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Live Cell Microscopy and Flow Cytometry to Study Streptolysin S-Mediated Erythrocyte Hemolysis. Methods Mol Biol 2020. [PMID: 32430826 DOI: 10.1007/978-1-0716-0467-0_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The ability to induce hemolysis, the rupturing of erythrocytes with the consequent release of their intracellular contents, is a phenotypic hallmark of a number of microbial toxins. Streptococcus pyogenes or Group A Streptococcus (GAS) is a human pathogen responsible for a wide range of diseases from mild pharyngitis to severe conditions such as toxic shock syndrome. GAS produces a powerful hemolytic toxin called streptolysin S (SLS). Herein, we describe a procedure for the preparation of SLS toxin and the use of two complementary approaches, live microscopy and flow cytometry, to study the effects of the SLS toxin on erythrocytes. In addition to providing insights into SLS-mediated hemolysis, these assays have the potential to be modified for the study of other hemolytic toxins and compounds.
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2
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The Role of Streptococcal and Staphylococcal Exotoxins and Proteases in Human Necrotizing Soft Tissue Infections. Toxins (Basel) 2019; 11:toxins11060332. [PMID: 31212697 PMCID: PMC6628391 DOI: 10.3390/toxins11060332] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [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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3
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Ginsburg I, Korem M, Koren E, Varani J. Pro-inflammatory agents released by pathogens, dying host cells, and neutrophils act synergistically to destroy host tissues: a working hypothesis. J Inflamm Res 2019; 12:35-47. [PMID: 30774411 PMCID: PMC6350637 DOI: 10.2147/jir.s190007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We postulate that the extensive cell and tissue damage inflicted by many infectious, inflammatory and post-inflammatory episodes is an enled result of a synergism among the invading microbial agents, host neutrophils and dead and dying cells in the nidus. Microbial toxins and other metabolites along with the plethora of pro-inflammatory agents released from activated neutrophils massively recruited to the infectious sites and high levels of cationic histones, other cationic peptides, proteinases and Th1 cytokines released from activated polymorphonuclear neutrophils (PMNs) and from necrotized tissues may act in concert (synergism) to bring about cell killing and tissue destruction. Multiple, diverse interactions among the many potential pro-inflammatory moieties have been described in these complex lesions. Such infections are often seen in the skin and aerodigestive tract where the tissue is exposed to the environment, but can occur in any tissue. Commonly, the tissue-destructive infections are caused by group A streptococci, pneumococci, Staphylococcus aureus, meningococci, Escherichia coli and Shigella, although many other microbial species are seen on occasion. All these microbial agents are characterized by their ability to recruit large numbers of PMNs. Given the complex nature of the disease process, it is proposed that, to treat these multifactorial disorders, a "cocktail" of anti-inflammatory agents combined with non-bacteriolytic antibiotics and measures to counteract the critical toxic role of cationic moieties might prove more effective than a strategy based on attacking the bacteria alone.
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Affiliation(s)
- Isaac Ginsburg
- Institute of Dental Sciences, Faculty of Dental Medicine, The Hebrew University, Jerusalem, Israel,
| | - Maya Korem
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel,
| | - Erez Koren
- Research and Development Department, Clexio Biosciences Ltd, Petah Tikva, Israel
| | - James Varani
- Department of Pathology, The University of Michigan Medical School, Ann Arbor, MI, USA
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4
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Saroj SD, Maudsdotter L, Tavares R, Jonsson AB. Lactobacilli Interfere with Streptococcus pyogenes Hemolytic Activity and Adherence to Host Epithelial Cells. Front Microbiol 2016; 7:1176. [PMID: 27524981 PMCID: PMC4965460 DOI: 10.3389/fmicb.2016.01176] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 07/18/2016] [Indexed: 01/31/2023] Open
Abstract
Streptococcus pyogenes [Group A streptococcus (GAS)], a frequent colonizer of the respiratory tract mucosal surface, causes a variety of human diseases, ranging from pharyngitis to the life-threatening streptococcal toxic shock-like syndrome. Lactobacilli have been demonstrated to colonize the respiratory tract. In this study, we investigated the interference of lactobacilli with the virulence phenotypes of GAS. The Lactobacillus strains L. rhamnosus Kx151A1 and L. reuteri PTA-5289, but not L. salivarius LMG9477, inhibited the hemolytic activity of S. pyogenes S165. The inhibition of hemolytic activity was attributed to a decrease in the production of streptolysin S (SLS). Conditioned medium (CM) from the growth of L. rhamnosus Kx151A1 and L. reuteri PTA-5289 was sufficient to down-regulate the expression of the sag operon, encoding SLS. The Lactobacillus strains L. rhamnosus Kx151A1, L. reuteri PTA-5289, and L. salivarius LMG9477 inhibited the initial adherence of GAS to host epithelial cells. Intriguingly, competition with a combination of Lactobacillus species reduced GAS adherence to host cells most efficiently. The data suggest that an effector molecule released from certain Lactobacillus strains attenuates the production of SLS at the transcriptional level and that combinations of Lactobacillus strains may protect the pharyngeal mucosa more efficiently from the initial colonization of GAS. The effector molecules released from Lactobacillus strains affecting the virulence phenotypes of pathogens hold potential in the development of a new generation of therapeutics.
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Affiliation(s)
- Sunil D Saroj
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University Stockholm, Sweden
| | - Lisa Maudsdotter
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University Stockholm, Sweden
| | - Raquel Tavares
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University Stockholm, Sweden
| | - Ann-Beth Jonsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University Stockholm, Sweden
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5
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Barnett TC, Cole JN, Rivera-Hernandez T, Henningham A, Paton JC, Nizet V, Walker MJ. Streptococcal toxins: role in pathogenesis and disease. Cell Microbiol 2015; 17:1721-41. [PMID: 26433203 DOI: 10.1111/cmi.12531] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/13/2015] [Accepted: 09/02/2015] [Indexed: 12/15/2022]
Abstract
Group A Streptococcus (Streptococcus pyogenes), group B Streptococcus (Streptococcus agalactiae) and Streptococcus pneumoniae (pneumococcus) are host-adapted bacterial pathogens among the leading infectious causes of human morbidity and mortality. These microbes and related members of the genus Streptococcus produce an array of toxins that act against human cells or tissues, resulting in impaired immune responses and subversion of host physiological processes to benefit the invading microorganism. This toxin repertoire includes haemolysins, proteases, superantigens and other agents that ultimately enhance colonization and survival within the host and promote dissemination of the pathogen.
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Affiliation(s)
- Timothy C Barnett
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Jason N Cole
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia.,Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Tania Rivera-Hernandez
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Anna Henningham
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia.,Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Victor Nizet
- Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Mark J Walker
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
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6
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Disease manifestations and pathogenic mechanisms of Group A Streptococcus. Clin Microbiol Rev 2014. [PMID: 24696436 DOI: 10.1128/cmr.00101-13)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Streptococcus pyogenes, also known as group A Streptococcus (GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease. Combined, these diseases account for over half a million deaths per year globally. Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host. This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies. While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern. Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials. The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority.
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Walker MJ, Barnett TC, McArthur JD, Cole JN, Gillen CM, Henningham A, Sriprakash KS, Sanderson-Smith ML, Nizet V. Disease manifestations and pathogenic mechanisms of Group A Streptococcus. Clin Microbiol Rev 2014; 27:264-301. [PMID: 24696436 PMCID: PMC3993104 DOI: 10.1128/cmr.00101-13] [Citation(s) in RCA: 566] [Impact Index Per Article: 56.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Streptococcus pyogenes, also known as group A Streptococcus (GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease. Combined, these diseases account for over half a million deaths per year globally. Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host. This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies. While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern. Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials. The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority.
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Affiliation(s)
- Mark J. Walker
- School of Chemistry and Molecular Biosciences and the Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia
| | - Timothy C. Barnett
- School of Chemistry and Molecular Biosciences and the Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia
| | - Jason D. McArthur
- School of Biological Sciences and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Jason N. Cole
- School of Chemistry and Molecular Biosciences and the Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia
- Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - Christine M. Gillen
- School of Chemistry and Molecular Biosciences and the Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia
| | - Anna Henningham
- School of Chemistry and Molecular Biosciences and the Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia
- Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - K. S. Sriprakash
- QIMR Berghofer Medical Research Institute, Herston, Brisbane, QLD, Australia
| | - Martina L. Sanderson-Smith
- School of Biological Sciences and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Victor Nizet
- Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
- Rady Children's Hospital, San Diego, California, USA
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Zhou Y, Hanks TS, Feng W, Li J, Liu G, Liu M, Lei B. The sagA/pel locus does not regulate the expression of the M protein of the M1T1 lineage of group A Streptococcus. Virulence 2013; 4:698-706. [PMID: 24121654 DOI: 10.4161/viru.26413] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Altered expression of Group A Streptococcus (GAS) virulence factors, including the M protein, can result as a consequence of spontaneous genetic changes that occur during laboratory and animal passage. Occurrence of such secondary mutations during targeted gene deletion could confound the interpretation of effects attributable to the function of the gene being investigated. Contradicting reports on whether the sagA/pel locus regulates the M protein-encoding emm might be due to inconsistent occurrence of mutations unrelated with sagA. This study examined the possibility that altered emm expression observed in association with sagA/pel deletion mutants is artifactual. sagA deletion mutants (MGAS2221ΔsagA) of M1T1 isolate MGAS2221 obtained using liquid broth for GAS growth during the deletion process had diminished emm transcription and no detectable M protein production. In contrast, a ΔsagA mutant of another closely genetically related M1T1 isolate had normal emm expression. The sagB gene does not regulate emm; however, one of three MGAS2221ΔsagB mutants had diminished emm expression. The emm regulator mga was downregulated in these M protein expression-negative strains. These results argue that sagA deletion does not directly cause the downregulation of emm expression. Indeed, two MGAS2221ΔsagA mutants obtained using agar plates for GAS growth during the deletion process both had normal emm expression. We conclude that the sagA/pel locus does not regulate emm expression in the M1T1 lineage and provide a protocol for targeted gene deletion that we find less prone to the generation of mutants exhibiting downregulation in emm expression.
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Affiliation(s)
- Yang Zhou
- State Key Laboratory of Agricultural Microbiology; College of Veterinary Medicine; Huazhong Agricultural University; Wuhan, P.R. China; Department of Immunology and Infectious Diseases; Montana State University; Bozeman, MT USA
| | - Tracey S Hanks
- Department of Immunology and Infectious Diseases; Montana State University; Bozeman, MT USA
| | - Wenchao Feng
- Department of Immunology and Infectious Diseases; Montana State University; Bozeman, MT USA
| | - Jinquan Li
- State Key Laboratory of Agricultural Microbiology; College of Veterinary Medicine; Huazhong Agricultural University; Wuhan, P.R. China; Department of Immunology and Infectious Diseases; Montana State University; Bozeman, MT USA
| | - Guanghui Liu
- Department of Immunology and Infectious Diseases; Montana State University; Bozeman, MT USA
| | - Mengyao Liu
- Department of Immunology and Infectious Diseases; Montana State University; Bozeman, MT USA
| | - Benfang Lei
- Department of Immunology and Infectious Diseases; Montana State University; Bozeman, MT USA
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10
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Molloy EM, Cotter PD, Hill C, Mitchell DA, Ross RP. Streptolysin S-like virulence factors: the continuing sagA. Nat Rev Microbiol 2011; 9:670-81. [PMID: 21822292 DOI: 10.1038/nrmicro2624] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Streptolysin S (SLS) is a potent cytolytic toxin and virulence factor that is produced by nearly all Streptococcus pyogenes strains. Despite a 100-year history of research on this toxin, it has only recently been established that SLS is just one of an extended family of post-translationally modified virulence factors (the SLS-like peptides) that are produced by some streptococci and other Gram-positive pathogens, such as Listeria monocytogenes and Clostridium botulinum. In this Review, we describe the identification, genetics, biochemistry and various functions of SLS. We also discuss the shared features of the virulence-associated SLS-like peptides, as well as their place within the rapidly expanding family of thiazole/oxazole-modified microcins (TOMMs).
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Affiliation(s)
- Evelyn M Molloy
- Department of Microbiology, University College Cork, Cork, Ireland
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11
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Chang A, Khemlani A, Kang H, Proft T. Functional analysis of Streptococcus pyogenes nuclease A (SpnA), a novel group A streptococcal virulence factor. Mol Microbiol 2011; 79:1629-42. [PMID: 21231972 DOI: 10.1111/j.1365-2958.2011.07550.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Streptococcus pyogenes nuclease A (SpnA) is a recently discovered DNase that plays a role in virulence as shown in a mouse infection model. SpnA is the only cell wall-anchored DNase found in S. pyogenes thus far and shows a unique protein architecture. The C-terminal nuclease domain contains highly conserved catalytic site and Mg(2+) binding site residues. However, expression of the SpnA nuclease domain alone resulted in a soluble, but enzymatically inactive protein. We found that at least two out of three oligonucleotide/oligosaccharide-binding fold motifs found in the N-terminal domain are required for SpnA activity, probably contributing to substrate binding. Using a combination of a spnA deletion mutant and a Lactococcus lactis'gain-of-function' mutant, we have shown that SpnA promotes survival in whole human blood and in neutrophil killing assays and this is, at least in part, achieved by the destruction of neutrophil extracellular traps (NETs). We observed higher frequencies for anti-SpnA antibodies in streptococcal disease patient sera (79%, n = 19) compared with sera from healthy donors (33%, n = 9) suggesting that SpnA is expressed during infection. Detection of anti-SpnA antibodies in patient serum might be useful for the diagnostic of post-streptococcal diseases, such as acute rheumatic fever or glomerulonephritis.
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Affiliation(s)
- Ann Chang
- Department of Molecular Medicine & Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
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12
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Lin A, Loughman JA, Zinselmeyer BH, Miller MJ, Caparon MG. Streptolysin S inhibits neutrophil recruitment during the early stages of Streptococcus pyogenes infection. Infect Immun 2009; 77:5190-201. [PMID: 19687200 PMCID: PMC2772533 DOI: 10.1128/iai.00420-09] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 05/24/2009] [Accepted: 08/10/2009] [Indexed: 11/20/2022] Open
Abstract
In contrast to infection of superficial tissues, Streptococcus pyogenes infection of deeper tissue can be associated with a significantly diminished inflammatory response, suggesting that this bacterium has the ability to both promote and suppress inflammation. To examine this, we analyzed the behavior of an S. pyogenes mutant deficient in expression of the cytolytic toxin streptolysin S (SLS-) and evaluated events that occur during the first few hours of infection by using several models including injection of zebrafish (adults, larvae, and embryos), a transepithelial polymorphonuclear leukocyte (PMN) migration assay, and two-photon microscopy of mice in vivo. In contrast to wild-type S. pyogenes, the SLS- mutant was associated with the robust recruitment of neutrophils and significantly reduced lethal myositis in adult zebrafish. Similarly, the mutant was attenuated in embryos in its ability to cause lethality. Infection of larva muscle allowed an analysis of inflammation in real time, which revealed that the mutant had recruited PMNs to the infection site. Analysis of transepithelial migration in vitro suggested that SLS inhibited the host cells' production of signals chemotactic for neutrophils, which contrasted with the proinflammatory effect of an unrelated cytolytic toxin, streptolysin O. Using two-photon microscopy of mice in vivo, we showed that the extravasation of neutrophils during infection with SLS- mutant bacteria was significantly accelerated compared to infection with wild-type S. pyogenes. Taken together, these data support a role for SLS in the inhibition of neutrophil recruitment during the early stages of S. pyogenes infection.
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Affiliation(s)
- Ada Lin
- Department of Pediatrics, Department of Pathology and Immunology, Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri 63110-1093
| | - Jennifer A. Loughman
- Department of Pediatrics, Department of Pathology and Immunology, Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri 63110-1093
| | - Bernd H. Zinselmeyer
- Department of Pediatrics, Department of Pathology and Immunology, Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri 63110-1093
| | - Mark J. Miller
- Department of Pediatrics, Department of Pathology and Immunology, Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri 63110-1093
| | - Michael G. Caparon
- Department of Pediatrics, Department of Pathology and Immunology, Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri 63110-1093
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13
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Graham MR, Virtaneva K, Porcella SF, Gardner DJ, Long RD, Welty DM, Barry WT, Johnson CA, Parkins LD, Wright FA, Musser JM. Analysis of the transcriptome of group A Streptococcus in mouse soft tissue infection. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 169:927-42. [PMID: 16936267 PMCID: PMC1698835 DOI: 10.2353/ajpath.2006.060112] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Molecular mechanisms mediating group A Streptococcus (GAS)-host interactions remain poorly understood but are crucial for diagnostic, therapeutic, and vaccine development. An optimized high-density microarray was used to analyze the transcriptome of GAS during experimental mouse soft tissue infection. The transcriptome of a wild-type serotype M1 GAS strain and an isogenic transcriptional regulator knockout mutant (covR) also were compared. Array datasets were verified by quantitative real-time reverse transcriptase-polymerase chain reaction and in situ immunohistochemistry. The results unambiguously demonstrate that coordinated expression of proven and putative GAS virulence factors is directed toward overwhelming innate host defenses leading to severe cellular damage. We also identified adaptive metabolic responses triggered by nutrient signals and hypoxic/acidic conditions in the host, likely facilitating pathogen persistence and proliferation in soft tissues. Key discoveries included that oxidative stress genes, virulence genes, genes related to amino acid and maltodextrin utilization, and several two-component transcriptional regulators were highly expressed in vivo. This study is the first global analysis of the GAS transcriptome during invasive infection. Coupled with parallel analysis of the covR mutant strain, novel insights have been made into the regulation of GAS virulence in vivo, resulting in new avenues for targeted therapeutic and vaccine research.
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Affiliation(s)
- Morag R Graham
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Veterinary Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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14
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Datta V, Myskowski SM, Kwinn LA, Chiem DN, Varki N, Kansal RG, Kotb M, Nizet V. Mutational analysis of the group A streptococcal operon encoding streptolysin S and its virulence role in invasive infection. Mol Microbiol 2005; 56:681-95. [PMID: 15819624 DOI: 10.1111/j.1365-2958.2005.04583.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The pathogen group A Streptococcus (GAS) produces a wide spectrum of infections including necrotizing fasciitis (NF). Streptolysin S (SLS) produces the hallmark beta-haemolytic phenotype produced by GAS. The nine-gene GAS locus (sagA-sagI) resembling a bacteriocin biosynthetic operon is necessary and sufficient for SLS production. Using precise, in-frame allelic exchange mutagenesis and single-gene complementation, we show sagA, sagB, sagC, sagD, sagE, sagF and sagG are each individually required for SLS production, and that sagE may further serve an immunity function. Limited site-directed mutagenesis of specific amino acids in the SagA prepropeptide supports the designation of SLS as a bacteriocin-like toxin. No significant pleotrophic effects of sagA deletion were observed on M protein, capsule or cysteine protease production. In a murine model of NF, the SLS-negative M1T1 GAS mutant was markedly diminished in its ability to produce necrotic skin ulcers and spread to the systemic circulation. The SLS toxin impaired phagocytic clearance and promoted epithelial cell cytotoxicity, the latter phenotype being enhanced by the effects of M protein and streptolysin O. We conclude that all genetic components of the sag operon are required for expression of functional SLS, an important virulence factor in the pathogenesis of invasive M1T1 GAS infection.
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Affiliation(s)
- Vivekanand Datta
- Department of Pediatrics, Division of Infectious Diseases, University of California, San Diego, La Jolla, CA, USA
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15
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Alouf JE. Molecular features of the cytolytic pore-forming bacterial protein toxins. Folia Microbiol (Praha) 2003; 48:5-16. [PMID: 12744072 DOI: 10.1007/bf02931271] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The repertoire of the cytolytic pore-forming protein toxins (PFT) comprises 81 identified members. The essential feature of these cytolysins is their capacity to provoke the formation of hydrophilic pores in the cytoplasmic membranes of target eukaryotic cells. This process results from the binding of the proteins on the cell surface, followed by their oligomerization which leads to the insertion of the oligomers into the membrane and formation of protein-lined channels. It impairs the osmotic balance of the cell and causes cytolysis. In this review the molecular aspects of a number of important PFT and their respective encoding structural genes will be briefly described.
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Affiliation(s)
- J E Alouf
- Institut Pasteur, 75 015 Paris, France.
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16
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Fontaine MC, Lee JJ, Kehoe MA. Combined contributions of streptolysin O and streptolysin S to virulence of serotype M5 Streptococcus pyogenes strain Manfredo. Infect Immun 2003; 71:3857-65. [PMID: 12819070 PMCID: PMC162000 DOI: 10.1128/iai.71.7.3857-3865.2003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptolysin O (SLO) and streptolysin S (SLS) are potent cytolytic toxins produced by almost all clinical isolates of group A streptococci (GAS). Allele-replacement mutagenesis was used to construct nonpolar (in-frame) deletion mutations in the slo and sagB genes of the serotype M5 GAS strain Manfredo, producing isogenic single and double SLO- and SLS-defective mutants. In contrast to recent reports on SLS-defective insertion mutants (I. Biswas, P. Germon, K. McDade, and J. Scott, Infect. Immun. 69:7029-7038, 2001; Z. Li, D. Sledjeski, B. Kreikemeyer, A.Podbielski, and M. Boyle, J. Bacteriol. 181:6019-6027, 1999), none of the mutants described here had notable pleiotropic effects on the expression of other virulence factors examined. Comparison of isogenic parent and mutant strains in various virulence models revealed no differences in their abilities to multiply in human blood or in their 50% lethal doses (LD(50)s) upon intraperitoneal infection of BALB/c mice. A single log unit difference in the LD(50)s of the parent and SLS-defective mutant strains was observed upon infection by the subcutaneous (s.c.) route. Comparisons over a range of infective doses showed that both SLO and SLS contributed to the early stages of infection and to the induction of necrotic lesions in the murine s.c. model. Individually, each toxin made an incremental contribution to virulence that was not apparent at higher infective doses, although the absence of both toxins reduced virulence over the entire dose range examined. Interestingly, in some cases, the contribution of SLO to virulence was clear only from an analysis of the double-mutant strain, highlighting the value of not confining virulence studies to mutant strains defective in the expression of only single virulence factors.
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Affiliation(s)
- Michael C Fontaine
- School of Cell and Molecular Biosciences, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, United Kingdom
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Abstract
A zone of beta-hemolysis surrounding colonies on blood-agar media is a hallmark phenotypic feature of the pathogens group A Streptococcus (GAS) and group B Streptococcus (GBS). In each case, lysis of red blood cells reflects the action of a potent protein exotoxin. Although these toxins have been the subjects of numerous investigations over the years, their purification and molecular identification have proven elusive. These difficulties reflect the instability of hemolytic activity, as both toxins function only in the context of the bacterial surface or certain high molecular weight 'stabilizer' molecules. This review highlights the recent discoveries of two markedly distinct genetic loci, necessary and sufficient for the beta-hemolytic phenotypes of GAS and GBS, respectively. The generation of isogenic GAS and GBS beta-hemolysin-deficient mutants and their analysis using in vitro and in vivo model systems has shown that both toxins function as virulence factors in the pathogenesis of invasive infections.
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Affiliation(s)
- Victor Nizet
- Division of Pediatric Infectious Diseases, University of California, San Diego, 9500 Gilman Drive, MC 0672, La Jolla 92093, USA.
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Humar D, Datta V, Bast DJ, Beall B, De Azavedo JCS, Nizet V. Streptolysin S and necrotising infections produced by group G streptococcus. Lancet 2002; 359:124-9. [PMID: 11809255 DOI: 10.1016/s0140-6736(02)07371-3] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND We encountered three patients with severe necrotising soft tissue infections due to beta-haemolytic group G streptococcus. Due to strong clinical similarities with invasive infections produced by group A streptococcus, we investigated a potential link of shared beta-haemolytic phenotype to disease pathogenesis. METHODS Hybridisation, DNA sequencing, targeted mutagenesis, and complementation studies were used to establish the genetic basis for group G streptococcus beta-haemolytic activity. The requirement of group G streptococcus beta-haemolysin in producing necrotising infection was examined in mice. FINDINGS Each patient had an underlying medical condition. beta-haemolytic group G streptococcus was the sole microbial isolate from debrided necrotic tissue. The group G streptococcus chromosome contained a homologue of the nine-gene group A streptococcus sag operon encoding the beta-haemolysin streptolysin S (SLS). Targeted mutagenesis of the putative SLS structural gene sagA in group G streptococcus eliminated beta-haemolytic activity. Mice injected subcutaneously with wild-type group A streptococcus or group G streptococcus developed an inflammatory lesion with high bacterial counts, marked neutrophil infiltration, and histopathological evidence of diffuse tissue necrosis. These changes were not found in mice injected with the isogenic group A streptococcus or group G streptococcus SLS-negative mutants. INTERPRETATION In patients with underlying medical conditions, beta-haemolytic group G streptococcus can produce necrotising soft tissue infections resembling those produced by group A streptococcus. The beta-haemolytic phenotype of group G streptococcus is produced by the exotoxin SLS, encoded by a functional homologue of the nine-gene group A streptococcus sag operon. SLS expression contributes to the pathogenesis of streptococcal necrotising soft tissue infection.
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Affiliation(s)
- Deepali Humar
- Department of Medicine, Division of Infectious Diseases, University of California, San Diego 92093, USA.
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Eberhard TH, Sledjeski DD, Boyle MDP. Mouse skin passage of a Streptococcus pyogenes Tn917 mutant of sagA/pel restores virulence, beta-hemolysis and sagA/pel expression without altering the position or sequence of the transposon. BMC Microbiol 2001; 1:33. [PMID: 11801184 PMCID: PMC64569 DOI: 10.1186/1471-2180-1-33] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2001] [Accepted: 12/17/2001] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Streptolysin S (SLS), the oxygen-stable hemolysin of Streptococcus pyogenes, has recently been shown to be encoded by the sagA/pel gene. Mutants lacking expression of this gene were less virulent in a dermonecrotic mouse infection model. Inactivation of the sagA/pel gene affect the expression of a variety of virulence factors in addition to the hemolysin. Insertion of a Tn917 transposon into the promoter region of the sagA/pel gene of S. pyogenes isolate CS101 eliminated expression of SLS, as well as decreased expression of the streptococcal pyrogenic exotoxin B, streptokinase and M protein. RESULTS In this study a mouse skin air sac model was utilized to analyze the effect of biological pressures on expression of SLS and other sagA/pel regulated gene products. The insertion delayed the lethal effect of S. pyogenes in a mouse skin infection model. Despite this, bacteria could be cultured from the kidneys 72 hours post infection. These kidney-recovered isolates were beta-hemolytic despite the transposon being present in its original location and had equivalent virulence to the wild type isolate when re-injected into naive mice. Northern blot analysis of the kidney-recovered isolates confirmed that transcription of sagA/pel was restored; however the expression of all sagA/pel regulated genes was not restored to wild type levels. CONCLUSIONS These results show that biological pressure present in the mouse can select for variants with altered expression of key virulence factor genes in S. pyogenes.
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Affiliation(s)
- Thomas H Eberhard
- Department of Microbiology and Immunology, Medical College of Ohio, Toledo, Ohio, 43614, USA
| | - Darren D Sledjeski
- Department of Microbiology and Immunology, Medical College of Ohio, Toledo, Ohio, 43614, USA
| | - Michael DP Boyle
- Department of Microbiology and Immunology, Medical College of Ohio, Toledo, Ohio, 43614, USA
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Carr A, Sledjeski DD, Podbielski A, Boyle MD, Kreikemeyer B. Similarities between complement-mediated and streptolysin S-mediated hemolysis. J Biol Chem 2001; 276:41790-6. [PMID: 11546819 DOI: 10.1074/jbc.m107401200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The oxygen-stable hemolysin streptolysin S (SLS) of Streptococcus pyogenes is encoded in part by the pel/sagA gene product. Antibodies to a synthetic peptide from the C terminus of the Pel/SagA open reading frame inhibited hemolysis mediated by both culture supernatants from multiple M serotypes of S. pyogenes isolates or a commercially available SLS preparation. Analysis of the SLS-mediated hemolytic reaction demonstrated that it was temperature- and concentration-dependent. Like complement-mediated hemolysis it conforms to the prediction of a one-hit mechanism of hemolysis. A number of intermediates in the SLS-mediated hemolysis of sheep erythrocytes could be distinguished. SLS could bind to erythrocytes below 17 degrees C; however, lysis could only occur at temperatures >23 degrees C. Following binding of SLS and washing, a papain-sensitive intermediate could be distinguished prior to insertion of the SLS complex into the erythrocyte membrane, which resulted in formation of a transmembrane pore and led to irreversible osmotic lysis of the cell. These intermediates were similar to those described previously during complement-mediated hemolysis.
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Affiliation(s)
- A Carr
- Department of Microbiology & Immunology, Medical College of Ohio, Toledo, Ohio 43614-5806, USA
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