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Lu M, Parel JM, Miller D. Interactions between staphylococcal enterotoxins A and D and superantigen-like proteins 1 and 5 for predicting methicillin and multidrug resistance profiles among Staphylococcus aureus ocular isolates. PLoS One 2021; 16:e0254519. [PMID: 34320020 PMCID: PMC8318242 DOI: 10.1371/journal.pone.0254519] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/29/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant (MDR) S. aureus strains are well recognized as posing substantial problems in treating ocular infections. S. aureus has a vast array of virulence factors, including superantigens and enterotoxins. Their interactions and ability to signal antibiotics resistance have not been explored. OBJECTIVES To predict the relationship between superantigens and methicillin and multidrug resistance among S. aureus ocular isolates. METHODS We used a DNA microarray to characterize the enterotoxin and superantigen gene profiles of 98 S. aureus isolates collected from common ocular sources. The outcomes contained phenotypic and genotypic expressions of MRSA. We also included the MDR status as an outcome, categorized as resistance to three or more drugs, including oxacillin, penicillin, erythromycin, clindamycin, moxifloxacin, tetracycline, trimethoprim-sulfamethoxazole and gentamicin. We identified gene profiles that predicted each outcome through a classification analysis utilizing Random Forest machine learning techniques. FINDINGS Our machine learning models predicted the outcomes accurately utilizing 67 enterotoxin and superantigen genes. Strong correlates predicting the genotypic expression of MRSA were enterotoxins A, D, J and R and superantigen-like proteins 1, 3, 7 and 10. Among these virulence factors, enterotoxin D and superantigen-like proteins 1, 5 and 10 were also significantly informative for predicting both MDR and MRSA in terms of phenotypic expression. Strong interactions were identified including enterotoxins A (entA) interacting with superantigen-like protein 1 (set6-var1_11), and enterotoxin D (entD) interacting with superantigen-like protein 5 (ssl05/set3_probe 1): MRSA and MDR S. aureus are associated with the presence of both entA and set6-var1_11, or both entD and ssl05/set3_probe 1, while the absence of these genes in pairs indicates non-multidrug-resistant and methicillin-susceptible S. aureus. CONCLUSIONS MRSA and MDR S. aureus show a different spectrum of ocular pathology than their non-resistant counterparts. When assessing the role of enterotoxins in predicting antibiotics resistance, it is critical to consider both main effects and interactions.
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Affiliation(s)
- Min Lu
- Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, FL, United States of America
| | - Jean-Marie Parel
- Department of Ophthalmology, Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Darlene Miller
- Department of Ophthalmology, Ocular Microbiology Laboratory, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States of America
- * E-mail:
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2
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Abstract
Staphylococcus aureus is both a commensal and a pathogenic bacterium for humans. Its ability to induce severe infections is based on a wide range of virulence factors. S. aureus community-acquired pneumonia (SA-CAP) is rare and severe, and the contribution of certain virulence factors in this disease has been recognized over the past 2 decades. First, the factors involved in metabolism adaptation are crucial for S. aureus survival in the lower respiratory tract, and toxins and enzymes are required for it to cross the pulmonary epithelial barrier. S. aureus subsequently faces host defense mechanisms, including the epithelial barrier, but most importantly the immune system. Here, again, S. aureus uses myriad virulence factors to successfully escape from the host's defenses and takes advantage of them. The impact of S. aureus virulence, combined with the collateral damage caused by an overwhelming immune response, leads to severe tissue damage and adverse clinical outcomes. In this review, we summarize step by step all of the S. aureus factors implicated in CAP and described to date, and we provide an outlook for future research.
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Affiliation(s)
- Mariane Pivard
- CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Karen Moreau
- CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - François Vandenesch
- CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
- Centre National de Référence des Staphylocoques, Institut des agents infectieux, Hospices Civils de Lyon, Lyon, France
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3
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Staphylococcus aureus Isolated from Skin from Atopic-Dermatitis Patients Produces Staphylococcal Enterotoxin Y, Which Predominantly Induces T-Cell Receptor Vα-Specific Expansion of T Cells. Infect Immun 2020; 88:IAI.00360-19. [PMID: 31740530 DOI: 10.1128/iai.00360-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/29/2019] [Indexed: 11/20/2022] Open
Abstract
While investigating the virulence traits of Staphylococcus aureus adhering to the skin of atopic-dermatitis (AD) patients, we identified a novel open reading frame (ORF) with structural similarity to a superantigen from genome sequence data of an isolate from AD skin. Concurrently, the same ORF was identified in a bovine isolate of S. aureus and designated SElY (H. K. Ono, Y. Sato'o, K. Narita, I. Naito, et al., Appl Environ Microbiol 81:7034-7040, 2015, https://doi.org/10.1128/AEM.01873-15). Recombinant SElYbov had superantigen activity in human peripheral blood mononuclear cells. It further demonstrated emetic activity in a primate animal model, and it was proposed that SElY be renamed SEY (H. K. Ono, S. Hirose, K. Narita, M. Sugiyama, et al., PLoS Pathog 15:e1007803, 2019, https://doi.org/10.1371/journal.ppat.1007803). Here, we investigated the prevalence of the sey gene in 270 human clinical isolates of various origins in Japan. Forty-two strains were positive for the sey gene, and the positive isolates were from patients with the skin diseases atopic dermatitis and impetigo/staphylococcal scalded skin syndrome (SSSS), with a detection rate of ∼17 to 22%. There were three variants of SEY (SEY1, SEY2, and SEY3), and isolates producing SEY variants formed three distinct clusters corresponding to clonal complexes (CCs) 121, 59, and 20, respectively. Most sey + isolates produced SEY in broth culture. Unlike SEYbov, the three recombinant SEY variants exhibited stability against heat treatment. SEY predominantly activated human T cells with a particular T-cell receptor (TCR) Vα profile, a unique observation since most staphylococcal enterotoxins exert their superantigenic activities through activating T cells with specific TCR Vβ profiles. SEY may act to induce localized inflammation via skin-resident T-cell activation, facilitating the pathogenesis of S. aureus infection in disrupted epithelial barriers.
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4
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Trübe P, Hertlein T, Mrochen DM, Schulz D, Jorde I, Krause B, Zeun J, Fischer S, Wolf SA, Walther B, Semmler T, Bröker BM, Ulrich RG, Ohlsen K, Holtfreter S. Bringing together what belongs together: Optimizing murine infection models by using mouse-adapted Staphylococcus aureus strains. Int J Med Microbiol 2018; 309:26-38. [PMID: 30391222 DOI: 10.1016/j.ijmm.2018.10.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 10/05/2018] [Accepted: 10/18/2018] [Indexed: 02/06/2023] Open
Abstract
Staphylococcus (S.) aureus is a leading cause of bacterial infection world-wide, and currently no vaccine is available for humans. Vaccine development relies heavily on clinically relevant infection models. However, the suitability of mice for S. aureus infection models has often been questioned, because experimental infection of mice with human-adapted S. aureus requires very high infection doses. Moreover, mice were not considered to be natural hosts of S. aureus. The latter has been disproven by our recent findings, showing that both laboratory mice, as well as wild small mammals including mice, voles, and shrews, are naturally colonized with S. aureus. Here, we investigated whether mouse-and vole-derived S. aureus strains show an enhanced virulence in mice as compared to the human-adapted strain Newman. Using a step-wise approach based on the bacterial genotype and in vitro assays for host adaptation, we selected the most promising candidates for murine infection models out of a total of 254 S. aureus isolates from laboratory mice as well as wild rodents and shrews. Four strains representing the clonal complexes (CC) 8, 49, and 88 (n = 2) were selected and compared to the human-adapted S. aureus strain Newman (CC8) in murine pneumonia and bacteremia models. Notably, a bank vole-derived CC49 strain, named DIP, was highly virulent in BALB/c mice in pneumonia and bacteremia models, whereas the other murine and vole strains showed virulence similar to or lower than that of Newman. At one tenth of the standard infection dose DIP induced disease severity, bacterial load and host cytokine and chemokine responses in the murine bacteremia model similar to that of Newman. In the pneumonia model, DIP was also more virulent than Newman but the effect was less pronounced. Whole genome sequencing data analysis identified a pore-forming toxin gene, lukF-PV(P83)/lukM, in DIP but not in the other tested S. aureus isolates. To conclude, the mouse-adapted S. aureus strain DIP allows a significant reduction of the inoculation dose in mice and is hence a promising tool to develop clinically more relevant infection models.
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Affiliation(s)
- Patricia Trübe
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Tobias Hertlein
- Institute for Molecular Infection Biology, University of Würzburg, Germany
| | - Daniel M Mrochen
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Daniel Schulz
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Ilka Jorde
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Bettina Krause
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Julia Zeun
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Stefan Fischer
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Silver A Wolf
- Microbial Genomics (NG1), Robert Koch Institute, Berlin, Germany
| | - Birgit Walther
- Advanced Light and Electron Microscopy, Robert Koch Institute, Berlin, Germany
| | - Torsten Semmler
- Microbial Genomics (NG1), Robert Koch Institute, Berlin, Germany
| | - Barbara M Bröker
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Rainer G Ulrich
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Knut Ohlsen
- Institute for Molecular Infection Biology, University of Würzburg, Germany
| | - Silva Holtfreter
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany.
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5
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Karau MJ, Tilahun ME, Krogman A, Osborne BA, Goldsby RA, David CS, Mandrekar JN, Patel R, Rajagopalan G. Passive therapy with humanized anti-staphylococcal enterotoxin B antibodies attenuates systemic inflammatory response and protects from lethal pneumonia caused by staphylococcal enterotoxin B-producing Staphylococcus aureus. Virulence 2017; 8:1148-1159. [PMID: 27925510 PMCID: PMC5711449 DOI: 10.1080/21505594.2016.1267894] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 11/21/2016] [Accepted: 11/28/2016] [Indexed: 02/08/2023] Open
Abstract
Drugs such as linezolid that inhibit bacterial protein synthesis may be beneficial in treating infections caused by toxigenic Staphylococcus aureus. As protein synthesis inhibitors have no effect on preformed toxins, neutralization of pathogenic exotoxins with anti-toxin antibodies may be beneficial in conjunction with antibacterial therapy. Herein, we evaluated the efficacy of human-mouse chimeric high-affinity neutralizing anti-staphylococcal enterotoxin B (SEB) antibodies in the treatment of experimental pneumonia caused by SEB-producing S. aureus. Since HLA class II transgenic mice mount a stronger systemic immune response following challenge with SEB and are more susceptible to SEB-induced lethal toxic shock than conventional mice strains, HLA-DR3 transgenic mice were used. Lethal pneumonia caused by SEB-producing S. aureus in HLA-DR3 transgenic mice was characterized by robust T cell activation and elevated systemic levels of several pro-inflammatory cytokines and chemokines. Prophylactic administration of a single dose of linezolid 30 min prior to the onset of infection attenuated the systemic inflammatory response and protected from mortality whereas linezolid administered 60 min after the onset of infection failed to confer significant protection. Human-mouse chimeric high-affinity neutralizing anti-SEB antibodies alone, but not polyclonal human IgG, mitigated this response and protected from death when administered immediately after initiation of infection. Further, anti-SEB antibodies as well as intact polyclonal human IgG, but not its Fab or Fc fragments, protected from lethal pneumonia when followed with linezolid therapy 60 min later. In conclusion, neutralization of superantigens with high-affinity antibodies may have beneficial effects in pneumonia.
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Affiliation(s)
- Melissa J. Karau
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Mulualem E. Tilahun
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
- Department of Biology, Amherst College, Amherst, MA, USA
| | - Ashton Krogman
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Barbara A. Osborne
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | | | - Chella S. David
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Jayawant N. Mandrekar
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Robin Patel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
- Division of Infectious Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Govindarajan Rajagopalan
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
- Division of Infectious Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
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6
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Svedova J, Ménoret A, Mittal P, Ryan JM, Buturla JA, Vella AT. Therapeutic blockade of CD54 attenuates pulmonary barrier damage in T cell-induced acute lung injury. Am J Physiol Lung Cell Mol Physiol 2017; 313:L177-L191. [PMID: 28473322 DOI: 10.1152/ajplung.00050.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/27/2017] [Accepted: 04/27/2017] [Indexed: 12/19/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a serious, often fatal condition without available pharmacotherapy. Although the role of innate cells in ARDS has been studied extensively, emerging evidence suggests that T cells may be involved in disease etiology. Staphylococcus aureus enterotoxins are potent T-cell mitogens capable of triggering life-threatening shock. We demonstrate that 2 days after inhalation of S. aureus enterotoxin A, mice developed T cell-mediated increases in vascular permeability, as well as expression of injury markers and caspases in the lung. Pulmonary endothelial cells underwent sequential phenotypic changes marked by rapid activation coinciding with inflammatory events secondary to T-cell priming, followed by reductions in endothelial cell number juxtaposing simultaneous T-cell expansion and cytotoxic differentiation. Although initial T-cell activation influenced the extent of lung injury, CD54 (ICAM-1) blocking antibody administered well after enterotoxin exposure substantially attenuated pulmonary barrier damage. Thus CD54-targeted therapy may be a promising candidate for further exploration into its potential utility in treating ARDS patients.
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Affiliation(s)
- Julia Svedova
- Department of Immunology, School of Medicine, UConn Health, Farmington, Connecticut
| | - Antoine Ménoret
- Department of Immunology, School of Medicine, UConn Health, Farmington, Connecticut.,Institute for Systems Genomics, UConn Health, Farmington, Connecticut; and
| | - Payal Mittal
- Department of Immunology, School of Medicine, UConn Health, Farmington, Connecticut
| | - Joseph M Ryan
- Department of Immunology, School of Medicine, UConn Health, Farmington, Connecticut
| | - James A Buturla
- Department of Internal Medicine, UConn Health, Farmington, Connecticut
| | - Anthony T Vella
- Department of Immunology, School of Medicine, UConn Health, Farmington, Connecticut;
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7
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The Spl Serine Proteases Modulate Staphylococcus aureus Protein Production and Virulence in a Rabbit Model of Pneumonia. mSphere 2016; 1:mSphere00208-16. [PMID: 27747296 PMCID: PMC5061998 DOI: 10.1128/msphere.00208-16] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/23/2016] [Indexed: 01/09/2023] Open
Abstract
Staphylococcus aureus is a versatile human pathogen that produces an array of virulence factors, including several proteases. Of these, six proteases called the Spls are the least characterized. Previous evidence suggests that the Spls are expressed during human infection; however, their function is unknown. Our study shows that the Spls are required for S. aureus to cause disseminated lung damage during pneumonia. Further, we present the first example of a human protein cut by an Spl protease. Although the Spls were predicted not to cut staphylococcal proteins, we also show that an spl mutant has altered abundance of both secreted and surface-associated proteins. This work provides novel insight into the function of Spls during infection and their potential ability to degrade both staphylococcal and human proteins. The Spl proteases are a group of six serine proteases that are encoded on the νSaβ pathogenicity island and are unique to Staphylococcus aureus. Despite their interesting biochemistry, their biological substrates and functions in virulence have been difficult to elucidate. We found that an spl operon mutant of the community-associated methicillin-resistant S. aureus USA300 strain LAC induced localized lung damage in a rabbit model of pneumonia, characterized by bronchopneumonia observed histologically. Disease in the mutant-infected rabbits was restricted in distribution compared to that in wild-type USA300-infected rabbits. We also found that SplA is able to cleave the mucin 16 glycoprotein from the surface of the CalU-3 lung cell line, suggesting a possible mechanism for wild-type USA300 spreading pneumonia to both lungs. Investigation of the secreted and surface proteomes of wild-type USA300 and the spl mutant revealed multiple alterations in metabolic proteins and virulence factors. This study demonstrates that the Spls modulate S. aureus physiology and virulence, identifies a human target of SplA, and suggests potential S. aureus targets of the Spl proteases. IMPORTANCEStaphylococcus aureus is a versatile human pathogen that produces an array of virulence factors, including several proteases. Of these, six proteases called the Spls are the least characterized. Previous evidence suggests that the Spls are expressed during human infection; however, their function is unknown. Our study shows that the Spls are required for S. aureus to cause disseminated lung damage during pneumonia. Further, we present the first example of a human protein cut by an Spl protease. Although the Spls were predicted not to cut staphylococcal proteins, we also show that an spl mutant has altered abundance of both secreted and surface-associated proteins. This work provides novel insight into the function of Spls during infection and their potential ability to degrade both staphylococcal and human proteins.
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8
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Critical Role of Alpha-Toxin and Protective Effects of Its Neutralization by a Human Antibody in Acute Bacterial Skin and Skin Structure Infections. Antimicrob Agents Chemother 2016; 60:5640-8. [PMID: 27401576 DOI: 10.1128/aac.00710-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/01/2016] [Indexed: 12/20/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) causes large-scale epidemics of acute bacterial skin and skin structure infections (ABSSSI) within communities across the United States. Animal models that reproduce ABSSSI as they occur in humans are urgently needed to test new therapeutic strategies. Alpha-toxin plays a critical role in a variety of staphylococcal infection models in mice, but its role in the pathogenesis of ABSSSI remains to be elucidated in rabbits, which are similar to humans in their susceptibility to S. aureus superantigens and certain bicomponent pore-forming leukocidins. We report here a new rabbit model of ABSSSI and show that those infected with a mutant deficient in expression of alpha-toxin (Δhla) developed a small dermonecrotic lesion, whereas those infected with isogenic USA300 MRSA wild-type or complemented Δhla strains developed ABSSSI that mimic the severe infections that occur in humans, including the large central dermonecrotic core surrounded by erythema, induration, and marked subcutaneous hemorrhage. More importantly, immunoprophylaxis with MEDI4893*, an anti-alpha-toxin human monoclonal antibody, significantly reduced the severity of disease caused by a USA300 wild-type strain to that caused by the Δhla mutant, indicating that this toxin could be completely neutralized during infection. Thus, this study illustrates a potential high standard for the development of new immunotherapeutic agents in which a toxin-neutralizing antibody provides protection to the same degree achieved with a toxin gene knockout. When MEDI4893* was administered as adjunctive therapy with a subtherapeutic dose of linezolid, the combination was significantly more efficacious than either agent alone in reducing the severity of ABSSSI.
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9
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Selle M, Hertlein T, Oesterreich B, Klemm T, Kloppot P, Müller E, Ehricht R, Stentzel S, Bröker BM, Engelmann S, Ohlsen K. Global antibody response to Staphylococcus aureus live-cell vaccination. Sci Rep 2016; 6:24754. [PMID: 27103319 PMCID: PMC4840433 DOI: 10.1038/srep24754] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/05/2016] [Indexed: 02/06/2023] Open
Abstract
The pathogen Staphylococcus aureus causes a broad range of severe diseases and is feared for its ability to rapidly develop resistance to antibiotic substances. The increasing number of highly resistant S. aureus infections has accelerated the search for alternative treatment options to close the widening gap in anti-S. aureus therapy. This study analyses the humoral immune response to vaccination of Balb/c mice with sublethal doses of live S. aureus. The elicited antibody pattern in the sera of intravenously and intramuscularly vaccinated mice was determined using of a recently developed protein array. We observed a specific antibody response against a broad set of S. aureus antigens which was stronger following i.v. than i.m. vaccination. Intravenous but not intramuscular vaccination protected mice against an intramuscular challenge infection with a high bacterial dose. Vaccine protection was correlated with the strength of the anti-S. aureus antibody response. This study identified novel vaccine candidates by using protein microarrays as an effective tool and showed that successful vaccination against S. aureus relies on the optimal route of administration.
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Affiliation(s)
- Martina Selle
- University Würzburg, Institute for Molecular Infection Biology, Würzburg, Germany
| | - Tobias Hertlein
- University Würzburg, Institute for Molecular Infection Biology, Würzburg, Germany
| | - Babett Oesterreich
- University Würzburg, Institute for Molecular Infection Biology, Würzburg, Germany
| | - Theresa Klemm
- University Würzburg, Institute for Molecular Infection Biology, Würzburg, Germany
| | - Peggy Kloppot
- University Greifswald, Institute for Microbiology, Greifswald, Germany
| | - Elke Müller
- Alere Technologies GmbH, Jena, Germany.,InfectoGnostics Research Campus Jena, Germany
| | - Ralf Ehricht
- Alere Technologies GmbH, Jena, Germany.,InfectoGnostics Research Campus Jena, Germany
| | - Sebastian Stentzel
- University Medicine Greifswald, Department of Immunology, Greifswald, Germany
| | - Barbara M Bröker
- University Medicine Greifswald, Department of Immunology, Greifswald, Germany
| | - Susanne Engelmann
- Technical University Braunschweig, Institute for Microbiology, Braunschweig, Germany.,Helmholtz-Zentrum für Infektionsforschung, Mikrobielle Proteomik, Braunschweig, Germany
| | - Knut Ohlsen
- University Würzburg, Institute for Molecular Infection Biology, Würzburg, Germany
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10
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Stach CS, Herrera A, Schlievert PM. Staphylococcal superantigens interact with multiple host receptors to cause serious diseases. Immunol Res 2015; 59:177-81. [PMID: 24838262 DOI: 10.1007/s12026-014-8539-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Staphylococcus aureus strains that cause human diseases produce a large family of pyrogenic toxin superantigens (SAgs). These include toxic shock syndrome toxin-1 (TSST-1), the staphylococcal enterotoxins (SEs), and the SE-like proteins; to date, 23 staphylococcal SAgs have been described. Among the SAgs, three have been highly associated with human diseases (TSST-1, SEB, and SEC), likely because they are produced in high concentrations compared to other SAgs. Another major family of exotoxins produced by S. aureus is the cytolysins, particularly α-, β-, γ-, and δ-toxins, phenol soluble modulins, and leukocidins. This review discusses the association of SAgs with human diseases and particularly the "outside-in" signaling mechanism that leads to SAg-associated diseases. We discuss SAg interactions with three host immune cell receptors, including variable regions of the β-chain of the T cell receptor, MHC II α- and/or β-chains, and an epithelial/endothelial cell receptor that may include CD40. To a lesser extent, we discuss the role of cytolysins in facilitating disease production by SAgs.
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Affiliation(s)
- Christopher S Stach
- Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, IA, 52242, USA
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11
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Staphylococcal toxic shock syndrome: superantigen-mediated enhancement of endotoxin shock and adaptive immune suppression. Immunol Res 2015; 59:182-7. [PMID: 24816557 DOI: 10.1007/s12026-014-8538-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Infectious diseases caused by Staphylococcus aureus present a significant clinical and public health problem. S. aureus causes some of the most severe hospital-associated and community-acquired illnesses. Specifically, it is the leading cause of infective endocarditis and osteomyelitis, and the second leading cause of sepsis in the USA. While pathogenesis of S. aureus infections is at the center of current research, many questions remain about the mechanisms underlying staphylococcal toxic shock syndrome (TSS) and associated adaptive immune suppression. Both conditions are mediated by staphylococcal superantigens (SAgs)-secreted staphylococcal toxins that are major S. aureus virulence factors. Toxic shock syndrome toxin-1 (TSST-1) is the SAg responsible for almost all menstrual TSS cases in the USA. TSST-1, staphylococcal enterotoxin B and C are also responsible for most cases of non-menstrual TSS. While SAgs mediate all of the hallmark features of TSS, such as fever, rash, hypotension, and multi-organ dysfunction, they are also capable of enhancing the toxic effects of endogenous endotoxin. This interaction appears to be critical in mediating the severity of TSS and related mortality. In addition, interaction between SAgs and the host immune system has been recognized to result in a unique form of adaptive immune suppression, contributing to poor outcomes of S. aureus infections. Utilizing rabbit models of S. aureus infective endocarditis, pneumonia and sepsis, and molecular genetics techniques, we aim to elucidate the mechanisms of SAg and endotoxin synergism in the pathogenesis of TSS, and examine the cellular and molecular mechanisms underlying SAg-mediated immune dysfunction.
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12
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Koymans KJ, Vrieling M, Gorham RD, van Strijp JAG. Staphylococcal Immune Evasion Proteins: Structure, Function, and Host Adaptation. Curr Top Microbiol Immunol 2015; 409:441-489. [PMID: 26919864 DOI: 10.1007/82_2015_5017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Staphylococcus aureus is a successful human and animal pathogen. Its pathogenicity is linked to its ability to secrete a large amount of virulence factors. These secreted proteins interfere with many critical components of the immune system, both innate and adaptive, and hamper proper immune functioning. In recent years, numerous studies have been conducted in order to understand the molecular mechanism underlying the interaction of evasion molecules with the host immune system. Structural studies have fundamentally contributed to our understanding of the mechanisms of action of the individual factors. Furthermore, such studies revealed one of the most striking characteristics of the secreted immune evasion molecules: their conserved structure. Despite high-sequence variability, most immune evasion molecules belong to a small number of structural categories. Another remarkable characteristic is that S. aureus carries most of these virulence factors on mobile genetic elements (MGE) or ex-MGE in its accessory genome. Coevolution of pathogen and host has resulted in immune evasion molecules with a highly host-specific function and prevalence. In this review, we explore how these shared structures and genomic locations relate to function and host specificity. This is discussed in the context of therapeutic options for these immune evasion molecules in infectious as well as in inflammatory diseases.
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Affiliation(s)
- Kirsten J Koymans
- Department of Medical Microbiology, University Medical Center Utrecht, G04-614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
| | - Manouk Vrieling
- Department of Medical Microbiology, University Medical Center Utrecht, G04-614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Ronald D Gorham
- Department of Medical Microbiology, University Medical Center Utrecht, G04-614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, G04-614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
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13
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Narewski ER, Kim V, Marchetti N, Jacobs MR, Criner GJ. Is Methicillin-Resistant Staphylococcus Aureus Colonization Associated with Worse Outcomes in COPD Hospitalizations? CHRONIC OBSTRUCTIVE PULMONARY DISEASES-JOURNAL OF THE COPD FOUNDATION 2015. [PMID: 28626792 DOI: 10.15326/jcopdf.2.3.2014.0147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BACKGROUND Although methicillin-resistant Staphylococcus aureus (MRSA) colonization is common in chronic obstructive pulmonary disease (COPD) patients, its effect on the course of COPD hospitalization remains unknown. METHODS Records of 160 patients hospitalized at our institution January 1, 2008 to May 1, 2010 with acute exacerbations of COPD who were screened for MRSA were examined and outcomes from their hospitalizations were quantified. RESULTS Of the 160 patients, 33 (20.6%) were MRSA colonized on screening. These patients had similar demographics, spirometry, Charlson Indexes, and APACHE-II scores when compared to patients who were not MRSA colonized (n=127), but MRSA colonized patients had more hospitalizations within the 2 years prior to admission (2 [1-4.8] versus 1 [0-3], p = 0.03). While hospitalized, MRSA colonized patients had a longer length of stay (9 [5.3-15.5] versus 5 [3-7.8] days, p = 0.01) and more antibiotic days (7 [5-10.8] versus 5 [0-7] days, p = 0.01). They were also more likely to receive intensive care (51.5% versus 23.6%, p = 0.01) and to develop respiratory failure that required noninvasive ventilation (56.3% versus 38.2%, p = 0.05). Trends towards increased use of invasive mechanical ventilation and readmission within 30 days were also present. CONCLUSIONS COPD patients colonized with MRSA have longer hospitalizations, require longer courses of antibiotics, and are more likely to require intensive care.
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Affiliation(s)
- Erin R Narewski
- Temple University Hospital, Division of Pulmonary and Critical Care Medicine, Philadelphia, Pennsylvania
| | - Victor Kim
- Temple University Hospital, Division of Pulmonary and Critical Care Medicine, Philadelphia, Pennsylvania
| | - Nathaniel Marchetti
- Temple University Hospital, Division of Pulmonary and Critical Care Medicine, Philadelphia, Pennsylvania
| | - Michael R Jacobs
- Temple University Hospital, Division of Pulmonary and Critical Care Medicine, Philadelphia, Pennsylvania
| | - Gerard J Criner
- Temple University Hospital, Division of Pulmonary and Critical Care Medicine, Philadelphia, Pennsylvania
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14
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Models matter: the search for an effective Staphylococcus aureus vaccine. Nat Rev Microbiol 2014; 12:585-91. [PMID: 24998740 DOI: 10.1038/nrmicro3308] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Staphylococcus aureus is a highly successful bacterial pathogen owing to its abundance of cell surface and secreted virulence factors. It is estimated that 30% of the population is colonized with S. aureus, usually on mucosal surfaces, and methicillin-resistant S. aureus is a major public health concern. There have been multiple attempts to develop an S. aureus vaccine using one or more cell surface virulence factors as antigens; all of these vaccine trials have failed. In this Opinion article, we suggest that an over-reliance on rodent models and a focus on targeting cell surface components have been major contributing factors to this failure.
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15
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Merriman JA, Schlievert PM. Are we close to a vaccination against Staphylococcus aureus? Future Microbiol 2014; 9:717-20. [DOI: 10.2217/fmb.14.40] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Joseph A Merriman
- Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, Iowa, 52242 USA
| | - Patrick M Schlievert
- Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, Iowa, 52242 USA
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16
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Stich N, Model N, Samstag A, Gruener CS, Wolf HM, Eibl MM. Toxic shock syndrome toxin-1-mediated toxicity inhibited by neutralizing antibodies late in the course of continual in vivo and in vitro exposure. Toxins (Basel) 2014; 6:1724-41. [PMID: 24887085 PMCID: PMC4073126 DOI: 10.3390/toxins6061724] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/07/2014] [Accepted: 05/20/2014] [Indexed: 02/05/2023] Open
Abstract
Toxic shock syndrome (TSS) results from the host's overwhelming inflammatory response and cytokine storm mainly due to superantigens (SAgs). There is no effective specific therapy. Application of immunoglobulins has been shown to improve the outcome of the disease and to neutralize SAgs both in vivo and in vitro. However, in most experiments that have been performed, antiserum was either pre-incubated with SAg, or both were applied simultaneously. To mirror more closely the clinical situation, we applied a multiple dose (over five days) lethal challenge in a rabbit model. Treatment with toxic shock syndrome toxin 1 (TSST-1) neutralizing antibody was fully protective, even when administered late in the course of the challenge. Kinetic studies on the effect of superantigen toxins are scarce. We performed in vitro kinetic studies by neutralizing the toxin with antibodies at well-defined time points. T-cell activation was determined by assessing T-cell proliferation (3H-thymidine incorporation), determination of IL-2 release in the cell supernatant (ELISA), and IL-2 gene activation (real-time PCR (RT-PCR)). Here we show that T-cell activation occurs continuously. The application of TSST-1 neutralizing antiserum reduced IL-2 and TNFα release into the cell supernatant, even if added at later time points. Interference with the prolonged stimulation of proinflammatory cytokines is likely to be in vivo relevant, as postexposure treatment protected rabbits against the multiple dose lethal SAg challenge. Our results shed new light on the treatment of TSS by specific antibodies even at late stages of exposure.
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MESH Headings
- Animals
- Antibodies, Neutralizing/pharmacology
- Antibodies, Neutralizing/therapeutic use
- Antitoxins/pharmacology
- Antitoxins/therapeutic use
- Bacterial Toxins/antagonists & inhibitors
- Bacterial Toxins/genetics
- Bacterial Toxins/metabolism
- Bacterial Toxins/toxicity
- Cell Proliferation/drug effects
- Cells, Cultured
- Disease Models, Animal
- Enterotoxins/antagonists & inhibitors
- Enterotoxins/genetics
- Enterotoxins/metabolism
- Enterotoxins/toxicity
- Female
- Gene Expression Regulation/drug effects
- Humans
- Interleukin-2/genetics
- Interleukin-2/metabolism
- Leukocytes, Mononuclear/cytology
- Leukocytes, Mononuclear/drug effects
- Leukocytes, Mononuclear/immunology
- Leukocytes, Mononuclear/metabolism
- Lymphocyte Activation/drug effects
- Male
- Mutant Proteins/antagonists & inhibitors
- Mutant Proteins/metabolism
- Mutant Proteins/toxicity
- Rabbits
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Recombinant Proteins/toxicity
- Shock, Septic/drug therapy
- Shock, Septic/etiology
- Shock, Septic/immunology
- Shock, Septic/metabolism
- Superantigens/genetics
- Superantigens/metabolism
- Superantigens/toxicity
- Survival Analysis
- T-Lymphocytes/drug effects
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Toxicokinetics
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Norbert Stich
- Biomedizinische ForschungsgmbH Lazarettgasse 19/2, Vienna A-1090, Austria.
| | - Nina Model
- Biomedizinische ForschungsgmbH Lazarettgasse 19/2, Vienna A-1090, Austria.
| | - Aysen Samstag
- Immunology Outpatient Clinic, Schwarzspanierstrasse 15, Vienna A-1090, Austria.
| | - Corina S Gruener
- Biomedizinische ForschungsgmbH Lazarettgasse 19/2, Vienna A-1090, Austria.
| | - Hermann M Wolf
- Immunology Outpatient Clinic, Schwarzspanierstrasse 15, Vienna A-1090, Austria.
| | - Martha M Eibl
- Biomedizinische ForschungsgmbH Lazarettgasse 19/2, Vienna A-1090, Austria.
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17
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Abstract
SUMMARY This review begins with a discussion of the large family of Staphylococcus aureus and beta-hemolytic streptococcal pyrogenic toxin T lymphocyte superantigens from structural and immunobiological perspectives. With this as background, the review then discusses the major known and possible human disease associations with superantigens, including associations with toxic shock syndromes, atopic dermatitis, pneumonia, infective endocarditis, and autoimmune sequelae to streptococcal illnesses. Finally, the review addresses current and possible novel strategies to prevent superantigen production and passive and active immunization strategies.
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18
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Spaulding AR, Salgado-Pabón W, Merriman JA, Stach CS, Ji Y, Gillman AN, Peterson ML, Schlievert PM. Vaccination against Staphylococcus aureus pneumonia. J Infect Dis 2013; 209:1955-62. [PMID: 24357631 DOI: 10.1093/infdis/jit823] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Staphylococcus aureus causes serious infections in both hospital and community settings. Attempts have been made to prevent human infection through vaccination against bacterial cell-surface antigens; thus far all have failed. Here we show that superantigens and cytolysins, when used in vaccine cocktails, provide protection from S. aureus USA100-USA400 intrapulmonary challenge. METHODS Rabbits were actively vaccinated (wild-type toxins or toxoids) or passively immunized (hyperimmune serum) against combinations of superantigens (toxic shock syndrome toxin 1, enterotoxins B and C, and enterotoxin-like X) and cytolysins (α-, β-, and γ-toxins) and challenged intrapulmonarily with multiple strains of S. aureus, both methicillin-sensitive and methicillin-resistant. RESULTS Active vaccination against a cocktail containing bacterial cell-surface antigens enhanced disease severity as tested by infective endocarditis. Active vaccination against secreted superantigens and cytolysins resulted in protection of 86 of 88 rabbits when challenged intrapulmonarily with 9 different S. aureus strains, compared to only 1 of 88 nonvaccinated animals. Passive immunization studies demonstrated that production of neutralizing antibodies was an important mechanism of protection. CONCLUSIONS The data suggest that vaccination against bacterial cell-surface antigens increases disease severity, but vaccination against secreted virulence factors provides protection against S. aureus. These results advance our understanding of S. aureus pathogenesis and have important implications in disease prevention.
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Affiliation(s)
- Adam R Spaulding
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
| | - Wilmara Salgado-Pabón
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
| | - Joseph A Merriman
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
| | - Christopher S Stach
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
| | - Yinduo Ji
- Department of Veterinary Biosciences, College of Veterinary Medicine
| | - Aaron N Gillman
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis
| | - Marnie L Peterson
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis
| | - Patrick M Schlievert
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
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19
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Walker JN, Crosby HA, Spaulding AR, Salgado-Pabón W, Malone CL, Rosenthal CB, Schlievert PM, Boyd JM, Horswill AR. The Staphylococcus aureus ArlRS two-component system is a novel regulator of agglutination and pathogenesis. PLoS Pathog 2013; 9:e1003819. [PMID: 24367264 PMCID: PMC3868527 DOI: 10.1371/journal.ppat.1003819] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 10/21/2013] [Indexed: 01/31/2023] Open
Abstract
Staphylococcus aureus is a prominent bacterial pathogen that is known to agglutinate in the presence of human plasma to form stable clumps. There is increasing evidence that agglutination aids S. aureus pathogenesis, but the mechanisms of this process remain to be fully elucidated. To better define this process, we developed both tube based and flow cytometry methods to monitor clumping in the presence of extracellular matrix proteins. We discovered that the ArlRS two-component system regulates the agglutination mechanism during exposure to human plasma or fibrinogen. Using divergent S. aureus strains, we demonstrated that arlRS mutants are unable to agglutinate, and this phenotype can be complemented. We found that the ebh gene, encoding the Giant Staphylococcal Surface Protein (GSSP), was up-regulated in an arlRS mutant. By introducing an ebh complete deletion into an arlRS mutant, agglutination was restored. To assess whether GSSP is the primary effector, a constitutive promoter was inserted upstream of the ebh gene on the chromosome in a wildtype strain, which prevented clump formation and demonstrated that GSSP has a negative impact on the agglutination mechanism. Due to the parallels of agglutination with infective endocarditis development, we assessed the phenotype of an arlRS mutant in a rabbit combined model of sepsis and endocarditis. In this model the arlRS mutant displayed a large defect in vegetation formation and pathogenesis, and this phenotype was partially restored by removing GSSP. Altogether, we have discovered that the ArlRS system controls a novel mechanism through which S. aureus regulates agglutination and pathogenesis. Staphylococcus aureus is a bacterial pathogen that is responsible for causing significant disease in humans. The development of antibiotic resistant strains has made these infections more difficult to treat, and an improved understanding of how this pathogen causes infections will facilitate the development of new tools for treatment. It has long been recognized that S. aureus can bind human matrix proteins to form stable clumps in a process called agglutination, but the importance of agglutination during infection is only just becoming understood. In this work, we developed several techniques to investigate the S. aureus agglutination mechanism. We discovered that the ArlRS two-component regulatory system controls agglutination by regulating the expression of the ebh gene, which encodes the Giant Staphylococcal Surface Protein (GSSP). When ArlRS is non-functional, S. aureus agglutination is prevented through the action of GSSP. These phenotypes were confirmed in a rabbit model of sepsis and infective endocarditis, demonstrating that ArlRS is an important regulator of virulence. Taken together, the identification of ArlRS as a regulator of S. aureus agglutination and pathogenesis may lead to innovative directions for therapeutic development.
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Affiliation(s)
- Jennifer N Walker
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Heidi A Crosby
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Adam R Spaulding
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Wilmara Salgado-Pabón
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Cheryl L Malone
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Carolyn B Rosenthal
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Patrick M Schlievert
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Jeffrey M Boyd
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Alexander R Horswill
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
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20
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Superantigens are critical for Staphylococcus aureus Infective endocarditis, sepsis, and acute kidney injury. mBio 2013; 4:mBio.00494-13. [PMID: 23963178 PMCID: PMC3747586 DOI: 10.1128/mbio.00494-13] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED Infective endocarditis and kidney infections are serious complications of Staphylococcus aureus sepsis. We investigated the role of superantigens (SAgs) in the development of lethal sepsis, infective endocarditis, and kidney infections. SAgs cause toxic shock syndrome, but it is unclear if SAgs contribute to infective endocarditis and kidney infections secondary to sepsis. We show in the methicillin-resistant S. aureus strain MW2 that lethal sepsis, infective endocarditis, and kidney infections in rabbits are critically dependent on high-level SAgs. In contrast, the isogenic strain lacking staphylococcal enterotoxin C (SEC), the major SAg in this strain, is attenuated in virulence, while complementation restores disease production. SAgs' role in infective endocarditis appears to be both superantigenicity and direct endothelial cell stimulation. Maintenance of elevated blood pressure by fluid therapy significantly protects from infective endocarditis, possibly through preventing bacterial accumulation on valves and increased SAg elimination. These data should facilitate better methods to manage these serious illnesses. IMPORTANCE The Centers for Disease Control and Prevention reported in 2007 that Staphylococcus aureus is the most significant cause of serious infectious diseases in the United States (R. M. Klevens, M. A. Morrison, J. Nadle, S. Petit, K. Gershman, et al., JAMA 298:1763-1771, 2007). Among these infections are sepsis, infective endocarditis, and acute kidney injury. Infective endocarditis occurs in 30 to 60% of patients with S. aureus bacteremia and carries a mortality rate of 40 to 50%. Over the past decades, infective endocarditis outcomes have not improved, and infection rates are steadily increasing (D. H. Bor, S. Woolhandler, R. Nardin, J. Brusch, D. U. Himmelstein, PLoS One 8:e60033, 2013). There is little understanding of the S. aureus virulence factors that are key for infective endocarditis development and kidney abscess formation. We demonstrate that superantigens are critical in the causation of all three infections. We show that their association results from both superantigenicity and direct toxic effects on endothelial cells, the latter likely contributing to delayed endothelium healing. Our studies contribute significantly to understanding the development of these illnesses and are expected to lead to development of important therapies to treat such illnesses.
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21
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Day SR, Moore CM, Kundzins JR, Sifri CD. Community-associated and healthcare-associated methicillin-resistant Staphylococcus aureus virulence toward Caenorhabditis elegans compared. Virulence 2012; 3:576-82. [PMID: 23076331 DOI: 10.4161/viru.22120] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged as major human pathogens. CA-MRSA virulence appears to be distinct from healthcare-associated (HA) MRSA with several factors [α-hemolysin (Hla), Panton-Valentine leukocidin (PVL), α-type phenol soluble modulins (PSMα) and SCCmec IV] postulated to enhance virulence or fitness. Using the Caenorhabditis elegans infection model, we compared the virulence of clinical and laboratory isolates of CA-MRSA and HA-MRSA and explored the contribution of CA-MRSA associated virulence factors to nematode killing. All CA-MRSA strains were highly pathogenic to nematodes, while HA-MRSA strains demonstrated variable nematode killing. Nematode killing by isogenic mutants of hla or the loci for PVL, PSMα, PSMβ, PSMδ or SCCmec IV was not different than the parental strains. These results demonstrate that CA-MRSA is highly virulent, shows some strains of HA-MRSA are equally virulent toward nematodes and suggests CA-MRSA virulence in C. elegans is not linked to a single virulence factor.
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Affiliation(s)
- Shandra R Day
- Division of Infectious Diseases and International Health, University of Virginia Health System, Charlottesville, VA, USA
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22
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Linezolid is superior to vancomycin in experimental pneumonia caused by Superantigen-Producing staphylococcus aureus in HLA class II transgenic mice. Antimicrob Agents Chemother 2012; 56:5401-5. [PMID: 22850509 DOI: 10.1128/aac.01080-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Superantigens (SAg), the potent activators of the immune system, are important determinants of Staphylococcus aureus virulence and pathogenicity. Superior response to SAg in human leukocyte antigen (HLA)-DR3 transgenic mice rendered them more susceptible than C57BL/6 mice to pneumonia caused by SAg-producing strains of S. aureus. Linezolid, a bacterial protein synthesis inhibitor, was superior to vancomycin in inhibiting SAg production by S. aureus in vitro and conferred greater protection from pneumonia caused by SAg-producing staphylococci.
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23
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Spaulding AR, Satterwhite EA, Lin YC, Chuang-Smith ON, Frank KL, Merriman JA, Schaefers MM, Yarwood JM, Peterson ML, Schlievert PM. Comparison of Staphylococcus aureus strains for ability to cause infective endocarditis and lethal sepsis in rabbits. Front Cell Infect Microbiol 2012; 2:18. [PMID: 22919610 PMCID: PMC3417574 DOI: 10.3389/fcimb.2012.00018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 02/07/2012] [Indexed: 11/21/2022] Open
Abstract
Staphylococcus aureus is a major cause of infective endocarditis (IE) and sepsis. Both methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) strains cause these illnesses. Common S. aureus strains include pulsed-field gel electrophoresis (PFGE) types USA200, 300, and 400 types where we hypothesize that secreted virulence factors contribute to both IE and sepsis. Rabbit cardiac physiology is considered similar to humans, and rabbits exhibit susceptibility to S. aureus superantigens (SAgs) and cytolysins. As such, rabbits are an excellent model for studying IE and sepsis, which over the course of four days develop IE vegetations and/or fatal septicemia. We examined the ability of MRSA and MSSA strains (4 USA200, 2 USA300, 2 USA400, and three additional common strains, FRI1169, Newman, and COL) to cause vegetations and lethal sepsis in rabbits. USA200, TSST-1+ strains that produce only low amounts of α-toxin, exhibited modest LD50 in sepsis (1 × 108 – 5 × 108) colony-forming units (CFUs), and 3/4 caused significant IE. USA200 strain MNPE, which produces high-levels of α-toxin, was both highly lethal (LD50 5 × 106 CFUs) and effective in causing IE. In contrast, USA300 strains were highly effective in causing lethal sepsis (LD50s 1 × 106 and 5 × 107 CFUs) but were minimally capable of causing IE. Strain Newman, which is phylogenetically related to USA300 strains, was not highly lethal (LD50 of 2 × 109 CFUs) and was effective in causing IE. USA400 strains were both highly lethal (LD50s of 1 × 107 and 5 × 107 CFUs) and highly effective causes of IE. The menstrual TSS isolate FRI1169, that is TSST-1+, produces high-levels of α-toxin, but is not USA200, was both highly lethal and effective in causing IE. Additional studies showed that phenol soluble modulins (PSMs) produced by FRI1169 were important for sepsis but did not contribute to IE. Our studies show that these clonal groups of S. aureus differ in abilities to cause IE and lethal sepsis and suggest that secreted virulence factors, including SAgs and cytolysins, account for some of these differences.
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Affiliation(s)
- Adam R Spaulding
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City IA, USA
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Xiao Z, Wu L, Mo H, Kong T. Increased T Cell Chemotaxis Response to Staphylococcus Enterotoxin B Mediated Human Endothelial Cell Damage In Vitro. Scand J Immunol 2012; 75:147-56. [DOI: 10.1111/j.1365-3083.2011.02638.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Tilahun AY, Karau MJ, Clark CR, Patel R, Rajagopalan G. The impact of tacrolimus on the immunopathogenesis of staphylococcal enterotoxin-induced systemic inflammatory response syndrome and pneumonia. Microbes Infect 2012; 14:528-36. [PMID: 22273732 DOI: 10.1016/j.micinf.2012.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 12/28/2011] [Accepted: 01/02/2012] [Indexed: 01/24/2023]
Abstract
Staphylococcal superantigens (SAg) are a family of potent exotoxins produced by Staphylococcus aureus. They play an important role in the pathogenesis of staphylococcal shock and pneumonia by causing a robust activation of the immune system and eliciting a strong surge in systemic cytokine and chemokine levels. Given the biological functions of SAg, we evaluated the efficacy of tacrolimus, a potent immunosuppressive agent, in the prophylaxis and therapy of staphylococcal TSS and pneumonia using human leukocyte antigen (HLA)-DR3 transgenic mice. Tacrolimus significantly inhibited staphylococcal SAg induced T cell activation in vitro. In vivo, tacrolimus significantly suppressed the SAg-induced elevation in serum cytokine and chemokine levels when given prophylactically, when administered immediately or even 2 h following systemic SAg challenge. Paradoxically, neither the prophylactic nor post-exposure treatment with tacrolimus protected mice from lethal SAg-induced TSS. A closer examination revealed that tacrolimus failed to suppress SAg-induced T cell proliferation and systemic pathology, including gut dysfunction. Tacrolimus also failed to protect from lethal pneumonia induced by a SAg-producing S. aureus strain. Thus, our study showed that even though T cell activation by SAg plays a major role in the immunopathogenesis of TSS and pneumonia, tacrolimus alone has no beneficial effect.
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Wilson GJ, Seo KS, Cartwright RA, Connelley T, Chuang-Smith ON, Merriman JA, Guinane CM, Park JY, Bohach GA, Schlievert PM, Morrison WI, Fitzgerald JR. A novel core genome-encoded superantigen contributes to lethality of community-associated MRSA necrotizing pneumonia. PLoS Pathog 2011; 7:e1002271. [PMID: 22022262 PMCID: PMC3192841 DOI: 10.1371/journal.ppat.1002271] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 08/01/2011] [Indexed: 01/08/2023] Open
Abstract
Bacterial superantigens (SAg) stimulate T-cell hyper-activation resulting in immune modulation and severe systemic illnesses such as Staphylococcus aureus toxic shock syndrome. However, all known S. aureus SAgs are encoded by mobile genetic elements and are made by only a proportion of strains. Here, we report the discovery of a novel SAg staphylococcal enterotoxin-like toxin X (SElX) encoded in the core genome of 95% of phylogenetically diverse S. aureus strains from human and animal infections, including the epidemic community-associated methicillin-resistant S. aureus (CA-MRSA) USA300 clone. SElX has a unique predicted structure characterized by a truncated SAg B-domain, but exhibits the characteristic biological activities of a SAg including Vβ-specific T-cell mitogenicity, pyrogenicity and endotoxin enhancement. In addition, SElX is expressed by clinical isolates in vitro, and during human, bovine, and ovine infections, consistent with a broad role in S. aureus infections of multiple host species. Phylogenetic analysis suggests that the selx gene was acquired horizontally by a progenitor of the S. aureus species, followed by allelic diversification by point mutation and assortative recombination resulting in at least 17 different alleles among the major pathogenic clones. Of note, SElX variants made by human- or ruminant-specific S. aureus clones demonstrated overlapping but distinct Vβ activation profiles for human and bovine lymphocytes, indicating functional diversification of SElX in different host species. Importantly, SElX made by CA-MRSA USA300 contributed to lethality in a rabbit model of necrotizing pneumonia revealing a novel virulence determinant of CA-MRSA disease pathogenesis. Taken together, we report the discovery and characterization of a unique core genome-encoded superantigen, providing new insights into the evolution of pathogenic S. aureus and the molecular basis for severe infections caused by the CA-MRSA USA300 epidemic clone. Staphylococcus aureus is a global pathogen, responsible for an array of different illnesses in humans and animals. In particular, community-associated methicillin-resistant S. aureus (CA-MRSA) strains of the pandemic USA300 clone have the capacity to cause lethal human necrotizing pneumonia, but the molecular basis for the enhanced virulence remains unclear. Bacterial superantigens (SAg) stimulate T-cell hyper-activation resulting in severe systemic illnesses such as toxic shock syndrome (TSS). However, all S. aureus SAgs identified to date are encoded by mobile genetic elements found only in a proportion of clinical isolates. Here, we report the discovery of a unique core genome-encoded SAg (SElX) which was acquired by an ancestor of the S. aureus species and which has undergone genetic and functional diversification in pathogenic clones infecting humans and animals. Importantly, we report that SElX made by pandemic USA300 contributes to lethality in a rabbit model of human necrotizing pneumonia revealing a novel virulence determinant of severe CA-MRSA infection.
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Affiliation(s)
- Gillian J. Wilson
- The Roslin Institute and Centre for Infectious Diseases, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - Keun Seok Seo
- Department of Basic Sciences, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Robyn A. Cartwright
- The Roslin Institute and Centre for Infectious Diseases, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - Timothy Connelley
- The Roslin Institute and Centre for Infectious Diseases, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - Olivia N. Chuang-Smith
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Joseph A. Merriman
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Caitriona M. Guinane
- The Roslin Institute and Centre for Infectious Diseases, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - Joo Youn Park
- Department of Basic Sciences, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Gregory A. Bohach
- Department of Basic Sciences, Mississippi State University, Mississippi State, Mississippi, United States of America
- Department of Biochemistry and Molecular Biology, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Patrick M. Schlievert
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - W. Ivan Morrison
- The Roslin Institute and Centre for Infectious Diseases, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - J. Ross Fitzgerald
- The Roslin Institute and Centre for Infectious Diseases, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
- * E-mail:
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Frequency of panton-valentine leukocidin-producing methicillin-sensitive Staphylococcus strains in patients with complicated skin and soft tissue infection in bronx, new york. J Clin Microbiol 2011; 49:2992-5. [PMID: 21653777 DOI: 10.1128/jcm.00704-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
lukF-PV was present in 36% of skin and soft tissue infection (SSTI)-derived methicillin-susceptible Staphylococcus aureus (MSSA) strains and comprised six distinct clones, which contained fewer enterotoxin genes than strains without lukF-PV. Clinical presentations and outcomes of lukF-PV(+) methicillin-resistant S. aureus (MRSA) and MSSA SSTIs were comparable. In multivariable analysis, the presence of lukF-PV remained a significant predictor for incision and drainage among MSSA strains.
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28
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A single, engineered protein therapeutic agent neutralizes exotoxins from both Staphylococcus aureus and Streptococcus pyogenes. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:1781-9. [PMID: 20861327 DOI: 10.1128/cvi.00277-10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Staphylococcus aureus and Streptococcus pyogenes secrete exotoxins that act as superantigens, proteins that cause hyperimmune reactions by binding the variable domain of the T-cell receptor beta chain (Vβ), leading to stimulation of a large fraction of the T-cell repertoire. To develop potential neutralizing agents, we engineered Vβ mutants with high affinity for the superantigens staphylococcal enterotoxin B (SEB), SEC3, and streptococcal pyrogenic exotoxin A (SpeA). Unexpectedly, the high-affinity Vβ mutants generated against SEB cross-reacted with SpeA to a greater extent than they did with SEC3, despite greater sequence similarity between SEB and SEC3. Likewise, the Vβ mutants generated against SpeA cross-reacted with SEB to a greater extent than with SEC3. The structural basis of the high affinity and cross-reactivity was examined by single-site mutational analyses. The cross-reactivity seems to involve only one or two toxin residues. Soluble forms of the cross-reactive Vβ regions neutralized both SEB and SpeA in vivo, suggesting structure-based strategies for generating high-affinity neutralizing agents that can cross-react with multiple exotoxins.
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29
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Schlievert PM, Strandberg KL, Lin YC, Peterson ML, Leung DYM. Secreted virulence factor comparison between methicillin-resistant and methicillin-sensitive Staphylococcus aureus, and its relevance to atopic dermatitis. J Allergy Clin Immunol 2010; 125:39-49. [PMID: 20109735 DOI: 10.1016/j.jaci.2009.10.039] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 10/23/2009] [Accepted: 10/26/2009] [Indexed: 12/21/2022]
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains have emerged as serious health threats in the last 15 years. They are associated with large numbers of atopic dermatitis skin and soft tissue infections, but when they originate from skin and mucous membranes, have the capacity to produce sepsis and highly fatal pulmonary infections characterized as necrotizing pneumonia, purpura fulminans, and postviral toxic shock syndrome. This review is a discussion of the emergence of 3 major CA-MRSA organisms, designated CA-MRSA USA400, followed by USA300, and most recently USA200. CA-MRSA USA300 and USA400 isolates and their methicillin-sensitive counterparts (community-associated methicillin-sensitive S aureus) typically produce highly inflammatory cytolysins alpha-toxin, gamma-toxin, delta-toxin (as representative of the phenol soluble modulin family of cytolysins), and Panton Valentine leukocidin. USA300 isolates produce the superantigens enterotoxin-like Q and a highly pyrogenic deletion variant of toxic shock syndrome toxin 1 (TSST-1), whereas USA400 isolates produce the superantigens staphylococcal enterotoxin B or staphylococcal enterotoxin C. USA200 CA-MRSA isolates produce small amounts of cytolysins but produce high levels of TSST-1. In contrast, their methicillin-sensitive S aureus counterparts produce various cytolysins, apparently in part dependent on the niche occupied in the host and levels of TSST-1 expressed. Significant differences seen in production of secreted virulence factors by CA-MRSA versus hospital-associated methicillin-resistant S aureus and community-associated methicillin-sensitive S aureus strains appear to be a result of the need to specialize as the result of energy drains from both virulence factor production and methicillin resistance.
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Affiliation(s)
- Patrick M Schlievert
- Department of Microbiology, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
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