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Catton EA, Bonsor DA, Herrera C, Stålhammar-Carlemalm M, Lyndin M, Turner CE, Soden J, van Strijp JAG, Singer BB, van Sorge NM, Lindahl G, McCarthy AJ. Human CEACAM1 is targeted by a Streptococcus pyogenes adhesin implicated in puerperal sepsis pathogenesis. Nat Commun 2023; 14:2275. [PMID: 37080973 PMCID: PMC10119177 DOI: 10.1038/s41467-023-37732-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 03/27/2023] [Indexed: 04/22/2023] Open
Abstract
Life-threatening bacterial infections in women after childbirth, known as puerperal sepsis, resulted in classical epidemics and remain a global health problem. While outbreaks of puerperal sepsis have been ascribed to Streptococcus pyogenes, little is known about disease mechanisms. Here, we show that the bacterial R28 protein, which is epidemiologically associated with outbreaks of puerperal sepsis, specifically targets the human receptor CEACAM1. This interaction triggers events that would favor the development of puerperal sepsis, including adhesion to cervical cells, suppression of epithelial wound repair and subversion of innate immune responses. High-resolution structural analysis showed that an R28 domain with IgI3-like fold binds to the N-terminal domain of CEACAM1. Together, these findings demonstrate that a single adhesin-receptor interaction can drive the pathogenesis of bacterial sepsis and provide molecular insights into the pathogenesis of one of the most important infectious diseases in medical history.
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Affiliation(s)
- Erin A Catton
- Centre for Bacterial Resistance Biology, Section of Molecular Microbiology, Department of Infectious Diseases, Imperial College London, London, SW7 2AZ, UK
| | - Daniel A Bonsor
- University of Maryland, Baltimore, MD, 21201, USA
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Carolina Herrera
- Section of Immunology of Infection, Department of Infectious Disease, Imperial College London, London, W2 1NY, UK
| | | | - Mykola Lyndin
- Sumy State University, Sumy, 40000, Ukraine
- Institute of Anatomy, Medical Faculty, University of Duisburg-Essen, Essen, 45147, Germany
| | - Claire E Turner
- The School of Biosciences, The Florey Institute, The University of Sheffield, Sheffield, S10 2TN, UK
| | - Jo Soden
- Retrogenix, Chinley, High Peak, SK23 6FJ, Chinley, UK
| | - Jos A G van Strijp
- Department of Medical Microbiology, UMC Utrecht, Utrecht, 3584 CX, The Netherlands
| | - Bernhard B Singer
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC location University of Amsterdam, Amsterdam Institute for Infection and Immunity, Amsterdam, 1105 AZ, The Netherlands
| | - Nina M van Sorge
- Department of Medical Microbiology, UMC Utrecht, Utrecht, 3584 CX, The Netherlands.
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC location University of Amsterdam, Amsterdam Institute for Infection and Immunity, Amsterdam, 1105 AZ, The Netherlands.
- Netherlands Reference Laboratory for Bacterial Meningitis, Amsterdam UMC, location AMC, Amsterdam, 1105 AZ, The Netherlands.
| | - Gunnar Lindahl
- Department of Laboratory Medicine, Division of Medical Microbiology, Lund University, Lund, 223 62, Sweden.
- Department of Chemistry, Division of Applied Microbiology, Lund University, Lund, 221 00, Sweden.
| | - Alex J McCarthy
- Centre for Bacterial Resistance Biology, Section of Molecular Microbiology, Department of Infectious Diseases, Imperial College London, London, SW7 2AZ, UK.
- Department of Medical Microbiology, UMC Utrecht, Utrecht, 3584 CX, The Netherlands.
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Nayar G, Terrizzano I, Seabolt E, Agarwal A, Boucher C, Ruiz J, Slizovskiy IB, Kaufman JH, Noyes NR. ggMOB: Elucidation of genomic conjugative features and associated cargo genes across bacterial genera using genus-genus mobilization networks. Front Genet 2022; 13:1024577. [PMID: 36568361 PMCID: PMC9779932 DOI: 10.3389/fgene.2022.1024577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 10/25/2022] [Indexed: 12/14/2022] Open
Abstract
Horizontal gene transfer mediated by conjugation is considered an important evolutionary mechanism of bacteria. It allows organisms to quickly evolve new phenotypic properties including antimicrobial resistance (AMR) and virulence. The frequency of conjugation-mediated cargo gene exchange has not yet been comprehensively studied within and between bacterial taxa. We developed a frequency-based network of genus-genus conjugation features and candidate cargo genes from whole-genome sequence data of over 180,000 bacterial genomes, representing 1,345 genera. Using our method, which we refer to as ggMOB, we revealed that over half of the bacterial genomes contained one or more known conjugation features that matched exactly to at least one other genome. Moreover, the proportion of genomes containing these conjugation features varied substantially by genus and conjugation feature. These results and the genus-level network structure can be viewed interactively in the ggMOB interface, which allows for user-defined filtering of conjugation features and candidate cargo genes. Using the network data, we observed that the ratio of AMR gene representation in conjugative versus non-conjugative genomes exceeded 5:1, confirming that conjugation is a critical force for AMR spread across genera. Finally, we demonstrated that clustering genomes by conjugation profile sometimes correlated well with classical phylogenetic structuring; but that in some cases the clustering was highly discordant, suggesting that the importance of the accessory genome in driving bacterial evolution may be highly variable across both time and taxonomy. These results can advance scientific understanding of bacterial evolution, and can be used as a starting point for probing genus-genus gene exchange within complex microbial communities that include unculturable bacteria. ggMOB is publicly available under the GNU licence at https://ruiz-hci-lab.github.io/ggMOB/.
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Affiliation(s)
- Gowri Nayar
- Department of Biomedical Informatics, Stanford University, Stanford, CA, United States
| | | | - Ed Seabolt
- IBM Research Almaden, San Jose, CA, United States
| | | | - Christina Boucher
- Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL, United States
| | - Jaime Ruiz
- Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL, United States
| | - Ilya B. Slizovskiy
- Department of Veterinary Population Medicine, University of Minnesota, Minneapolis, MN, United States
| | | | - Noelle R. Noyes
- Department of Veterinary Population Medicine, University of Minnesota, Minneapolis, MN, United States,*Correspondence: Noelle R. Noyes,
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The Integrative Conjugative Element ICESpyM92 Contributes to Pathogenicity of Emergent Antimicrobial-Resistant emm92 Group A Streptococcus. Infect Immun 2022; 90:e0008022. [PMID: 35913172 PMCID: PMC9387263 DOI: 10.1128/iai.00080-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Antimicrobial resistance-encoding mobile genetic elements (MGEs) may contribute to the disease potential of bacterial pathogens. We previously described the association of Group A Streptococcus (GAS) derived from invasive disease with increasingly frequent antimicrobial resistance (AMR). We hypothesized that a 65-kb AMR-encoding MGE (ICESpyM92), highly conserved among closely related emergent invasive emm92 GAS, contributes to GAS disease potential. Here, we provide evidence that a combination of ICESpyM92- and core genome-dependent differential gene expression (DGE) contributes to invasive disease phenotypes of emergent emm92 GAS. Using isogenic ICESpyM92 mutants generated in distinct emm92 genomic backgrounds, we determined the presence of ICESpyM92 enhances GAS virulence in a mouse subcutaneous infection model. Measurement of in vitro and ex vivo DGE indicates ICESpyM92 influences GAS global gene expression in a background-dependent manner. Our study links virulence and AMR on a unique MGE via MGE-related DGE and highlights the importance of investigating associations between AMR-encoding MGEs and pathogenicity.
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The RD2 Pathogenicity Island Modifies the Disease Potential of the Group A Streptococcus. Infect Immun 2021; 89:e0072220. [PMID: 33820819 DOI: 10.1128/iai.00722-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Serotype M28 isolates of the group A Streptococcus (GAS; Streptococcus pyogenes) are nonrandomly associated with cases of puerperal sepsis, a potentially life-threatening infection that can occur in women following childbirth. Previously, we discovered that the 36.3-kb RD2 pathogenicity island, which is present in serotype M28 isolates but lacking from most other isolates, promotes the ability of M28 GAS to colonize the female reproductive tract. Here, we performed a gain-of-function study in which we introduced RD2 into representative serotype M1, M49, and M59 isolates and assessed the phenotypic consequences of RD2 acquisition. All RD2-containing derivatives colonized a higher percentage of mice, and at higher CFU levels, than did the parental isolates in a mouse vaginal colonization model. However, for two additional phenotypes, survival in heparinized whole human blood and adherence to two human vaginal epithelial cell lines, there were serotype-specific differences from RD2 acquisition. Using transcriptomic comparisons, we identified that such differences may be a consequence of RD2 altering the abundance of transcripts from select core genome genes along serotype-specific lines. Our study is the first that interrogates RD2 function in GAS serotypes other than M28 isolates, shedding light on variability in the phenotypic consequences of RD2 acquisition and informing on why this mobile genetic element is not ubiquitous in the GAS population.
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Boukthir S, Moullec S, Cariou ME, Meygret A, Morcet J, Faili A, Kayal S. A prospective survey of Streptococcus pyogenes infections in French Brittany from 2009 to 2017: Comprehensive dynamic of new emergent emm genotypes. PLoS One 2020; 15:e0244063. [PMID: 33332468 PMCID: PMC7746304 DOI: 10.1371/journal.pone.0244063] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/02/2020] [Indexed: 12/15/2022] Open
Abstract
Streptococcus pyogenes or group A Streptococcus (GAS) causes diseases ranging from uncomplicated pharyngitis to life-threatening infections. It has complex epidemiology driven by the diversity, the temporal and geographical fluctuations of the circulating strains. Despite the global burden of GAS diseases, there is currently no available vaccination strategy against GAS infections. This study, based on a longitudinal population survey, aimed to understand the dynamic of GAS emm types and to give leads to better recognition of underlying mechanisms for the emergence of successful clones. From 2009 to 2017, we conducted a systematic culture-based diagnosis of GAS infections in a French Brittany population with a prospective recovery of clinical data. The epidemiological analysis was performed using emm typing combined with the structural and functional cluster-typing system for all the recovered strains. Risk factors for the invasiveness, identified by univariate analysis, were computed in a multiple logistic regression analysis, and the only independent risk factor remaining in the model was the age (OR for the entire range [CI95%] = 6.35 [3.63, 11.10]; p<0.0001). Among the 61 different emm types identified, the most prevalent were emm28 (16%), emm89 (15%), emm1 (14%), and emm4 (8%), which accounted for more than 50% of circulating strains. During the study period, five genotypes identified as emm44, 66, 75, 83, 87 emerged successively and belonged to clusters D4, E2, E3, and E6 that were different from those gathering “Prevalent” emm types (clusters A-C3 to 5, E1 and E4). We previously reported significant genetic modifications for emm44, 66, 83 and 75 types resulting possibly from a short adaptive evolution. Herein we additionally observed that the emergence of a new genotype could occur in a susceptible population having specific risk factors or probably lacking a naturally-acquired cluster-specific immune cross-protection. Among emergent emm types, emm75 and emm87 tend to become prevalent with a stable annual incidence and the risk of a clonal expansion have to be considered.
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Affiliation(s)
- Sarrah Boukthir
- CHU de Rennes, Service de Bactériologie-Hygiène Hospitalière, Rennes, France
- Inserm, CIC 1414, Rennes, France
- Université Rennes 1, Faculté de Médecine, Rennes, France
| | - Séverine Moullec
- Inserm, CIC 1414, Rennes, France
- Université Rennes 1, Faculté de Médecine, Rennes, France
| | | | - Alexandra Meygret
- CHU de Rennes, Service de Bactériologie-Hygiène Hospitalière, Rennes, France
- Université Rennes 1, Faculté de Médecine, Rennes, France
| | - Jeff Morcet
- CHU de Rennes, Service de Bactériologie-Hygiène Hospitalière, Rennes, France
- Inserm, CIC 1414, Rennes, France
| | - Ahmad Faili
- Inserm, CIC 1414, Rennes, France
- Université Rennes 1, Faculté de Pharmacie, Rennes, France
| | - Samer Kayal
- CHU de Rennes, Service de Bactériologie-Hygiène Hospitalière, Rennes, France
- Inserm, CIC 1414, Rennes, France
- Université Rennes 1, Faculté de Médecine, Rennes, France
- * E-mail:
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6
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Manzer HS, Nobbs AH, Doran KS. The Multifaceted Nature of Streptococcal Antigen I/II Proteins in Colonization and Disease Pathogenesis. Front Microbiol 2020; 11:602305. [PMID: 33329493 PMCID: PMC7732690 DOI: 10.3389/fmicb.2020.602305] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 10/29/2020] [Indexed: 12/22/2022] Open
Abstract
Streptococci are Gram-positive bacteria that belong to the natural microbiota of humans and animals. Certain streptococcal species are known as opportunistic pathogens with the potential to cause severe invasive disease. Antigen I/II (AgI/II) family proteins are sortase anchored cell surface adhesins that are nearly ubiquitous across streptococci and contribute to many streptococcal diseases, including dental caries, respiratory tract infections, and meningitis. They appear to be multifunctional adhesins with affinities to various host substrata, acting to mediate attachment to host surfaces and stimulate immune responses from the colonized host. Here we will review the literature including recent work that has demonstrated the multifaceted nature of AgI/II family proteins, focusing on their overlapping and distinct functions and their important contribution to streptococcal colonization and disease.
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Affiliation(s)
- Haider S. Manzer
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Angela H. Nobbs
- Bristol Dental School, University of Bristol, Bristol, United Kingdom
| | - Kelly S. Doran
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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Jespersen MG, Lacey JA, Tong SYC, Davies MR. Global genomic epidemiology of Streptococcus pyogenes. INFECTION GENETICS AND EVOLUTION 2020; 86:104609. [PMID: 33147506 DOI: 10.1016/j.meegid.2020.104609] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/20/2020] [Accepted: 10/23/2020] [Indexed: 02/04/2023]
Abstract
Streptococcus pyogenes is one of the Top 10 human infectious disease killers worldwide causing a range of clinical manifestations in humans. Colonizing a range of ecological niches within its sole host, the human, is key to the ability of this opportunistic pathogen to cause direct and post-infectious manifestations. The expansion of genome sequencing capabilities and data availability over the last decade has led to an improved understanding of the evolutionary dynamics of this pathogen within a global framework where epidemiological relationships and evolutionary mechanisms may not be universal. This review uses the recent publication by Davies et al., 2019 as an updated global framework to address S. pyogenes population genomics, highlighting how genomics is being used to gain new insights into evolutionary processes, transmission pathways, and vaccine design.
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Affiliation(s)
- Magnus G Jespersen
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Jake A Lacey
- Doherty Department, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Steven Y C Tong
- Doherty Department, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia; Victorian Infectious Diseases Service, The Royal Melbourne Hospital, at the Peter Doherty Institute for Infection and Immunity, VIC, Australia
| | - Mark R Davies
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.
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A Al-Kafaween M, Mohd Hilmi AB, A Nagi Al-Jamal H, A Elsahoryi N, Jaffar N, Khairi Zahri M. Pseudomonas Aeruginosa and Streptococcus Pyogenes Exposed to Malaysian Trigona Honey In Vitro Demonstrated Downregulation of Virulence Factor. IRANIAN JOURNAL OF BIOTECHNOLOGY 2020; 18:e2542. [PMID: 34056021 PMCID: PMC8148639 DOI: 10.30498/ijb.2020.2542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Background Honey has been known as a traditional medicine for centuries with its antibacterial properties. It is considered one of the most enduring substances used in wound management. Objectives This study aimed to: (i) evaluate the effects of Malaysian Trigona honey on bacterial structure and (ii) assess the anti-virulence potential of this honey by examining their impacts on the expression of selected genes (involved in stress survival and biofilm formation) in a test organism. Materials and Methods Trigona honey's impacts on the bacterial structure (cell morphology) and the expression profiles of select Pseudomonas Aeruginosa and Streptococcus Pyogenes genes were examined using scanning electron microscopy (SEM) and real-time PCR (RT-qPCR) analysis, respectively. Results SEM showed that the decreased cell density deformed, disrupted, and damaged cells for both bacteria. RT-qPCR showed that the expression of fleN, fleQ, and fleR genes of P.aeruginosa were decreased, 4.26-fold, 3.80-fold and 2.66- fold respectively. In addition, scpA, ftsY, and emm13 of S.pyogenes were decreased, 2.87-fold, 3.24-fold, and 4.65-fold respectively. Conclusion Our results indicate that Trigona honey may be an effective inhibitor and virulence modulator of P. aeruginosa and S. pyogenes via multiple molecular targets. This deduction needs to be investigated in vivo.
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Affiliation(s)
| | - Abu Bakar Mohd Hilmi
- Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | | | - Nour A Elsahoryi
- Department of Nutrition /Faculty of Pharmacy and Medical Sciences/University of Petra/Amman/Jordan
| | - Norzawani Jaffar
- Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | - Mohd Khairi Zahri
- Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
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9
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Antibiotic resistance related to biofilm formation in Streptococcus suis. Appl Microbiol Biotechnol 2020; 104:8649-8660. [PMID: 32897417 DOI: 10.1007/s00253-020-10873-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/23/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022]
Abstract
Streptococcus suis (S. suis) is an important zoonotic agent, which seriously impacts the pig industry and human health in various countries. Biofilm formation is likely contributing to the virulence and drug resistance in S. suis. A better knowledge of biofilm formation as well as to biofilm-dependent drug resistance mechanisms in S. suis can be of great significance for the prevention and treatment of S. suis infections. This literature review updates the latest scientific data related to biofilm formation in S. suis and its impact on drug tolerance and resistance.Key points• Biofilm formation is the important reasons for drug resistance of SS infections.• The review includes the regulatory mechanism of SS biofilm formation.• The review includes the drug resistance mechanisms of SS biofilm.
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Anani H, Zgheib R, Hasni I, Raoult D, Fournier PE. Interest of bacterial pangenome analyses in clinical microbiology. Microb Pathog 2020; 149:104275. [PMID: 32562810 DOI: 10.1016/j.micpath.2020.104275] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/12/2022]
Abstract
Thanks to the progress and decreasing costs in genome sequencing technologies, more than 250,000 bacterial genomes are currently available in public databases, covering most, if not all, of the major human-associated phylogenetic groups of these microorganisms, pathogenic or not. In addition, for many of them, sequences from several strains of a given species are available, thus enabling to evaluate their genetic diversity and study their evolution. In addition, the significant cost reduction of bacterial whole genome sequencing as well as the rapid increase in the number of available bacterial genomes have prompted the development of pangenomic software tools. The study of bacterial pangenome has many applications in clinical microbiology. It can unveil the pathogenic potential and ability of bacteria to resist antimicrobials as well identify specific sequences and predict antigenic epitopes that allow molecular or serologic assays and vaccines to be designed. Bacterial pangenome constitutes a powerful method for understanding the history of human bacteria and relating these findings to diagnosis in clinical microbiology laboratories in order to optimize patient management.
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Affiliation(s)
- Hussein Anani
- Aix Marseille Univ, Institut de Recherche pour le Développement (IRD), Service de Santé des Armées, AP-HM, UMR Vecteurs Infections Tropicales et Méditerranéennes (VITROME), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France; Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Rita Zgheib
- Aix Marseille Univ, Institut de Recherche pour le Développement (IRD), Service de Santé des Armées, AP-HM, UMR Vecteurs Infections Tropicales et Méditerranéennes (VITROME), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France; Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Issam Hasni
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France; Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), UMR Microbes Evolution Phylogeny and Infections (MEPHI), Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Didier Raoult
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France; Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), UMR Microbes Evolution Phylogeny and Infections (MEPHI), Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France; Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Pierre-Edouard Fournier
- Aix Marseille Univ, Institut de Recherche pour le Développement (IRD), Service de Santé des Armées, AP-HM, UMR Vecteurs Infections Tropicales et Méditerranéennes (VITROME), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France; Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France.
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11
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Jain I, Sarkar P, Danger JL, Medicielo J, Roshika R, Calfee G, Ramalinga A, Burgess C, Sumby P. A Mobile Genetic Element Promotes the Association Between Serotype M28 Group A Streptococcus Isolates and Cases of Puerperal Sepsis. J Infect Dis 2020; 220:882-891. [PMID: 31107945 DOI: 10.1093/infdis/jiz195] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 04/18/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Bacterial infections following childbirth-so-called puerperal infections-cause morbidity in 5%-10% of all new mothers. At low frequency, the infection can spread to the blood, resulting in life-threatening sepsis known as puerperal sepsis. Pathogens causing puerperal sepsis include group A Streptococcus (GAS), and epidemiological analyses have identified isolates of a single serotype, M28, as being nonrandomly associated with cases of puerperal sepsis. The genomes of serotype M28 GAS isolates harbor a 36.3-kb mobile genetic element of apparent group B Streptococcus origin, termed region of difference 2 (RD2). METHODS The phenotypic (determined via tissue culture and a vaginal colonization model) and regulatory (determined via RNA sequencing analysis) contributions of RD2 were assessed by comparing parental, RD2 deletion mutant, and complemented mutant serotype M28 GAS strains. RESULTS RD2 affords serotype M28 isolates an enhanced ability to adhere to human vaginal epithelial cells and to colonize the female reproductive tract in a mouse model of infection. In addition, RD2 influences the abundance of messenger RNAs from >100 core chromosomal GAS genes. CONCLUSIONS The data are consistent with RD2 directly, via encoded virulence factors, and indirectly, via encoded regulatory proteins, modifying the virulence potential of GAS and contributing to the decades-old association of serotype M28 isolates with cases of puerperal sepsis.
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Affiliation(s)
- Ira Jain
- Department of Microbiology and Immunology, University of Nevada-Reno School of Medicine
| | - Poulomee Sarkar
- Department of Microbiology and Immunology, University of Nevada-Reno School of Medicine
| | - Jessica L Danger
- Department of Microbiology and Immunology, University of Nevada-Reno School of Medicine
| | - Josette Medicielo
- Department of Microbiology and Immunology, University of Nevada-Reno School of Medicine
| | - Roshika Roshika
- Department of Microbiology and Immunology, University of Nevada-Reno School of Medicine
| | - Gregory Calfee
- Department of Microbiology and Immunology, University of Nevada-Reno School of Medicine
| | - Anupama Ramalinga
- Department of Microbiology and Immunology, University of Nevada-Reno School of Medicine
| | - Cameron Burgess
- Department of Microbiology and Immunology, University of Nevada-Reno School of Medicine
| | - Paul Sumby
- Department of Microbiology and Immunology, University of Nevada-Reno School of Medicine
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12
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Genetic evolution of invasive emm28 Streptococcus pyogenes strains and significant association with puerperal infections in young women in Finland. Clin Microbiol Infect 2020; 27:420-427. [PMID: 32289480 PMCID: PMC7780161 DOI: 10.1016/j.cmi.2020.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 03/20/2020] [Accepted: 04/04/2020] [Indexed: 02/08/2023]
Abstract
OBJECTIVES Streptococcus pyogenes or group A streptococcus (GAS) is a human specific pathogen that annually infects over 700 million individuals. GAS strains of type emm28 are an abundant cause of invasive infections in Europe and North America. METHODS We conducted a population-based study on bacteraemic emm28 GAS cases in Finland, from 1995 to 2015. Whole-genome sequencing (WGS) was used to genetically characterize the bacterial isolates. Bayesian analysis of the population structure was used to define genetic clades. Register-linkage analysis was performed to test for association of emm28 GAS with delivery- or postpartum-related infections. A genome-wide association study was used to search for DNA sequences associated with delivery or puerperal infections. RESULTS Among 3060 bacteraemic cases reported during the study period, 714 were caused by emm28. Women comprised a majority of cases (59 %, 422/714), and were significantly over-represented (84.4 %, 162/192, p < 0.0001) among cases in the childbearing age group (20-40 years). Register-linkage analysis revealed strong association (p < 0.0001) of emm28 bacteraemias with delivery and puerperium. In this register-linkage analysis, 120 women with GAS bacteraemia were identified and linked to delivery, infections during delivery or puerperium time. Among these the proportion of cases caused by emm28 was significantly higher than any other emm type (55.8%, 67/120, p < 0.0001). Among the four genetic subclades identified, SC1B has dominated among the bacteraemic cases since 2000. Altogether 620 of 653 (94.9%) isolates belonged to SC1B. No specific sequence or genetic clade was found nonrandomly associated with delivery or puerperal infections. CONCLUSIONS Women of childbearing age were significantly overrepresented among bacteraemic emm28 GAS cases, and in particular were strongly associated with delivery and puerperium cases over the 21 years studied. The molecular mechanisms behind these associations are unclear and warrant further investigation.
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13
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Eraso JM, Kachroo P, Olsen RJ, Beres SB, Zhu L, Badu T, Shannon S, Cantu CC, Saavedra MO, Kubiak SL, Porter AR, DeLeo FR, Musser JM. Genetic heterogeneity of the Spy1336/R28-Spy1337 virulence axis in Streptococcus pyogenes and effect on gene transcript levels and pathogenesis. PLoS One 2020; 15:e0229064. [PMID: 32214338 PMCID: PMC7098570 DOI: 10.1371/journal.pone.0229064] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/28/2020] [Indexed: 12/20/2022] Open
Abstract
Streptococcus pyogenes is a strict human pathogen responsible for more than 700 million infections annually worldwide. Strains of serotype M28 S. pyogenes are typically among the five more abundant types causing invasive infections and pharyngitis in adults and children. Type M28 strains also have an unusual propensity to cause puerperal sepsis and neonatal disease. We recently discovered that a one-nucleotide indel in an intergenic homopolymeric tract located between genes Spy1336/R28 and Spy1337 altered virulence in a mouse model of infection. In the present study, we analyzed size variation in this homopolymeric tract and determined the extent of heterogeneity in the number of tandemly-repeated 79-amino acid domains in the coding region of Spy1336/R28 in large samples of strains recovered from humans with invasive infections. Both repeat sequence elements are highly polymorphic in natural populations of M28 strains. Variation in the homopolymeric tract results in (i) changes in transcript levels of Spy1336/R28 and Spy1337 in vitro, (ii) differences in virulence in a mouse model of necrotizing myositis, and (iii) global transcriptome changes as shown by RNAseq analysis of isogenic mutant strains. Variation in the number of tandem repeats in the coding sequence of Spy1336/R28 is responsible for size variation of R28 protein in natural populations. Isogenic mutant strains in which genes encoding R28 or transcriptional regulator Spy1337 are inactivated are significantly less virulent in a nonhuman primate model of necrotizing myositis. Our findings provide impetus for additional studies addressing the role of R28 and Spy1337 variation in pathogen-host interactions.
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Affiliation(s)
- Jesus M. Eraso
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Priyanka Kachroo
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Randall J. Olsen
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
- Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, New York, New York, United States of America
| | - Stephen B. Beres
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Luchang Zhu
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Traci Badu
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Sydney Shannon
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Concepcion C. Cantu
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Matthew Ojeda Saavedra
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Samantha L. Kubiak
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Adeline R. Porter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Frank R. DeLeo
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - James M. Musser
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
- Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, New York, New York, United States of America
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14
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Genome-Wide Screens Identify Group A Streptococcus Surface Proteins Promoting Female Genital Tract Colonization and Virulence. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:862-873. [PMID: 32200972 DOI: 10.1016/j.ajpath.2019.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/04/2019] [Accepted: 12/17/2019] [Indexed: 02/07/2023]
Abstract
Group A streptococcus (GAS) is a major pathogen that impacts health and economic affairs worldwide. Although the oropharynx is the primary site of infection, GAS can colonize the female genital tract and cause severe diseases, such as puerperal sepsis, neonatal infections, and necrotizing myometritis. Our understanding of how GAS genes contribute to interaction with the primate female genital tract is limited by the lack of relevant animal models. Using two genome-wide transposon mutagenesis screens, we identified 69 GAS genes required for colonization of the primate vaginal mucosa in vivo and 96 genes required for infection of the uterine wall ex vivo. We discovered a common set of 39 genes important for GAS fitness in both environments. They include genes encoding transporters, surface proteins, transcriptional regulators, and metabolic pathways. Notably, the genes that encode the surface-exclusion protein (SpyAD) and the immunogenic secreted protein 2 (Isp2) were found to be crucial for GAS fitness in the female primate genital tract. Targeted gene deletion confirmed that isogenic mutant strains ΔspyAD and Δisp2 are significantly impaired in ability to colonize the primate genital tract and cause uterine wall pathologic findings. Our studies identified novel GAS genes that contribute to female reproductive tract interaction that warrant translational research investigation.
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15
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The Group B Streptococcal surface antigen I/II protein, BspC, interacts with host vimentin to promote adherence to brain endothelium and inflammation during the pathogenesis of meningitis. PLoS Pathog 2019; 15:e1007848. [PMID: 31181121 PMCID: PMC6586375 DOI: 10.1371/journal.ppat.1007848] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 06/20/2019] [Accepted: 05/16/2019] [Indexed: 12/29/2022] Open
Abstract
Streptococcus agalactiae (Group B Streptococcus, GBS) normally colonizes healthy adults but can cause invasive disease, such as meningitis, in the newborn. To gain access to the central nervous system, GBS must interact with and penetrate brain or meningeal blood vessels; however, the exact mechanisms are still being elucidated. Here, we investigate the contribution of BspC, an antigen I/II family adhesin, to the pathogenesis of GBS meningitis. Disruption of the bspC gene reduced GBS adherence to human cerebral microvascular endothelial cells (hCMEC), while heterologous expression of BspC in non-adherent Lactococcus lactis conferred bacterial attachment. In a murine model of hematogenous meningitis, mice infected with ΔbspC mutants exhibited lower mortality as well as decreased brain bacterial counts and inflammatory infiltrate compared to mice infected with WT GBS strains. Further, BspC was both necessary and sufficient to induce neutrophil chemokine expression. We determined that BspC interacts with the host cytoskeleton component vimentin and confirmed this interaction using a bacterial two-hybrid assay, microscale thermophoresis, immunofluorescent staining, and imaging flow cytometry. Vimentin null mice were protected from WT GBS infection and also exhibited less inflammatory cytokine production in brain tissue. These results suggest that BspC and the vimentin interaction is critical for the pathogenesis of GBS meningitis. Group B Streptococcus (GBS) typically colonizes healthy adults but can cause severe disease in immune-compromised individuals, including newborns. Despite wide-spread intrapartum antibiotic prophylaxis given to pregnant women, GBS remains a leading cause of neonatal meningitis. To cause meningitis, GBS must interact with and penetrate the blood-brain barrier (BBB), which separates bacteria and immune cells in the blood from the brain. In order to develop targeted therapies to treat GBS meningitis, it is important to understand the mechanisms of BBB crossing. Here, we describe the role of the GBS surface factor, BspC, in promoting meningitis and discover the host ligand for BspC, vimentin, which is an intermediate filament protein that is constitutively expressed by endothelial cells. We determined that BspC interacts with the C-terminal domain of cell-surface vimentin to promote bacterial attachment to brain endothelial cells and that purified BspC protein can induce immune signaling pathways. In a mouse model of hematogenous meningitis, we observed that a GBS mutant lacking BspC was less virulent compared to WT GBS and resulted in less inflammatory disease. We also observed that mice lacking vimentin were protected from GBS infection. These results reveal the importance of the BspC-vimentin interaction in the progression of GBS meningitis disease.
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16
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Issa E, Salloum T, Panossian B, Ayoub D, Abboud E, Tokajian S. Genome Mining and Comparative Analysis of Streptococcus intermedius Causing Brain Abscess in a Child. Pathogens 2019; 8:pathogens8010022. [PMID: 30781742 PMCID: PMC6471051 DOI: 10.3390/pathogens8010022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/18/2019] [Accepted: 01/30/2019] [Indexed: 01/09/2023] Open
Abstract
Streptococcus intermedius (SI) is associated with prolonged hospitalization and low survival rates. The genetic mechanisms involved in brain abscess development and genome evolution in comparison to other members of the Streptococcus anginosus group are understudied. We performed a whole-genome comparative analysis of an SI isolate, LAU_SINT, associated with brain abscess following sinusitis with all SI genomes in addition to S. constellatus and S. anginosus. Selective pressure on virulence factors, phages, pan-genome evolution and single-nucleotide polymorphism analysis were assessed. The structural details of the type seven secretion system (T7SS) was elucidated and compared with different organisms. ily and nanA were both abundant and conserved. Nisin resistance determinants were found in 47% of the isolates. Pan-genome and SNPs-based analysis didn’t reveal significant geo-patterns. Our results showed that two SC isolates were misidentified as SI. We propose the presence of four T7SS modules (I–IV) located on various genomic islands. We detected a variety of factors linked to metal ions binding on the GIs carrying T7SS. This is the first detailed report characterizing the T7SS and its link to nisin resistance and metal ions binding in SI. These and yet uncharacterized T7SS transmembrane proteins merit further studies and could represent potential therapeutic targets.
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Affiliation(s)
- Elio Issa
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Byblos 36, Lebanon.
| | - Tamara Salloum
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Byblos 36, Lebanon.
| | - Balig Panossian
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Byblos 36, Lebanon.
| | - David Ayoub
- Department of Neurosurgery, the Middle East Institute of Health University Hospital, Beirut 60-387, Lebanon.
| | - Edmond Abboud
- Laboratory Department, the Middle East Institute of Health University Hospital, Beirut 60-387, Lebanon.
| | - Sima Tokajian
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Byblos 36, Lebanon.
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17
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Weckel A, Ahamada D, Bellais S, Méhats C, Plainvert C, Longo M, Poyart C, Fouet A. The N-terminal domain of the R28 protein promotes emm28 group A Streptococcus adhesion to host cells via direct binding to three integrins. J Biol Chem 2018; 293:16006-16018. [PMID: 30150299 DOI: 10.1074/jbc.ra118.004134] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/20/2018] [Indexed: 01/07/2023] Open
Abstract
Group A Streptococcus (GAS) is a human-specific pathogen responsible for a wide range of diseases, ranging from superficial to life-threatening invasive infections, including endometritis, and autoimmune sequelae. GAS strains express a vast repertoire of virulence factors that varies depending on the strain genotype, and many adhesin proteins that enable GAS to adhere to host cells are restricted to some genotypes. GAS emm28 is the third most prevalent genotype in invasive infections in France and is associated with gyneco-obstetrical infections. emm28 strains harbor R28, a cell wall-anchored surface protein that has previously been reported to promote adhesion to cervical epithelial cells. Here, using cellular and biochemical approaches, we sought to determine whether R28 supports adhesion also to other cells and to characterize its cognate receptor. We show that through its N-terminal domain, R28Nt, R28 promotes bacterial adhesion to both endometrial-epithelial and endometrial-stromal cells. R28Nt was further subdivided into two domains, and we found that both are involved in cell binding. R28Nt and both subdomains interacted directly with the laminin-binding α3β1, α6β1, and α6β4 integrins; interestingly, these bindings events did not require divalent cations. R28 is the first GAS adhesin reported to bind directly to integrins that are expressed in most epithelial cells. Finally, R28Nt also promoted binding to keratinocytes and pulmonary epithelial cells, suggesting that it may be involved in supporting the prevalence in invasive infections of the emm28 genotype.
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Affiliation(s)
- Antonin Weckel
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Dorian Ahamada
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Samuel Bellais
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Céline Méhats
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Céline Plainvert
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and.,the Centre National de Référence des Streptocoques and.,the Hôpitaux Universitaires Paris Centre, Institut Cochin, Assistance Publique Hôpitaux de Paris, 75014 Paris, France
| | - Magalie Longo
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and
| | - Claire Poyart
- From the INSERM U1016, Institut Cochin.,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and.,the Centre National de Référence des Streptocoques and.,the Hôpitaux Universitaires Paris Centre, Institut Cochin, Assistance Publique Hôpitaux de Paris, 75014 Paris, France
| | - Agnès Fouet
- From the INSERM U1016, Institut Cochin, .,CNRS UMR 8104, and.,Université Paris Descartes, UMR-S1016 Paris, France and.,the Centre National de Référence des Streptocoques and
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18
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Sitkiewicz I. How to become a killer, or is it all accidental? Virulence strategies in oral streptococci. Mol Oral Microbiol 2017; 33:1-12. [PMID: 28727895 DOI: 10.1111/omi.12192] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2017] [Indexed: 01/03/2023]
Abstract
Streptococci are a diverse group of Gram-positive microorganisms sharing common virulence traits and similar strategies to escape the oral niche and establish an infection in other parts of the host organism. Invasive infection with oral streptococci is "a perfect storm" that requires the concerted action of multiple biotic and abiotic factors. Our understanding of streptococcal pathogenicity and infectivity should probably be less mechanistic and driven not only by the identification of novel virulence factors. The observed diversity of the genus, including the range of virulence and pathogenicity mechanisms, is most likely the result of interspecies interactions, a massive horizontal gene transfer between streptococci within a shared oral niche, recombination events, selection of specialized clones, and modification of regulatory circuits. Selective pressure by the host and bacterial communities is a driving force for the selection of virulence traits and shaping the streptococcal genome. Global regulatory events driving niche adaptation and interactions with bacterial communities and the host steer research interests towards attempts to define the oral interactome on the transcriptional level and define signal cross-feeding and co-expression and co-regulation of virulence genes.
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Affiliation(s)
- I Sitkiewicz
- Department of Molecular Microbiology, National Medicines Institute, Warsaw, Poland
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19
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Chuzeville S, Auger JP, Dumesnil A, Roy D, Lacouture S, Fittipaldi N, Grenier D, Gottschalk M. Serotype-specific role of antigen I/II in the initial steps of the pathogenesis of the infection caused by Streptococcus suis. Vet Res 2017; 48:39. [PMID: 28705175 PMCID: PMC5513104 DOI: 10.1186/s13567-017-0443-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 06/19/2017] [Indexed: 01/15/2023] Open
Abstract
Streptococcus suis is one of the most important post-weaning porcine bacterial pathogens worldwide. The serotypes 2 and 9 are often considered the most virulent and prevalent serotypes involved in swine infections, especially in Europe. However, knowledge of the bacterial factors involved in the first steps of the pathogenesis of the infection remains scarce. In several pathogenic streptococci, expression of multimodal adhesion proteins known as antigen I/II (AgI/II) have been linked with persistence in the upper respiratory tract and the oral cavity, as well as with bacterial dissemination. Herein, we report expression of these immunostimulatory factors by S. suis serotype 2 and 9 strains and that AgI/II-encoding genes are carried by integrative and conjugative elements. Using mutagenesis and different in vitro assays, we demonstrate that the contribution of AgI/II to the virulence of the serotype 2 strain used herein appears to be modest. In contrast, data demonstrate that the serotype 9 AgI/II participates in self-aggregation, induces salivary glycoprotein 340-related aggregation, contributes to biofilm formation and increased strain resistance to low pH, as well as in bacterial adhesion to extracellular matrix proteins and epithelial cells. Moreover, the use of a porcine infection model revealed that AgI/II contributes to colonization of the upper respiratory tract of pigs. Taken together, these findings suggest that surface exposed AgI/II likely play a key role in the first steps of the pathogenesis of the S. suis serotype 9 infection.
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Affiliation(s)
- Sarah Chuzeville
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Saint-Hyacinthe, QC, Canada.,Groupe de recherche sur les maladies infectieuses en production animale (GREMIP), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte St., Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Jean-Philippe Auger
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Saint-Hyacinthe, QC, Canada.,Groupe de recherche sur les maladies infectieuses en production animale (GREMIP), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte St., Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Audrey Dumesnil
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Saint-Hyacinthe, QC, Canada.,Groupe de recherche sur les maladies infectieuses en production animale (GREMIP), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte St., Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - David Roy
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Saint-Hyacinthe, QC, Canada.,Groupe de recherche sur les maladies infectieuses en production animale (GREMIP), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte St., Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Sonia Lacouture
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Saint-Hyacinthe, QC, Canada.,Groupe de recherche sur les maladies infectieuses en production animale (GREMIP), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte St., Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Nahuel Fittipaldi
- Public Health Ontario Laboratory Toronto and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Daniel Grenier
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Saint-Hyacinthe, QC, Canada.,Oral Ecology Research Group, Faculty of Dentistry, Laval University, Quebec City, QC, Canada
| | - Marcelo Gottschalk
- Swine and Poultry Infectious Diseases Research Center (CRIPA), Saint-Hyacinthe, QC, Canada. .,Groupe de recherche sur les maladies infectieuses en production animale (GREMIP), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, 3200 Sicotte St., Saint-Hyacinthe, QC, J2S 2M2, Canada.
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20
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Rego S, Heal TJ, Pidwill GR, Till M, Robson A, Lamont RJ, Sessions RB, Jenkinson HF, Race PR, Nobbs AH. Structural and Functional Analysis of Cell Wall-anchored Polypeptide Adhesin BspA in Streptococcus agalactiae. J Biol Chem 2016; 291:15985-6000. [PMID: 27311712 DOI: 10.1074/jbc.m116.726562] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Indexed: 12/21/2022] Open
Abstract
Streptococcus agalactiae (group B Streptococcus, GBS) is the predominant cause of early-onset infectious disease in neonates and is responsible for life-threatening infections in elderly and immunocompromised individuals. Clinical manifestations of GBS infection include sepsis, pneumonia, and meningitis. Here, we describe BspA, a deviant antigen I/II family polypeptide that confers adhesive properties linked to pathogenesis in GBS. Heterologous expression of BspA on the surface of the non-adherent bacterium Lactococcus lactis confers adherence to scavenger receptor gp340, human vaginal epithelium, and to the fungus Candida albicans Complementary crystallographic and biophysical characterization of BspA reveal a novel β-sandwich adhesion domain and unique asparagine-dependent super-helical stalk. Collectively, these findings establish a new bacterial adhesin structure that has in effect been hijacked by a pathogenic Streptococcus species to provide competitive advantage in human mucosal infections.
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Affiliation(s)
- Sara Rego
- From the School of Oral and Dental Sciences, University of Bristol, Bristol BS1 2LY, United Kingdom, the School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Timothy J Heal
- the School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom, the Bristol Centre for Functional Nanomaterials, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Grace R Pidwill
- From the School of Oral and Dental Sciences, University of Bristol, Bristol BS1 2LY, United Kingdom
| | - Marisa Till
- the School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom, the BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom, and
| | - Alice Robson
- the School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Richard J Lamont
- the Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, Kentucky 40202
| | - Richard B Sessions
- the School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom, the BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom, and
| | - Howard F Jenkinson
- From the School of Oral and Dental Sciences, University of Bristol, Bristol BS1 2LY, United Kingdom
| | - Paul R Race
- the School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom, the BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom, and
| | - Angela H Nobbs
- From the School of Oral and Dental Sciences, University of Bristol, Bristol BS1 2LY, United Kingdom,
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21
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Carraro N, Libante V, Morel C, Charron-Bourgoin F, Leblond P, Guédon G. Plasmid-like replication of a minimal streptococcal integrative and conjugative element. MICROBIOLOGY-SGM 2016; 162:622-632. [PMID: 26825653 DOI: 10.1099/mic.0.000219] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Integrative and conjugative elements (ICEs) are mobile genetic elements encoding their own excision from a replicon of their bacterial host, transfer by conjugation to a recipient bacterium and reintegration for maintenance. The conjugation, recombination and regulation modules of ICEs of the ICESt3 family are grouped together in a region called the ICE 'core region'. In addition to this core region, elements belonging to this family carry a highly variable region including cargo genes that could be involved in bacterial adaptation or in the maintenance of the element. Although ICEs are a major class of mobile elements through bacterial genomes, the functionality of an element encoding only its excision, transfer, integration and regulation has never been demonstrated experimentally. We engineered MiniICESt3, an artificial ICE derived from ICESt3, devoid of its cargo genes and thus only harbouring the core region. The functionality of this minimal element was assessed. MiniICESt3 was found to be able to excise at a rate of 3.1 %, transfer with a frequency of 1.0 × 10- 5 transconjugants per donor cell and stably maintain by site-specific integration into the 3' end of the fda gene, the same as ICESt3. Furthermore, MiniICESt3 was found in ∼10 copies per chromosome, this multicopy state likely contributing to its stability for >100 generations even in the absence of selection. Therefore, although ICEs were primarily assumed to only replicate along with the chromosome, our results uncovered extrachromosomal rolling-circle replicating plasmid-like forms of MiniICESt3.
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Affiliation(s)
- Nicolas Carraro
- INRA, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France.,Université de Lorraine, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France
| | - Virginie Libante
- INRA, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France.,Université de Lorraine, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France
| | - Catherine Morel
- Université de Lorraine, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France.,INRA, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France
| | - Florence Charron-Bourgoin
- Université de Lorraine, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France.,INRA, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France
| | - Pierre Leblond
- Université de Lorraine, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France.,INRA, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France
| | - Gérard Guédon
- Université de Lorraine, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France.,INRA, DynAMic, UMR1128, Vandoeuvre-lès-Nancy, France
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22
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Abstract
Integrative and Conjugative Elements (ICEs) are bacterial mobile genetic elements that play a key role in bacterial genomes dynamics and evolution. ICEs are widely distributed among virtually all bacterial genera. Recent extensive studies have unraveled their high diversity and complexity. The present review depicts the general conserved features of ICEs and describes more precisely three major families of ICEs that have been extensively studied in the past decade for their biology, their evolution and their impact on genomes dynamics. First, the large SXT/R391 family of ICEs disseminates antibiotic resistance genes and drives the exchange of mobilizable genomic islands (MGIs) between many enteric pathogens such as Vibrio cholerae. Second, ICEBs1 of Bacillus subtilis is the most well understood ICE of Gram-positive bacteria, notably regarding the regulation of its dissemination and its initially unforeseen extrachromosomal replication, which could be a common feature of ICEs of both Gram-positive and Gram-negative bacteria. Finally, ICESt1 and ICESt3 of Streptococcus thermophilus are the prototypes of a large family of ICEs widely distributed among various streptococci. These ICEs carry an original regulation module that associates regulators related to those of both SXT/R391 and ICEBs1. Study of ICESt1 and ICESt3 uncovered the cis-mobilization of related genomic islands (CIMEs) by a mechanism called accretion-mobilization, which likely represents a paradigm for the evolution of many ICEs and genomic islands. These three major families of ICEs give a glimpse about ICEs dynamics and their high impact on bacterial adaptation.
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Huang J, Liang Y, Guo D, Shang K, Ge L, Kashif J, Wang L. Comparative Genomic Analysis of the ICESa2603 Family ICEs and Spread of erm(B)- and tet(O)-Carrying Transferable 89K-Subtype ICEs in Swine and Bovine Isolates in China. Front Microbiol 2016; 7:55. [PMID: 26870017 PMCID: PMC4735348 DOI: 10.3389/fmicb.2016.00055] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 01/13/2016] [Indexed: 11/13/2022] Open
Abstract
Integrative and conjugative elements (ICEs) of the ICESa2603 family have been isolated from several species of Streptococcus spp.; however, the comparative genomic and evolutionary analyses of these particular ICEs are currently only at their initial stages. By investigating 13 ICEs of the ICESa2603 family and two ICESa2603 family-like ICEs derived from diverse hosts and locations, we have determined that ICEs comprised a backbone of 30 identical syntenic core genes and accessory genes that were restricted to the intergenic sites or the 3′-end of the non-conserved domain of core genes to maintain its function. ICESa2603 family integrase IntICESa2603 specifically recognized a 15-bp att sequence (TTATTTAAGAGTAAC) at the 3′-end of rplL, which was highly conserved in genus Streptococcus. Phylogenetic analyses suggest that extensive recombination/insertion and the occurrence of a hybrid/mosaic in the ICESa2603 family were responsible for the significant increase in ICE diversity, thereby broadening its host range. Approximately 42.5 and 38.1% of the tested Streptococcus suis and Streptococcus agalactiae clinical isolates respectively contained ICESa2603 family Type IV secretion system (T4SS) genes, and 80.5 and 62.5% of which also respectively carried intICESa2603, indicating that ICESa2603 family is widely distributed across these bacteria. Sequencing and conjugation transfer of a novel sequence type ST303 clinical S. suis isolate HB1011 demonstrated that the 89K-subtype ICESsuHB1011 retained its transferrable function, thereby conferring tetracycline and macrolide resistance.
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Affiliation(s)
- Jinhu Huang
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Yuan Liang
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Dawei Guo
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Kexin Shang
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Lin Ge
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Jam Kashif
- Department of Veterinary Pharmacology, Sindh Agricultural University Tandojam, Pakistan
| | - Liping Wang
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
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Ambroset C, Coluzzi C, Guédon G, Devignes MD, Loux V, Lacroix T, Payot S, Leblond-Bourget N. New Insights into the Classification and Integration Specificity of Streptococcus Integrative Conjugative Elements through Extensive Genome Exploration. Front Microbiol 2016; 6:1483. [PMID: 26779141 PMCID: PMC4701971 DOI: 10.3389/fmicb.2015.01483] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 12/08/2015] [Indexed: 12/30/2022] Open
Abstract
Recent genome analyses suggest that integrative and conjugative elements (ICEs) are widespread in bacterial genomes and therefore play an essential role in horizontal transfer. However, only a few of these elements are precisely characterized and correctly delineated within sequenced bacterial genomes. Even though previous analysis showed the presence of ICEs in some species of Streptococci, the global prevalence and diversity of ICEs was not analyzed in this genus. In this study, we searched for ICEs in the completely sequenced genomes of 124 strains belonging to 27 streptococcal species. These exhaustive analyses revealed 105 putative ICEs and 26 slightly decayed elements whose limits were assessed and whose insertion site was identified. These ICEs were grouped in seven distinct unrelated or distantly related families, according to their conjugation modules. Integration of these streptococcal ICEs is catalyzed either by a site-specific tyrosine integrase, a low-specificity tyrosine integrase, a site-specific single serine integrase, a triplet of site-specific serine integrases or a DDE transposase. Analysis of their integration site led to the detection of 18 target-genes for streptococcal ICE insertion including eight that had not been identified previously (ftsK, guaA, lysS, mutT, rpmG, rpsI, traG, and ebfC). It also suggests that all specificities have evolved to minimize the impact of the insertion on the host. This overall analysis of streptococcal ICEs emphasizes their prevalence and diversity and demonstrates that exchanges or acquisitions of conjugation and recombination modules are frequent.
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Affiliation(s)
- Chloé Ambroset
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
| | - Charles Coluzzi
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
| | - Gérard Guédon
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
| | - Marie-Dominique Devignes
- Laboratoire Lorrain de Recherche en Informatique et ses Applications, Faculté des Sciences et Technologies, Université de Lorraine, UMR 7503Vandœuvre-lès-Nancy, France; CNRS, Laboratoire Lorrain de Recherche en Informatique et ses Applications, UMR 7503Vandśuvre-lès-Nancy, France
| | - Valentin Loux
- UR 1404 Mathématiques et Informatique Appliquées du Génome à l'Environnement, Institut National de la Recherche Agronomique Jouy-en-Josas, France
| | - Thomas Lacroix
- UR 1404 Mathématiques et Informatique Appliquées du Génome à l'Environnement, Institut National de la Recherche Agronomique Jouy-en-Josas, France
| | - Sophie Payot
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
| | - Nathalie Leblond-Bourget
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
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25
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Pietrocola G, Rindi S, Rosini R, Buccato S, Speziale P, Margarit I. The Group B Streptococcus-Secreted Protein CIP Interacts with C4, Preventing C3b Deposition via the Lectin and Classical Complement Pathways. THE JOURNAL OF IMMUNOLOGY 2015; 196:385-94. [PMID: 26608922 DOI: 10.4049/jimmunol.1501954] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/30/2015] [Indexed: 02/06/2023]
Abstract
The group B Streptococcus (GBS) is a leading cause of neonatal invasive disease. GBS bacteria are surrounded by a thick capsular polysaccharide that is a potent inhibitor of complement deposition via the alternative pathway. Several of its surface molecules can however activate the classical and lectin complement pathways, rendering this species still vulnerable to phagocytic killing. In this study we have identified a novel secreted protein named complement interfering protein (CIP) that downregulates complement activation via the classical and lectin pathways, but not the alternative pathway. The CIP protein showed high affinity toward C4b and inhibited its interaction with C2, presumably preventing the formation of the C4bC2a convertase. Addition of recombinant CIP to GBS cip-negative bacteria resulted in decreased deposition of C3b on their surface and in diminished phagocytic killing in a whole-blood assay. Our data reveal a novel strategy exploited by GBS to counteract innate immunity and could be valuable for the development of anti-infective agents against this important pathogen.
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Affiliation(s)
- Giampiero Pietrocola
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, 27100 Pavia, Italy; and
| | - Simonetta Rindi
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, 27100 Pavia, Italy; and
| | | | | | - Pietro Speziale
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, 27100 Pavia, Italy; and
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Carraro N, Burrus V. The dualistic nature of integrative and conjugative elements. Mob Genet Elements 2015; 5:98-102. [PMID: 26942046 PMCID: PMC4755238 DOI: 10.1080/2159256x.2015.1102796] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 09/26/2015] [Indexed: 11/23/2022] Open
Abstract
Integrative and conjugative elements (ICEs) are mobile genetic elements that play a key role in bacterial adaptation. Such elements are found in almost every bacterial genera and species, and often code for adaptive traits conferring selective advantages to their host. ICEs maintain by integrating into and replicating along with a replicon of the host genome. ICEs can propagate by conjugative transfer toward a recipient cell following excision from the replicon as a circular covalently-closed molecule. For a long time, the excised form of ICEs was assumed to be non-replicative. This assumption predicts that excised ICEs are sensitive to loss during cell division, unless they carry stabilization systems such as addiction modules or antibiotic resistance genes. Over the past few years, growing evidence have been presented that support conditional replication of the circular intermediate as an intrinsic feature of ICEs. We recently confirmed this feature in the large family of SXT/R391 ICEs, which thrive in several species of Enterobacteriaceae and Vibrionaceae. Furthermore, we demonstrated that SXT/R391 ICEs encode a functional plasmid-like type II partition system that enhances their stability, such systems being probably encoded by other ICEs. The lifecycle of ICEs is therefore much more complex than initially thought as many ICEs may use plasmid-like features to improve their stability and dissemination.
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Affiliation(s)
- Nicolas Carraro
- Laboratory of Bacterial Molecular Genetics; Département de Biologie; Université de Sherbrooke ; Sherbrooke, Canada
| | - Vincent Burrus
- Laboratory of Bacterial Molecular Genetics; Département de Biologie; Université de Sherbrooke ; Sherbrooke, Canada
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27
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Abstract
Horizontal gene transfer plays a major role in microbial evolution, allowing microbes to acquire new genes and phenotypes. Integrative and conjugative elements (ICEs, a.k.a. conjugative transposons) are modular mobile genetic elements integrated into a host genome and are passively propagated during chromosomal replication and cell division. Induction of ICE gene expression leads to excision, production of the conserved conjugation machinery (a type IV secretion system), and the potential to transfer DNA to appropriate recipients. ICEs typically contain cargo genes that are not usually related to the ICE life cycle and that confer phenotypes to host cells. We summarize the life cycle and discovery of ICEs, some of the regulatory mechanisms, and how the types of cargo have influenced our view of ICEs. We discuss how ICEs can acquire new cargo genes and describe challenges to the field and various perspectives on ICE biology.
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Affiliation(s)
- Christopher M Johnson
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; ,
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Poulin-Laprade D, Carraro N, Burrus V. The extended regulatory networks of SXT/R391 integrative and conjugative elements and IncA/C conjugative plasmids. Front Microbiol 2015; 6:837. [PMID: 26347724 PMCID: PMC4542580 DOI: 10.3389/fmicb.2015.00837] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 07/31/2015] [Indexed: 12/14/2022] Open
Abstract
Nowadays, healthcare systems are challenged by a major worldwide drug resistance crisis caused by the massive and rapid dissemination of antibiotic resistance genes and associated emergence of multidrug resistant pathogenic bacteria, in both clinical and environmental settings. Conjugation is the main driving force of gene transfer among microorganisms. This mechanism of horizontal gene transfer mediates the translocation of large DNA fragments between two bacterial cells in direct contact. Integrative and conjugative elements (ICEs) of the SXT/R391 family (SRIs) and IncA/C conjugative plasmids (ACPs) are responsible for the dissemination of a broad spectrum of antibiotic resistance genes among diverse species of Enterobacteriaceae and Vibrionaceae. The biology, diversity, prevalence and distribution of these two families of conjugative elements have been the subject of extensive studies for the past 15 years. Recently, the transcriptional regulators that govern their dissemination through the expression of ICE- or plasmid-encoded transfer genes have been described. Unrelated repressors control the activation of conjugation by preventing the expression of two related master activator complexes in both types of elements, i.e., SetCD in SXT/R391 ICEs and AcaCD in IncA/C plasmids. Finally, in addition to activating ICE- or plasmid-borne genes, these master activators have been shown to specifically activate phylogenetically unrelated mobilizable genomic islands (MGIs) that also disseminate antibiotic resistance genes and other adaptive traits among a plethora of pathogens such as Vibrio cholerae and Salmonella enterica.
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Affiliation(s)
- Dominic Poulin-Laprade
- Laboratory of Bacterial Molecular Genetics, Département de Biologie, Faculté des Sciences, Université de Sherbrooke , Sherbrooke, QC, Canada
| | - Nicolas Carraro
- Laboratory of Bacterial Molecular Genetics, Département de Biologie, Faculté des Sciences, Université de Sherbrooke , Sherbrooke, QC, Canada
| | - Vincent Burrus
- Laboratory of Bacterial Molecular Genetics, Département de Biologie, Faculté des Sciences, Université de Sherbrooke , Sherbrooke, QC, Canada
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29
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Bessen DE, McShan WM, Nguyen SV, Shetty A, Agrawal S, Tettelin H. Molecular epidemiology and genomics of group A Streptococcus. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2015; 33:393-418. [PMID: 25460818 PMCID: PMC4416080 DOI: 10.1016/j.meegid.2014.10.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 10/11/2014] [Accepted: 10/13/2014] [Indexed: 12/15/2022]
Abstract
Streptococcus pyogenes (group A Streptococcus; GAS) is a strict human pathogen with a very high prevalence worldwide. This review highlights the genetic organization of the species and the important ecological considerations that impact its evolution. Recent advances are presented on the topics of molecular epidemiology, population biology, molecular basis for genetic change, genome structure and genetic flux, phylogenomics and closely related streptococcal species, and the long- and short-term evolution of GAS. The application of whole genome sequence data to addressing key biological questions is discussed.
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Affiliation(s)
- Debra E Bessen
- Department of Microbiology & Immunology, New York Medical College, Valhalla, NY 10595, USA.
| | - W Michael McShan
- University of Oklahoma Health Sciences Center, Department of Pharmaceutical Sciences, College of Pharmacy, Oklahoma City, OK 73117, USA.
| | - Scott V Nguyen
- University of Oklahoma Health Sciences Center, Department of Pharmaceutical Sciences, College of Pharmacy, Oklahoma City, OK 73117, USA.
| | - Amol Shetty
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Sonia Agrawal
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Hervé Tettelin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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30
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Generic determinants of Streptococcus colonization and infection. INFECTION GENETICS AND EVOLUTION 2015; 33:361-70. [DOI: 10.1016/j.meegid.2014.09.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/10/2014] [Accepted: 09/14/2014] [Indexed: 11/20/2022]
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31
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Carraro N, Poulin D, Burrus V. Replication and Active Partition of Integrative and Conjugative Elements (ICEs) of the SXT/R391 Family: The Line between ICEs and Conjugative Plasmids Is Getting Thinner. PLoS Genet 2015; 11:e1005298. [PMID: 26061412 PMCID: PMC4489591 DOI: 10.1371/journal.pgen.1005298] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 05/23/2015] [Indexed: 02/07/2023] Open
Abstract
Integrative and Conjugative Elements (ICEs) of the SXT/R391 family disseminate multidrug resistance among pathogenic Gammaproteobacteria such as Vibrio cholerae. SXT/R391 ICEs are mobile genetic elements that reside in the chromosome of their host and eventually self-transfer to other bacteria by conjugation. Conjugative transfer of SXT/R391 ICEs involves a transient extrachromosomal circular plasmid-like form that is thought to be the substrate for single-stranded DNA translocation to the recipient cell through the mating pore. This plasmid-like form is thought to be non-replicative and is consequently expected to be highly unstable. We report here that the ICE R391 of Providencia rettgeri is impervious to loss upon cell division. We have investigated the genetic determinants contributing to R391 stability. First, we found that a hipAB-like toxin/antitoxin system improves R391 stability as its deletion resulted in a tenfold increase of R391 loss. Because hipAB is not a conserved feature of SXT/R391 ICEs, we sought for alternative and conserved stabilization mechanisms. We found that conjugation itself does not stabilize R391 as deletion of traG, which abolishes conjugative transfer, did not influence the frequency of loss. However, deletion of either the relaxase-encoding gene traI or the origin of transfer (oriT) led to a dramatic increase of R391 loss correlated with a copy number decrease of its plasmid-like form. This observation suggests that replication initiated at oriT by TraI is essential not only for conjugative transfer but also for stabilization of SXT/R391 ICEs. Finally, we uncovered srpMRC, a conserved locus coding for two proteins distantly related to the type II (actin-type ATPase) parMRC partitioning system of plasmid R1. R391 and plasmid stabilization assays demonstrate that srpMRC is active and contributes to reducing R391 loss. While partitioning systems usually stabilizes low-copy plasmids, srpMRC is the first to be reported that stabilizes a family of ICEs.
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Affiliation(s)
- Nicolas Carraro
- Laboratory of bacterial molecular genetics, Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Dominique Poulin
- Laboratory of bacterial molecular genetics, Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Vincent Burrus
- Laboratory of bacterial molecular genetics, Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
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32
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McNeilly CL, McMillan DJ. Horizontal gene transfer and recombination in Streptococcus dysgalactiae subsp. equisimilis. Front Microbiol 2014; 5:676. [PMID: 25566202 PMCID: PMC4266089 DOI: 10.3389/fmicb.2014.00676] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 11/19/2014] [Indexed: 11/13/2022] Open
Abstract
Streptococcus dysgalactiae subsp. equisimilis (SDSE) is a human pathogen that colonizes the skin or throat, and causes a range of diseases from relatively benign pharyngitis to potentially fatal invasive diseases. While not as virulent as the close relative Streptococcus pyogenes the two share a number of virulence factors and are known to coexist in a human host. Both pre- and post-genomic studies have revealed that horizontal gene transfer (HGT) and recombination occurs between these two organisms and plays a major role in shaping the population structure of SDSE. This review summarizes our current knowledge of HGT and recombination in the evolution of SDSE.
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Affiliation(s)
- Celia L McNeilly
- Bacterial Pathogenesis Laboratory, QIMR Berghofer Medical Research Institute , Herston, QLD, Australia
| | - David J McMillan
- Inflammation and Healing Research Cluster, School of Health and Sport Sciences, University of the Sunshine Coast , Maroochydore, QLD, Australia
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33
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Bellanger X, Payot S, Leblond-Bourget N, Guédon G. Conjugative and mobilizable genomic islands in bacteria: evolution and diversity. FEMS Microbiol Rev 2014; 38:720-60. [DOI: 10.1111/1574-6976.12058] [Citation(s) in RCA: 223] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 11/15/2013] [Accepted: 12/19/2013] [Indexed: 11/28/2022] Open
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DrsG from Streptococcus dysgalactiae subsp. equisimilis inhibits the antimicrobial peptide LL-37. Infect Immun 2014; 82:2337-44. [PMID: 24664506 DOI: 10.1128/iai.01411-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SIC and DRS are related proteins present in only 4 of the >200 Streptococcus pyogenes emm types. These proteins inhibit complement-mediated lysis and/or the activity of certain antimicrobial peptides (AMPs). A gene encoding a homologue of these proteins, herein called DrsG, has been identified in the related bacterium Streptococcus dysgalactiae subsp. equisimilis. Here we show that geographically dispersed isolates representing 14 of 50 emm types examined possess variants of drsG. However, not all isolates within the drsG-positive emm types possess the gene. Sequence comparisons also revealed a high degree of conservation in different S. dysgalactiae subsp. equisimilis emm types. To examine the biological activity of DrsG, recombinant versions of two major DrsG variants, DrsGS and DrsGL, were expressed and purified. Western blot analysis using antisera raised to these proteins demonstrated both variants to be expressed and secreted into culture supernatants. Unlike SIC, but similar to DRS, DrsG does not inhibit complement-mediated lysis. However, like both SIC and DRS, DrsG is a ligand of the cathelicidin LL-37 and is inhibitory to its bactericidal activity in in vitro assays. Conservation of prolines in the C-terminal region also suggests that these residues are important in the biology of this family of proteins. This is the first report demonstrating the activity of an AMP-inhibitory protein in S. dysgalactiae subsp. equisimilis and suggests that inhibition of AMP activity is the primary function of this family of proteins. The acquisition of the complement-inhibitory activity of SIC may reflect its continuing evolution.
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35
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Marks LR, Mashburn-Warren L, Federle MJ, Hakansson AP. Streptococcus pyogenes biofilm growth in vitro and in vivo and its role in colonization, virulence, and genetic exchange. J Infect Dis 2014; 210:25-34. [PMID: 24465015 DOI: 10.1093/infdis/jiu058] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Group A streptococcus (GAS) commonly colonizes the oropharynx and nonintact skin. However, colonization has been little studied and the role of biofilm formation is unclear, as biofilm experiments to date have not been conducted under conditions that mimic the host environment. METHODS In this study we grew GAS biofilms on human keratinocytes under various environmental conditions and used this model to evaluate colonization, invasive disease and natural transformation. RESULTS GAS grown on epithelial cells, but not biofilms grown on abiotic surfaces, produced biofilms with characteristics similar to in vivo colonization. These biofilm bacteria showed a 100-fold higher bacterial burden of nasal-associated lymphoid tissue in mice than broth-grown bacteria, and were not virulent during septic infection, which was attributed in part to down-regulation of genes typically involved in localized and invasive disease. We also showed for the first time that GAS were naturally transformable when grown in biofilms and during colonization of NALT in vivo. CONCLUSIONS These findings provide novel model systems to study biofilm formation of GAS in vitro and in vivo, suggest an important role for biofilm formation during GAS colonization, and provide an explanation for the known genome diversity within the GAS population.
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36
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Gherardi G, Imperi M, Palmieri C, Magi G, Facinelli B, Baldassarri L, Pataracchia M, Creti R. Genetic diversity and virulence properties of Streptococcus dysgalactiae subsp. equisimilis from different sources. J Med Microbiol 2014; 63:90-98. [DOI: 10.1099/jmm.0.062109-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A recent increase in virulence of pathogenic Streptococcus dysgalactiae subsp. equisimilis (SDSE) has been widely proposed. Such an increase may be partly explained by the acquisition of new virulence traits by horizontal gene transfer from related streptococci such as Streptococcus pyogenes (GAS) and Streptococcus agalactiae (GBS). A collection of 54 SDSE strains isolated in Italy in the years 2000–2010 from different sources (paediatric throat carriage, invasive and non-invasive diseases) was characterized by emm typing and pulsed-field gel electrophoresis (PFGE) analysis. The virulence repertoire was evaluated by PCR for the presence of GAS superantigen (spe) genes, the streptolysin S (sagA) gene, the group G fibronectin-binding protein (gfbA) gene and GAS–GBS alpha-like protein family (alp) genes; moreover, the ability to invade human epithelial cells was investigated. Resistance to tetracycline, erythromycin and clindamycin was assessed. The combined use of emm typing and PFGE proved to be a reliable strategy for the epidemiological analysis of SDSE isolates. The most frequent emm types were the same as those more frequently reported in other studies, thus indicating the diffusion of a limited number of a few successful emm types fit to disseminate in humans. The speG gene was detected in SDSE strains of different genetic backgrounds. Erythromycin resistance determined by the erm(T) gene, and the unusual, foggy MLSB phenotype, observed in one and seven strains, respectively, have never previously, to our knowledge, been reported in SDSE. Moreover, a new member of the alp family was identified. The identification of new antibiotic and virulence determinants, despite the small size of the sample analysed, shows the importance of constant attention to monitoring the extent of lateral gene transfer in this emerging pathogen.
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Affiliation(s)
- Giovanni Gherardi
- Dipartimento di Centro Integrato di Ricerca (CIR), Università Campus Bio-Medico, Rome, Italy
| | - Monica Imperi
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| | - Claudio Palmieri
- Dipartimento di Scienze Biomediche e Sanità Pubblica, Sezione Microbiologia, Università Politecnica delle Marche, Ancona, Italy
| | - Gloria Magi
- Dipartimento di Scienze Biomediche e Sanità Pubblica, Sezione Microbiologia, Università Politecnica delle Marche, Ancona, Italy
| | - Bruna Facinelli
- Dipartimento di Scienze Biomediche e Sanità Pubblica, Sezione Microbiologia, Università Politecnica delle Marche, Ancona, Italy
| | - Lucilla Baldassarri
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| | - Marco Pataracchia
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| | - Roberta Creti
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
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Kreuzer KN. DNA damage responses in prokaryotes: regulating gene expression, modulating growth patterns, and manipulating replication forks. Cold Spring Harb Perspect Biol 2013; 5:a012674. [PMID: 24097899 DOI: 10.1101/cshperspect.a012674] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Recent advances in the area of bacterial DNA damage responses are reviewed here. The SOS pathway is still the major paradigm of bacterial DNA damage response, and recent studies have clarified the mechanisms of SOS induction and key physiological roles of SOS including a very major role in genetic exchange and variation. When considering diverse bacteria, it is clear that SOS is not a uniform pathway with one purpose, but rather a platform that has evolved for differing functions in different bacteria. Relating in part to the SOS response, the field has uncovered multiple apparent cell-cycle checkpoints that assist cell survival after DNA damage and remarkable pathways that induce programmed cell death in bacteria. Bacterial DNA damage responses are also much broader than SOS, and several important examples of LexA-independent regulation will be reviewed. Finally, some recent advances that relate to the replication and repair of damaged DNA will be summarized.
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Affiliation(s)
- Kenneth N Kreuzer
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710
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Selective pressures to maintain attachment site specificity of integrative and conjugative elements. PLoS Genet 2013; 9:e1003623. [PMID: 23874222 PMCID: PMC3715440 DOI: 10.1371/journal.pgen.1003623] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 05/27/2013] [Indexed: 11/19/2022] Open
Abstract
Integrative and conjugative elements (ICEs) are widespread mobile genetic elements that are usually found integrated in bacterial chromosomes. They are important agents of evolution and contribute to the acquisition of new traits, including antibiotic resistances. ICEs can excise from the chromosome and transfer to recipients by conjugation. Many ICEs are site-specific in that they integrate preferentially into a primary attachment site in the bacterial genome. Site-specific ICEs can also integrate into secondary locations, particularly if the primary site is absent. However, little is known about the consequences of integration of ICEs into alternative attachment sites or what drives the apparent maintenance and prevalence of the many ICEs that use a single attachment site. Using ICEBs1, a site-specific ICE from Bacillus subtilis that integrates into a tRNA gene, we found that integration into secondary sites was detrimental to both ICEBs1 and the host cell. Excision of ICEBs1 from secondary sites was impaired either partially or completely, limiting the spread of ICEBs1. Furthermore, induction of ICEBs1 gene expression caused a substantial drop in proliferation and cell viability within three hours. This drop was dependent on rolling circle replication of ICEBs1 that was unable to excise from the chromosome. Together, these detrimental effects provide selective pressure against the survival and dissemination of ICEs that have integrated into alternative sites and may explain the maintenance of site-specific integration for many ICEs.
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Franklin L, Nobbs AH, Bricio-Moreno L, Wright CJ, Maddocks SE, Sahota JS, Ralph J, O’Connor M, Jenkinson HF, Kadioglu A. The AgI/II family adhesin AspA is required for respiratory infection by Streptococcus pyogenes. PLoS One 2013; 8:e62433. [PMID: 23638083 PMCID: PMC3640068 DOI: 10.1371/journal.pone.0062433] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 03/21/2013] [Indexed: 11/19/2022] Open
Abstract
Streptococcus pyogenes (GAS) is a human pathogen that causes pharyngitis and invasive diseases such as toxic shock syndrome and sepsis. The upper respiratory tract is the primary reservoir from which GAS can infect new hosts and cause disease. The factors involved in colonisation are incompletely known however. Previous evidence in oral streptococci has shown that the AgI/II family proteins are involved. We hypothesized that the AspA member of this family might be involved in GAS colonization. We describe a novel mouse model of GAS colonization of the nasopharynx and lower respiratory tract to elucidate these interactions. We used two clinical M serotypes expressing AspA, and their aspA gene deletant isogenic mutants in experiments using adherence assays to respiratory epithelium, macrophage phagocytosis and neutrophil killing assays and in vivo models of respiratory tract colonisation and infection. We demonstrated the requirement for AspA in colonization of the respiratory tract. AspA mutants were cleared from the respiratory tract and were deficient in adherence to epithelial cells, and susceptible to phagocytosis. Expression of AspA in the surrogate host Lactococcus lactis protected bacteria from phagocytosis. Our results suggest that AspA has an essential role in respiratory infection, and may function as a novel anti-phagocytic factor.
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Affiliation(s)
- Linda Franklin
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
- School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom
| | - Angela H. Nobbs
- School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom
| | - Laura Bricio-Moreno
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | | | - Sarah E. Maddocks
- School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom
| | - Jaspreet Singh Sahota
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Joe Ralph
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Matthew O’Connor
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Howard F. Jenkinson
- School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom
| | - Aras Kadioglu
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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Thomas J, Lee CA, Grossman AD. A conserved helicase processivity factor is needed for conjugation and replication of an integrative and conjugative element. PLoS Genet 2013; 9:e1003198. [PMID: 23326247 PMCID: PMC3542172 DOI: 10.1371/journal.pgen.1003198] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 11/12/2012] [Indexed: 01/20/2023] Open
Abstract
Integrative and conjugative elements (ICEs) are agents of horizontal gene transfer and have major roles in evolution and acquisition of new traits, including antibiotic resistances. ICEs are found integrated in a host chromosome and can excise and transfer to recipient bacteria via conjugation. Conjugation involves nicking of the ICE origin of transfer (oriT) by the ICE–encoded relaxase and transfer of the nicked single strand of ICE DNA. For ICEBs1 of Bacillus subtilis, nicking of oriT by the ICEBs1 relaxase NicK also initiates rolling circle replication. This autonomous replication of ICEBs1 is critical for stability of the excised element in growing cells. We found a conserved and previously uncharacterized ICE gene that is required for conjugation and replication of ICEBs1. Our results indicate that this gene, helP (formerly ydcP), encodes a helicase processivity factor that enables the host-encoded helicase PcrA to unwind the double-stranded ICEBs1 DNA. HelP was required for both conjugation and replication of ICEBs1, and HelP and NicK were the only ICEBs1 proteins needed for replication from ICEBs1 oriT. Using chromatin immunoprecipitation, we measured association of HelP, NicK, PcrA, and the host-encoded single-strand DNA binding protein Ssb with ICEBs1. We found that NicK was required for association of HelP and PcrA with ICEBs1 DNA. HelP was required for association of PcrA and Ssb with ICEBs1 regions distal, but not proximal, to oriT, indicating that PcrA needs HelP to progress beyond nicked oriT and unwind ICEBs1. In vitro, HelP directly stimulated the helicase activity of the PcrA homologue UvrD. Our findings demonstrate that HelP is a helicase processivity factor needed for efficient unwinding of ICEBs1 for conjugation and replication. Homologues of HelP and PcrA-type helicases are encoded on many known and putative ICEs. We propose that these factors are essential for ICE conjugation, replication, and genetic stability. Integrative and conjugative elements (ICEs) are mobile DNA elements that transfer genetic material between bacteria, driving bacterial evolution and the acquisition of new traits, including the spread of antibiotic resistances. ICEs typically reside integrated in a bacterial chromosome and are passively propagated along with the host genome. Under some conditions, an ICE can excise from the chromosome to form a circle and, if appropriate recipient bacteria are present, can transfer from donor to recipient. It has recently been recognized that some, and perhaps many, ICEs undergo autonomous replication after excision from the host chromosome and that replication is important for stability and propagation of these ICEs in growing cells. Using ICEBs1, an ICE from Bacillus subtilis, we found a conserved and previously uncharacterized ICE gene that is required for conjugation and replication. We found that this gene, helP, encodes a helicase processivity factor that associates with ICEBs1 DNA and enables the host-encoded helicase PcrA to unwind the double-stranded ICEBs1 DNA, making a template for both conjugation and DNA replication. Homologues of helP are found in many ICEs, indicating that this mechanism of unwinding is likely conserved among these elements.
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Affiliation(s)
- Jacob Thomas
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Catherine A. Lee
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Alan D. Grossman
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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Conjugative transfer and cis-mobilization of a genomic island by an integrative and conjugative element of Streptococcus agalactiae. J Bacteriol 2012; 195:1142-51. [PMID: 23275243 DOI: 10.1128/jb.02199-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Putative integrative and conjugative elements (ICEs), i.e., genomic islands which could excise, self-transfer by conjugation, and integrate into the chromosome of the bacterial host strain, were previously identified by in silico analysis in the sequenced genomes of Streptococcus agalactiae (M. Brochet et al., J. Bacteriol. 190:6913-6917, 2008). We investigated here the mobility of the elements integrated into the 3' end of a tRNA(Lys) gene. Three of the four putative ICEs tested were found to excise but only one (ICE_515_tRNA(Lys)) was found to transfer by conjugation not only to S. agalactiae strains but also to a Streptococcus pyogenes strain. Transfer was observed even if recipient cell already carries a related resident ICE or a genomic island flanked by attL and attR recombination sites but devoid of conjugation or recombination genes (CIs-Mobilizable Element [CIME]). The incoming ICE preferentially integrates into the 3' end of the tRNA(Lys) gene (i.e., the attR site of the resident element), leading to a CIME-ICE structure. Transfer of the whole composite element CIME-ICE was obtained, showing that the CIME is mobilizable in cis by the ICE. Therefore, genomic islands carrying putative virulence genes but lacking the mobility gene can be mobilized by a related ICE after site-specific accretion.
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Chuzeville S, Puymège A, Madec JY, Haenni M, Payot S. Characterization of a new CAMP factor carried by an integrative and conjugative element in Streptococcus agalactiae and spreading in Streptococci. PLoS One 2012; 7:e48918. [PMID: 23152820 PMCID: PMC3494709 DOI: 10.1371/journal.pone.0048918] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 10/03/2012] [Indexed: 12/24/2022] Open
Abstract
Genetic exchanges between Streptococci occur frequently and contribute to their genome diversification. Most of sequenced streptococcal genomes carry multiple mobile genetic elements including Integrative and Conjugative Elements (ICEs) that play a major role in these horizontal gene transfers. In addition to genes involved in their mobility and regulation, ICEs also carry genes that can confer selective advantages to bacteria. Numerous elements have been described in S. agalactiae especially those integrated at the 3' end of a tRNA(Lys) encoding gene. In strain 515 of S. agalactiae, an invasive neonate human pathogen, the ICE (called 515_tRNA(Lys)) is functional and carries different putative virulence genes including one encoding a putative new CAMP factor in addition to the one previously described. This work demonstrated the functionality of this CAMP factor (CAMP factor II) in Lactococcus lactis but also in pathogenic strains of veterinary origin. The search for co-hemolytic factors in a collection of field strains revealed their presence in S. uberis, S. dysgalactiae, but also for the first time in S. equisimilis and S. bovis. Sequencing of these genes revealed the prevalence of a species-specific factor in S. uberis strains (Uberis factor) and the presence of a CAMP factor II encoding gene in S. bovis and S. equisimilis. Furthermore, most of the CAMP factor II positive strains also carried an element integrated in the tRNA(Lys) gene. This work thus describes a CAMP factor that is carried by a mobile genetic element and has spread to different streptococcal species.
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Affiliation(s)
- Sarah Chuzeville
- Unité Antibiorésistance et Virulence Bactériennes, Anses Lyon, Lyon, France
- INRA, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
- Université de Lorraine, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
| | - Aurore Puymège
- INRA, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
- Université de Lorraine, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
| | - Jean-Yves Madec
- Unité Antibiorésistance et Virulence Bactériennes, Anses Lyon, Lyon, France
| | - Marisa Haenni
- Unité Antibiorésistance et Virulence Bactériennes, Anses Lyon, Lyon, France
| | - Sophie Payot
- INRA, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
- Université de Lorraine, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
- * E-mail:
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Analysis of a Streptococcus pyogenes puerperal sepsis cluster by use of whole-genome sequencing. J Clin Microbiol 2012; 50:2224-8. [PMID: 22518858 DOI: 10.1128/jcm.00675-12] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Between June and November 2010, a concerning rise in the number of cases of puerperal sepsis, a postpartum pelvic bacterial infection contracted by women after childbirth, was observed in the New South Wales, Australia, hospital system. Group A streptococcus (GAS; Streptococcus pyogenes) isolates PS001 to PS011 were recovered from nine patients. Pulsed-field gel electrophoresis and emm sequence typing revealed that GAS of emm1.40, emm75.0, emm77.0, emm89.0, and emm89.9 were each recovered from a single patient, ruling out a single source of infection. However, emm28.8 GAS were recovered from four different patients. To investigate the relatedness of these emm28 isolates, whole-genome sequencing was undertaken and the genome sequences were compared to the genome sequence of the emm28.4 reference strain, MGAS6180. A total of 186 single nucleotide polymorphisms were identified, for which the phylogenetic reconstruction indicated an outbreak of a polyclonal nature. While two isolates collected from different hospitals were not closely related, isolates from two puerperal sepsis patients from the same hospital were indistinguishable, suggesting patient-to-patient transmission or infection from a common source. The results of this study indicate that traditional typing protocols, such as pulsed-field gel electrophoresis, may not be sensitive enough to allow fine epidemiological discrimination of closely related bacterial isolates. Whole-genome sequencing presents a valid alternative that allows accurate fine-scale epidemiological investigation of bacterial infectious disease.
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Differential regulation of two closely related integrative and conjugative elements from Streptococcus thermophilus. BMC Microbiol 2011; 11:238. [PMID: 22024428 PMCID: PMC3234194 DOI: 10.1186/1471-2180-11-238] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 10/24/2011] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Two closely related ICEs, ICESt1 and ICESt3, have been identified in the lactic acid bacterium Streptococcus thermophilus. While their conjugation and recombination modules are almost identical (95% nucleotide identity) and their regulation modules related, previous work has demonstrated that transconjugants carrying ICESt3 were generated at rate exceeding by a 1000 factor that of ICESt1. RESULTS The functional regulation of ICESt1 and ICESt3 transcription, excision and replication were investigated under different conditions (exponential growth or stationary phase, DNA damage by exposition to mitomycin C). Analysis revealed an identical transcriptional organization of their recombination and conjugation modules (long unique transcript) whereas the transcriptional organization of their regulation modules were found to be different (two operons in ICESt1 but only one in ICESt3) and to depend on the conditions (promoter specific of stationary phase in ICESt3). For both elements, stationary phase and DNA damage lead to the rise of transcript levels of the conjugation-recombination and regulation modules. Whatever the growth culture conditions, excision of ICESt1 was found to be lower than that of ICESt3, which is consistent with weaker transfer frequencies. Furthermore, for both elements, excision increases in stationary phase (8.9-fold for ICESt1 and 1.31-fold for ICESt3) and is strongly enhanced by DNA damage (38-fold for ICESt1 and 18-fold for ICESt3). Although ICEs are generally not described as replicative elements, the copy number of ICESt3 exhibited a sharp increase (9.6-fold) after mitomycin C exposure of its harboring strain CNRZ385. This result was not observed when ICESt3 was introduced in a strain deriving ICESt1 host strain CNRZ368, deleted for this element. This finding suggests an impact of the host cell on ICE behavior. CONCLUSIONS All together, these results suggest a novel mechanism of regulation shared by ICESt1, ICESt3 and closely related ICEs, which we identified by analysis of recently sequenced genomes of firmicutes. This is the first report of a partial shutdown of the activity of an ICE executed by a strain belonging to its primary host species. The sharp increase of ICESt3 copy number suggests an induction of replication; such conditional intracellular replication may be common among ICEs.
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