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Sanford TC, Tweten RK, Abrahamsen HL. Bacterial cholesterol-dependent cytolysins and their interaction with the human immune response. Curr Opin Infect Dis 2024; 37:164-169. [PMID: 38527455 DOI: 10.1097/qco.0000000000001010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
PURPOSE OF REVIEW Many cholesterol-dependent cytolysin (CDC)-producing pathogens pose a significant threat to human health. Herein, we review the pore-dependent and -independent properties CDCs possess to assist pathogens in evading the host immune response. RECENT FINDINGS Within the last 5 years, exciting new research suggests CDCs can act to inhibit important immune functions, disrupt critical cell signaling pathways, and have tissue-specific effects. Additionally, recent studies have identified a key region of CDCs that generates robust immunity, providing resources for the development of CDC-based vaccines. SUMMARY This review provides new information on how CDCs alter host immune responses to aid bacteria in pathogenesis. These studies can assist in the design of more efficient vaccines and therapeutics against CDCs that will enhance the immune response to CDC-producing pathogens while mitigating the dampening effects CDCs have on the host immune response.
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Affiliation(s)
- Tristan C Sanford
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
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Tölken LA, Paulikat AD, Jachmann LH, Reder A, Salazar MG, Medina LMP, Michalik S, Völker U, Svensson M, Norrby-Teglund A, Hoff KJ, Lammers M, Siemens N. Reduced interleukin-18 secretion by human monocytic cells in response to infections with hyper-virulent Streptococcus pyogenes. J Biomed Sci 2024; 31:26. [PMID: 38408992 PMCID: PMC10898077 DOI: 10.1186/s12929-024-01014-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 02/20/2024] [Indexed: 02/28/2024] Open
Abstract
BACKGROUND Streptococcus pyogenes (group A streptococcus, GAS) causes a variety of diseases ranging from mild superficial infections of the throat and skin to severe invasive infections, such as necrotizing soft tissue infections (NSTIs). Tissue passage of GAS often results in mutations within the genes encoding for control of virulence (Cov)R/S two component system leading to a hyper-virulent phenotype. Dendritic cells (DCs) are innate immune sentinels specialized in antigen uptake and subsequent T cell priming. This study aimed to analyze cytokine release by DCs and other cells of monocytic origin in response to wild-type and natural covR/S mutant infections. METHODS Human primary monocyte-derived (mo)DCs were used. DC maturation and release of pro-inflammatory cytokines in response to infections with wild-type and covR/S mutants were assessed via flow cytometry. Global proteome changes were assessed via mass spectrometry. As a proof-of-principle, cytokine release by human primary monocytes and macrophages was determined. RESULTS In vitro infections of moDCs and other monocytic cells with natural GAS covR/S mutants resulted in reduced secretion of IL-8 and IL-18 as compared to wild-type infections. In contrast, moDC maturation remained unaffected. Inhibition of caspase-8 restored secretion of both molecules. Knock-out of streptolysin O in GAS strain with unaffected CovR/S even further elevated the IL-18 secretion by moDCs. Of 67 fully sequenced NSTI GAS isolates, 28 harbored mutations resulting in dysfunctional CovR/S. However, analyses of plasma IL-8 and IL-18 levels did not correlate with presence or absence of such mutations. CONCLUSIONS Our data demonstrate that strains, which harbor covR/S mutations, interfere with IL-18 and IL-8 responses in monocytic cells by utilizing the caspase-8 axis. Future experiments aim to identify the underlying mechanism and consequences for NSTI patients.
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Affiliation(s)
- Lea A Tölken
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Antje D Paulikat
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Lana H Jachmann
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Alexander Reder
- Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | | | - Laura M Palma Medina
- Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Stephan Michalik
- Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Uwe Völker
- Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Mattias Svensson
- Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Anna Norrby-Teglund
- Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Katharina J Hoff
- Institute of Mathematics and Computer Science, University of Greifswald, Greifswald, Germany
| | - Michael Lammers
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Nikolai Siemens
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany.
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Lei B, Hanks TS, Bao Y, Liu M. Slipped-strand mispairing within a polycytidine tract in transcriptional regulator mga leads to M protein phase variation and Mga length polymorphism in Group A Streptococcus. Front Microbiol 2023; 14:1212149. [PMID: 37434706 PMCID: PMC10330708 DOI: 10.3389/fmicb.2023.1212149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 06/06/2023] [Indexed: 07/13/2023] Open
Abstract
The M protein, a major virulence factor of Group A Streptococcus (GAS), is regulated by the multigene regulator Mga. An unexplained phenomena frequently occurring with in vitro genetic manipulation or culturing of M1T1 GAS strains is the loss of M protein production. This study was aimed at elucidating the basis for the loss of M protein production. The majority of M protein-negative (M-) variants had one C deletion at a tract of 8 cytidines starting at base 1,571 of the M1 mga gene, which is designated as c.1571C[8]. The C deletion led to a c.1571C[7] mga variant that has an open reading frame shift and encodes a Mga-M protein fusion protein. Transformation with a plasmid containing wild-type mga restored the production of the M protein in the c.1571C[7] mga variant. Isolates producing M protein (M+) were recovered following growth of the c.1571C[7] M protein-negative variant subcutaneously in mice. The majority of the recovered isolates with reestablished M protein production had reverted back from c.1571C[7] to c.1571C[8] tract and some M+ isolates lost another C in the c.1571C[7] tract, leading to a c.1571C[6] variant that encodes a functional Mga with 13 extra amino acid residues at the C-terminus compared with wild-type Mga. The nonfunctional c.1571C[7] and functional c.1571C[6] variants are present in M1, M12, M14, and M23 strains in NCBI genome databases, and a G-to-A nonsense mutation at base 1,657 of M12 c.1574C[7] mga leads to a functional c.1574C[7]/1657A mga variant and is common in clinical M12 isolates. The numbers of the C repeats in this polycytidine tract and the polymorphism at base 1,657 lead to polymorphism in the size of Mga among clinical isolates. These findings demonstrate the slipped-strand mispairing within the c.1574C[8] tract of mga as a reversible switch controlling M protein production phase variation in multiple GAS common M types.
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Affiliation(s)
- Benfang Lei
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Tracey S. Hanks
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Yunjuan Bao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Mengyao Liu
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
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Plainvert C, Rosinski-Chupin I, Weckel A, Lambert C, Touak G, Sauvage E, Poyart C, Glaser P, Fouet A. A Novel CovS Variant Harbored by a Colonization Strain Reduces Streptococcus pyogenes Virulence. J Bacteriol 2023; 205:e0003923. [PMID: 36920220 PMCID: PMC10127592 DOI: 10.1128/jb.00039-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 02/16/2023] [Indexed: 03/16/2023] Open
Abstract
Streptococcus pyogenes, also known as group A Streptococcus, causes a wide variety of diseases ranging from mild noninvasive to severe invasive infections. To identify possible causes of colonization-to-invasive switches, we determined the genomic sequences of 10 isolates from five pairs each composed of an invasive strain and a carriage strain originating from five infectious clusters. Among them, one pair displayed a single-nucleotide difference in covS, encoding the sensor histidine kinase of the two-component CovRS system that controls the expression of 15% of the genome. In contrast to previously described cases where the invasive strains harbor nonfunctional CovS proteins, the carriage strain possessed the mutation covST115C, leading to the replacement of the tyrosine at position 39 by a histidine. The CovSY39H mutation affected the expression of the genes from the CovR regulon in a unique fashion. Genes usually overexpressed in covS mutant strains were underexpressed and vice versa. Furthermore, the covS mutant strain barely responded to the addition of the CovS-signaling compounds Mg2+ and LL-37. The variations in the accumulation of two virulence factors paralleled the transcription modifications. In addition, the covST115C mutant strain showed less survival than its wild-type counterpart in murine macrophages. Finally, in two murine models of infection, the covS mutant strain was less virulent than the wild-type strain. Our study suggests that the CovSY39H protein compromises CovS phosphatase activity and that this yields a noninvasive strain. IMPORTANCE Streptococcus pyogenes, also known as group A Streptococcus, causes a wide variety of diseases, leading to 517,000 deaths yearly. The two-component CovRS system, which responds to MgCl2 and the antimicrobial peptide LL-37, controls the expression of 15% of the genome. Invasive strains may harbor nonfunctional CovS sensor proteins that lead to the derepression of most virulence genes. We isolated a colonization strain that harbors a novel covS mutation. This mutant strain harbored a transcriptome profile opposite that of other covS mutant strains, barely responded to environmental signals, and was less virulent than the wild-type strain. This supports the importance of the derepression of the expression of most virulence genes, via mutations that impact the phosphorylation of the regulator CovR, for favoring S. pyogenes invasive infections.
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Affiliation(s)
- Céline Plainvert
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
- Service de Bactériologie, CNR des Streptocoques, Hôpitaux Universitaires Paris Centre, Paris, France
| | - Isabelle Rosinski-Chupin
- Institut Pasteur, Ecologie et Evolution de la Résistance aux Antibiotiques, UMR3525, Paris, France
| | - Antonin Weckel
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Clara Lambert
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Gérald Touak
- Service de Bactériologie, CNR des Streptocoques, Hôpitaux Universitaires Paris Centre, Paris, France
| | - Elisabeth Sauvage
- Institut Pasteur, Ecologie et Evolution de la Résistance aux Antibiotiques, UMR3525, Paris, France
| | - Claire Poyart
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
- Service de Bactériologie, CNR des Streptocoques, Hôpitaux Universitaires Paris Centre, Paris, France
| | - Philippe Glaser
- Institut Pasteur, Ecologie et Evolution de la Résistance aux Antibiotiques, UMR3525, Paris, France
| | - Agnès Fouet
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
- Service de Bactériologie, CNR des Streptocoques, Hôpitaux Universitaires Paris Centre, Paris, France
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Johnson AF, Sands JS, Trivedi KM, Russell R, LaRock DL, LaRock CN. Constitutive secretion of pro-IL-18 allows keratinocytes to initiate inflammation during bacterial infection. PLoS Pathog 2023; 19:e1011321. [PMID: 37068092 PMCID: PMC10138833 DOI: 10.1371/journal.ppat.1011321] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/27/2023] [Accepted: 03/27/2023] [Indexed: 04/18/2023] Open
Abstract
Group A Streptococcus (GAS, Streptococcus pyogenes) is a professional human pathogen that commonly infects the skin. Keratinocytes are one of the first cells to contact GAS, and by inducing inflammation, they can initiate the earliest immune responses to pathogen invasion. Here, we characterized the proinflammatory cytokine repertoire produced by primary human keratinocytes and surrogate cell lines commonly used in vitro. Infection induces several cytokines and chemokines, but keratinocytes constitutively secrete IL-18 in a form that is inert (pro-IL-18) and lacks proinflammatory activity. Canonically, IL-18 activation and secretion are coupled through a single proteolytic event that is regulated intracellularly by the inflammasome protease caspase-1 in myeloid cells. The pool of extracellular pro-IL-18 generated by keratinocytes is poised to sense extracellular proteases. It is directly processed into a mature active form by SpeB, a secreted GAS protease that is a critical virulent factor during skin infection. This mechanism contributes to the proinflammatory response against GAS, resulting in T cell activation and the secretion of IFN-γ. Under these conditions, isolates of several other major bacterial pathogens and microbiota of the skin were found to not have significant IL-18-maturing ability. These results suggest keratinocyte-secreted IL-18 is a sentinel that sounds an early alarm that is highly sensitive to GAS, yet tolerant to non-invasive members of the microbiota.
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Affiliation(s)
- Anders F Johnson
- Department of Microbiology and Immunology and Department of Medicine, Emory School of Medicine, Atlanta, Georgia, United States of America
| | - Jenna S Sands
- Department of Microbiology and Immunology and Department of Medicine, Emory School of Medicine, Atlanta, Georgia, United States of America
| | - Keya M Trivedi
- Department of Microbiology and Immunology and Department of Medicine, Emory School of Medicine, Atlanta, Georgia, United States of America
| | - Raedeen Russell
- Department of Microbiology and Immunology and Department of Medicine, Emory School of Medicine, Atlanta, Georgia, United States of America
| | - Doris L LaRock
- Department of Microbiology and Immunology and Department of Medicine, Emory School of Medicine, Atlanta, Georgia, United States of America
| | - Christopher N LaRock
- Department of Microbiology and Immunology and Department of Medicine, Emory School of Medicine, Atlanta, Georgia, United States of America
- Department of Medicine, Division of Infectious Diseases, Emory School of Medicine, Atlanta, Georgia, United States of America
- Emory Antibiotic Resistance Center, Atlanta, Georgia, United States of America
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Langshaw EL, Reynolds S, Ozberk V, Dooley J, Calcutt A, Zaman M, Walker MJ, Batzloff MR, Davies MR, Good MF, Pandey M. Streptolysin O Deficiency in Streptococcus pyogenes M1T1 covR/S Mutant Strain Attenuates Virulence in In Vitro and In Vivo Infection Models. mBio 2023; 14:e0348822. [PMID: 36744883 PMCID: PMC9972915 DOI: 10.1128/mbio.03488-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 02/07/2023] Open
Abstract
Mutation within the Streptococcus pyogenes (Streptococcus group A; Strep A) covR/S regulatory system has been associated with a hypervirulent phenotype resulting from the upregulation of several virulence factors, including the pore-forming toxin, streptolysin O (SLO). In this study, we utilized a range of covR/S mutants, including M1T1 clonal strains (5448 and a covS mutant generated through mouse passage designated 5448AP), to investigate the contribution of SLO to the pathogenesis of covR/S mutant Strep A disease. Up-regulation of slo in 5448AP resulted in increased SLO-mediated hemolysis, decreased dendritic cell (DC) viability post coculture with Strep A, and increased production of tumor necrosis factor (TNF) and monocyte chemoattractant protein 1 (MCP-1) by DCs. Mouse passage of an isogenic 5448 slo-deletion mutant resulted in recovery of several covR/S mutants within the 5448Δslo background. Passage also introduced mutations in non-covR/S genes, but these were considered to have no impact on virulence. Although slo-deficient mutants exhibited the characteristic covR/S-controlled virulence factor upregulation, these mutants caused increased DC viability with reduced inflammatory cytokine production by infected DCs. In vivo, slo expression correlated with decreased DC numbers in infected murine skin and significant bacteremia by 3 days postinfection, with severe pathology at the infection site. Conversely, the absence of slo in the infecting strain (covR/S mutant or wild-type) resulted in detection of DCs in the skin and attenuated virulence in a murine model of pyoderma. slo-sufficient and -deficient covR/S mutants were susceptible to immune clearance mediated by a combination vaccine consisting of a conserved M protein peptide and a peptide from the CXC chemokine protease SpyCEP. IMPORTANCE Streptococcus pyogenes is responsible for significant numbers of invasive and noninvasive infections which cause significant morbidity and mortality globally. Strep A isolates with mutations in the covR/S system display greater propensity to cause severe invasive diseases, which are responsible for more than 163,000 deaths each year. This is due to the upregulation of virulence factors, including the pore-forming toxin streptolysin O. Utilizing covR/S and slo-knockout mutants, we investigated the role of SLO in virulence. We found that SLO alters interactions with host cell populations and increases Strep A viability at sterile sites of the host, such as the blood, and that its absence results in significantly less virulence. This work underscores the importance of SLO in Strep A virulence while highlighting the complex nature of Strep A pathogenesis. This improved insight into host-pathogen interactions will enable a better understanding of host immune evasion mechanisms and inform streptococcal vaccine development programs.
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Affiliation(s)
- Emma L. Langshaw
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Simone Reynolds
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Victoria Ozberk
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Jessica Dooley
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Ainslie Calcutt
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Mehfuz Zaman
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Mark J. Walker
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | | | - Mark R. Davies
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Michael F. Good
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Manisha Pandey
- Institute for Glycomics, Griffith University, Queensland, Australia
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Kuryłek A, Stasiak M, Kern-Zdanowicz I. Virulence factors of Streptococcus anginosus - a molecular perspective. Front Microbiol 2022; 13:1025136. [PMID: 36386673 PMCID: PMC9643698 DOI: 10.3389/fmicb.2022.1025136] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/10/2022] [Indexed: 07/21/2023] Open
Abstract
Streptococcus anginosus together with S. constellatus and S. intermedius constitute the Streptococcus anginosus group (SAG), until recently considered to be benign commensals of the human mucosa isolated predominantly from oral cavity, but also from upper respiratory, intestinal, and urogenital tracts. For years the virulence potential of SAG was underestimated, mainly due to complications in correct species identification and their assignment to the physiological microbiota. Still, SAG representatives have been associated with purulent infections at oral and non-oral sites resulting in abscesses formation and empyema. Also, life threatening blood infections caused by SAG have been reported. However, the understanding of SAG as potential pathogen is only fragmentary, albeit certain aspects of SAG infection seem sufficiently well described to deserve a systematic overview. In this review we summarize the current state of knowledge of the S. anginosus pathogenicity factors and their mechanisms of action.
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Horstmann N, Myers KS, Tran CN, Flores AR, Shelburne III SA. CovS inactivation reduces CovR promoter binding at diverse virulence factor encoding genes in group A Streptococcus. PLoS Pathog 2022; 18:e1010341. [PMID: 35180278 PMCID: PMC8893699 DOI: 10.1371/journal.ppat.1010341] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/03/2022] [Accepted: 02/04/2022] [Indexed: 11/18/2022] Open
Abstract
The control of virulence gene regulator (CovR), also called caspsule synthesis regulator (CsrR), is critical to how the major human pathogen group A Streptococcus fine-tunes virulence factor production. CovR phosphorylation (CovR~P) levels are determined by its cognate sensor kinase CovS, and functional abrogating mutations in CovS can occur in invasive GAS isolates leading to hypervirulence. Presently, the mechanism of CovR-DNA binding specificity is unclear, and the impact of CovS inactivation on global CovR binding has not been assessed. Thus, we performed CovR chromatin immunoprecipitation sequencing (ChIP-seq) analysis in the emm1 strain MGAS2221 and its CovS kinase deficient derivative strain 2221-CovS-E281A. We identified that CovR bound in the promoter regions of nearly all virulence factor encoding genes in the CovR regulon. Additionally, direct CovR binding was observed for numerous genes encoding proteins involved in amino acid metabolism, but we found limited direct CovR binding to genes encoding other transcriptional regulators. The consensus sequence AATRANAAAARVABTAAA was present in the promoters of genes directly regulated by CovR, and mutations of highly conserved positions within this motif relieved CovR repression of the hasA and MGAS2221_0187 promoters. Analysis of strain 2221-CovS-E281A revealed that binding of CovR at repressed, but not activated, promoters is highly dependent on CovR~P state. CovR repressed virulence factor encoding genes could be grouped dependent on how CovR~P dependent variation in DNA binding correlated with gene transcript levels. Taken together, the data show that CovR repression of virulence factor encoding genes is primarily direct in nature, involves binding to a newly-identified DNA binding motif, and is relieved by CovS inactivation. These data provide new mechanistic insights into one of the most important bacterial virulence regulators and allow for subsequent focused investigations into how CovR-DNA interaction at directly controlled promoters impacts GAS pathogenesis. Tight regulation of virulence factor production is a critical, but poorly understood aspect of bacterial pathogenesis. The OmpR/PhoB family member control of virulence regulator (CovR) is the master virulence factor controller in group A Streptococcus (GAS), a bacterium which commonly causes a diverse array of human infections. Mutations in the cognate kinase of CovR, CovS, are commonly observed among invasive GAS isolates, but the functional impact of CovS on global CovR function is unknown. Herein, we defined CovR global DNA binding locations, identified a consensus CovR binding motif, and determined how inactivation of the CovR cognate sensor kinase, CovS, impacts CovR-DNA interaction. Our findings show that CovR-repressed virulence factor encoding genes are directly regulated by CovR and that CovS inactivation markedly reduces CovR binding at CovR-repressed promoters. Given the widespread nature of CovR homologues in streptococci and other Gram-positive pathogens, these findings extend understanding of mechanisms by which OmpR/PhoB family members impact the ability of bacteria to cause serious infections.
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Affiliation(s)
- Nicola Horstmann
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Kevin S. Myers
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Chau Nguyen Tran
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Anthony R. Flores
- Center for Antimicrobial Resistance and Microbial Genomics McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Samuel A. Shelburne III
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- * E-mail:
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Oliveira LT, Alves LA, Harth-Chu EN, Nomura R, Nakano K, Mattos-Graner RO. VicRK and CovR polymorphisms in Streptococcus mutans strains associated with cardiovascular infections. J Med Microbiol 2021; 70. [PMID: 34939562 DOI: 10.1099/jmm.0.001457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Introduction. Streptococcus mutans, a common species of the oral microbiome, expresses virulence genes promoting cariogenic dental biofilms, persistence in the bloodstream and cardiovascular infections.Gap statement. Virulence gene expression is variable among S. mutans strains and controlled by the transcription regulatory systems VicRK and CovR.Aim. This study investigates polymorphisms in the vicRK and covR loci in S. mutans strains isolated from the oral cavity or from the bloodstream, which were shown to differ in expression of covR, vicRK and downstream genes.Methodology. The transcriptional activities of covR, vicR and vicK were compared by RT-qPCR between blood and oral strains after exposure to human serum. PCR-amplified promoter and/or coding regions of covR and vicRK of 18 strains (11 oral and 7 blood) were sequenced and compared to the reference strain UA159.Results. Serum exposure significantly reduced covR and vicR/K transcript levels in most strains (P<0.05), but reductions were higher in oral than in blood strains. Single-nucleotide polymorphisms (SNPs) were detected in covR regulatory and coding regions, but SNPs affecting the CovR effector domain were only present in two blood strains. Although vicR was highly conserved, vicK showed several SNPs, and SNPs affecting VicK regions important for autokinase activity were found in three blood strains.Conclusions. This study reveals transcriptional and structural diversity in covR and vicR/K, and identifies polymorphisms of functional relevance in blood strains, indicating that covR and vicRK might be important loci for S. mutans adaptation to host selective pressures associated with virulence diversity.
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Affiliation(s)
- Letícia T Oliveira
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Lívia A Alves
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Erika N Harth-Chu
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Ryota Nomura
- Department of Pediatric Dentistry, Osaka University, Graduate School of Dentistry, Osaka, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Osaka University, Graduate School of Dentistry, Osaka, Japan
| | - Renata O Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
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Isaka M, Okamoto A, Miura Y, Tatsuno I, Maeyama JI, Hasegawa T. Streptococcus pyogenes TrxSR Two-Component System Regulates Biofilm Production in Acidic Environments. Infect Immun 2021; 89:e0036021. [PMID: 34424754 DOI: 10.1128/IAI.00360-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Bacteria form biofilms for their protection against environmental stress and produce virulence factors within the biofilm. Biofilm formation in acidified environments is regulated by a two-component system, as shown by studies on isogenic mutants of the sensor protein of the two-component regulatory system in Streptococcus pyogenes. In this study, we found that the LiaS histidine kinase sensor mediates biofilm production and pilus expression in an acidified environment through glucose fermentation. The liaS isogenic mutant produced biofilms in a culture acidified by hydrochloric acid but not glucose, suggesting that the acidified environment is sensed by another protein. In addition, the trxS isogenic mutant could not produce biofilms or activate the mga promoter in an acidified environment. Mass spectrometry analysis showed that TrxS regulates M protein, consistent with the transcriptional regulation of emm, which encodes M protein. Our results demonstrate that biofilm production during environmental acidification is directly under the control of TrxS.
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11
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Finn MB, Ramsey KM, Dove SL, Wessels MR. Identification of Group A Streptococcus Genes Directly Regulated by CsrRS and Novel Intermediate Regulators. mBio 2021; 12:e0164221. [PMID: 34253064 DOI: 10.1128/mBio.01642-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Adaptation of group A Streptococcus (GAS) to its human host is mediated by two-component systems that transduce external stimuli to regulate bacterial physiology. Among such systems, CsrRS (also known as CovRS) is the most extensively characterized for its role in regulating ∼10% of the GAS genome, including several virulence genes. Here, we show that extracellular magnesium and the human antimicrobial peptide LL-37 have opposing effects on the phosphorylation of the response regulator CsrR by the receptor kinase CsrS. Genetic inactivation of CsrS phosphatase or kinase activity, respectively, had similar but more pronounced effects on CsrR phosphorylation compared to growth in magnesium or LL-37. These changes in CsrR phosphorylation were correlated with the repression or activation of CsrR-regulated genes as assessed by NanoString analysis. Chromatin immunoprecipitation and DNA sequencing (ChIP-seq) revealed CsrR occupancy at CsrRS-regulated promoters and lower-affinity associations at many other locations on the GAS chromosome. Because ChIP-seq did not detect CsrR occupancy at promoters associated with some CsrR-regulated genes, we investigated whether these genes might be controlled indirectly by intermediate regulators whose expression is modulated by CsrR. Transcriptional profiling of mutant strains deficient in the expression of either of two previously uncharacterized transcription regulators in the CsrR regulon indicated that one or both proteins participated in the regulation of 22 of the 42 CsrR-regulated promoters for which no CsrR association was detected by ChIP-seq. Taken together, these results illuminate CsrRS-mediated regulation of GAS gene expression through modulation of CsrR phosphorylation, CsrR association with regulated promoters, and the control of intermediate transcription regulators. IMPORTANCE Group A Streptococcus (GAS) is an important public health threat as a cause of sore throat, skin infections, life-threatening invasive infections, and the postinfectious complications of acute rheumatic fever, a leading cause of acquired heart disease. This work characterizes CsrRS, a GAS system for the detection of environmental signals that enables adaptation of the bacteria for survival in the human throat by regulating the production of products that allow the bacteria to resist clearance by the human immune system. CsrRS consists of two proteins: CsrS, which is on the bacterial surface to detect specific stimuli, and CsrR, which receives signals from CsrS and, in response, represses or activates the expression of genes coding for proteins that enhance bacterial survival. Some of the genes regulated by CsrR encode proteins that are themselves regulators of gene expression, thereby creating a regulatory cascade.
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12
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Wilde S, Johnson AF, LaRock CN. Playing With Fire: Proinflammatory Virulence Mechanisms of Group A Streptococcus. Front Cell Infect Microbiol 2021; 11:704099. [PMID: 34295841 PMCID: PMC8290871 DOI: 10.3389/fcimb.2021.704099] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 06/23/2021] [Indexed: 01/06/2023] Open
Abstract
Group A Streptococcus is an obligate human pathogen that is a major cause of infectious morbidity and mortality. It has a natural tropism for the oropharynx and skin, where it causes infections with excessive inflammation due to its expression of proinflammatory toxins and other virulence factors. Inflammation directly contributes to the severity of invasive infections, toxic shock syndrome, and the induction of severe post-infection autoimmune disease caused by autoreactive antibodies. This review discusses what is known about how the virulence factors of Group A Streptococcus induce inflammation and how this inflammation can promote disease. Understanding of streptococcal pathogenesis and the role of hyper-immune activation during infection may provide new therapeutic targets to treat the often-fatal outcome of severe disease.
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Affiliation(s)
- Shyra Wilde
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, United States
| | - Anders F Johnson
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, United States
| | - Christopher N LaRock
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, United States.,Department of Microbiology and Immunology, Division of Infectious Diseases, Department of Medicine, and Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA, United States
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13
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Siemens N, Lütticken R. Streptococcus pyogenes ("Group A Streptococcus"), a Highly Adapted Human Pathogen-Potential Implications of Its Virulence Regulation for Epidemiology and Disease Management. Pathogens 2021; 10:776. [PMID: 34205500 DOI: 10.3390/pathogens10060776] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/02/2021] [Accepted: 06/17/2021] [Indexed: 11/16/2022] Open
Abstract
Streptococcus pyogenes (group A streptococci; GAS) is an exclusively human pathogen. It causes a variety of suppurative and non-suppurative diseases in people of all ages worldwide. Not all can be successfully treated with antibiotics. A licensed vaccine, in spite of its global importance, is not yet available. GAS express an arsenal of virulence factors responsible for pathological immune reactions. The transcription of all these virulence factors is under the control of three types of virulence-related regulators: (i) two-component systems (TCS), (ii) stand-alone regulators, and (iii) non-coding RNAs. This review summarizes major TCS and stand-alone transcriptional regulatory systems, which are directly associated with virulence control. It is suggested that this treasure of knowledge on the genetics of virulence regulation should be better harnessed for new therapies and prevention methods for GAS infections, thereby changing its global epidemiology for the better.
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14
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Herrera AL, Callegari EA, Chaussee MS. The Streptococcus pyogenes signaling peptide SpoV regulates streptolysin O and enhances survival in murine blood. J Bacteriol 2021; 203:JB. [PMID: 33722844 DOI: 10.1128/JB.00586-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pyogenes (Group A Streptococcus, GAS) is a human pathogen that causes a wide range of diseases. For successful colonization within a variety of host niches, GAS must sense and respond to environmental changes. Intercellular communication mediated by peptides is one way GAS coordinates gene expression in response to diverse environmental stressors, which enhances bacterial survival and contributes to virulence. Using peptidomics we identified SpoV (Streptococcal peptide controlling virulence) in culture supernatant fluids. SpoV is a secreted peptide encoded near the gene encoding the extracellular cholesterol-dependent cytolysin streptolysin O (slo) The addition of synthetic SpoV peptide derivatives, but not control peptides, increased slo transcript abundance in an M49 isolate but not in an M3 isolate. Deletion of spoV decreased slo transcript abundance, extracellular SLO protein levels, and SLO-specific hemolytic activity. Complementation of the spoV mutant increased slo transcript abundance. Lastly, a spoV mutant was deficient in the ability to survive in murine blood compared to the parental strain. Moreover, pre-incubation of the spoV mutant with synthetic SpoV peptide derivatives increased GAS survival. Our findings show that slo expression is regulated, in part, by the GAS-specific signaling peptide SpoV.IMPORTANCEGAS secretes signaling peptides that can alter gene expression and impact virulence. We used peptidomics to identify a signaling peptide designated SpoV. Further, we showed that SpoV altered the expression of the cholesterol-dependent cytolysin SLO. Peptide signaling plays an important regulatory role during disease progression among several bacterial pathogens, including GAS. The therapeutic potential of manipulating peptide-controlled regulatory networks is an attractive option for the development of novel therapeutic strategies that disrupt virulence gene expression.
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15
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Hirose Y, Yamaguchi M, Takemoto N, Miyoshi-Akiyama T, Sumitomo T, Nakata M, Ikebe T, Hanada T, Yamaguchi T, Kawahara R, Okuno R, Otsuka H, Matsumoto Y, Terashima Y, Kazawa Y, Nakanishi N, Uchida K, Akiyama Y, Iwabuchi K, Nakagawa C, Yamamoto K, Nizet V, Kawabata S. Genetic Characterization of Streptococcus pyogenes emm89 Strains Isolated in Japan From 2011 to 2019. Infect Microbes Dis 2020; 2:160-166. [PMID: 38630060 PMCID: PMC7769053 DOI: 10.1097/im9.0000000000000038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 04/19/2024]
Abstract
Invasive infection caused by Streptococcus pyogenes emm89 strains has been increasing in several countries linked to a recently emergent clade of emm89 strains, designated clade 3. In Japan, the features of emm89 S. pyogenes strains, such as clade classification, remains unknown. In this study, we collected emm89 strains isolated from both streptococcal toxic shock syndrome (STSS) (89 STSS isolates) and noninvasive infections (72 non-STSS isolates) in Japan from 2011 to 2019, and conducted whole-genome sequencing and comparative analysis, which resulted in classification of a large majority into clade 3 regardless of disease severity. In addition, invasive disease-associated factors were found among emm89 strains, including mutations of control of virulence sensor, and absence of the hylP1 gene encoding hyaluronidase. These findings provide new insights into genetic features of emm89 strains.
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Affiliation(s)
- Yujiro Hirose
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
- Department of Pediatrics, University of California at San Diego School of Medicine, La Jolla, CA, USA
| | - Masaya Yamaguchi
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Norihiko Takemoto
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Tohru Miyoshi-Akiyama
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Tomoko Sumitomo
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Masanobu Nakata
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Tadayoshi Ikebe
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tomoki Hanada
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Takahiro Yamaguchi
- Division of Microbiology, Osaka Institute of Public Health, Osaka City, Osaka, Japan
| | - Ryuji Kawahara
- Division of Microbiology, Osaka Institute of Public Health, Osaka City, Osaka, Japan
| | - Rumi Okuno
- Department of Microbiology, Tokyo Metropolitan Institute of Public Health, Tokyo, Japan
| | - Hitoshi Otsuka
- Department of Public Health Sciences, Yamaguchi Prefectural Institute of Public Health and Environment Yamaguchi City, Yamaguchi, Japan
| | - Yuko Matsumoto
- Microbiological Testing and Research Division, Yokohama City Institute of Public Health, Yokohama, Kanagawa, Japan
| | - Yuji Terashima
- Department of Microbiology, Fukushima Prefectural Institute of Public Health, Fukushima City, Fukushima, Japan
| | - Yu Kazawa
- Department of Microbiology, Fukushima Prefectural Institute of Public Health, Fukushima City, Fukushima, Japan
| | - Noriko Nakanishi
- Department of Infectious Diseases, Kobe Institute of Health, Kobe, Hyogo, Japan
| | - Kaoru Uchida
- Department of Bacteriology, Toyama Institute of Health, Imizu, Toyama, Japan
| | - Yumi Akiyama
- Infectious Disease Research Division, Hyogo Prefectural Institute of Public Health Science, Kakogawa, Hyogo, Japan
| | - Kaori Iwabuchi
- Department of Health Science, Iwate Prefectural Research Institute for Environmental Sciences and Public Health, Morioka, Iwate, Japan
| | - Chikara Nakagawa
- Division of Microbiology, Kyoto City Institute of Health and Environmental Sciences, Kyoto City, Kyoto, Japan
| | - Kazunari Yamamoto
- Niigata City Institute of Public Health and the Environment, Niigata City, Niigata, Japan
| | - Victor Nizet
- Department of Pediatrics, University of California at San Diego School of Medicine, La Jolla, CA, USA
- Skaggs School of Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA, USA
| | - Shigetada Kawabata
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
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16
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Alves LA, Ganguly T, Harth-Chú ÉN, Kajfasz J, Lemos JA, Abranches J, Mattos-Graner RO. PepO is a target of the two-component systems VicRK and CovR required for systemic virulence of Streptococcus mutans. Virulence 2020; 11:521-536. [PMID: 32427040 PMCID: PMC7239026 DOI: 10.1080/21505594.2020.1767377] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/10/2020] [Accepted: 03/29/2020] [Indexed: 12/14/2022] Open
Abstract
Streptococcus mutans, a cariogenic species, is often associated with cardiovascular infections. Systemic virulence of specific S. mutans serotypes has been associated with the expression of the collagen- and laminin-binding protein Cnm, which is transcriptionally regulated by VicRK and CovR. In this study, we characterized a VicRK- and CovR-regulated gene, pepO, coding for a conserved endopeptidase. Transcriptional and protein analyses revealed that pepO is highly expressed in S. mutans strains resistant to complement immunity (blood isolates) compared to oral isolates. Gel mobility assay, transcriptional, and Western blot analyses revealed that pepO is repressed by VicR and induced by CovR. Deletion of pepO in the Cnm+ strain OMZ175 (OMZpepO) or in the Cnm- UA159 (UApepO) led to an increased susceptibility to C3b deposition, and to low binding to complement proteins C1q and C4BP. Additionally, pepO mutants showed diminished ex vivo survival in human blood and impaired capacity to kill G. mellonella larvae. Inactivation of cnm in OMZ175 (OMZcnm) resulted in increased resistance to C3b deposition and unaltered blood survival, although both pepO and cnm mutants displayed attenuated virulence in G. mellonella. Unlike OMZcnm, OMZpepO could invade HCAEC endothelial cells. Supporting these phenotypes, recombinant proteins rPepO and rCnmA showed specific profiles of binding to C1q, C4BP, and to other plasma (plasminogen, fibronectin) and extracellular matrix proteins (type I collagen, laminin). Therefore this study identifies a novel VicRK/CovR-target required for immune evasion and host persistence, pepO, expanding the roles of VicRK and CovR in regulating S. mutans virulence.
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Affiliation(s)
- Lívia A. Alves
- Department of Oral Diagnosis, Piracicaba Dental School – State University of Campinas, Piracicaba, SP, Brazil
| | - Tridib Ganguly
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Érika N. Harth-Chú
- Department of Oral Diagnosis, Piracicaba Dental School – State University of Campinas, Piracicaba, SP, Brazil
| | - Jessica Kajfasz
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - José A. Lemos
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Jacqueline Abranches
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Renata O. Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School – State University of Campinas, Piracicaba, SP, Brazil
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17
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LaRock DL, Russell R, Johnson AF, Wilde S, LaRock CN. Group A Streptococcus Infection of the Nasopharynx Requires Proinflammatory Signaling through the Interleukin-1 Receptor. Infect Immun 2020; 88:e00356-20. [PMID: 32719155 PMCID: PMC7504964 DOI: 10.1128/iai.00356-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 07/20/2020] [Indexed: 12/19/2022] Open
Abstract
Group A Streptococcus (GAS) is the etiologic agent of numerous high-morbidity and high-mortality diseases. Infections are typically highly proinflammatory. During the invasive infection necrotizing fasciitis, this is in part due to the GAS protease SpeB directly activating interleukin-1β (IL-1β) independent of the canonical inflammasome pathway. The upper respiratory tract is the primary site for GAS colonization, infection, and transmission, but the host-pathogen interactions at this site are still largely unknown. We found that in the murine nasopharynx, SpeB enhanced IL-1β-mediated inflammation and the chemotaxis of neutrophils. However, neutrophilic inflammation did not restrict infection and instead promoted GAS replication and disease. Inhibiting IL-1β or depleting neutrophils, which both promote invasive infection, prevented GAS infection of the nasopharynx. Mice pretreated with penicillin became more susceptible to GAS challenge, and this reversed the attenuation from neutralization or depletion of IL-1β, neutrophils, or SpeB. Collectively, our results suggest that SpeB is essential to activate an IL-1β-driven neutrophil response. Unlike during invasive tissue infections, this is beneficial in the upper respiratory tract because it disrupts colonization resistance mediated by the microbiota. This provides experimental evidence that the notable inflammation of strep throat, which presents with significant swelling, pain, and neutrophil influx, is not an ineffectual immune response but rather is a GAS-directed remodeling of this niche for its pathogenic benefit.
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Affiliation(s)
- Doris L LaRock
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Raedeen Russell
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Anders F Johnson
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, USA
| | - Shyra Wilde
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, USA
| | - Christopher N LaRock
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Medicine, Division of Infectious Disease, Emory University School of Medicine, Atlanta, Georgia, USA
- Antimicrobial Resistance Center, Emory University, Atlanta, Georgia, USA
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18
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Siggins MK, Lynskey NN, Lamb LE, Johnson LA, Huse KK, Pearson M, Banerji S, Turner CE, Woollard K, Jackson DG, Sriskandan S. Extracellular bacterial lymphatic metastasis drives Streptococcus pyogenes systemic infection. Nat Commun 2020; 11:4697. [PMID: 32943639 PMCID: PMC7498588 DOI: 10.1038/s41467-020-18454-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 08/24/2020] [Indexed: 12/15/2022] Open
Abstract
Unassisted metastasis through the lymphatic system is a mechanism of dissemination thus far ascribed only to cancer cells. Here, we report that Streptococcus pyogenes also hijack lymphatic vessels to escape a local infection site, transiting through sequential lymph nodes and efferent lymphatic vessels to enter the bloodstream. Contrasting with previously reported mechanisms of intracellular pathogen carriage by phagocytes, we show S. pyogenes remain extracellular during transit, first in afferent and then efferent lymphatics that carry the bacteria through successive draining lymph nodes. We identify streptococcal virulence mechanisms important for bacterial lymphatic dissemination and show that metastatic streptococci within infected lymph nodes resist and subvert clearance by phagocytes, enabling replication that can seed intense bloodstream infection. The findings establish the lymphatic system as both a survival niche and conduit to the bloodstream for S. pyogenes, explaining the phenomenon of occult bacteraemia. This work provides new perspectives in streptococcal pathogenesis with implications for immunity. Pathogenic agents can spread from an initial to a secondary site via the lymphatics. Here, using a mouse model of infection, the authors show that S. pyogenes readily transit through sequential lymph nodes within efferent lymphatics to reach the bloodstream and drive systemic infection, while remaining extracellular.
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Affiliation(s)
- Matthew K Siggins
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK. .,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK. .,NLHI, Imperial College London, London, W2 1PG, UK.
| | - Nicola N Lynskey
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK.,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK.,The Roslin Institute, University of Edinburgh, Edinburgh, EH25 9RG, UK
| | - Lucy E Lamb
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK
| | - Louise A Johnson
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Kristin K Huse
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK.,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK
| | - Max Pearson
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK.,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK
| | - Suneale Banerji
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Claire E Turner
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK.,The Florey Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Kevin Woollard
- Centre for Inflammatory Disease, Department of Immunology & Inflammation, Imperial College London, London, W12 0NN, UK
| | - David G Jackson
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Shiranee Sriskandan
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK. .,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK.
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19
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Ijaz M, Ameen F, Alfoteih YA, Shamim S, Alshehri WA, Murtaza G. Dissecting Streptococcus pyogenes interaction with human. Arch Microbiol 2020; 202:2023-32. [PMID: 32504132 DOI: 10.1007/s00203-020-01932-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/26/2020] [Accepted: 05/29/2020] [Indexed: 10/24/2022]
Abstract
Streptococcus pyogenes is a species of Gram-positive bacteria. It is also known as Group A Streptococcus (GAS) that causes pathogenesis to humans only. The GAS infection has several manifestations including invasive illness. Current research has linked the molecular modes of GAS virulence with substantial sequencing determinations for the isolation of genomes. These advances help to comprehend the molecular evolution resulting in the pandemic strains. Thus, it is indispensable to reconsider the philosophy that involves GAS pathogenesis. The recent investigations involve studying GAS in the nasopharynx and its capability to cause infection or asymptomatically reside in the host. These advances have been discussed in this article with an emphasis on the natural history of GAS and the evolutionary change in the pandemic strains. In addition, this review describes the unique functions for major pathogenicity determinants to comprehend their physiological effects.
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20
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Otsuji K, Fukuda K, Maruoka T, Ogawa M, Saito M. Acquisition of genetic mutations in Group A Streptococci at infection site and subsequent systemic dissemination of the mutants with lethal mutations in a streptococcal toxic shock syndrome mouse model. Microb Pathog 2020; 143:104116. [PMID: 32135223 DOI: 10.1016/j.micpath.2020.104116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 02/29/2020] [Accepted: 03/01/2020] [Indexed: 10/24/2022]
Abstract
Streptococcal toxic shock syndrome (STSS) is caused mainly by Streptococcus pyogenes (Group A Streptococci, GAS), and it has a fatality rate of 25%. Mutations in CsrRS and RopB, which suppress the transcription of many virulence factors, were recently found in clinical isolates from STSS patients, but it is not fully understood when and where GAS acquires the mutations in the host. To resolve this question, we used our mouse model of human STSS to recover GAS strains from injections sites, spleens and blood of moribund mice with STSS-like symptoms, and analyzed the sequence of the covR/covS genes and ropB gene that encode CsrRS and RopB. Fifteen out of twenty mice that were inoculated transdermally into muscles with GAS organisms became moribund with STSS-like symptoms after more than 20 days after inoculation. We found that all the disseminated GAS strains recovered from the blood and spleens of the moribund mice had mutations in either the covR genes or the covS genes. The mutation sites in the GAS strains recovered from the blood and spleen were identical in each mouse, whereas the strains recovered from the muscles included a mix of disseminated strains, other mutant strains, and the parent strain. The mutant strains killed mice significantly earlier than the parent strain. Our data indicated that GAS organisms remained at the injection site, and various mutants appeared there, among which the strain that acquires the mutation in the covR/S gene is expected to overexpress various virulence factors simultaneously and cause systemic infection such as STSS.
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Affiliation(s)
- Ken Otsuji
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Japan; Department of Critical Care Medicine, Hospital of the University of Occupational and Environmental Health, Japan.
| | - Kazumasa Fukuda
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Tsukasa Maruoka
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Midori Ogawa
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Mitsumasa Saito
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Japan
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21
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Kachroo P, Eraso JM, Olsen RJ, Zhu L, Kubiak SL, Pruitt L, Yerramilli P, Cantu CC, Ojeda Saavedra M, Pensar J, Corander J, Jenkins L, Kao L, Granillo A, Porter AR, DeLeo FR, Musser JM. New Pathogenesis Mechanisms and Translational Leads Identified by Multidimensional Analysis of Necrotizing Myositis in Primates. mBio 2020; 11:e03363-19. [PMID: 32071274 PMCID: PMC7029145 DOI: 10.1128/mbio.03363-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 01/06/2020] [Indexed: 01/08/2023] Open
Abstract
A fundamental goal of contemporary biomedical research is to understand the molecular basis of disease pathogenesis and exploit this information to develop targeted and more-effective therapies. Necrotizing myositis caused by the bacterial pathogen Streptococcus pyogenes is a devastating human infection with a high mortality rate and few successful therapeutic options. We used dual transcriptome sequencing (RNA-seq) to analyze the transcriptomes of S. pyogenes and host skeletal muscle recovered contemporaneously from infected nonhuman primates. The in vivo bacterial transcriptome was strikingly remodeled compared to organisms grown in vitro, with significant upregulation of genes contributing to virulence and altered regulation of metabolic genes. The transcriptome of muscle tissue from infected nonhuman primates (NHPs) differed significantly from that of mock-infected animals, due in part to substantial changes in genes contributing to inflammation and host defense processes. We discovered significant positive correlations between group A streptococcus (GAS) virulence factor transcripts and genes involved in the host immune response and inflammation. We also discovered significant correlations between the magnitude of bacterial virulence gene expression in vivo and pathogen fitness, as assessed by previously conducted genome-wide transposon-directed insertion site sequencing (TraDIS). By integrating the bacterial RNA-seq data with the fitness data generated by TraDIS, we discovered five new pathogen genes, namely, S. pyogenes 0281 (Spy0281 [dahA]), ihk-irr, slr, isp, and ciaH, that contribute to necrotizing myositis and confirmed these findings using isogenic deletion-mutant strains. Taken together, our study results provide rich new information about the molecular events occurring in severe invasive infection of primate skeletal muscle that has extensive translational research implications.IMPORTANCE Necrotizing myositis caused by Streptococcus pyogenes has high morbidity and mortality rates and relatively few successful therapeutic options. In addition, there is no licensed human S. pyogenes vaccine. To gain enhanced understanding of the molecular basis of this infection, we employed a multidimensional analysis strategy that included dual RNA-seq and other data derived from experimental infection of nonhuman primates. The data were used to target five streptococcal genes for pathogenesis research, resulting in the unambiguous demonstration that these genes contribute to pathogen-host molecular interactions in necrotizing infections. We exploited fitness data derived from a recently conducted genome-wide transposon mutagenesis study to discover significant correlation between the magnitude of bacterial virulence gene expression in vivo and pathogen fitness. Collectively, our findings have significant implications for translational research, potentially including vaccine efforts.
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Affiliation(s)
- 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, USA
| | - 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, USA
| | - 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, USA
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, New York, USA
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - 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, USA
| | - 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, USA
| | - Layne Pruitt
- 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, USA
| | - Prasanti Yerramilli
- 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, USA
| | - 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, USA
| | - 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, USA
| | - Johan Pensar
- Department of Mathematics and Statistics, Helsinki Institute of Information Technology, University of Helsinki, Helsinki, Finland
| | - Jukka Corander
- Department of Mathematics and Statistics, Helsinki Institute of Information Technology, University of Helsinki, Helsinki, Finland
- Department of Biostatistics, University of Oslo, Oslo, Norway
| | - Leslie Jenkins
- Comparative Medicine Program, Houston Methodist Research Institute, Houston, Texas, USA
| | - Lillian Kao
- Department of Surgery, University of Texas McGovern Medical School, Houston, Texas, USA
| | - Alejandro Granillo
- Department of Internal Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, USA
| | - Adeline R Porter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Frank R DeLeo
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - 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, USA
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, New York, USA
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
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22
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Harth-Chu EN, Alves LA, Theobaldo JD, Salomão MF, Höfling JF, King WF, Smith DJ, Mattos-Graner RO. PcsB Expression Diversity Influences on Streptococcus mitis Phenotypes Associated With Host Persistence and Virulence. Front Microbiol 2019; 10:2567. [PMID: 31798545 PMCID: PMC6861525 DOI: 10.3389/fmicb.2019.02567] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 10/23/2019] [Indexed: 12/31/2022] Open
Abstract
S. mitis is an abundant member of the commensal microbiota of the oral cavity and pharynx, which has the potential to promote systemic infections. By analyzing a collection of S. mitis strains isolated from the oral cavity at commensal states or from systemic infections (blood strains), we established that S. mitis ubiquitously express the surface immunodominant protein, PcsB (also called GbpB), required for binding to sucrose-derived exopolysaccharides (EPS). Immuno dot blot assays with anti-PcsB antibodies and RT-qPCR transcription analyses revealed strain-specific profiles of PcsB production associated with diversity in pcsB transcriptional activities. Additionally, blood strains showed significantly higher levels of PcsB expression compared to commensal isolates. Because Streptococcus mutans co-colonizes S. mitis dental biofilms, and secretes glucosyltransferases (GtfB/C/D) for the synthesis of highly insoluble EPS from sucrose, profiles of S. mitis binding to EPS, biofilm formation and evasion of the complement system were assessed in sucrose-containing BHI medium supplemented or not with filter-sterilized S. mutans culture supernatants. These analyses showed significant S. mitis binding to EPS and biofilm formation in the presence of S. mutans supernatants supplemented with sucrose, compared to BHI or BHI-sucrose medium. In addition, these phenotypes were abolished if strains were grown in culture supernatants of a gtfBCD-defective S. mutans mutant. Importantly, GtfB/C/D-associated phenotypes were enhanced in high PcsB-expressing strains, compared to low PcsB producers. Increased PcsB expression was further correlated with increased resistance to deposition of C3b/iC3b of the complement system after exposure to human serum, when strains were previously grown in the presence of S. mutans supernatants. Finally, analyses of PcsB polymorphisms and bioinformatic prediction of epitopes with significant binding to MHC class II alleles revealed that blood isolates harbor PcsB polymorphisms in its functionally conserved CHAP-domain, suggesting antigenic variation. These findings reveal important roles of PcsB in S. mitis-host interactions under commensal and pathogenic states, highlighting the need for studies to elucidate mechanisms regulating PcsB expression in this species.
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Affiliation(s)
- Erika N Harth-Chu
- Department of Oral Diagnosis, Piracicaba Dental School, UNICAMP, Piracicaba, Brazil
| | - Lívia A Alves
- Department of Oral Diagnosis, Piracicaba Dental School, UNICAMP, Piracicaba, Brazil
| | - Jéssica D Theobaldo
- Department of Oral Diagnosis, Piracicaba Dental School, UNICAMP, Piracicaba, Brazil
| | - Mariana F Salomão
- Department of Oral Diagnosis, Piracicaba Dental School, UNICAMP, Piracicaba, Brazil
| | - José F Höfling
- Department of Oral Diagnosis, Piracicaba Dental School, UNICAMP, Piracicaba, Brazil
| | - William F King
- Department of Immunology and Infectious Disease, The Forsyth Institute, Cambridge, MA, United States
| | - Daniel J Smith
- Department of Immunology and Infectious Disease, The Forsyth Institute, Cambridge, MA, United States
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23
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Jain I, Danger JL, Burgess C, Uppal T, Sumby P. The group A Streptococcus accessory protein RocA: regulatory activity, interacting partners and influence on disease potential. Mol Microbiol 2019; 113:190-207. [PMID: 31660653 PMCID: PMC7028121 DOI: 10.1111/mmi.14410] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2019] [Indexed: 12/11/2022]
Abstract
The group A Streptococcus (GAS) causes diseases that range from mild (e.g. pharyngitis) to severely invasive (e.g. necrotizing fasciitis). Strain‐ and serotype‐specific differences influence the ability of isolates to cause individual diseases. At the center of this variability is the CovR/S two‐component system and the accessory protein RocA. Through incompletely defined mechanisms, CovR/S and RocA repress the expression of more than a dozen immunomodulatory virulence factors. Alleviation of this repression is selected for during invasive infections, leading to the recovery of covR, covS or rocA mutant strains. Here, we investigated how RocA promotes CovR/S activity, identifying that RocA is a pseudokinase that interacts with CovS. Disruption of CovS kinase or phosphatase activities abolishes RocA function, consistent with RocA acting through the modulation of CovS activity. We also identified, in conflict with a previous study, that the RocA regulon includes the secreted protease‐encoding gene speB. Finally, we discovered an inverse correlation between the virulence of wild‐type, rocA mutant, covS mutant and covR mutant strains during invasive infection and their fitness in an ex vivo upper respiratory tract model. Our data inform on mechanisms that control GAS disease potential and provide an explanation for observed strain‐ and serotype‐specific variability in RocA function.
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Affiliation(s)
- Ira Jain
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Jessica L Danger
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Cameron Burgess
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Timsy Uppal
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Paul Sumby
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
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24
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Hirose Y, Yamaguchi M, Okuzaki D, Motooka D, Hamamoto H, Hanada T, Sumitomo T, Nakata M, Kawabata S. Streptococcus pyogenes Transcriptome Changes in the Inflammatory Environment of Necrotizing Fasciitis. Appl Environ Microbiol 2019; 85:e01428-19. [PMID: 31471300 DOI: 10.1128/AEM.01428-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/23/2019] [Indexed: 12/31/2022] Open
Abstract
Necrotizing fasciitis, a life-threatening subcutaneous soft-tissue infection, is principally caused by S. pyogenes. The inflammatory environment at the site of infection causes global gene expression changes for survival of the bacterium and pathogenesis. However, no known study regarding transcriptomic profiling of S. pyogenes in cases of necrotizing fasciitis has been presented. We identified 483 bacterial genes whose expression was consistently altered during infection. Our results showed that S. pyogenes infection induces drastic upregulation of the expression of virulence-associated genes and shifts metabolic pathway usage. In particular, high-level expression of toxins, such as cytolysins, proteases, and nucleases, was observed at infection sites. In addition, genes identified as consistently enriched included those related to metabolism of arginine and histidine as well as carbohydrate uptake and utilization. Conversely, genes associated with the oxidative stress response and cell division were consistently downregulated during infection. The present findings provide useful information for establishing novel treatment strategies. Streptococcus pyogenes is a major cause of necrotizing fasciitis, a life-threatening subcutaneous soft-tissue infection. At the host infection site, the local environment and interactions between the host and bacteria have effects on bacterial gene expression profiles, while the gene expression pattern of S. pyogenes related to this disease remains unknown. In this study, we used a mouse model of necrotizing fasciitis and performed RNA-sequencing (RNA-seq) analysis of S. pyogenes M1T1 strain 5448 by isolating total RNA from infected hind limbs obtained at 24, 48, and 96 h postinfection. RNA-seq analysis results identified 483 bacterial genes whose expression was consistently altered in the infected hindlimbs compared to their expression under in vitro conditions. Genes showing consistent enrichment during infection included 306 encoding molecules involved in virulence, carbohydrate utilization, amino acid metabolism, trace-metal transport, and the vacuolar ATPase transport system. Surprisingly, drastic upregulation of 3 genes, encoding streptolysin S precursor (sagA), cysteine protease (speB), and secreted DNase (spd), was noted in the present mouse model (log2 fold change, >6.0, >9.4, and >7.1, respectively). Conversely, the number of consistently downregulated genes was 177, including those associated with the oxidative stress response and cell division. These results suggest that in necrotizing fasciitis, S. pyogenes shows an altered metabolism, decreased cell proliferation, and upregulation of expression of major toxins. Our findings are considered to provide critical information for developing novel treatment strategies and vaccines for necrotizing fasciitis. IMPORTANCE Necrotizing fasciitis, a life-threatening subcutaneous soft-tissue infection, is principally caused by S. pyogenes. The inflammatory environment at the site of infection causes global gene expression changes for survival of the bacterium and pathogenesis. However, no known study regarding transcriptomic profiling of S. pyogenes in cases of necrotizing fasciitis has been presented. We identified 483 bacterial genes whose expression was consistently altered during infection. Our results showed that S. pyogenes infection induces drastic upregulation of the expression of virulence-associated genes and shifts metabolic pathway usage. In particular, high-level expression of toxins, such as cytolysins, proteases, and nucleases, was observed at infection sites. In addition, genes identified as consistently enriched included those related to metabolism of arginine and histidine as well as carbohydrate uptake and utilization. Conversely, genes associated with the oxidative stress response and cell division were consistently downregulated during infection. The present findings provide useful information for establishing novel treatment strategies.
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25
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Tatsuno I, Isaka M, Matsumoto M, Nishio N, Matsui H, Hasegawa T. Complete Genome Sequence of emm 1 Streptococcus pyogenes 10-85, a Strain Isolated from a Patient with Streptococcal Toxic Shock Syndrome in Japan. Microbiol Resour Announc 2019; 8. [PMID: 31196924 PMCID: PMC6588041 DOI: 10.1128/mra.00453-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Here, we announce the complete genome sequence of Streptococcus pyogenes strain 10-85 (type emm1), isolated from a patient with streptococcal toxic shock syndrome (STSS). The strain lacks the genomic regions encoding SalR-SalK, a two‐component regulatory system, and the adjacent type I restriction modification system. Here, we announce the complete genome sequence of Streptococcus pyogenes strain 10-85 (type emm1), isolated from a patient with streptococcal toxic shock syndrome (STSS). The strain lacks the genomic regions encoding SalR-SalK, a two‐component regulatory system, and the adjacent type I restriction modification system.
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26
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Shumba P, Mairpady Shambat S, Siemens N. The Role of Streptococcal and Staphylococcal Exotoxins and Proteases in Human Necrotizing Soft Tissue Infections. Toxins (Basel) 2019; 11:E332. [PMID: 31212697 DOI: 10.3390/toxins11060332] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 06/04/2019] [Accepted: 06/10/2019] [Indexed: 12/31/2022] Open
Abstract
Necrotizing soft tissue infections (NSTIs) are critical clinical conditions characterized by extensive necrosis of any layer of the soft tissue and systemic toxicity. Group A streptococci (GAS) and Staphylococcus aureus are two major pathogens associated with monomicrobial NSTIs. In the tissue environment, both Gram-positive bacteria secrete a variety of molecules, including pore-forming exotoxins, superantigens, and proteases with cytolytic and immunomodulatory functions. The present review summarizes the current knowledge about streptococcal and staphylococcal toxins in NSTIs with a special focus on their contribution to disease progression, tissue pathology, and immune evasion strategies.
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Alves LA, de Carli TR, Harth-Chu EN, Mariano FS, Höfling JF, Stipp RN, Mattos-Graner RO. Oral streptococci show diversity in resistance to complement immunity. J Med Microbiol 2019; 68:600-608. [PMID: 30843785 DOI: 10.1099/jmm.0.000955] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Mechanisms underlying systemic infections by oral species of Mitis (Streptococcus mitis, Streptococcus oralis) and Sanguinis (Streptococcus gordonii, Streptococcus sanguinis) commensal streptococci are poorly understood. This study investigates profiles of susceptibility to complement-mediated host immunity in representative strains of these four species, which were isolated from oral sites or from the bloodstream. METHODOLOGY Deposition of complement opsonins (C3b/iC3b), and surface binding to C-reactive protein (CRP) and to IgG antibodies were quantified by flow cytometry in 34 strains treated with human serum (HS), and compared to rates of opsonophagocytosis by human PMN mediated by complement (CR1/3) and/or IgG Fc (FcγRII/III) receptors. RESULTS S. sanguinis strains showed reduced susceptibility to complement opsonization and low binding to CRP and to IgG compared to other species. Surface levels of C3b/iC3b in S. sanguinis strains were 4.5- and 7.8-fold lower than that observed in S. gordonii and Mitis strains, respectively. Diversity in C3b/iC3b deposition was evident among Mitis species, in which C3b/iC3b deposition was significantly associated with CR/FcγR-dependent opsonophagocytosis by PMN (P<0.05). Importantly, S. gordonii and Mitis group strains isolated from systemic infections showed resistance to complement opsonization when compared to oral isolates of the respective species (P<0.05). CONCLUSIONS This study establishes species-specific profiles of susceptibility to complement immunity in Mitis and Sanguinis streptococci, and indicates that strains associated with systemic infections have increased capacity to evade complement immunity. These findings highlight the need for studies identifying molecular functions involved in complement evasion in oral streptococci.
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Affiliation(s)
- Lívia A Alves
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Thaís R de Carli
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Erika N Harth-Chu
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Flávia S Mariano
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - José F Höfling
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Rafael N Stipp
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Renata O Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
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28
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Kachroo P, Eraso JM, Beres SB, Olsen RJ, Zhu L, Nasser W, Bernard PE, Cantu CC, Saavedra MO, Arredondo MJ, Strope B, Do H, Kumaraswami M, Vuopio J, Gröndahl-Yli-Hannuksela K, Kristinsson KG, Gottfredsson M, Pesonen M, Pensar J, Davenport ER, Clark AG, Corander J, Caugant DA, Gaini S, Magnussen MD, Kubiak SL, Nguyen HAT, Long SW, Porter AR, DeLeo FR, Musser JM. Integrated analysis of population genomics, transcriptomics and virulence provides novel insights into Streptococcus pyogenes pathogenesis. Nat Genet 2019; 51:548-59. [PMID: 30778225 DOI: 10.1038/s41588-018-0343-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 12/21/2018] [Indexed: 12/22/2022]
Abstract
Streptococcus pyogenes causes 700 million human infections annually worldwide, yet, despite a century of intensive effort, there is no licensed vaccine against this bacterium. Although a number of large-scale genomic studies of bacterial pathogens have been published, the relationships among the genome, transcriptome, and virulence in large bacterial populations remain poorly understood. We sequenced the genomes of 2,101 emm28 S. pyogenes invasive strains, from which we selected 492 phylogenetically diverse strains for transcriptome analysis and 50 strains for virulence assessment. Data integration provided a novel understanding of the virulence mechanisms of this model organism. Genome-wide association study, expression quantitative trait loci analysis, machine learning, and isogenic mutant strains identified and confirmed a one-nucleotide indel in an intergenic region that significantly alters global transcript profiles and ultimately virulence. The integrative strategy that we used is generally applicable to any microbe and may lead to new therapeutics for many human pathogens.
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Hasegawa T, Matsumoto M, Hata N, Yano H, Isaka M, Tatsuno I. Homologous role of CovRS two-component regulatory system in NAD+-glycohydrolase activity inStreptococcus dysgalactiaesubsp.equisimilisas inStreptococcus pyogenes. APMIS 2019; 127:87-92. [DOI: 10.1111/apm.12914] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 11/26/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Tadao Hasegawa
- Department of Bacteriology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Masakado Matsumoto
- Department of Microbiology and Medical Zoology; Aichi Prefectural Institute of Public Health; Nagoya Japan
| | - Nanako Hata
- Department of Microbiology; Nagoya City University Hospital; Nagoya Japan
| | - Hisako Yano
- Department of Infection Control and Prevention Nursing; Nagoya City University Graduate School of Nursing; Nagoya Japan
| | - Masanori Isaka
- Department of Bacteriology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Ichiro Tatsuno
- Department of Bacteriology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
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Abstract
Group A Streptococcus (GAS) causes common pharyngitis and skin infections and occasional severe invasive infections. This review describes the recent progress on the pathogenesis of hypervirulent GAS. CovRS mutations are frequent among invasive GAS isolates and lead to hypervirulence. GAS CovRS mutants can be selected in vivo by neutrophils. The role of protease SpeB in source-sink dynamics of wild-type GAS and hypervirulent variants is discussed. Streptolysin S and PAF acetylhydrolase Sse critically and synergistically contribute to the inhibition of neutrophil recruitment by GAS CovS mutants. CovS mutations in emm3 GAS lead to the vascular invasion and enhance systemic GAS dissemination.
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31
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Galloway-Peña J, DebRoy S, Brumlow C, Li X, Tran TT, Horstmann N, Yao H, Chen K, Wang F, Pan BF, Hawke DH, Thompson EJ, Arias CA, Fowler VG, Bhatti MM, Kalia A, Flores AR, Shelburne SA. Hypervirulent group A Streptococcus emergence in an acaspular background is associated with marked remodeling of the bacterial cell surface. PLoS One 2018; 13:e0207897. [PMID: 30517150 PMCID: PMC6281247 DOI: 10.1371/journal.pone.0207897] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 11/06/2018] [Indexed: 12/28/2022] Open
Abstract
Inactivating mutations in the control of virulence two-component regulatory system (covRS) often account for the hypervirulent phenotype in severe, invasive group A streptococcal (GAS) infections. As CovR represses production of the anti-phagocytic hyaluronic acid capsule, high level capsule production is generally considered critical to the hypervirulent phenotype induced by CovRS inactivation. There have recently been large outbreaks of GAS strains lacking capsule, but there are currently no data on the virulence of covRS-mutated, acapsular strains in vivo. We investigated the impact of CovRS inactivation in acapsular serotype M4 strains using a wild-type (M4-SC-1) and a naturally-occurring CovS-inactivated strain (M4-LC-1) that contains an 11bp covS insertion. M4-LC-1 was significantly more virulent in a mouse bacteremia model but caused smaller lesions in a subcutaneous mouse model. Over 10% of the genome showed significantly different transcript levels in M4-LC-1 vs. M4-SC-1 strain. Notably, the Mga regulon and multiple cell surface protein-encoding genes were strongly upregulated–a finding not observed for CovS-inactivated, encapsulated M1 or M3 GAS strains. Consistent with the transcriptomic data, transmission electron microscopy revealed markedly altered cell surface morphology of M4-LC-1 compared to M4-SC-1. Insertional inactivation of covS in M4-SC-1 recapitulated the transcriptome and cell surface morphology. Analysis of the cell surface following CovS-inactivation revealed that the upregulated proteins were part of the Mga regulon. Inactivation of mga in M4-LC-1 reduced transcript levels of multiple cell surface proteins and reversed the cell surface alterations consistent with the effect of CovS inactivation on cell surface composition being mediated by Mga. CovRS-inactivating mutations were detected in 20% of current invasive serotype M4 strains in the United States. Thus, we discovered that hypervirulent M4 GAS strains with covRS mutations can arise in an acapsular background and that such hypervirulence is associated with profound alteration of the cell surface.
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Affiliation(s)
- Jessica Galloway-Peña
- Department of Infectious Diseases Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Sruti DebRoy
- Department of Infectious Diseases Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Chelcy Brumlow
- Department of Infectious Diseases Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Xiqi Li
- Department of Infectious Diseases Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Truc T. Tran
- Center for Antimicrobial Resistance and Microbial Genomics and Division of Infectious Diseases, UTHealth McGovern Medical School, Houston, Texas, United States of America
| | - Nicola Horstmann
- Department of Infectious Diseases Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Hui Yao
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Ken Chen
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Fang Wang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Bih-Fang Pan
- The Proteomics and Metabolomics Facility, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - David H. Hawke
- The Proteomics and Metabolomics Facility, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Erika J. Thompson
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Cesar A. Arias
- Center for Antimicrobial Resistance and Microbial Genomics and Division of Infectious Diseases, UTHealth McGovern Medical School, Houston, Texas, United States of America
- Center for Infectious Diseases, UTHealth School of Public Health, Houston, Texas, United States of America
- Molecular Genetics and Antimicrobial Resistance Unit-International Center for Microbial Genomics, Universidad El Bosque, Bogota, Colombia
| | - Vance G. Fowler
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Micah M. Bhatti
- Department of Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Awdhesh Kalia
- Graduate Program in Diagnostic Genetics, School of Health Professions, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Anthony R. Flores
- Center for Antimicrobial Resistance and Microbial Genomics and Division of Infectious Diseases, UTHealth McGovern Medical School, Houston, Texas, United States of America
- Department of Pediatrics, University of Texas Health Science Center McGovern Medical School, Houston, Texas, United States of America
| | - Samuel A. Shelburne
- Department of Infectious Diseases Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- The Proteomics and Metabolomics Facility, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
- * E-mail:
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Horstmann N, Tran CN, Brumlow C, DebRoy S, Yao H, Nogueras Gonzalez G, Makthal N, Kumaraswami M, Shelburne SA. Phosphatase activity of the control of virulence sensor kinase CovS is critical for the pathogenesis of group A streptococcus. PLoS Pathog 2018; 14:e1007354. [PMID: 30379939 PMCID: PMC6231683 DOI: 10.1371/journal.ppat.1007354] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 11/12/2018] [Accepted: 09/14/2018] [Indexed: 12/15/2022] Open
Abstract
The control of virulence regulator/sensor kinase (CovRS) two-component system is critical to the infectivity of group A streptococcus (GAS), and CovRS inactivating mutations are frequently observed in GAS strains causing severe human infections. CovS modulates the phosphorylation status and with it the regulatory effect of its cognate regulator CovR via its kinase and phosphatase activity. However, the contribution of each aspect of CovS function to GAS pathogenesis is unknown. We created isoallelic GAS strains that differ only by defined mutations which either abrogate CovR phosphorylation, CovS kinase or CovS phosphatase activity in order to test the contribution of CovR phosphorylation levels to GAS virulence, emergence of hypervirulent CovS-inactivated strains during infection, and GAS global gene expression. These sets of strains were created in both serotype M1 and M3 backgrounds, two prevalent GAS disease-causing serotypes, to ascertain whether our observations were serotype-specific. In both serotypes, GAS strains lacking CovS phosphatase activity (CovS-T284A) were profoundly impaired in their ability to cause skin infection or colonize the oropharynx in mice and to survive neutrophil killing in human blood. Further, response to the human cathelicidin LL-37 was abrogated. Hypervirulent GAS isolates harboring inactivating CovRS mutations were not recovered from mice infected with M1 strain M1-CovS-T284A and only sparsely recovered from mice infected with M3 strain M3-CovS-T284A late in the infection course. Consistent with our virulence data, transcriptome analyses revealed increased repression of a broad array of virulence genes in the CovS phosphatase deficient strains, including the genes encoding the key anti-phagocytic M protein and its positive regulator Mga, which are not typically part of the CovRS transcriptome. Taken together, these data establish a key role for CovS phosphatase activity in GAS pathogenesis and suggest that CovS phosphatase activity could be a promising therapeutic target in GAS without promoting emergence of hypervirulent CovS-inactivated strains. Group A streptococcus (GAS), also known as Streptococcus pyogenes, causes a broad array of human infections of varying severity. Tight control of production of virulence factors is critical to GAS pathogenesis, and the control of virulence two-component signaling system (CovRS) is central to this process. The activity of the bifunctional histidine kinase CovS determines the phosphorylation status and thereby the activity of its cognate response regulator CovR. Herein, we sought to determine how varying CovR phosphorylation level (CovR~P) impacts GAS pathophysiology. Using three infection models, we discovered that GAS strains lacking CovS phosphatase activity resulting in high CovR~P levels had markedly impaired infectivity. Transcriptome analysis revealed that the hypovirulent phenotype of CovS phosphatase deficient strains is due to down-regulation of numerous genes encoding GAS virulence factors. We identified repression of additional virulence genes that are typically not controlled by CovR, thus expanding the CovR regulon at high CovR~P concentrations. Our data indicate that phosphatase activity of CovS sensor kinase is crucial for spatiotemporal regulation of GAS virulence gene expression. Thus, we propose that targeting the phosphatase activity of CovS sensor kinase could be a promising novel therapeutic approach to combat GAS disease.
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Affiliation(s)
- Nicola Horstmann
- Department of Infectious Diseases, Infection Control and Employee Health, MD Anderson Cancer Center, Houston TX, United States of America
| | - Chau Nguyen Tran
- Department of Infectious Diseases, Infection Control and Employee Health, MD Anderson Cancer Center, Houston TX, United States of America
| | - Chelcy Brumlow
- Department of Infectious Diseases, Infection Control and Employee Health, MD Anderson Cancer Center, Houston TX, United States of America
| | - Sruti DebRoy
- Department of Infectious Diseases, Infection Control and Employee Health, MD Anderson Cancer Center, Houston TX, United States of America
| | - Hui Yao
- Department of Bioinformatics and Computational Biology, MD Anderson Cancer Center, Houston TX, United States of America
| | - Graciela Nogueras Gonzalez
- Department of Bioinformatics and Computational Biology, MD Anderson Cancer Center, Houston TX, United States of America
| | - Nishanth Makthal
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, United States of America
| | - Muthiah Kumaraswami
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, United States of America
| | - Samuel A. Shelburne
- Department of Infectious Diseases, Infection Control and Employee Health, MD Anderson Cancer Center, Houston TX, United States of America
- Department of Genomic Medicine, MD Anderson Cancer Center, Houston TX, United States of America
- * E-mail:
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Lamb LE, Siggins MK, Scudamore C, Macdonald W, Turner CE, Lynskey NN, Tan LKK, Sriskandan S. Impact of contusion injury on intramuscular emm1 group a streptococcus infection and lymphatic spread. Virulence 2018; 9:1074-1084. [PMID: 30052105 PMCID: PMC6068544 DOI: 10.1080/21505594.2018.1482180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Invasive group A Streptococcus (iGAS) is frequently associated with emm1 isolates, with an attendant mortality of around 20%. Cases occasionally arise in previously healthy individuals with a history of upper respiratory tract infection, soft tissue contusion, and no obvious portal of entry. Using a new murine model of contusion, we determined the impact of contusion on iGAS bacterial burden and phenotype. Calibrated mild blunt contusion did not provide a focus for initiation or seeding of GAS that was detectable following systemic GAS bacteremia, but instead enhanced GAS migration to the local draining lymph node following GAS inoculation at the same time and site of contusion. Increased migration to lymph node was associated with emergence of mucoid bacteria, although was not specific to mucoid bacteria. In one study, mucoid colonies demonstrated a significant increase in capsular hyaluronan that was not linked to a covRS or rocA mutation, but to a deletion in the promoter of the capsule synthesis locus, hasABC, resulting in a strain with increased fitness for lymph node migration. In summary, in the mild contusion model used, we could not detect seeding of muscle by GAS. Contusion promoted bacterial transit to the local lymph node. The consequences of contusion-associated bacterial lymphatic migration may vary depending on the pathogen and virulence traits selected.
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Affiliation(s)
- L E Lamb
- a Section of Infectious Diseases and Immunity, Department of Medicine , Imperial College London , London , UK.,b Royal Centre for Defence Medicine , University of Birmingham , Birmingham , UK
| | - M K Siggins
- a Section of Infectious Diseases and Immunity, Department of Medicine , Imperial College London , London , UK
| | - C Scudamore
- c Harwell Science and Innovation Campus , MRC Harwell , Oxfordshire , UK
| | - W Macdonald
- d Department of Bio-engineering , Royal School of Mines, Imperial College London , London , UK
| | - C E Turner
- a Section of Infectious Diseases and Immunity, Department of Medicine , Imperial College London , London , UK
| | - N N Lynskey
- a Section of Infectious Diseases and Immunity, Department of Medicine , Imperial College London , London , UK
| | - L K K Tan
- a Section of Infectious Diseases and Immunity, Department of Medicine , Imperial College London , London , UK
| | - S Sriskandan
- a Section of Infectious Diseases and Immunity, Department of Medicine , Imperial College London , London , UK
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Sarkar P, Danger JL, Jain I, Meadows LA, Beam C, Medicielo J, Burgess C, Musser JM, Sumby P. Phenotypic Variation in the Group A Streptococcus Due to Natural Mutation of the Accessory Protein-Encoding Gene rocA. mSphere 2018; 3:e00519-18. [PMID: 30333182 DOI: 10.1128/mSphere.00519-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Populations of a bacterial pathogen, whether recovered from a single patient or from a worldwide study, are often a heterogeneous mix of genetically and phenotypically divergent strains. Such heterogeneity is of value in changing environments and arises via mechanisms such as gene gain or gene mutation. Here, we identify an isolate of serotype M12 group A Streptococcus (GAS) (Streptococcus pyogenes) that has a natural mutation in rocA, which encodes an accessory protein to the virulence-regulating two-component system CovR/CovS (CovR/S). Disruption of RocA activity results in the differential expression of multiple GAS virulence factors, including the anti-phagocytic hyaluronic acid capsule and the chemokine protease SpyCEP. While some of our data regarding RocA-regulated genes overlaps with previous studies, which were performed with isolates of alternate GAS serotypes, some variability was also observed. Perhaps as a consequence of this alternate regulatory activity, we discovered that the contribution of RocA to the ability of the M12 isolate to survive and proliferate in human blood ex vivo is opposite that previously observed in M1, M3, and M18 GAS strains. Specifically, rocA mutation reduced, rather than enhanced, survival of the isolate. Finally, we also present data from an analysis of rocA transcription and show that rocA is transcribed in both mono- and polycistronic mRNAs. In aggregate, our data provide insight into the important regulatory role of RocA and into the mechanisms and consequences of GAS phenotypic heterogeneity.IMPORTANCE This study investigates the regulatory and phenotypic consequences of a naturally occurring mutation in a strain of the bacterial pathogen the group A Streptococcus (Streptococcus pyogenes). We show that this mutation, which occurs in a regulator-encoding gene, rocA, leads to altered virulence factor expression and reduces the ability of this isolate to survive in human blood. Critically, the blood survival phenotype and the assortment of genes regulated by RocA differ compared to previous studies into RocA activity. The data are consistent with there being strain- or serotype-specific variability in RocA function. Given that phenotypic variants can lead to treatment failures and escape from preventative regimes, our data provide information with regard to a mechanism of phenotypic variation in a prevalent Gram-positive pathogen.
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Pato C, Melo-Cristino J, Ramirez M, Friães A. Streptococcus pyogenes Causing Skin and Soft Tissue Infections Are Enriched in the Recently Emerged emm89 Clade 3 and Are Not Associated With Abrogation of CovRS. Front Microbiol 2018; 9:2372. [PMID: 30356787 PMCID: PMC6189468 DOI: 10.3389/fmicb.2018.02372] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 09/18/2018] [Indexed: 11/29/2022] Open
Abstract
Although skin and soft tissue infections (SSTI) are the most common focal infections associated with invasive disease caused by Streptococcus pyogenes (Lancefield Group A streptococci - GAS), there is scarce information on the characteristics of isolates recovered from SSTI in temperate-climate regions. In this study, 320 GAS isolated from SSTI in Portugal were characterized by multiple typing methods and tested for antimicrobial susceptibility and SpeB activity. The covRS and ropB genes of isolates with no detectable SpeB activity were sequenced. The antimicrobial susceptibility profile was similar to that of previously characterized isolates from invasive infections (iGAS), presenting a decreasing trend in macrolide resistance. However, the clonal composition of SSTI between 2005 and 2009 was significantly different from that of contemporary iGAS. Overall, iGAS were associated with emm1 and emm3, while SSTI were associated with emm89, the dominant emm type among SSTI (19%). Within emm89, SSTI were only significantly associated with isolates lacking the hasABC locus, suggesting that the recently emerged emm89 clade 3 may have an increased potential to cause SSTI. Reflecting these associations between emm type and disease presentation, there were also differences in the distribution of emm clusters, sequence types, and superantigen gene profiles between SSTI and iGAS. According to the predicted ability of each emm cluster to interact with host proteins, iGAS were associated with the ability to bind fibrinogen and albumin, whereas SSTI isolates were associated with the ability to bind C4BP, IgA, and IgG. SpeB activity was absent in 79 isolates (25%), in line with the proportion previously observed among iGAS. Null covS and ropB alleles (predicted to eliminate protein function) were detected in 10 (3%) and 12 (4%) isolates, corresponding to an underrepresentation of mutations impairing CovRS function in SSTI relative to iGAS. Overall, these results indicate that the isolates responsible for SSTI are genetically distinct from those recovered from normally sterile sites, supporting a role for mutations impairing CovRS activity specifically in invasive infection and suggesting that this role relies on a differential regulation of other virulence factors besides SpeB.
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Affiliation(s)
- Catarina Pato
- Author Affiliations: Centro Hospitalar do Barlavento Algarvio; Centro Hospitalar de Entre Douro e Vouga; Centro Hospitalar de Leiria; Centro Hospitalar de Vila Nova de Gaia/Espinho; Centro Hospitalar do Alto Ave; Centro Hospitalar do Porto; Centro Hospitalar da Póvoa do Varzim/Vila do Conde; Hospital Central do Funchal; Centro Hospitalar de Lisboa Central; Centro Hospitalar Lisboa Norte; Centro Hospitalar Lisboa Ocidental; Centro Hospitalar do Baixo Vouga; Hospital de Vila Real; Hospitais da Universidade de Coimbra; Hospital de Cascais; Hospital de São João, Porto; Hospital de Braga; Hospital de Santa Luzia, Elvas; Hospital dos SAMS, Lisboa; Hospital Dr. Fernando da Fonseca, Amadora/Sintra; Hospital do Espírito Santo, Évora; Hospital Garcia de Orta, Almada; Hospital Pedro Hispano, Matosinhos; Unidade Local de Saúde do Baixo Alentejo, Beja.,Faculdade de Medicina, Instituto de Microbiologia, Instituto de Medicina Molecular, Universidade de Lisboa, Lisboa, Portugal
| | - José Melo-Cristino
- Author Affiliations: Centro Hospitalar do Barlavento Algarvio; Centro Hospitalar de Entre Douro e Vouga; Centro Hospitalar de Leiria; Centro Hospitalar de Vila Nova de Gaia/Espinho; Centro Hospitalar do Alto Ave; Centro Hospitalar do Porto; Centro Hospitalar da Póvoa do Varzim/Vila do Conde; Hospital Central do Funchal; Centro Hospitalar de Lisboa Central; Centro Hospitalar Lisboa Norte; Centro Hospitalar Lisboa Ocidental; Centro Hospitalar do Baixo Vouga; Hospital de Vila Real; Hospitais da Universidade de Coimbra; Hospital de Cascais; Hospital de São João, Porto; Hospital de Braga; Hospital de Santa Luzia, Elvas; Hospital dos SAMS, Lisboa; Hospital Dr. Fernando da Fonseca, Amadora/Sintra; Hospital do Espírito Santo, Évora; Hospital Garcia de Orta, Almada; Hospital Pedro Hispano, Matosinhos; Unidade Local de Saúde do Baixo Alentejo, Beja.,Faculdade de Medicina, Instituto de Microbiologia, Instituto de Medicina Molecular, Universidade de Lisboa, Lisboa, Portugal
| | - Mario Ramirez
- Author Affiliations: Centro Hospitalar do Barlavento Algarvio; Centro Hospitalar de Entre Douro e Vouga; Centro Hospitalar de Leiria; Centro Hospitalar de Vila Nova de Gaia/Espinho; Centro Hospitalar do Alto Ave; Centro Hospitalar do Porto; Centro Hospitalar da Póvoa do Varzim/Vila do Conde; Hospital Central do Funchal; Centro Hospitalar de Lisboa Central; Centro Hospitalar Lisboa Norte; Centro Hospitalar Lisboa Ocidental; Centro Hospitalar do Baixo Vouga; Hospital de Vila Real; Hospitais da Universidade de Coimbra; Hospital de Cascais; Hospital de São João, Porto; Hospital de Braga; Hospital de Santa Luzia, Elvas; Hospital dos SAMS, Lisboa; Hospital Dr. Fernando da Fonseca, Amadora/Sintra; Hospital do Espírito Santo, Évora; Hospital Garcia de Orta, Almada; Hospital Pedro Hispano, Matosinhos; Unidade Local de Saúde do Baixo Alentejo, Beja.,Faculdade de Medicina, Instituto de Microbiologia, Instituto de Medicina Molecular, Universidade de Lisboa, Lisboa, Portugal
| | - Ana Friães
- Author Affiliations: Centro Hospitalar do Barlavento Algarvio; Centro Hospitalar de Entre Douro e Vouga; Centro Hospitalar de Leiria; Centro Hospitalar de Vila Nova de Gaia/Espinho; Centro Hospitalar do Alto Ave; Centro Hospitalar do Porto; Centro Hospitalar da Póvoa do Varzim/Vila do Conde; Hospital Central do Funchal; Centro Hospitalar de Lisboa Central; Centro Hospitalar Lisboa Norte; Centro Hospitalar Lisboa Ocidental; Centro Hospitalar do Baixo Vouga; Hospital de Vila Real; Hospitais da Universidade de Coimbra; Hospital de Cascais; Hospital de São João, Porto; Hospital de Braga; Hospital de Santa Luzia, Elvas; Hospital dos SAMS, Lisboa; Hospital Dr. Fernando da Fonseca, Amadora/Sintra; Hospital do Espírito Santo, Évora; Hospital Garcia de Orta, Almada; Hospital Pedro Hispano, Matosinhos; Unidade Local de Saúde do Baixo Alentejo, Beja.,Faculdade de Medicina, Instituto de Microbiologia, Instituto de Medicina Molecular, Universidade de Lisboa, Lisboa, Portugal
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Buckley SJ, Timms P, Davies MR, McMillan DJ. In silico characterisation of the two-component system regulators of Streptococcus pyogenes. PLoS One 2018; 13:e0199163. [PMID: 29927994 PMCID: PMC6013163 DOI: 10.1371/journal.pone.0199163] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/02/2018] [Indexed: 12/14/2022] Open
Abstract
Bacteria respond to environmental changes through the co-ordinated regulation of gene expression, often mediated by two-component regulatory systems (TCS). Group A Streptococcus (GAS), a bacterium which infects multiple human body sites and causes multiple diseases, possesses up to 14 TCS. In this study we examined genetic variation in the coding sequences and non-coding DNA upstream of these TCS as a method for evaluating relationships between different GAS emm-types, and potential associations with GAS disease. Twelve of the 14 TCS were present in 90% of the genomes examined. The length of the intergenic regions (IGRs) upstream of TCS coding regions varied from 39 to 345 nucleotides, with an average nucleotide diversity of 0.0064. Overall, IGR allelic variation was generally conserved with an emm-type. Subsequent phylogenetic analysis of concatenated sequences based on all TCS IGR sequences grouped genomes of the same emm-type together. However grouping with emm-pattern and emm-cluster-types was much weaker, suggesting epidemiological and functional properties associated with the latter are not due to evolutionary relatedness of emm-types. All emm5, emm6 and most of the emm18 genomes, all historically considered rheumatogenic emm-types clustered together, suggesting a shared evolutionary history. However emm1, emm3 and several emm18 genomes did not cluster within this group. These latter emm18 isolates were epidemiologically distinct from other emm18 genomes in study, providing evidence for local variation. emm-types associated with invasive disease or nephritogenicity also did not cluster together. Considering the TCS coding sequences (cds), correlation with emm-type was weaker than for the IGRs, and no strong correlation with disease was observed. Deletion of the malate transporter, maeP, was identified that serves as a putative marker for the emm89.0 subtype, which has been implicated in invasive outbreaks. A recombination-related, subclade-forming DNA motif was identified in the putative receiver domain of the Spy1556 response regulator that correlated with throat-associated emm-pattern-type A-C strains.
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Affiliation(s)
- Sean J. Buckley
- Inflammation and Healing Biomedical Research Cluster, and School of Health and Sports Sciences, Faculty of Science, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Peter Timms
- Inflammation and Healing Biomedical Research Cluster, and School of Health and Sports Sciences, Faculty of Science, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Mark R. Davies
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - David J. McMillan
- Inflammation and Healing Biomedical Research Cluster, and School of Health and Sports Sciences, Faculty of Science, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
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Lei B, Minor D, Feng W, Liu M. Hypervirulent Group A Streptococcus of Genotype emm3 Invades the Vascular System in Pulmonary Infection of Mice. Infect Immun 2018; 86:e00080-18. [PMID: 29610254 PMCID: PMC5964506 DOI: 10.1128/iai.00080-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 03/22/2018] [Indexed: 11/20/2022] Open
Abstract
Natural mutations of the two-component regulatory system CovRS are frequently associated with invasive group A Streptococcus (GAS) isolates and lead to the enhancement of virulence gene expression, innate immune evasion, systemic dissemination, and virulence. How CovRS mutations enhance systemic dissemination is not well understood. A hypervirulent GAS isolate of the emm3 genotype, MGAS315, was characterized using a mouse model of pulmonary infection to understand systemic dissemination. This strain has a G1370T mutation in the sensor kinase covS gene of CovRS. Intratracheal inoculation of MGAS315 led to the lung infection that displayed extensive Gram staining at the alveolar ducts, alveoli, and peribronchovascular and perivascular interstitium. The correction of the covS mutation did not alter the infection at the alveolar ducts and alveoli but prevented GAS invasion of the peribronchovascular and perivascular interstitium. Furthermore, the covS mutation allowed MGAS315 to disrupt and degrade the smooth muscle and endothelial layers of the blood vessels, directly contributing to systemic dissemination. It is concluded that hypervirulent emm3 GAS covS mutants can invade the perivascular interstitium and directly attack the vascular system for systemic dissemination.
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Affiliation(s)
- Benfang Lei
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Dylan Minor
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Wenchao Feng
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Mengyao Liu
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
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Feng W, Minor D, Liu M, Lei B. Requirement and Synergistic Contribution of Platelet-Activating Factor Acetylhydrolase Sse and Streptolysin S to Inhibition of Neutrophil Recruitment and Systemic Infection by Hypervirulent emm3 Group A Streptococcus in Subcutaneous Infection of Mice. Infect Immun 2017; 85:e00530-17. [PMID: 28947648 DOI: 10.1128/IAI.00530-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 09/18/2017] [Indexed: 01/18/2023] Open
Abstract
Hypervirulent group A streptococcus (GAS) can inhibit neutrophil recruitment and cause systemic infection in a mouse model of skin infection. The purpose of this study was to determine whether platelet-activating factor acetylhydrolase Sse and streptolysin S (SLS) have synergistic contributions to inhibition of neutrophil recruitment and systemic infection in subcutaneous infection of mice by MGAS315, a hypervirulent genotype emm3 GAS strain. Deletion of sse and sagA in MGAS315 synergistically reduced the skin lesion size and GAS burden in the liver and spleen. However, the mutants were persistent at skin sites and had similar growth factors in nonimmune blood. Thus, the low numbers of Δsse ΔsagA mutants in the liver and spleen were likely due to their reduction in the systemic dissemination. Few intact and necrotic neutrophils were detected at MGAS315 infection sites. In contrast, many neutrophils and necrotic cells were present at the edge of Δsse mutant infection sites on day 1 and at the edge of and inside Δsse mutant infection sites on day 2. ΔsagA mutant infection sites had massive numbers of and few intact neutrophils at the edge and center of the infection sites, respectively, on day 1 and were full of intact neutrophils or necrotic cells on day 2. Δsse ΔsagA mutant infection sites had massive numbers of intact neutrophils throughout the whole infection site. These sse and sagA deletion-caused changes in the histological pattern at skin infection sites could be complemented. Thus, the sse and sagA deletions synergistically enhance neutrophil recruitment. These findings indicate that both Sse and SLS are required but that neither is sufficient for inhibition of neutrophil recruitment and systemic infection by hypervirulent GAS.
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Jain I, Miller EW, Danger JL, Pflughoeft KJ, Sumby P. RocA Is an Accessory Protein to the Virulence-Regulating CovRS Two-Component System in Group A Streptococcus. Infect Immun 2017; 85:e00274-17. [PMID: 28808155 DOI: 10.1128/IAI.00274-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 08/05/2017] [Indexed: 11/20/2022] Open
Abstract
Regulating gene expression during infection is critical to the ability of pathogens to circumvent the immune response and cause disease. This is true for the group A Streptococcus (GAS), a pathogen that causes both invasive (e.g., necrotizing fasciitis) and noninvasive (e.g., pharyngitis) diseases. The control of virulence (CovRS) two-component system has a major role in regulating GAS virulence factor expression. The regulator of cov (RocA) protein, which is a predicted kinase, functions in an undetermined manner through CovRS to alter gene expression and reduce invasive disease virulence. Here, we show that the ectopic expression of a truncated RocA derivative, harboring the membrane-spanning domains but not the dimerization or HATPase domain, is sufficient to complement a rocA mutant strain. Coupled with a previous bioinformatic study, the data are consistent with RocA being a pseudokinase. RocA reduces the ability of serotype M1 GAS isolates to express capsule and to evade killing in human blood, phenotypes that are not observed for M3 or M18 GAS due to isolates of these serotypes naturally harboring mutant rocA alleles. In addition, we found that varying the RocA concentration attenuates the regulatory activity of Mg2+ and the antimicrobial peptide LL-37, which positively and negatively regulate CovS function, respectively. Thus, we propose that RocA is an accessory protein to the CovRS system that influences the ability of GAS to modulate gene expression in response to host factors. A model of how RocA interacts with CovRS, and of the regulatory consequences of such activity, is presented.
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Oppegaard O. Unravelling pathogenetic mechanisms of epidemic lineages. Virulence 2017; 8:1102-1104. [DOI: 10.1080/21505594.2017.1328344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Oddvar Oppegaard
- Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
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Oppegaard O, Mylvaganam H, Skrede S, Lindemann PC, Kittang BR. Emergence of a Streptococcus dysgalactiae subspecies equisimilis stG62647-lineage associated with severe clinical manifestations. Sci Rep 2017; 7:7589. [PMID: 28790435 PMCID: PMC5548910 DOI: 10.1038/s41598-017-08162-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 07/07/2017] [Indexed: 12/03/2022] Open
Abstract
Increasing incidence rates of invasive Streptococcus dysgalactiae subspecies equisimilis (SDSE) infections have been reported worldwide, but the evolutionary mechanisms underlying this development remain elusive. Through prospective surveillance of invasive SDSE infections in western Norway, we observed the emergence of a novel and virulent SDSE genotype, stG62647. This emm-type, rarely encountered as a cause of invasive disease during 1999–2012, emerged in 2013 as the predominant SDSE-genotype. The stG62647-infections were associated with an aggressive clinical course, including the occurrence of streptococcal toxic shock syndrome, necrotizing soft-tissue infections and endocarditis. All the invasive stG62647-isolates were subjected to whole genome sequencing, attempting to explore the genetic events underpinning its epidemicity. Although 10% of the genomes was unique for stG62647-genotype, notably 18 out of 19 isolates contained a disrupted streptococcal invasive locus (sil) due to the insertion of a transposase, IS1548, into the silB-gene. We postulate that the virulence of stG6267-isolates could be partly attributable to the abrogation of the attenuating control normally exerted by this regulon, although experimental verification was not performed. To the best of our knowledge, this is the first study employing large scale whole genome sequencing to illuminate the genetic landscape of epidemic lineages in SDSE.
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Affiliation(s)
- Oddvar Oppegaard
- Department of Medicine, Haukeland University Hospital, Bergen, Norway. .,Department of Clinical Science, University of Bergen, Bergen, Norway.
| | - Haima Mylvaganam
- Department of Microbiology, Haukeland University Hospital, Bergen, Norway
| | - Steinar Skrede
- Department of Medicine, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Science, University of Bergen, Bergen, Norway
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Wilkening RV, Federle MJ. Evolutionary Constraints Shaping Streptococcus pyogenes-Host Interactions. Trends Microbiol 2017; 25:562-572. [PMID: 28216292 DOI: 10.1016/j.tim.2017.01.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/15/2016] [Accepted: 01/23/2017] [Indexed: 02/07/2023]
Abstract
Research on the Gram-positive human-restricted pathogen Streptococcus pyogenes (Group A Streptococcus, GAS) has long focused on invasive illness, the most severe manifestations of GAS infection. Recent advances in descriptions of molecular mechanisms of GAS virulence, coupled with massive sequencing efforts to isolate genomes, have allowed the field to better understand the molecular and evolutionary changes leading to pandemic strains. These findings suggest that it is necessary to rethink the dogma involving GAS pathogenesis, and that the most productive avenues for research going forward may be investigations into GAS in its 'normal' habitat, the nasopharynx, and its ability to either live with its host in an asymptomatic lifestyle or as an agent of superficial infections. This review will consider these advances, focusing on the natural history of GAS, the evolution of pandemic strains, and novel roles for several key virulence factors that may allow the field to better understand their physiological role.
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Affiliation(s)
- Reid V Wilkening
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL 60607, USA; Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Michael J Federle
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, IL 60607, USA; Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
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43
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Honda-Ogawa M, Sumitomo T, Mori Y, Hamd DT, Ogawa T, Yamaguchi M, Nakata M, Kawabata S. Streptococcus pyogenes Endopeptidase O Contributes to Evasion from Complement-mediated Bacteriolysis via Binding to Human Complement Factor C1q. J Biol Chem 2017; 292:4244-4254. [PMID: 28154192 DOI: 10.1074/jbc.m116.749275] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 01/18/2017] [Indexed: 01/14/2023] Open
Abstract
Streptococcus pyogenes secretes various virulence factors for evasion from complement-mediated bacteriolysis. However, full understanding of the molecules possessed by this organism that interact with complement C1q, an initiator of the classical complement pathway, remains elusive. In this study, we identified an endopeptidase of S. pyogenes, PepO, as an interacting molecule, and investigated its effects on complement immunity and pathogenesis. Enzyme-linked immunosorbent assay and surface plasmon resonance analysis findings revealed that S. pyogenes recombinant PepO bound to human C1q in a concentration-dependent manner under physiological conditions. Sites of inflammation are known to have decreased pH levels, thus the effects of PepO on bacterial evasion from complement immunity was analyzed in a low pH condition. Notably, under low pH conditions, PepO exhibited a higher affinity for C1q as compared with IgG, and PepO inhibited the binding of IgG to C1q. In addition, pepO deletion rendered S. pyogenes more susceptible to the bacteriocidal activity of human serum. Also, observations of the morphological features of the pepO mutant strain (ΔpepO) showed damaged irregular surfaces as compared with the wild-type strain (WT). WT-infected tissues exhibited greater severity and lower complement activity as compared with those infected by ΔpepO in a mouse skin infection model. Furthermore, WT infection resulted in a larger accumulation of C1q than that with ΔpepO. Our results suggest that interaction of S. pyogenes PepO with C1q interferes with the complement pathway, which enables S. pyogenes to evade complement-mediated bacteriolysis under acidic conditions, such as seen in inflammatory sites.
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Affiliation(s)
- Mariko Honda-Ogawa
- From the Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry
| | - Tomoko Sumitomo
- From the Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry
| | - Yasushi Mori
- From the Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry.,Division of Special Care Dentistry, Osaka University Dental Hospital, and
| | - Dalia Talat Hamd
- From the Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry
| | - Taiji Ogawa
- Department of Prosthodontics, Gerodontology and Oral Rehabilitation, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masaya Yamaguchi
- From the Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry
| | - Masanobu Nakata
- From the Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry
| | - Shigetada Kawabata
- From the Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry,
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Feng W, Minor D, Liu M, Li J, Ishaq SL, Yeoman C, Lei B. Null Mutations of Group A Streptococcus Orphan Kinase RocA: Selection in Mouse Infection and Comparison with CovS Mutations in Alteration of In Vitro and In Vivo Protease SpeB Expression and Virulence. Infect Immun 2017; 85:e00790-16. [PMID: 27795364 DOI: 10.1128/IAI.00790-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 10/17/2016] [Indexed: 12/19/2022] Open
Abstract
Group A Streptococcus (GAS) acquires mutations of the virulence regulator CovRS in human and mouse infections, and these mutations result in the upregulation of virulence genes and the downregulation of the protease SpeB. To identify in vivo mutants with novel phenotypes, GAS isolates from infected mice were screened by enzymatic assays for SpeB and the platelet-activating factor acetylhydrolase Sse, and a new type of variant that had enhanced Sse expression and normal levels of SpeB production was identified (the variants had a phenotype referred to as enhanced Sse activity [SseA+] and normal SpeB activity [SpeBA+]). SseA+ SpeBA+ variants had transcript levels of CovRS-controlled virulence genes comparable to those of a covS mutant but had no covRS mutations. Genome resequencing of an SseA+ SpeBA+ isolate identified a C605A nonsense mutation in orphan kinase gene rocA, and 6 other SseA+ SpeBA+ isolates also had nonsense mutations or small indels in rocA RocA and CovS mutants had similar levels of enhancement of the expression of CovRS-controlled virulence genes at the exponential growth phase; however, mutations of RocA but not mutations of CovS did not result in the downregulation of speB transcription at stationary growth phase or in subcutaneous infection of mice. GAS with RocA and CovS mutations caused greater enhancement of the expression of hasA than spyCEP in mouse skin infection than wild-type GAS did. RocA mutants ranked between wild-type GAS and CovS mutants in skin invasion, inhibition of neutrophil recruitment, and virulence in subcutaneous infection of mice. Thus, GAS RocA mutants can be selected in subcutaneous infections in mice and exhibit gene expression patterns and virulences distinct from those of CovS mutants. The findings provide novel information for understanding GAS fitness mutations in vivo, virulence gene regulation, in vivo gene expression, and virulence.
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Sarkar P, Sumby P. Regulatory gene mutation: a driving force behind group a Streptococcus strain- and serotype-specific variation. Mol Microbiol 2016; 103:576-589. [PMID: 27868255 DOI: 10.1111/mmi.13584] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2016] [Indexed: 01/13/2023]
Abstract
Data from multiple bacterial pathogens are consistent with regulator-encoding genes having higher mutation frequencies than the genome average. Such mutations drive both strain- and type- (e.g., serotype, haplotype) specific phenotypic heterogeneity, and may challenge public health due to the potential of variants to circumvent established treatment and/or preventative regimes. Here, using the human bacterial pathogen the group A Streptococcus (GAS; S. pyogenes) as a model organism, we review the types and regulatory-, phenotypic-, and disease-specific consequences of naturally occurring regulatory gene mutations. Strain-specific regulator mutations that will be discussed include examples that transform isolates into hyper-invasive forms by enhancing expression of immunomodulatory virulence factors, and examples that promote asymptomatic carriage of the organism. The discussion of serotype-specific regulator mutations focuses on serotype M3 GAS isolates, and how the identified rewiring of regulatory networks in this serotype may be contributing to a decades old epidemiological association of M3 isolates with particularly severe invasive infections. We conclude that mutation plays an outsized role in GAS pathogenesis and has clinical relevance. Given the phenotypic variability associated with regulatory gene mutations, the rapid examination of these genes in infecting isolates may inform with respect to potential patient complications and treatment options.
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Affiliation(s)
- Poulomee Sarkar
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Paul Sumby
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
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Alves LA, Nomura R, Mariano FS, Harth-Chu EN, Stipp RN, Nakano K, Mattos-Graner RO. CovR Regulates Streptococcus mutans Susceptibility To Complement Immunity and Survival in Blood. Infect Immun 2016; 84:3206-19. [PMID: 27572331 DOI: 10.1128/IAI.00406-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 08/20/2016] [Indexed: 02/05/2023] Open
Abstract
Streptococcus mutans, a major pathogen of dental caries, may promote systemic infections after accessing the bloodstream from oral niches. In this study, we investigate pathways of complement immunity against S. mutans and show that the orphan regulator CovR (CovRSm) modulates susceptibility to complement opsonization and survival in blood. S. mutans blood isolates showed reduced susceptibility to C3b deposition compared to oral isolates. Reduced expression of covRSm in blood strains was associated with increased transcription of CovRSm-repressed genes required for S. mutans interactions with glucans (gbpC, gbpB, and epsC), sucrose-derived exopolysaccharides (EPS). Consistently, blood strains showed an increased capacity to bind glucan in vitro Deletion of covRSm in strain UA159 (UAcov) impaired C3b deposition and binding to serum IgG and C-reactive protein (CRP) as well as phagocytosis through C3b/iC3b receptors and killing by neutrophils. Opposite effects were observed in mutants of gbpC, epsC, or gtfBCD (required for glucan synthesis). C3b deposition on UA159 was abolished in C1q-depleted serum, implying that the classical pathway is essential for complement activation on S. mutans Growth in sucrose-containing medium impaired the binding of C3b and IgG to UA159, UAcov, and blood isolates but had absent or reduced effects on C3b deposition in gtfBCD, gbpC, and epsC mutants. UAcov further showed increased ex vivo survival in human blood in an EPS-dependent way. Consistently, reduced survival was observed for the gbpC and epsC mutants. Finally, UAcov showed an increased ability to cause bacteremia in a rat model. These results reveal that CovRSm modulates systemic virulence by regulating functions affecting S. mutans susceptibility to complement opsonization.
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Feng W, Liu M, Chen DG, Yiu R, Fang FC, Lei B. Contemporary Pharyngeal and Invasive emm1 and Invasive emm12 Group A Streptococcus Isolates Exhibit Similar In Vivo Selection for CovRS Mutants in Mice. PLoS One 2016; 11:e0162742. [PMID: 27611332 PMCID: PMC5017694 DOI: 10.1371/journal.pone.0162742] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 08/26/2016] [Indexed: 12/15/2022] Open
Abstract
Group A Streptococcus (GAS) causes diverse infections ranging from common pharyngitis to rare severe invasive infections. Invasive GAS isolates can have natural mutations in the virulence regulator CovRS, which result in enhanced expression of multiple virulence genes, suppressed the expression of the protease SpeB, and increased virulence. It is believed that CovRS mutations arise during human infections with GAS carrying wild-type CovRS and are not transmissible. CovRS mutants of invasive GAS of the emm1 genotype arise readily during experimental infection in mice. It is possible that invasive GAS arises from pharyngeal GAS through rare genetic mutations that confer the capacity of mutated GAS to acquire covRS mutations during infection. The objective of this study was to determine whether contemporary pharyngeal emm1 GAS isolates have a reduced propensity to acquire CovRS mutations in vivo compared with invasive emm1 GAS and whether emm3, emm12, and emm28 GAS acquire CovRS mutants in mouse infection. The propensity of invasive and pharyngeal emm1 and invasive emm3, emm12, and emm28 SpeBA+ isolates to acquire variants with the SpeBA- phenotype was determined during subcutaneous infection of mice. The majority of both invasive and pharyngeal emm1 SpeBA+ isolates and two of three emm12 isolates, but not emm3 and emm28 isolates, were found to acquire SpeBA- variants during skin infection in mice. All analyzed SpeBA- variants of emm1 and emm12 GAS from the mouse infection acquired covRS mutations and produced more platelet-activating factor acetylhydrolase SsE. Thus, contemporary invasive and pharyngeal emm1 GAS isolates and emm12 GAS have a similar capacity to acquire covRS mutations in vivo. The rarity of severe invasive infections caused by GAS does not appear to be attributable to a reduced ability of pharyngeal isolates to acquire CovRS mutations.
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Affiliation(s)
- Wenchao Feng
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59718, United States of America
| | - Mengyao Liu
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59718, United States of America
| | - Daniel G. Chen
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59718, United States of America
| | - Rossana Yiu
- Harborview Medical Center Clinical Microbiology Laboratory and University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Ferric C. Fang
- Harborview Medical Center Clinical Microbiology Laboratory and University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Benfang Lei
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59718, United States of America
- * E-mail:
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48
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Zhu L, Olsen RJ, Horstmann N, Shelburne SA, Fan J, Hu Y, Musser JM. Intergenic Variable-Number Tandem-Repeat Polymorphism Upstream of rocA Alters Toxin Production and Enhances Virulence in Streptococcus pyogenes. Infect Immun 2016; 84:2086-93. [PMID: 27141081 DOI: 10.1128/IAI.00258-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/26/2016] [Indexed: 01/05/2023] Open
Abstract
Variable-number tandem-repeat (VNTR) polymorphisms are ubiquitous in bacteria. However, only a small fraction of them has been functionally studied. Here, we report an intergenic VNTR polymorphism that confers an altered level of toxin production and increased virulence in Streptococcus pyogenes The nature of the polymorphism is a one-unit deletion in a three-tandem-repeat locus upstream of the rocA gene encoding a sensor kinase. S. pyogenes strains with this type of polymorphism cause human infection and produce significantly larger amounts of the secreted cytotoxins S. pyogenes NADase (SPN) and streptolysin O (SLO). Using isogenic mutant strains, we demonstrate that deleting one or more units of the tandem repeats abolished RocA production, reduced CovR phosphorylation, derepressed multiple CovR-regulated virulence factors (such as SPN and SLO), and increased virulence in a mouse model of necrotizing fasciitis. The phenotypic effect of the VNTR polymorphism was nearly the same as that of inactivating the rocA gene. In summary, we identified and characterized an intergenic VNTR polymorphism in S. pyogenes that affects toxin production and virulence. These new findings enhance understanding of rocA biology and the function of VNTR polymorphisms in S. pyogenes.
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49
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Tatsuno I, Okada R, Matsumoto M, Hata N, Matsui H, Zhang Y, Isaka M, Hasegawa T. Relevance of spontaneousfabTmutations to a streptococcal toxic shock syndrome to non-streptococcal toxic shock syndrome transition in the novel-typeStreptococcus pyogenesisolates that lost asalRK. APMIS 2016; 124:414-24. [DOI: 10.1111/apm.12521] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/03/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Ichiro Tatsuno
- Department of Bacteriology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Ryo Okada
- Department of Bacteriology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Masakado Matsumoto
- Department of Microbiology and Medical Zoology; Aichi Prefectural Institute of Public Health; Nagoya Aichi Japan
| | - Nanako Hata
- Department of Microbiology; Nagoya City University Hospital; Nagoya Aichi Japan
| | - Hideyuki Matsui
- Department of Bacteriology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Yan Zhang
- Department of Bacteriology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Masanori Isaka
- Department of Bacteriology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Tadao Hasegawa
- Department of Bacteriology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
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50
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Wilkening RV, Chang JC, Federle MJ. PepO, a CovRS-controlled endopeptidase, disrupts Streptococcus pyogenes quorum sensing. Mol Microbiol 2015; 99:71-87. [PMID: 26418177 DOI: 10.1111/mmi.13216] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2015] [Indexed: 01/09/2023]
Abstract
Group A Streptococcus (GAS, Streptococcus pyogenes) is a human-restricted pathogen with a capacity to both colonize asymptomatically and cause illnesses ranging from pharyngitis to necrotizing fasciitis. An understanding of how and when GAS switches between genetic programs governing these different lifestyles has remained an enduring mystery and likely requires carefully tuned environmental sensors to activate and silence genetic schemes when appropriate. Herein, we describe the relationship between the Control of Virulence (CovRS, CsrRS) two-component system and the Rgg2/3 quorum-sensing pathway. We demonstrate that responses of CovRS to the stress signals Mg(2+) and a fragment of the antimicrobial peptide LL-37 result in modulated activity of pheromone signaling of the Rgg2/3 pathway through a means of proteolysis of SHP peptide pheromones. This degradation is mediated by the cytoplasmic endopeptidase PepO, which is the first identified enzymatic silencer of an RRNPP-type quorum-sensing pathway. These results suggest that under conditions in which the virulence potential of GAS is elevated (i.e. enhanced virulence gene expression), cellular responses mediated by the Rgg2/3 pathway are abrogated and allow individuals to escape from group behavior. These results also indicate that Rgg2/3 signaling is instead functional during non-virulent GAS lifestyles.
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Affiliation(s)
- Reid V Wilkening
- Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Jennifer C Chang
- Department of Medicinal Chemistry and Pharmacognosy, Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Michael J Federle
- Department of Medicinal Chemistry and Pharmacognosy, Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, 60607, USA
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