaoning province, No.56, Dongling Road, Shenyang, Liaoning, 110004, P. R. China
| | - G Q Wang
- College of life and health sciences, Northeastern University, No. 89, Wenhua East Road, Shenyang, Liaoning,110011, P. R. China
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Argemi X, Nanoukon C, Affolabi D, Keller D, Hansmann Y, Riegel P, Baba-Moussa L, Prévost G. Comparative Genomics and Identification of an Enterotoxin-Bearing Pathogenicity Island, SEPI-1/SECI-1, in Staphylococcus epidermidis Pathogenic Strains. Toxins (Basel) 2018; 10:E93. [PMID: 29495323 DOI: 10.3390/toxins10030093] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 02/22/2018] [Accepted: 02/22/2018] [Indexed: 02/08/2023] Open
Abstract
Staphylococcus epidermidis is a leading cause of nosocomial infections, majorly resistant to beta-lactam antibiotics, and may transfer several mobile genetic elements among the members of its own species, as well as to Staphylococcus aureus; however, a genetic exchange from S. aureus to S. epidermidis remains controversial. We recently identified two pathogenic clinical strains of S. epidermidis that produce a staphylococcal enterotoxin C3-like (SEC) similar to that by S. aureus pathogenicity islands. This study aimed to determine the genetic environment of the SEC-coding sequence and to identify the mobile genetic elements. Whole-genome sequencing and annotation of the S. epidermidis strains were performed using Illumina technology and a bioinformatics pipeline for assembly, which provided evidence that the SEC-coding sequences were located in a composite pathogenicity island that was previously described in the S. epidermidis strain FRI909, called SePI-1/SeCI-1, with 83.8–89.7% nucleotide similarity. Various other plasmids were identified, particularly p_3_95 and p_4_95, which carry antibiotic resistance genes (hsrA and dfrG, respectively), and share homologies with SAP085A and pUSA04-2-SUR11, two plasmids described in S. aureus. Eventually, one complete prophage was identified, ΦSE90, sharing 30 out of 52 coding sequences with the Acinetobacter phage vB_AbaM_IME200. Thus, the SePI-1/SeCI-1 pathogenicity island was identified in two pathogenic strains of S. epidermidis that produced a SEC enterotoxin causing septic shock. These findings suggest the existence of in vivo genetic exchange from S. aureus to S. epidermidis.
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Batista JH, da Silva Neto JF. Chromobacterium violaceum Pathogenicity: Updates and Insights from Genome Sequencing of Novel Chromobacterium Species. Front Microbiol 2017; 8:2213. [PMID: 29176969 PMCID: PMC5686120 DOI: 10.3389/fmicb.2017.02213] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/27/2017] [Indexed: 11/13/2022] Open
Abstract
Chromobacterium violaceum is an abundant component of the soil and water microbiota in tropical and subtropical regions around the world. For many years, it was mainly known as a producer of violacein and as a reporter for the discovery of quorum sensing molecules. However, C. violaceum has recently emerged as an important model of an environmental opportunistic pathogen. Its high virulence in human infections and a mouse infection model involves the possession of several predicted virulence traits, including two type III secretion systems (T3SSs). In this article, in addition to providing an update on the new clinical cases of human C. violaceum infections, we will focus on recent advances in understanding the molecular mechanisms regarding C. violaceum pathogenesis. It has been demonstrated that the C. violaceum Cpi-1 T3SS plays a pivotal role in interaction with host cells. It is required for the secretion of effector proteins and is the agonist recognized by the Nod-like receptor CARD domain-containing protein 4 (NLRC4) inflammasome from innate immune cells. Pyroptosis and its release of hepatocytes for killing by neutrophils are key events required for the clearance of C. violaceum. Given the prominent role of T3SSs in C. violaceum virulence, we examine their occurrence in the Chromobacterium genus, taking advantage of several draft genome sequences of Chromobacterium species that have recently become available. Our finding that the Cpi-1 T3SS is widespread among Chromobacterium species points toward the pathogenic potential of this genus for humans or to novel roles of the T3SS in the interaction of Chromobacterium species with other organisms.
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Affiliation(s)
- Juliana H Batista
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - José F da Silva Neto
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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Abstract
As Helicobacter pylori infects half the world's population and displays an extensive intraspecies diversity, genomics is a powerful tool to understand evolution and disease, to identify factors that confer higher risk of severe sequelae, and to find new approaches for therapy both among bacterial and host targets. In line with these objectives, this review article summarizes the major findings in Helicobacter genomics in papers published between April 2016 and March 2017.
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Affiliation(s)
- Kaisa Thorell
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Philippe Lehours
- INSERM, Univ. Bordeaux, UMR1053 Bordeaux Research In Translational Oncology, BaRITOn, Bordeaux, France
| | - Filipa F Vale
- Faculty of Pharmacy, Host-Pathogen Interactions Unit, Research Institute for Medicines (iMed-ULisboa), Universidade de Lisboa, Lisbon, Portugal
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Bowring J, Neamah MM, Donderis J, Mir-Sanchis I, Alite C, Ciges-Tomas JR, Maiques E, Medmedov I, Marina A, Penadés JR. Pirating conserved phage mechanisms promotes promiscuous staphylococcal pathogenicity island transfer. eLife 2017; 6:26487. [PMID: 28826473 PMCID: PMC5779228 DOI: 10.7554/elife.26487] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 08/07/2017] [Indexed: 11/15/2022] Open
Abstract
Targeting conserved and essential processes is a successful strategy to combat enemies. Remarkably, the clinically important Staphylococcus aureus pathogenicity islands (SaPIs) use this tactic to spread in nature. SaPIs reside passively in the host chromosome, under the control of the SaPI-encoded master repressor, Stl. It has been assumed that SaPI de-repression is effected by specific phage proteins that bind to Stl, initiating the SaPI cycle. Different SaPIs encode different Stl repressors, so each targets a specific phage protein for its de-repression. Broadening this narrow vision, we report here that SaPIs ensure their promiscuous transfer by targeting conserved phage mechanisms. This is accomplished because the SaPI Stl repressors have acquired different domains to interact with unrelated proteins, encoded by different phages, but in all cases performing the same conserved function. This elegant strategy allows intra- and inter-generic SaPI transfer, highlighting these elements as one of nature’s most fascinating subcellular parasites. Many harmful microbes can produce different molecules that make them more effective in causing and spreading diseases. These molecules can also be obtained from ‘mobile genetic elements’ that can be transferred between bacteria within a population. Pathogenicity islands are one such type of mobile genetic element and are very common among bacteria known as staphylococci. They spread toxin-encoding genes between bacteria, including one that can lead to a condition called toxic shock syndrome in humans. Pathogenicity islands are normally found within the DNA of the bacteria, where they are deactivated by specific repressor proteins. However, in the presence of another type of mobile genetic element – the bacteriophages – the repressor proteins start to interact with specific proteins encoded by the bacteriophages. This allows the pathogenicity islands to become active and spread to other bacteria. Previous research has shown that in the bacterium known as Staphylococcus aureus, different pathogenicity islands have different repressors. Scientists therefore assumed that the repressors are only able to interact with certain bacteriophage proteins. However, since pathogenicity islands are widespread in nature, it could be possible that they use other ways to hijack the bacteriophage machinery to ensure their transfer. To test this hypothesis, Bowring et al. studied two types of pathogenicity islands in S. aureus and revealed that their two different repressors did not interact with specific bacteriophage proteins as previously hypothesized. Instead, each repressor could interact with multiple bacteriophage proteins that had a variety of different structures, including proteins from completely different bacteriophages. Bowring et al. also discovered that each of the analyzed repressor proteins did not actually recognize any specific shared structural features on the bacteriophage proteins, but rather evolved to target proteins that play the same role in various bacteriophages. This suggests the repressors target a specific process rather than a single protein. This strategy allows them to be transferred within the same species, but also between different ones. A next step will be to better understand how a repressor can recognize structurally unrelated proteins, and establish what evolutionary forces are driving this phenomenon. A deeper knowledge of how pathogenicity islands spread between staphylococci is vital to understand how these bacteria can become resistant to treatments such as antibiotics.
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Affiliation(s)
- Janine Bowring
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Maan M Neamah
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.,Department of Microbiology, Faculty of Veterinary Medicine, University of Kufa, Kufa, Iraq
| | - Jorge Donderis
- Instituto de Biomedicina de Valencia (IBV-CSIC) and CIBER de Enfermedades Raras, Valencia, Spain
| | - Ignacio Mir-Sanchis
- Departamento de Ciencias Biomédicas, Universidad CEU Cardenal Herrera, Valencia, Spain
| | - Christian Alite
- Instituto de Biomedicina de Valencia (IBV-CSIC) and CIBER de Enfermedades Raras, Valencia, Spain
| | - J Rafael Ciges-Tomas
- Instituto de Biomedicina de Valencia (IBV-CSIC) and CIBER de Enfermedades Raras, Valencia, Spain
| | - Elisa Maiques
- Instituto de Biomedicina de Valencia (IBV-CSIC) and CIBER de Enfermedades Raras, Valencia, Spain.,Departamento de Ciencias Biomédicas, Universidad CEU Cardenal Herrera, Valencia, Spain
| | - Iltyar Medmedov
- Instituto de Biomedicina de Valencia (IBV-CSIC) and CIBER de Enfermedades Raras, Valencia, Spain
| | - Alberto Marina
- Instituto de Biomedicina de Valencia (IBV-CSIC) and CIBER de Enfermedades Raras, Valencia, Spain
| | - José R Penadés
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Merino E, Flores-Encarnación M, Aguilar-Gutiérrez GR. Functional interaction and structural characteristics of unique components of Helicobacter pylori T4SS. FEBS J 2017; 284:3540-3549. [PMID: 28470874 DOI: 10.1111/febs.14092] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 03/14/2017] [Accepted: 04/26/2017] [Indexed: 12/25/2022]
Abstract
The Helicobacter pylori infection of the human gastric mucosa causes chronic active gastritis and peptic ulcers and is associated with the development of gastric cancer. Epidemiological studies show that these gastric diseases are related to virulent H. pylori strains that harbor the cytotoxin-associated gene pathogenicity island (cag PAI). The cag PAI is a DNA insertion in the H. pylori chromosome that encodes ~ 27 proteins, including the oncoprotein CagA. Approximately 20 of these proteins have been designated as cag type IV secretion system (T4SS) components. However, only 11 of these proteins share function, structure, and/or sequence similarities with the prototypical VirB/VirD4 T4SS of Agrobacterium tumefaciens. The VirB/VirD4 orthologs of the cag T4SS of H. pylori are required for CagA translocation and stimulate the gastric epithelial cells to produce and secrete interleukin-8 (IL-8). The cag PAI encodes eight additional proteins, such as Cag3 (Cagδ/HP0522), CagM (Cag16/HP0537), CagU (Cag11/HP0531), CagI (Cag19/HP0540), and CagH (Cag20/HP0541), which are also required for the translocation of CagA and IL-8 secretion, meanwhile CagF (Cag22/HP0543), CagG (Cag21/HP0542), and CagZ (Cag6/HP0526) are just required for the translocation of CagA. However, relatively little is known about their functions and structural organization because they exhibit a nondetectable sequence similarity with T4SS components in the current databases. In this review, we conducted an exhaustive analysis of the literature to present the biochemistry, putative role, localization, and interactions of each of these eight additional cag T4SS components.
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Affiliation(s)
- Enrique Merino
- Enrique Merino, Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Marcos Flores-Encarnación
- Marcos Flores-Encarnación, Laboratorio de Microbiología Molecular y Celular, Facultad de Medicina, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Germán Rubén Aguilar-Gutiérrez
- Germán Rubén Aguilar-Gutiérrez, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
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Chalupowicz L, Barash I, Reuven M, Dror O, Sharabani G, Gartemann K, Eichenlaub R, Sessa G, Manulis‐Sasson S. Differential contribution of Clavibacter michiganensis ssp. michiganensis virulence factors to systemic and local infection in tomato. Mol Plant Pathol 2017; 18:336-346. [PMID: 26992141 PMCID: PMC6638269 DOI: 10.1111/mpp.12400] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 03/13/2016] [Accepted: 03/15/2016] [Indexed: 05/03/2023]
Abstract
Clavibacter michiganensis ssp. michiganensis (Cmm) causes substantial economic losses in tomato production worldwide. The disease symptoms observed in plants infected systemically by Cmm are wilting and canker on the stem, whereas blister-like spots develop in locally infected leaves. A wide repertoire of serine proteases and cell wall-degrading enzymes has been implicated in the development of wilt and canker symptoms. However, virulence factors involved in the formation of blister-like spots, which play an important role in Cmm secondary spread in tomato nurseries, are largely unknown. Here, we demonstrate that Cmm virulence factors play different roles during blister formation relative to wilting. Inoculation with a green fluorescent protein (GFP)-labelled Cmm382 indicates that penetration occurs mainly through trichomes. When spray inoculated on tomato leaves, the wild-type Cmm382 and Cmm100 (lacking plasmids pCM1 and pCM2) strains form blister-like spots on leaves, whereas Cmm27 (lacking the chp/tomA pathogenicity island) is non-pathogenic, indicating that plasmid-borne genes, which have a crucial role in wilting, are not required for blister formation. Conversely, mutations in chromosomal genes encoding serine proteases (chpC and sbtA), cell wall-degrading enzymes (pgaA and endX/Y), a transcriptional regulator (vatr2), a putative perforin (perF) and a putative sortase (srtA) significantly affect disease incidence and the severity of blister formation. The transcript levels of these genes, as measured by quantitative reverse transcription-polymerase chain reaction, showed that, during blister formation, they are expressed early at 8-16 h after inoculation, whereas, during wilting, they are expressed after 24-72 h or expressed at low levels. Plant gene expression studies suggest that chpC is involved in the suppression of host defence.
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Affiliation(s)
- Laura Chalupowicz
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
| | - Isaac Barash
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel Aviv UniversityTel Aviv69978Israel
| | - Michal Reuven
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
| | - Orit Dror
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
| | - Galit Sharabani
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
| | - Karl‐Heinz Gartemann
- Department of Genetechnology/MicrobiologyUniversity of BielefeldBielefeld33501Germany
| | - Rudolf Eichenlaub
- Department of Genetechnology/MicrobiologyUniversity of BielefeldBielefeld33501Germany
| | - Guido Sessa
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel Aviv UniversityTel Aviv69978Israel
| | - Shulamit Manulis‐Sasson
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
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Abstract
The phage-inducible chromosomal islands (PICIs) are a family of highly mobile genetic elements that contribute substantively to horizontal gene transfer, host adaptation, and virulence. Initially identified in Staphylococcus aureus, these elements are now thought to occur widely in gram-positive bacteria. They are molecular parasites that exploit certain temperate phages as helpers, using a variety of elegant strategies to manipulate the phage life cycle and promote their own spread, both intra- and intergenerically. At the same time, these PICI-encoded mechanisms severely interfere with helper phage reproduction, thereby enhancing survival of the bacterial population. In this review we discuss the genetics and the life cycle of these elements, with special emphasis on how they interact and interfere with the helper phage machinery for their own benefit. We also analyze the role that these elements play in driving bacterial and viral evolution.
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Affiliation(s)
- José R Penadés
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, G12 8TA Glasgow, United Kingdom;
| | - Gail E Christie
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298;
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Abstract
Helicobacter pylori is estimated to infect more than half of the worlds human population and represents a major risk factor for chronic gastritis, peptic ulcer disease, MALT lymphoma, and gastric adenocarcinoma. H. pylori infection and clinical consequences are controlled by highly complex interactions between the host, colonizing bacteria, and environmental parameters. Important bacterial determinants linked with gastric disease development include the cag pathogenicity island encoding a type IV secretion system (T4SS), the translocated effector protein CagA, vacuolating cytotoxin VacA, adhesin BabA, urease, serine protease HtrA, secreted outer membrane vesicles, and many others. The high quantity of these factors and allelic changes in the corresponding genes reveals a sophisticated picture and problems in evaluating the impact of each distinct component. Extensive work has been performed to pinpoint molecular processes related to H. pylori-triggered pathogenesis using Mongolian gerbils, mice, primary tissues, as well as novel in vitro model systems such as gastroids. The manipulation of host signaling cascades by the bacterium appears to be crucial for inducing pathogenic downstream activities and gastric disease progression. Here, we review the most recent advances in this important research area.
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Affiliation(s)
- Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Matthias Neddermann
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Gunter Maubach
- Institute of Experimental Internal Medicine, Otto von Guericke University, Magdeburg, Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Otto von Guericke University, Magdeburg, Germany
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Marcoleta AE, Berríos-Pastén C, Nuñez G, Monasterio O, Lagos R. Klebsiella pneumoniae Asparagine tDNAs Are Integration Hotspots for Different Genomic Islands Encoding Microcin E492 Production Determinants and Other Putative Virulence Factors Present in Hypervirulent Strains. Front Microbiol 2016; 7:849. [PMID: 27375573 PMCID: PMC4891358 DOI: 10.3389/fmicb.2016.00849] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/23/2016] [Indexed: 01/09/2023] Open
Abstract
Due to the developing of multi-resistant and invasive hypervirulent strains, Klebsiella pneumoniae has become one of the most urgent bacterial pathogen threats in the last years. Genomic comparison of a growing number of sequenced isolates has allowed the identification of putative virulence factors, proposed to be acquirable mainly through horizontal gene transfer. In particular, those related with synthesizing the antibacterial peptide microcin E492 (MccE492) and salmochelin siderophores were found to be highly prevalent among hypervirulent strains. The determinants for the production of both molecules were first reported as part of a 13-kbp segment of K. pneumoniae RYC492 chromosome, and were cloned and characterized in E. coli. However, the genomic context of this segment in K. pneumoniae remained uncharacterized. In this work, we provided experimental and bioinformatics evidence indicating that the MccE492 cluster is part of a highly conserved 23-kbp genomic island (GI) named GIE492, that was integrated in a specific asparagine-tRNA gene (asn-tDNA) and was found in a high proportion of isolates from liver abscesses sampled around the world. This element resulted to be unstable and its excision frequency increased after treating bacteria with mitomycin C and upon the overexpression of the island-encoded integrase. Besides the MccE492 genetic cluster, it invariably included an integrase-coding gene, at least seven protein-coding genes of unknown function, and a putative transfer origin that possibly allows this GI to be mobilized through conjugation. In addition, we analyzed the asn-tDNA loci of all the available K. pneumoniae assembled chromosomes to evaluate them as GI-integration sites. Remarkably, 73% of the strains harbored at least one GI integrated in one of the four asn-tDNA present in this species, confirming them as integration hotspots. Each of these tDNAs was occupied with different frequencies, although they were 100% identical. Also, we identified a total of 47 asn-tDNA-associated GIs that were classified into 12 groups of homology differing in theencoded functionalities but sharing with GIE492 a conserved recombination module and potentially its mobility features. Most of these GIs encoded factors with proven or potential role in pathogenesis, constituting a major reservoir of virulence factors in this species.
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Affiliation(s)
- Andrés E Marcoleta
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Santiago, Chile
| | - Camilo Berríos-Pastén
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Santiago, Chile
| | - Gonzalo Nuñez
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Santiago, Chile
| | - Octavio Monasterio
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Santiago, Chile
| | - Rosalba Lagos
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Santiago, Chile
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Chapleau M, Guertin JF, Farrokhi A, Lerat S, Burrus V, Beaulieu C. Identification of genetic and environmental factors stimulating excision from Streptomyces scabiei chromosome of the toxicogenic region responsible for pathogenicity. Mol Plant Pathol 2016; 17:501-9. [PMID: 26177341 PMCID: PMC6638466 DOI: 10.1111/mpp.12296] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The genes conferring pathogenicity in Streptomyces turgidiscabies, a pathogen causing common scab of potato, are grouped together on a pathogenicity island (PAI), which has been found to be mobile and appears to transfer and disseminate like an integrative and conjugative element (ICE). However, in Streptomyces scabiei, another common scab-inducing species, the pathogenicity genes are clustered in two regions: the toxicogenic region (TR) and the colonization region. The S. scabiei 87.22 genome was analysed to investigate the potential mobility of the TR. Attachment sites (att), short homologous sequences that delineate ICEs, were identified at both extremities of the TR. An internal att site was also found, suggesting that the TR has a composite structure (TR1 and TR2). Thaxtomin biosynthetic genes, essential for pathogenicity, were found in TR1, whereas candidate genes with known functions in recombination, replication and conjugal transfer were found in TR2. Excision of the TR1 or TR2 subregions alone, or of the entire TR region, was observed, although the excision frequency of TR was low. However, the excision frequency was considerably increased in the presence of either mitomycin C or Streptomyces coelicolor cells. A composite TR structure was not observed in all S. scabiei and Streptomyces acidiscabies strains tested. Of the ten strains analysed, seven lacked TR2 and no TR excision event could be detected in these strains, thus suggesting the implication of TR2 in the mobilization of S. scabiei TR.
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Affiliation(s)
- Mélanie Chapleau
- Centre SÈVE, Département de biologie, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1
| | - Julien F Guertin
- Centre SÈVE, Département de biologie, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1
| | - Ali Farrokhi
- Centre SÈVE, Département de biologie, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1
| | - Sylvain Lerat
- Centre SÈVE, Département de biologie, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1
| | - Vincent Burrus
- Centre SÈVE, Département de biologie, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1
| | - Carole Beaulieu
- Centre SÈVE, Département de biologie, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1
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Panda P, Vanga BR, Lu A, Fiers M, Fineran PC, Butler R, Armstrong K, Ronson CW, Pitman AR. Pectobacterium atrosepticum and Pectobacterium carotovorum Harbor Distinct, Independently Acquired Integrative and Conjugative Elements Encoding Coronafacic Acid that Enhance Virulence on Potato Stems. Front Microbiol 2016; 7:397. [PMID: 27065965 PMCID: PMC4814525 DOI: 10.3389/fmicb.2016.00397] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 03/14/2016] [Indexed: 12/25/2022] Open
Abstract
Integrative and conjugative elements (ICEs) play a central role in the evolution of bacterial virulence, their transmission between bacteria often leading to the acquisition of virulence factors that alter host range or aggressiveness. Much is known about the functions of the virulence determinants that ICEs harbor, but little is understood about the cryptic effects of ICEs on their host cell. In this study, the importance of horizontally acquired island 2 (HAI2), an ICE in the genome of Pectobacterium atrosepticum SCRI1043, was studied using a strain in which the entire ICE had been removed by CRISPR-Cas-mediated genome editing. HAI2 encodes coronafacic acid, a virulence factor that enhances blackleg disease of potato stems caused by P. atrosepticum SCRI1043. As expected, deletion of HAI2 resulted in reduced blackleg symptoms in potato stems. A subsequent screen for HAI2-related ICEs in other strains of the Pectobacterium genus revealed their ubiquitous nature in P. atrosepticum. Yet, HAI2-related ICEs were only detected in the genomes of a few P. carotovorum strains. These strains were notable as blackleg causing strains belonging to two different subspecies of P. carotovorum. Sequence analysis of the ICEs in different strains of both P. atrosepticum and P. carotovorum confirmed that they were diverse and were present in different locations on the genomes of their bacterial host, suggesting that the cfa cluster was probably acquired independently on a number of occasions via chromosomal insertion of related ICEs. Excision assays also demonstrated that the ICEs in both P. atrosepticum and P. carotovorum are mobilized from the host chromosome. Thus, the future spread of these ICEs via lateral gene transfer might contribute to an increase in the prevalence of blackleg-causing strains of P. carotovorum.
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Affiliation(s)
- Preetinanda Panda
- The Bio-Protection Research CentreLincoln, New Zealand
- Plant Pathology, The New Zealand Institute for Plant and Food Research LimitedLincoln, New Zealand
| | - Bhanupratap R. Vanga
- Plant Pathology, The New Zealand Institute for Plant and Food Research LimitedLincoln, New Zealand
- Department of Microbiology and Immunology, University of OtagoDunedin, New Zealand
| | - Ashley Lu
- Plant Pathology, The New Zealand Institute for Plant and Food Research LimitedLincoln, New Zealand
| | - Mark Fiers
- Plant Pathology, The New Zealand Institute for Plant and Food Research LimitedLincoln, New Zealand
| | - Peter C. Fineran
- The Bio-Protection Research CentreLincoln, New Zealand
- Department of Microbiology and Immunology, University of OtagoDunedin, New Zealand
| | - Ruth Butler
- Plant Pathology, The New Zealand Institute for Plant and Food Research LimitedLincoln, New Zealand
| | | | - Clive W. Ronson
- Department of Microbiology and Immunology, University of OtagoDunedin, New Zealand
| | - Andrew R. Pitman
- The Bio-Protection Research CentreLincoln, New Zealand
- Plant Pathology, The New Zealand Institute for Plant and Food Research LimitedLincoln, New Zealand
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Abstract
Among the prokaryotic genomic islands (GIs) involved in horizontal gene transfer (HGT) are the classical pathogenicity islands, including the integrative and conjugative elements (ICEs), the gene-transfer agents (GTAs), and the staphylococcal pathogenicity islands (SaPIs), the primary focus of this review. While the ICEs and GTAs mediate HGT autonomously, the SaPIs are dependent on specific phages. The ICEs transfer primarily their own DNA, the GTAs exclusively transfer unlinked host DNA, and the SaPIs combine the capabilities of both. Thus the SaPIs derive their importance from the genes they carry (their genetic cargo) and the genes they move. They act not only as versatile high-frequency mobilizers but also as mediators of phage interference and consequently are major benefactors of their host bacteria.
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Affiliation(s)
- Richard P Novick
- Department of Medicine, Skirball Institute, New York University Medical School, New York, NY 10016, USA; Department of Microbiology, Skirball Institute, New York University Medical School, New York, NY 10016, USA.
| | - Geeta Ram
- Department of Medicine, Skirball Institute, New York University Medical School, New York, NY 10016, USA; Department of Microbiology, Skirball Institute, New York University Medical School, New York, NY 10016, USA
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Solórzano C, Srikumar S, Canals R, Juárez A, Paytubi S, Madrid C. Hha has a defined regulatory role that is not dependent upon H-NS or StpA. Front Microbiol 2015; 6:773. [PMID: 26284052 PMCID: PMC4519777 DOI: 10.3389/fmicb.2015.00773] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/14/2015] [Indexed: 11/13/2022] Open
Abstract
The Hha family of proteins is involved in the regulation of gene expression in enterobacteria by forming complexes with H-NS-like proteins. Whereas several amino acid residues of both proteins participate in the interaction, some of them play a key role. Residue D48 of Hha protein is essential for the interaction with H-NS, thus the D48N substitution in Hha protein abrogates H-NS/Hha interaction. Despite being a paralog of H-NS protein, StpA interacts with HhaD48N with higher affinity than with the wild type Hha protein. To analyze whether Hha is capable of acting independently of H-NS and StpA, we conducted transcriptomic analysis on the hha and stpA deletion strains and the hhaD48N substitution strain of Salmonella Typhimurium using a custom microarray. The results obtained allowed the identification of 120 genes regulated by Hha in an H-NS/StpA-independent manner, 38% of which are horizontally acquired genes. A significant number of the identified genes are involved in functions related to cell motility, iron uptake, and pathogenicity. Thus, motility assays, siderophore detection and intra-macrophage replication assays were performed to confirm the transcriptomic data. Our findings point out the importance of Hha protein as an independent regulator in S. Typhimurium, highlighting a regulatory role on virulence.
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Affiliation(s)
- Carla Solórzano
- Departament de Microbiologia, Universitat de Barcelona Barcelona, Spain
| | | | - Rocío Canals
- Institute of Integrative Biology, University of Liverpool Liverpool, UK
| | - Antonio Juárez
- Departament de Microbiologia, Universitat de Barcelona Barcelona, Spain ; Institut de Bioenginyeria de Catalunya, Parc Científic de Barcelona Barcelona, Spain
| | - Sonia Paytubi
- Departament de Microbiologia, Universitat de Barcelona Barcelona, Spain
| | - Cristina Madrid
- Departament de Microbiologia, Universitat de Barcelona Barcelona, Spain
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Ram G, Chen J, Ross HF, Novick RP. An insight into staphylococcal pathogenicity island-mediated interference with phage late gene transcription. Bacteriophage 2015; 5:e1028608. [PMID: 26459624 DOI: 10.1080/21597081.2015.1028608] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/04/2015] [Accepted: 03/06/2015] [Indexed: 12/21/2022]
Abstract
Staphylococcal pathogenicity islands (SaPIs) are ∼15 kb chromosomally located mobile elements that parasitize "helper" phages which provide a de-repressor protein plus virion and lysis proteins which enable the release of infectious SaPI particles in very high titers. All SaPIs interfere with the reproduction of their helper phages, using 3 different mechanisms. The logic of SaPI reproduction requires that these interference mechanisms do not totally block phage production, as this would be lethal for them as well as for the phage. The discovery of 2 SaPI2 proteins that totally block phage 80 by interfering with late phage transcription was inconsistent with this principle and led to the discovery of a third protein that binds to one of the interference proteins and modulates its activity, thus preventing complete inhibition of the phage. These systems permit the SaPIs to engage in horizontal transfer of unlinked chromosomal genes as well as their own.
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Affiliation(s)
- Geeta Ram
- Departments of Microbiology and Medicine; New York University School of Medicine and Program in Molecular Pathogenesis; Skirball Institute ; New York, NY USA
| | - John Chen
- Departments of Microbiology and Medicine; New York University School of Medicine and Program in Molecular Pathogenesis; Skirball Institute ; New York, NY USA
| | - Hope F Ross
- Departments of Microbiology and Medicine; New York University School of Medicine and Program in Molecular Pathogenesis; Skirball Institute ; New York, NY USA
| | - Richard P Novick
- Departments of Microbiology and Medicine; New York University School of Medicine and Program in Molecular Pathogenesis; Skirball Institute ; New York, NY USA
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Wu Z, Wang W, Tang M, Shao J, Dai C, Zhang W, Fan H, Yao H, Zong J, Chen D, Wang J, Lu C. Comparative genomic analysis shows that Streptococcus suis meningitis isolate SC070731 contains a unique 105K genomic island. Gene 2013; 535:156-64. [PMID: 24316490 DOI: 10.1016/j.gene.2013.11.044] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 11/16/2013] [Accepted: 11/19/2013] [Indexed: 11/29/2022]
Abstract
Streptococcus suis (SS) is an important swine pathogen worldwide that occasionally causes serious infections in humans. SS infection may result in meningitis in pigs and humans. The pathogenic mechanisms of SS are poorly understood. Here, we provide the complete genome sequence of S. suis serotype 2 (SS2) strain SC070731 isolated from a pig with meningitis. The chromosome is 2,138,568bp in length. There are 1933 predicted protein coding sequences and 96.7% (57/59) of the known virulence-associated genes are present in the genome. Strain SC070731 showed similar virulence with SS2 virulent strains HA9801 and ZY05719, but was more virulent than SS2 virulent strain P1/7 in the zebrafish infection model. Comparative genomic analysis revealed a unique 105K genomic island in strain SC070731 that is absent in seven other sequenced SS2 strains. Further analysis of the 105K genomic island indicated that it contained a complete nisin locus similar to the nisin U locus in S. uberis strain 42, a prophage similar to S. oralis phage PH10 and several antibiotic resistance genes. Several proteins in the 105K genomic island, including nisin and RelBE toxin-antitoxin system, contribute to the bacterial fitness and virulence in other pathogenic bacteria. Further investigation of newly identified gene products, including four putative new virulence-associated surface proteins, will improve our understanding of SS pathogenesis.
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Affiliation(s)
- Zongfu Wu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China.
| | - Weixue Wang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Min Tang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Jing Shao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Chen Dai
- Experimental Teaching Center of Life Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Wei Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Hongjie Fan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Huochun Yao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Jie Zong
- Novel Bioinformatics Co., Ltd, Shanghai, China
| | - Dai Chen
- Novel Bioinformatics Co., Ltd, Shanghai, China
| | | | - Chengping Lu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China.
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Calhau V, Ribeiro G, Mendonça N, Da Silva GJ. Prevalent combination of virulence and plasmidic-encoded resistance in ST 131 Escherichia coli strains. Virulence 2013; 4:726-9. [PMID: 24128612 DOI: 10.4161/viru.26552] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Escherichia coli ST131 is an important cause of multidrug-resistant infections. Thus, the aim of this study was to evaluate the concomitant presence of resistance plasmids and pathogenicity islands (PAIs) in ST131 E. coli. From 97 extraintestinal E. coli characterized for antimicrobial susceptibility and extended-spectrum β-lactamase production, 16% of isolates were identified as CTX-M-15 producers. These strains were studied by PFGE, MLST, and phylogroups, plasmid groups, PAIs, and plasmid-mediated quinolone-resistance determinants. MLST identified one ST10 strain from phylogroup A and the remaining isolates were ST131, from group B2. Despite the genetic variability, 64% of ST131 strains presented a profile composed by PAI IV₅₃₆, PAI I(CFT073), and PAI II(CFT073), IncF plasmid, bla(CTX-M-15), and aac(6')-lb-cr genes. The prevalent virulence and resistance profile detected among the strains may constitute an optimal combination of factors, which allow E. coli ST131 to maintain both features becoming concomitantly virulent and extremely resistant.
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Affiliation(s)
- Vera Calhau
- Center of Pharmaceutical Studies and Laboratory of Microbiology; Faculty of Pharmacy; University of Coimbra; Coimbra, Portugal; Service of Clinical Pathology; University Hospital of Coimbra; Coimbra, Portugal
| | - Graça Ribeiro
- Service of Clinical Pathology; University Hospital of Coimbra; Coimbra, Portugal
| | - Nuno Mendonça
- Center of Pharmaceutical Studies and Laboratory of Microbiology; Faculty of Pharmacy; University of Coimbra; Coimbra, Portugal
| | - Gabriela Jorge Da Silva
- Center of Pharmaceutical Studies and Laboratory of Microbiology; Faculty of Pharmacy; University of Coimbra; Coimbra, Portugal
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Affiliation(s)
- Timothy L. Cover
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN,Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN,Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
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McGavin MJ, Arsic B, Nickerson NN. Evolutionary blueprint for host- and niche-adaptation in Staphylococcus aureus clonal complex CC30. Front Cell Infect Microbiol 2012; 2:48. [PMID: 22919639 PMCID: PMC3417553 DOI: 10.3389/fcimb.2012.00048] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 03/20/2012] [Indexed: 11/23/2022] Open
Abstract
Staphylococcus aureus clonal complex CC30 has caused infectious epidemics for more than 60 years, and, therefore, provides a model system to evaluate how evolution has influenced the disease potential of closely related strains. In previous multiple genome comparisons, phylogenetic analyses established three major branches that evolved from a common ancestor. Clade 1, comprised of historic pandemic phage type 80/81 methicillin susceptible S. aureus (MSSA), and Clade 2 comprised of contemporary community acquired methicillin resistant S. aureus (CA-MRSA) were hyper-virulent in murine infection models. Conversely, Clade 3 strains comprised of contemporary hospital associated MRSA (HA-MRSA) and clinical MSSA exhibited attenuated virulence, due to common single nucleotide polymorphisms (SNP's) that abrogate production of α-hemolysin Hla, and interfere with signaling of the accessory gene regulator agr. We have now completed additional in silico genome comparisons of 15 additional CC30 genomes in the public domain, to assess the hypothesis that Clade 3 has evolved to favor niche adaptation. In addition to SNP's that influence agr and hla, other common traits of Clade 3 include tryptophan auxotrophy due to a di-nucleotide deletion within trpD, a premature stop codon within isdH encoding an immunogenic cell surface protein involved in iron acquisition, loss of a genomic toxin–antitoxin (TA) addiction module, acquisition of S. aureus pathogenicity islands SaPI4, and SaPI2 encoding toxic shock syndrome toxin tst, and increased copy number of insertion sequence ISSau2, which appears to target transcription terminators. Compared to other Clade 3 MSSA, S. aureus MN8, which is associated with Staphylococcal toxic shock syndrome, exhibited a unique ISSau2 insertion, and enhanced production of toxic shock syndrome toxin encoded by SaPI2. Cumulatively, our data support the notion that Clade 3 strains are following an evolutionary blueprint toward niche-adaptation.
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Affiliation(s)
- Martin J McGavin
- Department of Microbiology, Schulich School of Medicine and Dentistry, Siebens Drake Research Institute and Centre for Human Immunology, University of Western Ontario, London ON, Canada. martin.mcgavin@ schulich.uwo.ca
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