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Gao S, Jin W, Quan Y, Li Y, Shen Y, Yuan S, Yi L, Wang Y, Wang Y. Bacterial capsules: Occurrence, mechanism, and function. NPJ Biofilms Microbiomes 2024; 10:21. [PMID: 38480745 PMCID: PMC10937973 DOI: 10.1038/s41522-024-00497-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 03/05/2024] [Indexed: 03/17/2024] Open
Abstract
In environments characterized by extended multi-stress conditions, pathogens develop a variety of immune escape mechanisms to enhance their ability to infect the host. The capsules, polymers that bacteria secrete near their cell wall, participates in numerous bacterial life processes and plays a crucial role in resisting host immune attacks and adapting to their niche. Here, we discuss the relationship between capsules and bacterial virulence, summarizing the molecular mechanisms of capsular regulation and pathogenesis to provide new insights into the research on the pathogenesis of pathogenic bacteria.
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Affiliation(s)
- Shuji Gao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Wenjie Jin
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Yingying Quan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Yue Li
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Yamin Shen
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Shuo Yuan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Li Yi
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
- College of Life Science, Luoyang Normal University, Luoyang, 471934, China
| | - Yuxin Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China.
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China.
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China.
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China.
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Lai CY, Xie JX, Lai MC, Wu ZY, Lin JS, Huang YT, Chi CY, Chiang-Ni C, Walker MJ, Chang YC. Conserved molecular chaperone PrsA stimulates protective immunity against group A Streptococcus. NPJ Vaccines 2024; 9:46. [PMID: 38409165 PMCID: PMC10897429 DOI: 10.1038/s41541-024-00839-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 02/09/2024] [Indexed: 02/28/2024] Open
Abstract
Group A Streptococcus (GAS) is a significant human pathogen that poses a global health concern. However, the development of a GAS vaccine has been challenging due to the multitude of diverse M-types and the risk of triggering cross-reactive immune responses. Our previous research has identified a critical role of PrsA1 and PrsA2, surface post-translational molecular chaperone proteins, in maintaining GAS proteome homeostasis and virulence traits. In this study, we aimed to further explore the potential of PrsA1 and PrsA2 as vaccine candidates for preventing GAS infection. We found that PrsA1 and PrsA2 are highly conserved among GAS isolates, demonstrating minimal amino acid variation. Antibodies specifically targeting PrsA1/A2 showed no cross-reactivity with human heart proteins and effectively enhanced neutrophil opsonophagocytic killing of various GAS serotypes. Additionally, passive transfer of PrsA1/A2-specific antibodies conferred protective immunity in infected mice. Compared to alum, immunization with CFA-adjuvanted PrsA1/A2 induced higher levels of Th1-associated IgG isotypes and complement activation and provided approximately 70% protection against invasive GAS challenge. These findings highlight the potential of PrsA1 and PrsA2 as universal vaccine candidates for the development of an effective GAS vaccine.
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Affiliation(s)
- Chien-Yu Lai
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Jia-Xun Xie
- Graduate Institute of Immunology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Meng-Chih Lai
- Graduate Institute of Immunology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Zhao-Yi Wu
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Jr-Shiuan Lin
- Graduate Institute of Immunology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Yu-Tsung Huang
- Department of Laboratory Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Chia-Yu Chi
- National Institute of Infectious Disease and Vaccinology, National Health Research Institutes, Miaoli, 300, Taiwan
| | - Chuan Chiang-Ni
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan
| | - Mark J Walker
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Yung-Chi Chang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan.
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3
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Wilde S, Dash A, Johnson A, Mackey K, Okumura CYM, LaRock CN. Detoxification of reactive oxygen species by the hyaluronic acid capsule of group A Streptococcus. Infect Immun 2023; 91:e0025823. [PMID: 37874162 PMCID: PMC10652860 DOI: 10.1128/iai.00258-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/17/2023] [Indexed: 10/25/2023] Open
Abstract
The pro-inflammatory cytokine IL-6 regulates antimicrobial responses that are broadly crucial in the defense against infection. Our prior work shows that IL-6 promotes the killing of the M4 serotype group A Streptococcus (GAS) but does not impact the globally disseminated M1T1 serotype associated with invasive infections. Using in vitro and in vivo infection models, we show that IL-6 induces phagocyte reactive oxygen species (ROS) that are responsible for the differential susceptibility of M4 and M1T1 GAS to IL-6-mediated defenses. Clinical isolates naturally deficient in capsule, or M1T1 strains deficient in capsule production, are sensitive to this ROS killing. The GAS capsule is made of hyaluronic acid, an antioxidant that detoxifies ROS and can protect acapsular M4 GAS when added exogenously. During in vitro interactions with macrophages and neutrophils, acapsular GAS can also be rescued with the antioxidant N-acetylcysteine, suggesting this is a major virulence contribution of the capsule. In an intradermal infection model with gp91phox -/- (chronic granulomatous disease [CGD]) mice, phagocyte ROS production had a modest effect on bacterial proliferation and the cytokine response but significantly limited the size of the bacterial lesion in the skin. These data suggest that the capsule broadly provides enhanced resistance to phagocyte ROS but is not essential for invasive infection. Since capsule-deficient strains are observed across several GAS serotypes and are competent for transmission and both mild and invasive infections, additional host or microbe factors may contribute to ROS detoxification during GAS infections.
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Affiliation(s)
- Shyra Wilde
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Ananya Dash
- Immunology and Molecular Pathogenesis Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Anders Johnson
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Kialani Mackey
- Department of Biology, Occidental College, Los Angeles, California, USA
| | | | - Christopher N. LaRock
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
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Alamiri F, André O, De S, Nordenfelt P, Hakansson AP. Role of serotype and virulence determinants of Streptococcus pyogenes biofilm bacteria in internalization and persistence in epithelial cells in vitro. Front Cell Infect Microbiol 2023; 13:1146431. [PMID: 37234777 PMCID: PMC10206268 DOI: 10.3389/fcimb.2023.1146431] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/21/2023] [Indexed: 05/28/2023] Open
Abstract
Streptococcus pyogenes causes a multitude of local and systemic infections, the most common being pharyngitis in children. Recurrent pharyngeal infections are common and are thought to be due to the re-emergence of intracellular GAS upon completion of antibiotic treatment. The role of colonizing biofilm bacteria in this process is not fully clear. Here, live respiratory epithelial cells were inoculated with broth-grown or biofilm bacteria of different M-types, as well as with isogenic mutants lacking common virulence factors. All M-types tested adhered to and were internalized into epithelial cells. Interestingly, internalization and persistence of planktonic bacteria varied significantly between strains, whereas biofilm bacteria were internalized in similar and higher numbers, and all strains persisted beyond 44 hours, showing a more homogenous phenotype. The M3 protein, but not the M1 or M5 proteins, was required for optimal uptake and persistence of both planktonic and biofilm bacteria inside cells. Moreover, the high expression of capsule and SLO inhibited cellular uptake and capsule expression was required for intracellular survival. Streptolysin S was required for optimal uptake and persistence of M3 planktonic bacteria, whereas SpeB improved intracellular survival of biofilm bacteria. Microscopy of internalized bacteria showed that planktonic bacteria were internalized in lower numbers as individual or small clumps of bacteria in the cytoplasm, whereas GAS biofilm bacteria displayed a pattern of perinuclear localization of bacterial aggregates that affected actin structure. Using inhibitors targeting cellular uptake pathways, we confirmed that planktonic GAS mainly uses a clathrin-mediated uptake pathway that also required actin and dynamin. Clathrin was not involved in biofilm internalization, but internalization required actin rearrangement and PI3 kinase activity, possibly suggesting macropinocytosis. Together these results provide a better understanding of the potential mechanisms of uptake and survival of various phenotypes of GAS bacteria relevant for colonization and recurrent infection.
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Affiliation(s)
- Feiruz Alamiri
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Oscar André
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Supradipta De
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Pontus Nordenfelt
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Anders P. Hakansson
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden
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5
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Hurst JR, Shannon BA, Craig HC, Rishi A, Tuffs SW, McCormick JK. The Streptococcus pyogenes hyaluronic acid capsule promotes experimental nasal and skin infection by preventing neutrophil-mediated clearance. PLoS Pathog 2022; 18:e1011013. [PMID: 36449535 PMCID: PMC9744330 DOI: 10.1371/journal.ppat.1011013] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 12/12/2022] [Accepted: 11/18/2022] [Indexed: 12/05/2022] Open
Abstract
Streptococcus pyogenes is a globally prominent human-specific pathogen responsible for an enormous burden of human illnesses, including >600 million pharyngeal and >100 million skin infections each year. Despite intensive efforts that focus on invasive indications, much remains unknown about this bacterium in its natural state during colonization of the nasopharynx and skin. Using acute experimental infection models in HLA-transgenic mice, we evaluated how the hyaluronic acid (HA) capsule contributes to S. pyogenes MGAS8232 infection within these limited biological niches. Herein, we demonstrate that HA capsule expression promotes bacterial burden in murine nasal turbinates and skin lesions by resisting neutrophil-mediated killing. HA capsule production is encoded by the hasABC operon and compared to wildtype S. pyogenes infections, mice infected with a ΔhasA mutant exhibited over a 1000-fold CFU reduction at 48-hours post-nasal challenge, and a 10,000-fold CFU reduction from skin lesions 72-hours post-skin challenge. HA capsule expression contributed substantially to skin lesion size development following subdermal inoculations. In the absence of capsule expression, S. pyogenes revealed drastically impeded growth in whole human blood and increased susceptibility to killing by isolated neutrophils ex vivo, highlighting its important role in resisting phagocytosis. Furthermore, we establish that neutrophil depletion in mice recovered the reduced burden by the ΔhasA mutant in both the nasopharynx and skin. Together, this work confirms that the HA capsule is a key virulence determinant during acute infections by S. pyogenes and demonstrates that its predominant function is to protect S. pyogenes against neutrophil-mediated killing.
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Affiliation(s)
- Jacklyn R. Hurst
- Department of Microbiology and Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Blake A. Shannon
- Department of Microbiology and Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Heather C. Craig
- Department of Microbiology and Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Aanchal Rishi
- Department of Microbiology and Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Stephen W. Tuffs
- Department of Microbiology and Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - John K. McCormick
- Department of Microbiology and Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
- Lawson Health Research Institute, London, Ontario, Canada
- * E-mail:
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A Role of Epithelial Cells and Virulence Factors in Biofilm Formation by Streptococcus pyogenes In Vitro. Infect Immun 2020; 88:IAI.00133-20. [PMID: 32661124 DOI: 10.1128/iai.00133-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 07/07/2020] [Indexed: 02/05/2023] Open
Abstract
Biofilm formation by Streptococcus pyogenes (group A streptococcus [GAS]) in model systems mimicking the respiratory tract is poorly documented. Most studies have been conducted on abiotic surfaces, which poorly represent human tissues. We have previously shown that GAS forms mature and antibiotic-resistant biofilms on physiologically relevant epithelial cells. However, the roles of the substratum, extracellular matrix (ECM) components, and GAS virulence factors in biofilm formation and structure are unclear. In this study, biofilm formation was measured on respiratory epithelial cells and keratinocytes by determining biomass and antibiotic resistance, and biofilm morphology was visualized using scanning electron microscopy. All GAS isolates tested formed biofilms that had similar, albeit not identical, biomass and antibiotic resistance for both cell types. Interestingly, functionally mature biofilms formed more rapidly on keratinocytes but were structurally denser and coated with more ECM on respiratory epithelial cells. The ECM was crucial for biofilm integrity, as protein- and DNA-degrading enzymes induced bacterial release from biofilms. Abiotic surfaces supported biofilm formation, but these biofilms were structurally less dense and organized. No major role for M protein, capsule, or streptolysin O was observed in biofilm formation on epithelial cells, although some morphological differences were detected. NAD-glycohydrolase was required for optimal biofilm formation, whereas streptolysin S and cysteine protease SpeB impaired this process. Finally, no correlation was found between cell adherence or autoaggregation and GAS biofilm formation. Combined, these results provide a better understanding of the role of biofilm formation in GAS pathogenesis and can potentially provide novel targets for future treatments against GAS infections.
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Davis KL, Gonzalez O, Kumar S, Dick EJ. Pathology Associated With Streptococcus spp. Infection in Baboons ( Papio spp.). Vet Pathol 2020; 57:714-722. [PMID: 32744146 PMCID: PMC7528403 DOI: 10.1177/0300985820941496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Streptococcus spp. are a source of morbidity and mortality in captive nonhuman primate populations. However, little is known about the lesions associated with naturally occurring streptococcal infections in baboons (Papio spp.). The pathology database of the Southwest National Primate Research Center was searched for all baboon autopsies from 1988 to 2018 in which Streptococcus spp. were cultured. Baboons on experimental protocol were excluded. The gross autopsy and histopathology reports were reviewed. Archived specimens were retrieved and reviewed as needed for confirmation or clarification. Fifty-six cultures were positive for Streptococcus spp. in 54 baboons with evidence of bacterial infection. Associated gross lesions included purulent exudate, fibrinous to fibrous adhesions, hemorrhage, mucosal thickening, organomegaly, and abscessation. Histologic lesions included suppurative inflammation, abscessation, necrosis, hemorrhage, fibrin accumulation, and thrombosis. Lungs and pleura (n = 31) were the most commonly infected organ followed by the central nervous system (n = 16), spleen (n = 15), soft tissues (n = 12), air sacs, liver, peritoneum, adrenal glands, heart, lymph nodes, uterus, kidneys, biliary system, bones, ears, umbilical structures, mammary glands, pancreas, placenta, and salivary glands. Infections by non-β-hemolytic Streptococcus spp. predominated in the lungs and air sacs; the most common isolate was Streptococcus pneumoniae. Infections by β-hemolytic Streptococcus spp. predominated in the soft tissues and reproductive tract. Naturally occurring β-hemolytic and non-β-hemolytic Streptococcus spp. infections cause morbidity and mortality in captive baboon populations. The lesions associated with streptococcal infection are similar to those reported in human infection. Thus, the baboon may represent an underutilized model for studying Streptococcus spp. as pathogens.
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Affiliation(s)
- Katelin L Davis
- 311308Purdue University, West Lafayette, IN, USA
- National Cancer Institute, Bethesda, MD, USA
| | - Olga Gonzalez
- Southwest National Primate Research Center, San Antonio, TX, USA
| | - Shyamesh Kumar
- Southwest National Primate Research Center, San Antonio, TX, USA
| | - Edward J Dick
- Southwest National Primate Research Center, San Antonio, TX, USA
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8
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Strain-Dependent Effect of Capsule on Transmission and Persistence in an Infant Mouse Model of Group A Streptococcus Infection. Infect Immun 2020; 88:IAI.00709-19. [PMID: 32014891 DOI: 10.1128/iai.00709-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 01/15/2020] [Indexed: 12/13/2022] Open
Abstract
Streptococcus pyogenes (group A Streptococcus [GAS]) is a human pathogen responsible for a wide range of diseases. Asymptomatic carriage of GAS in the human pharynx is commonplace and a potential reservoir for GAS transmission. Early studies showed that GAS transmission correlated with high bacterial burdens during the acute symptomatic phase of the disease. Human studies and the nonhuman primate model are generally impractical for investigation of the bacterial mechanisms contributing to GAS transmission and persistence. To address this gap, we adapted an infant mouse model of pneumococcal colonization and transmission to investigate factors that influence GAS transmission and persistence. The model recapitulated the direct correlation between GAS burden and transmission during the acute phase of infection observed in humans and nonhuman primates. Furthermore, our results indicate that the ratio of colonized to uncolonized hosts influences the rates of GAS transmission and persistence. We used the model to test the hypothesis that capsule production influences GAS transmission and persistence in a strain-dependent manner. We detected significant differences in rates of transmission and persistence between capsule-positive (emm3) and capsule-negative (emm87) GAS strains. Capsule was associated with higher levels of GAS shedding, independent of the strain background. In contrast to the capsule-positive emm3 strain, restoring capsule production in emm87 GAS did not increase transmissibility, and the absence of capsule enhanced persistence only in the capsule-negative (emm87) strain background. These data suggest that strain background (capsule positive versus capsule negative) influences the effect of capsule in GAS transmission and persistence and that as-yet-undefined factors are required for the transmission of capsule-negative emm types.
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Gogos A, Federle MJ. Modeling Streptococcus pyogenes Pharyngeal Colonization in the Mouse. Front Cell Infect Microbiol 2019; 9:137. [PMID: 31119108 PMCID: PMC6507483 DOI: 10.3389/fcimb.2019.00137] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/16/2019] [Indexed: 12/13/2022] Open
Abstract
Streptococcus pyogenes, or Group A Streptococcus (GAS), is a human-restricted pathogen most commonly found in the posterior oropharynx of the human host. The bacterium is responsible for 600 million annual cases of pharyngitis globally and has been found to asymptomatically colonize the pharynxes of 4-30% of the population. As such, many studies have utilized animals as models in order to decipher bacterial and host elements that contribute to the bacterial-pharyngeal interaction and determine differences between acute infection and asymptomatic colonization. The aim of this review is to first describe both bacterial and host factors that are important for the pharyngeal persistence of GAS in humans, then to detail the bacterial and host factors that are important for colonization in murine model, and finally to compare the two in order to evaluate the strength of murine pharyngeal colonization as a model for the human-GAS pharyngeal interaction.
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Affiliation(s)
- Artemis Gogos
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, United States
| | - Michael J. Federle
- Department of Medicinal Chemistry and Pharmacognosy, Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL, United States
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10
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Wessels MR. Capsular Polysaccharide of Group A Streptococcus. Microbiol Spectr 2019; 7:10.1128/microbiolspec.GPP3-0050-2018. [PMID: 30632480 PMCID: PMC6342470 DOI: 10.1128/microbiolspec.gpp3-0050-2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Indexed: 01/02/2023] Open
Abstract
Most clinical isolates of Streptococcus pyogenes elaborate a capsular polysaccharide, which is composed of hyaluronic acid, a high-molecular-mass polymer of alternating residues of N-acetyl glucosamine and glucuronic acid. Certain strains, particularly those of the M18 serotype, produce abundant amounts of capsule, resulting in formation of large, wet-appearing, translucent or "mucoid" colonies on solid media, whereas strains of M-types 4 and 22 produce none. Studies of acapsular mutant strains have provided evidence that the capsule enhances virulence in animal models of infection, an effect attributable, at least in part, to resistance to complement-mediated opsonophagocytic killing by leukocytes. The presence of the hyaluronic acid capsule may mask adhesins on the bacterial cell wall. However, the capsule itself can mediate bacterial attachment to host cells by binding to the hyaluronic-acid binding protein, CD44. Furthermore, binding of the S. pyogenes capsule to CD44 on host epithelial cells can trigger signaling events that disrupt cell-cell junctions and facilitate bacterial invasion into deep tissues. This article summarizes the biochemistry, genetics, regulation, and role in pathogenesis of this important virulence determinant.
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Affiliation(s)
- Michael R Wessels
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA
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11
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Lapek JD, Mills RH, Wozniak JM, Campeau A, Fang RH, Wei X, van de Groep K, Perez-Lopez A, van Sorge NM, Raffatellu M, Knight R, Zhang L, Gonzalez DJ. Defining Host Responses during Systemic Bacterial Infection through Construction of a Murine Organ Proteome Atlas. Cell Syst 2018; 6:579-592.e4. [PMID: 29778837 PMCID: PMC7868092 DOI: 10.1016/j.cels.2018.04.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/30/2018] [Accepted: 04/12/2018] [Indexed: 12/18/2022]
Abstract
Group A Streptococcus (GAS) remains one of the top 10 deadliest human pathogens worldwide despite its sensitivity to penicillin. Although the most common GAS infection is pharyngitis (strep throat), it also causes life-threatening systemic infections. A series of complex networks between host and pathogen drive invasive infections, which have not been comprehensively mapped. Attempting to map these interactions, we examined organ-level protein dynamics using a mouse model of systemic GAS infection. We quantified over 11,000 proteins, defining organ-specific markers for all analyzed tissues. From this analysis, an atlas of dynamically regulated proteins and pathways was constructed. Through statistical methods, we narrowed organ-specific markers of infection to 34 from the defined atlas. We show these markers are trackable in blood of infected mice, and a subset has been observed in plasma samples from GAS-infected clinical patients. This proteomics-based strategy provides insight into host defense responses, establishes potentially useful targets for therapeutic intervention, and presents biomarkers for determining affected organs during bacterial infection.
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Affiliation(s)
- John D Lapek
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Robert H Mills
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Computer Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Center for Microbiome Innovation, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jacob M Wozniak
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Anaamika Campeau
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Ronnie H Fang
- Department of Nanoengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Xiaoli Wei
- Department of Nanoengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Kirsten van de Groep
- Department of Epidemiology, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Heidelberglaan 100, G04.614, 3584 CX Utrecht, the Netherlands; Department of Intensive Care Medicine, University Medical Center Utrecht, Heidelberglaan 100, G04.614, 3584 CX Utrecht, the Netherlands
| | - Araceli Perez-Lopez
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Nina M van Sorge
- Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, G04.614, 3584 CX Utrecht, the Netherlands
| | - Manuela Raffatellu
- Chiba University-UC San Diego Center for Mucosal Immunology, Allergy, and Vaccines, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Center for Microbiome Innovation, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Rob Knight
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Computer Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Center for Microbiome Innovation, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Liangfang Zhang
- Department of Nanoengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - David J Gonzalez
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Center for Microbiome Innovation, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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12
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Streptococcal pharyngitis and rheumatic heart disease: the superantigen hypothesis revisited. INFECTION GENETICS AND EVOLUTION 2018. [PMID: 29530660 DOI: 10.1016/j.meegid.2018.03.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Streptococcus pyogenes is a human-specific and globally prominent bacterial pathogen that despite causing numerous human infections, this bacterium is normally found in an asymptomatic carrier state. This review provides an overview of both bacterial and human factors that likely play an important role in nasopharyngeal colonization and pharyngitis, as well as the development of acute rheumatic fever and rheumatic heart disease. Here we highlight a recently described role for bacterial superantigens in promoting acute nasopharyngeal infection, and discuss how these immune system activating toxins could be crucial to initiate the autoimmune process in rheumatic heart disease.
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13
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Raynes JM, Young PG, Proft T, Williamson DA, Baker EN, Moreland NJ. Protein adhesins as vaccine antigens for Group A Streptococcus. Pathog Dis 2018; 76:4919728. [DOI: 10.1093/femspd/fty016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 03/01/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- J M Raynes
- School of Medical Sciences, The University of Auckland, 85 Park Road, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
| | - P G Young
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
- School of Biological Sciences, University of Auckland, 5 Symonds Street, Auckland 1010, New Zealand
| | - T Proft
- School of Medical Sciences, The University of Auckland, 85 Park Road, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
| | - D A Williamson
- Microbiological Diagnostic Unit Public Health Laboratory, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria 3000, Australia
| | - E N Baker
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
- School of Biological Sciences, University of Auckland, 5 Symonds Street, Auckland 1010, New Zealand
| | - N J Moreland
- School of Medical Sciences, The University of Auckland, 85 Park Road, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
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14
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Differing Efficacies of Lead Group A Streptococcal Vaccine Candidates and Full-Length M Protein in Cutaneous and Invasive Disease Models. mBio 2016; 7:mBio.00618-16. [PMID: 27302756 PMCID: PMC4916377 DOI: 10.1128/mbio.00618-16] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Group A Streptococcus (GAS) is an important human pathogen responsible for both superficial infections and invasive diseases. Autoimmune sequelae may occur upon repeated infection. For this reason, development of a vaccine against GAS represents a major challenge, since certain GAS components may trigger autoimmunity. We formulated three combination vaccines containing the following: (i) streptolysin O (SLO), interleukin 8 (IL-8) protease (Streptococcus pyogenes cell envelope proteinase [SpyCEP]), group A streptococcal C5a peptidase (SCPA), arginine deiminase (ADI), and trigger factor (TF); (ii) the conserved M-protein-derived J8 peptide conjugated to ADI; and (iii) group A carbohydrate lacking the N-acetylglucosamine side chain conjugated to ADI. We compared these combination vaccines to a “gold standard” for immunogenicity, full-length M1 protein. Vaccines were adjuvanted with alum, and mice were immunized on days 0, 21, and 28. On day 42, mice were challenged via cutaneous or subcutaneous routes. High-titer antigen-specific antibody responses with bactericidal activity were detected in mouse serum samples for all vaccine candidates. In comparison with sham-immunized mice, all vaccines afforded protection against cutaneous challenge. However, only full-length M1 protein provided protection in the subcutaneous invasive disease model. This set of experiments demonstrates the inherent variability of mouse models for the characterization of GAS vaccine candidate protective efficacy. Such variability poses an important challenge for GAS vaccine development, as advancement of candidates to human clinical trials requires strong evidence of efficacy. This study highlights the need for an open discussion within the field regarding standardization of animal models for GAS vaccine development.
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15
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Emergence of a New Highly Successful Acapsular Group A Streptococcus Clade of Genotype emm89 in the United Kingdom. mBio 2015; 6:e00622. [PMID: 26173696 PMCID: PMC4502227 DOI: 10.1128/mbio.00622-15] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Group A Streptococcus (GAS) genotype emm89 is increasingly recognized as a leading cause of disease worldwide, yet factors that underlie the success of this emm type are unknown. Surveillance identified a sustained nationwide increase in emm89 invasive GAS disease in the United Kingdom, prompting longitudinal investigation of this genotype. Whole-genome sequencing revealed a recent dramatic shift in the emm89 population with the emergence of a new clade that increased to dominance over previous emm89 variants. Temporal analysis indicated that the clade arose in the early 1990s but abruptly increased in prevalence in 2008, coinciding with an increased incidence of emm89 infections. Although standard variable typing regions (emm subtype, tee type, sof type, and multilocus sequence typing [MLST]) remained unchanged, uniquely the emergent clade had undergone six distinct regions of homologous recombination across the genome compared to the rest of the sequenced emm89 population. Two of these regions affected known virulence factors, the hyaluronic acid capsule and the toxins NADase and streptolysin O. Unexpectedly, and in contrast to the rest of the sequenced emm89 population, the emergent clade-associated strains were genetically acapsular, rendering them unable to produce the hyaluronic acid capsule. The emergent clade-associated strains had also acquired an NADase/streptolysin O locus nearly identical to that found in emm12 and modern emm1 strains but different from the rest of the sequenced emm89 population. The emergent clade-associated strains had enhanced expression of NADase and streptolysin O. The genome remodeling in the new clade variant and the resultant altered phenotype appear to have conferred a selective advantage over other emm89 variants and may explain the changes observed in emm89 GAS epidemiology. Sudden upsurges or epidemic waves are common features of group A streptococcal disease. Although the mechanisms behind such changes are largely unknown, they are often associated with an expansion of a single genotype within the population. Using whole-genome sequencing, we investigated a nationwide increase in invasive disease caused by the genotype emm89 in the United Kingdom. We identified a new clade variant that had recently emerged in the emm89 population after having undergone several core genomic recombination-related changes, two of which affected known virulence factors. An unusual finding of the new variant was the loss of the hyaluronic acid capsule, previously thought to be essential for causing invasive disease. A further genomic adaptation in the NADase/streptolysin O locus resulted in enhanced production of these toxins. Recombination-related genome remodeling is clearly an important mechanism in group A Streptococcus that can give rise to more successful and potentially more pathogenic variants.
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16
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Brézillon C, Haustant M, Dupke S, Corre JP, Lander A, Franz T, Monot M, Couture-Tosi E, Jouvion G, Leendertz FH, Grunow R, Mock ME, Klee SR, Goossens PL. Capsules, toxins and AtxA as virulence factors of emerging Bacillus cereus biovar anthracis. PLoS Negl Trop Dis 2015; 9:e0003455. [PMID: 25830379 PMCID: PMC4382292 DOI: 10.1371/journal.pntd.0003455] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 12/04/2014] [Indexed: 11/18/2022] Open
Abstract
Emerging B. cereus strains that cause anthrax-like disease have been isolated in Cameroon (CA strain) and Côte d’Ivoire (CI strain). These strains are unusual, because their genomic characterisation shows that they belong to the B. cereus species, although they harbour two plasmids, pBCXO1 and pBCXO2, that are highly similar to the pXO1 and pXO2 plasmids of B. anthracis that encode the toxins and the polyglutamate capsule respectively. The virulence factors implicated in the pathogenicity of these B. cereus bv anthracis strains remain to be characterised. We tested their virulence by cutaneous and intranasal delivery in mice and guinea pigs; they were as virulent as wild-type B. anthracis. Unlike as described for pXO2-cured B. anthracis, the CA strain cured of the pBCXO2 plasmid was still highly virulent, showing the existence of other virulence factors. Indeed, these strains concomitantly expressed a hyaluronic acid (HA) capsule and the B. anthracis polyglutamate (PDGA) capsule. The HA capsule was encoded by the hasACB operon on pBCXO1, and its expression was regulated by the global transcription regulator AtxA, which controls anthrax toxins and PDGA capsule in B. anthracis. Thus, the HA and PDGA capsules and toxins were co-regulated by AtxA. We explored the respective effect of the virulence factors on colonisation and dissemination of CA within its host by constructing bioluminescent mutants. Expression of the HA capsule by itself led to local multiplication and, during intranasal infection, to local dissemination to the adjacent brain tissue. Co-expression of either toxins or PDGA capsule with HA capsule enabled systemic dissemination, thus providing a clear evolutionary advantage. Protection against infection by B. cereus bv anthracis required the same vaccination formulation as that used against B. anthracis. Thus, these strains, at the frontier between B. anthracis and B. cereus, provide insight into how the monomorphic B. anthracis may have emerged. Anthrax is caused by the bacterium Bacillus anthracis that affects all mammals worldwide. It emerged more than 10,000 years ago from a Bacillus cereus precursor. In the past decade, B. cereus bacteria were isolated in the USA from anthrax-like pneumonia cases. They harbour one virulence plasmid very similar to the toxin–encoding plasmid of B. anthracis. Recently, an anthrax-like disease in great apes in Africa was caused by emerging B. cereus strains, named B. cereus biovar anthracis. These strains are atypical as they possess both plasmids coding for toxin and capsule similar to those so far found only in B. anthracis. These unusual pathogenic B. cereus are currently neglected. We explored the virulence of these pathogens and their colonisation and dissemination capacity within the murine host. We found that these toxinogenic strains harbour two capsules, the classical B. anthracis capsule and an additional polysaccharidic capsule. This latter capsule confers virulence alone or in combination with toxins. Both capsules are concomitantly expressed, under the control of a common global regulator and host signals. Our results show that acquisition of new genetic information by these B. cereus clearly gives them a selective advantage, favouring their dissemination within infected hosts and the environment.
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Affiliation(s)
| | - Michel Haustant
- Institut Pasteur, Pathogénie des Toxi-Infections Bactériennes, Paris, France
| | - Susann Dupke
- Robert Koch-Institut, Centre for Biological Threats and Special Pathogens (ZBS 2), Berlin, Germany
| | - Jean-Philippe Corre
- Institut Pasteur, Pathogénie des Toxi-Infections Bactériennes, Paris, France
| | - Angelika Lander
- Robert Koch-Institut, Centre for Biological Threats and Special Pathogens (ZBS 2), Berlin, Germany
| | - Tatjana Franz
- Robert Koch-Institut, Centre for Biological Threats and Special Pathogens (ZBS 2), Berlin, Germany
| | - Marc Monot
- Institut Pasteur, Pathogenèse des bactéries anaérobies, Paris, France
| | | | - Gregory Jouvion
- Institut Pasteur, Unité Histopathologie Humaine et Modèles Animaux, Paris, France
| | - Fabian H. Leendertz
- Robert Koch-Institut, Epidemiology of Highly Pathogenic Microorganisms (P 3), Berlin, Germany
| | - Roland Grunow
- Robert Koch-Institut, Centre for Biological Threats and Special Pathogens (ZBS 2), Berlin, Germany
| | - Michèle E. Mock
- Institut Pasteur, Pathogénie des Toxi-Infections Bactériennes, Paris, France
| | - Silke R. Klee
- Robert Koch-Institut, Centre for Biological Threats and Special Pathogens (ZBS 2), Berlin, Germany
- * E-mail: (SRK); (PLG)
| | - Pierre L. Goossens
- Institut Pasteur, Pathogénie des Toxi-Infections Bactériennes, Paris, France
- * E-mail: (SRK); (PLG)
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17
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Henningham A, Yamaguchi M, Aziz RK, Kuipers K, Buffalo CZ, Dahesh S, Choudhury B, Van Vleet J, Yamaguchi Y, Seymour LM, Ben Zakour NL, He L, Smith HV, Grimwood K, Beatson SA, Ghosh P, Walker MJ, Nizet V, Cole JN. Mutual exclusivity of hyaluronan and hyaluronidase in invasive group A Streptococcus. J Biol Chem 2014; 289:32303-32315. [PMID: 25266727 PMCID: PMC4231703 DOI: 10.1074/jbc.m114.602847] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A recent analysis of group A Streptococcus (GAS) invasive infections in Australia has shown a predominance of M4 GAS, a serotype recently reported to lack the antiphagocytic hyaluronic acid (HA) capsule. Here, we use molecular genetics and bioinformatics techniques to characterize 17 clinical M4 isolates associated with invasive disease in children during this recent epidemiology. All M4 isolates lacked HA capsule, and whole genome sequence analysis of two isolates revealed the complete absence of the hasABC capsule biosynthesis operon. Conversely, M4 isolates possess a functional HA-degrading hyaluronate lyase (HylA) enzyme that is rendered nonfunctional in other GAS through a point mutation. Transformation with a plasmid expressing hasABC restored partial encapsulation in wild-type (WT) M4 GAS, and full encapsulation in an isogenic M4 mutant lacking HylA. However, partial encapsulation reduced binding to human complement regulatory protein C4BP, did not enhance survival in whole human blood, and did not increase virulence of WT M4 GAS in a mouse model of systemic infection. Bioinformatics analysis found no hasABC homologs in closely related species, suggesting that this operon was a recent acquisition. These data showcase a mutually exclusive interaction of HA capsule and active HylA among strains of this leading human pathogen.
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Affiliation(s)
- Anna Henningham
- Department of Pediatrics, University of California San Diego, La Jolla, California 92093; School of Chemistry and Molecular Biosciences and The University of Queensland, St. Lucia, Queensland 4072, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Masaya Yamaguchi
- Department of Pediatrics, University of California San Diego, La Jolla, California 92093; Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Ramy K Aziz
- Systems Biology Research Group, University of California San Diego, La Jolla, California 92093; Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo 11562, Egypt
| | - Kirsten Kuipers
- Department of Pediatrics, University of California San Diego, La Jolla, California 92093; Department of Pediatrics, Laboratory of Pediatric Infectious Diseases, Radboud University Medical Centre, 6500 HC Nijmegen, The Netherlands
| | - Cosmo Z Buffalo
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093
| | - Samira Dahesh
- Department of Pediatrics, University of California San Diego, La Jolla, California 92093
| | - Biswa Choudhury
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, California 92093
| | - Jeremy Van Vleet
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, California 92093
| | - Yuka Yamaguchi
- Department of Pediatrics, University of California San Diego, La Jolla, California 92093
| | - Lisa M Seymour
- School of Chemistry and Molecular Biosciences and The University of Queensland, St. Lucia, Queensland 4072, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Nouri L Ben Zakour
- School of Chemistry and Molecular Biosciences and The University of Queensland, St. Lucia, Queensland 4072, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Lingjun He
- Department of Mathematics and Statistics, San Diego State University, San Diego, California 92182
| | - Helen V Smith
- Queensland Health Forensic and Scientific Services, Coopers Plains, Queensland 4108, Australia
| | - Keith Grimwood
- Queensland Children's Medical Research Institute, Herston, Queensland 4029, Australia, and
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences and The University of Queensland, St. Lucia, Queensland 4072, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Partho Ghosh
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093
| | - Mark J Walker
- School of Chemistry and Molecular Biosciences and The University of Queensland, St. Lucia, Queensland 4072, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Victor Nizet
- Department of Pediatrics, University of California San Diego, La Jolla, California 92093; Skaggs School of Pharmacy and Pharmaceutical Sciences, and University of California San Diego, La Jolla, California 92093; Rady Children's Hospital, San Diego, California 92123
| | - Jason N Cole
- Department of Pediatrics, University of California San Diego, La Jolla, California 92093; School of Chemistry and Molecular Biosciences and The University of Queensland, St. Lucia, Queensland 4072, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia,.
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18
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Fan X, Wang X, Li N, Cui H, Hou B, Gao B, Cleary PP, Wang B. Sortase A induces Th17-mediated and antibody-independent immunity to heterologous serotypes of group A streptococci. PLoS One 2014; 9:e107638. [PMID: 25232948 PMCID: PMC4169422 DOI: 10.1371/journal.pone.0107638] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 08/17/2014] [Indexed: 01/01/2023] Open
Abstract
Group A streptococci (GAS) are associated with a variety of mucosal and invasive human infections. Recurrent infections by highly heterologous serotypes indicate that cross-serotype immunity is critical for prevention of GAS infections; however, mechanisms underlying serotype-independent protection are poorly understood. Here we report that intranasal vaccination of mice with Sortase A (SrtA), a conserved cell wall bound protein, reduced colonization of nasal-associated lymphoid tissue (NALT) by heterologous serotypes of GAS. Vaccination significantly increased CD4+ IL-17A+ cells in NALT and depletion of IL-17A by neutralizing antibody prevented GAS clearance from NALT which was dependent on immunization with SrtA. Vaccination also induced high levels of SrtA-specific antibodies; however, immunized, B cell-deficient mice cleared streptococcal challenges as efficiently as wild type mice, indicating that the cross-serotype protection is Th17-biased and antibody-independent. Furthermore, efficient GAS clearance from NALT was associated with a rapid neutrophil influx into NALT of immunized mice. These results suggest that serotype independent immune protection against GAS mucosal infection can be achieved by intranasal vaccination with SrtA and enhanced neutrophil function is critical for anti-GAS defense and might be a target for prevention of GAS infections.
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Affiliation(s)
- Xin Fan
- Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Beijing, China
| | - Xiaoshuang Wang
- Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Beijing, China
| | - Ning Li
- Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Beijing, China
| | - Honglian Cui
- Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Beijing, China
| | - Baidong Hou
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Bin Gao
- Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Beijing, China
| | - Paul Patrick Cleary
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Beinan Wang
- Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Beijing, China
- * E-mail:
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19
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Asymptomatic carriage of group A streptococcus is associated with elimination of capsule production. Infect Immun 2014; 82:3958-67. [PMID: 25024363 DOI: 10.1128/iai.01788-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Humans commonly carry pathogenic bacteria asymptomatically, but despite decades of study, the underlying molecular contributors remain poorly understood. Here, we show that a group A streptococcus carriage strain contains a frameshift mutation in the hasA gene resulting in loss of hyaluronic acid capsule biosynthesis. This mutation was repaired by allelic replacement, resulting in restoration of capsule production in the isogenic derivative strain. The "repaired" isogenic strain was significantly more virulent than the carriage strain in a mouse model of necrotizing fasciitis and had enhanced growth ex vivo in human blood. Importantly, the repaired isogenic strain colonized the mouse oropharynx with significantly greater bacterial burden and had significantly reduced ability to internalize into cultured epithelial cells than the acapsular carriage strain. We conducted full-genome sequencing of 81 strains cultured serially from 19 epidemiologically unrelated human subjects and discovered the common theme that mutations negatively affecting capsule biosynthesis arise in vivo in the has operon. The significantly decreased capsule production is a key factor contributing to the molecular détente between pathogen and host. Our discoveries suggest a general model for bacterial pathogens in which mutations that downregulate or ablate virulence factor production contribute to carriage.
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20
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Cress BF, Englaender JA, He W, Kasper D, Linhardt RJ, Koffas MAG. Masquerading microbial pathogens: capsular polysaccharides mimic host-tissue molecules. FEMS Microbiol Rev 2014; 38:660-97. [PMID: 24372337 PMCID: PMC4120193 DOI: 10.1111/1574-6976.12056] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/16/2013] [Accepted: 12/19/2013] [Indexed: 11/27/2022] Open
Abstract
The increasing prevalence of antibiotic-resistant bacteria portends an impending postantibiotic age, characterized by diminishing efficacy of common antibiotics and routine application of multifaceted, complementary therapeutic approaches to treat bacterial infections, particularly multidrug-resistant organisms. The first line of defense for most bacterial pathogens consists of a physical and immunologic barrier known as the capsule, commonly composed of a viscous layer of carbohydrates that are covalently bound to the cell wall in Gram-positive bacteria or often to lipids of the outer membrane in many Gram-negative bacteria. Bacterial capsular polysaccharides are a diverse class of high molecular weight polysaccharides contributing to virulence of many human pathogens in the gut, respiratory tree, urinary tract, and other host tissues, by hiding cell surface components that might otherwise elicit host immune response. This review highlights capsular polysaccharides that are structurally identical or similar to polysaccharides found in mammalian tissues, including polysialic acid and glycosaminoglycan capsules hyaluronan, heparosan, and chondroitin. Such nonimmunogenic coatings render pathogens insensitive to certain immune responses, effectively increasing residence time in host tissues and enabling pathologically relevant population densities to be reached. Biosynthetic pathways and capsular involvement in immune system evasion are described, providing a basis for potential therapies aimed at supplementing or replacing antibiotic treatment.
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Affiliation(s)
- Brady F Cress
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
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21
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Moreland NJ, Waddington CS, Williamson DA, Sriskandan S, Smeesters PR, Proft T, Steer AC, Walker MJ, Baker EN, Baker MG, Lennon D, Dunbar R, Carapetis J, Fraser JD. Working towards a Group A Streptococcal vaccine: Report of a collaborative Trans-Tasman workshop. Vaccine 2014; 32:3713-20. [DOI: 10.1016/j.vaccine.2014.05.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 05/01/2014] [Indexed: 11/25/2022]
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22
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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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23
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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: 556] [Impact Index Per Article: 55.6] [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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Neutrophils select hypervirulent CovRS mutants of M1T1 group A Streptococcus during subcutaneous infection of mice. Infect Immun 2014; 82:1579-90. [PMID: 24452689 DOI: 10.1128/iai.01458-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pathogen mutants arise during infections. Mechanisms of selection for pathogen variants are poorly understood. We tested whether neutrophils select mutations in the two-component regulatory system CovRS of group A Streptococcus (GAS) during infection using the lack of production of the protease SpeB (SpeB activity negative [SpeB(A-)]) as a marker. Depletion of neutrophils by antibodies RB6-8C5 and 1A8 reduced the percentage of SpeB(A-) variants (SpeB(A-)%) recovered from mice infected with GAS strain MGAS2221 by >76%. Neutrophil recruitment and SpeB(A-)% among recovered GAS were reduced by 95% and 92%, respectively, in subcutaneous MGAS2221 infection of CXCR2(-/-) mice compared with control mice. In air sac infection with MGAS2221, levels of neutrophils and macrophages in lavage fluid were reduced by 49% and increased by 287%, respectively, in CXCR2(-/-) mice compared with control mice, implying that macrophages play an insignificant role in the reduction of selection for SpeB(A-) variants in CXCR2(-/-) mice. One randomly chosen SpeB(A-) mutant outcompeted MGAS2221 in normal mice but was outcompeted by MGAS2221 in neutropenic mice and had enhancements in expression of virulence factors, innate immune evasion, skin invasion, and virulence. This and nine other SpeB(A-) variants from a mouse all had nonsynonymous covRS mutations that resulted in the SpeB(A-) phenotype and enhanced expression of the CovRS-controlled secreted streptococcal esterase (SsE). Our findings are consistent with a model that neutrophils select spontaneous covRS mutations that maximize the potential of GAS to evade neutrophil responses, resulting in variants with enhanced survival and virulence. To our knowledge, this is the first report of the critical contribution of neutrophils to the selection of pathogen variants.
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Lactobacillus plantarum reduces Streptococcus pyogenes virulence by modulating the IL-17, IL-23 and Toll-like receptor 2/4 expressions in human epithelial cells. Int Immunopharmacol 2013; 17:453-61. [DOI: 10.1016/j.intimp.2013.07.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/28/2013] [Accepted: 07/10/2013] [Indexed: 01/01/2023]
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Hyaluronic acid derived from other streptococci supports Streptococcus pneumoniae in vitro biofilm formation. BIOMED RESEARCH INTERNATIONAL 2013; 2013:690217. [PMID: 24171169 PMCID: PMC3792519 DOI: 10.1155/2013/690217] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/08/2013] [Accepted: 08/21/2013] [Indexed: 11/17/2022]
Abstract
We investigate the role of hyaluronic acid (HA) on S. pneumoniae in vitro biofilm formation and evaluate gene expressions of virulence and/or biofilm related genes. Biofilms were grown in medium supplied with HA derived from capsule of Streptococcus equi. The biomasses of biofilms were detected by crystal-violet (CV) microtiter plate assay, and the morphology was viewed under scanning electron microscope (SEM). The gene expressions were assessed by relative quantitative RT-PCR. The results showed that the HA support pneumococcal growth in planktonic form and within biofilms. The CV-microtiter plate assay detected significantly increased biofilm growth in medium containing HA. The SEM analysis revealed thick and organized biofilms in positive control and HA supplemented medium. The nanA, nanB, bgaA, strH, luxS, hysA, ugl, and PST-EIIA encoding genes were significantly upregulated in the planktonic cells grown in presence of HA, while the lytA and comA genes were downregulated. Similarly the luxS, hysA, ugl, and PST-EIIA encoding genes were significantly upregulated by more than 2-folds in HA biofilms. The results of this study indicate that the HA derived from capsule of S. equi supports pneumococcal growth in planktonic state and within biofilms and upregulated virulence and biofilm related genes.
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Natural variation in the promoter of the gene encoding the Mga regulator alters host-pathogen interactions in group a Streptococcus carrier strains. Infect Immun 2013; 81:4128-38. [PMID: 23980109 DOI: 10.1128/iai.00405-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Humans commonly carry pathogenic bacteria asymptomatically, but the molecular factors underlying microbial asymptomatic carriage are poorly understood. We previously reported that two epidemiologically unassociated serotype M3 group A Streptococcus (GAS) carrier strains had an identical 12-bp deletion in the promoter of the gene encoding Mga, a global positive gene regulator. Herein, we report on studies designed to test the hypothesis that the identified 12-bp deletion in the mga promoter alters GAS virulence, thereby potentially contributing to the asymptomatic carrier phenotype. Using allelic exchange, we introduced the variant promoter into a serotype M3 invasive strain and the wild-type promoter into an asymptomatic carrier strain. Compared to strains with the wild-type mga promoter, we discovered that strains containing the promoter with the 12-bp deletion produced significantly fewer mga and Mga-regulated gene transcripts. Consistent with decreased mga transcripts, strains containing the variant mga promoter were also significantly less virulent in in vivo and ex vivo models of GAS disease. Further, we provide evidence that the pleiotropic regulator protein CodY binds to the mga promoter and that the 12-bp deletion in the mga promoter reduces CodY-mediated mga transcription. We conclude that the naturally occurring 12-bp deletion in the mga promoter significantly alters the pathogen-host interaction of these asymptomatic carrier strains. Our findings provide new insight into the molecular basis of the carrier state of an important human pathogen.
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Characterization of streptococcal platelet-activating factor acetylhydrolase variants that are involved in innate immune evasion. Infect Immun 2013; 81:3128-38. [PMID: 23774595 DOI: 10.1128/iai.00398-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human pathogen group A streptococcus (GAS) has developed mechanisms to subvert innate immunity. We recently reported that the secreted esterase produced by serotype M1 GAS (SsE(M1)) reduces neutrophil recruitment by targeting platelet-activating factor (PAF). SsE(M1) and SsE produced by serotype M28 GAS (SsE(M28)) have a 37% sequence difference. This study aims at determining whether SsE(M28) is also a PAF acetylhydrolase and participates in innate immune evasion. We also examined whether SsE evolved to target PAF by characterizing the PAF acetylhydrolase (PAF-AH) activity and substrate specificity of SsE(M1), SsE(M28), SeE, the SsE homologue in Streptococcus equi, and human plasma PAF-AH (hpPAF-AH). PAF incubated with SsE(M28) or SeE was converted into lyso-PAF. SsE(M1) and SsE(M28) had kcat values of 373 s(-1) and 467 s(-1), respectively, that were ≥ 30-fold greater than that of hpPAF-AH (12 s(-1)). The comparison of SsE(M1), SsE(M28), and hpPAF-AH in kcat and Km in hydrolyzing triglycerides, acetyl esters, and PAF indicates that the SsE proteins are more potent hydrolases against PAF and have high affinity for PAF. SsE(M28) possesses much lower esterase activities against triglycerides and other esters than SsE(M1) but have similar potency with SsE(M1) in PAF hydrolysis. Deletion of sse(M28) in a covS deletion mutant of GAS increased neutrophil recruitment and reduced skin infection, whereas in trans expression of SsE(M28) in GAS reduced neutrophil infiltration and increased skin invasion in subcutaneous infection of mice. These results suggest that the SsE proteins evolved to target PAF for enhancing innate immune evasion and skin invasion.
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Regulation of inhibition of neutrophil infiltration by the two-component regulatory system CovRS in subcutaneous murine infection with group A streptococcus. Infect Immun 2013; 81:974-83. [PMID: 23319556 DOI: 10.1128/iai.01218-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Hypervirulent invasive group A streptococcus (GAS) isolates inhibit neutrophil infiltration more than pharyngitis isolates do, and the molecular basis of this difference is not well understood. This study was designed to first determine whether natural null mutation of the two-component regulatory system CovRS is responsible for the enhancement of the inhibition of neutrophil recruitment seen in hypervirulent GAS. Next, we examined the role of CovRS-regulated interleukin-8/CXC chemokine peptidase (SpyCEP), C5a peptidase (ScpA), and platelet-activating factor acetylhydrolase (SsE) in the enhanced innate immune evasion. Invasive isolate MGAS5005 induces less neutrophil infiltration and produced a greater lesion area than pharyngitis isolate MGAS2221 in subcutaneous infections of mice. It is known that MGAS5005, but not MGAS2221, has a natural 1-bp deletion in the covS gene. Replacement of covS(Δ1bp) in MGAS5005 with wild-type covS resulted in the MGAS2221 phenotype. Deletion of covS from MGAS2221 resulted in the MGAS5005 phenotype. Tests of single, double, and triple deletion mutants of the MGAS5005 sse, spyCEP, and scpA genes found that SsE plays a more important role than SpyCEP and ScpA in the inhibition of neutrophil recruitment and that SsE, SpyCEP, and ScpA do not have synergistic effects on innate immune evasion by MGAS5005. Deletion of sse, but not spyCEP or scpA, of MGAS2221 enhances neutrophil recruitment. Thus, covS null mutations can cause substantial inhibition of neutrophil recruitment by enhancing the expression of the chemoattractant-degrading virulence factors, and SsE, but not SpyCEP or ScpA, is required for CovRS-regulated GAS inhibition of neutrophil infiltration.
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Human disease isolates of serotype m4 and m22 group a streptococcus lack genes required for hyaluronic acid capsule biosynthesis. mBio 2012; 3:e00413-12. [PMID: 23131832 PMCID: PMC3487777 DOI: 10.1128/mbio.00413-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Group A streptococcus (GAS) causes human pharyngitis and invasive infections and frequently colonizes individuals asymptomatically. Many lines of evidence generated over decades have shown that the hyaluronic acid capsule is a major virulence factor contributing to these infections. While conducting a whole-genome analysis of the in vivo molecular genetic changes that occur in GAS during longitudinal human pharyngeal interaction, we discovered that serotypes M4 and M22 GAS strains lack the hasABC genes necessary for hyaluronic acid capsule biosynthesis. Using targeted PCR, we found that all 491 temporally and geographically diverse disease isolates of these two serotypes studied lack the hasABC genes. Consistent with the lack of capsule synthesis genes, none of the strains produced detectable hyaluronic acid. Despite the lack of a hyaluronic acid capsule, all strains tested multiplied extensively ex vivo in human blood. Thus, counter to the prevailing concept in GAS pathogenesis research, strains of these two serotypes do not require hyaluronic acid to colonize the upper respiratory tract or cause abundant mucosal or invasive human infections. We speculate that serotype M4 and M22 GAS have alternative, compensatory mechanisms that promote virulence. A century of study of the antiphagocytic hyaluronic acid capsule made by group A streptococcus has led to the concept that it is a major virulence factor contributing to human pharyngeal and invasive infections. However, the discovery that some strains that cause abundant human infections lack hyaluronic acid biosynthetic genes and fail to produce this capsule provides a new stimulus for research designed to understand the group A streptococcus factors contributing to pharyngeal infection and invasive disease episodes.
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Vaccination Against Rheumatic Heart Disease: A Review of Current Research Strategies and Challenges. Curr Infect Dis Rep 2012; 14:381-90. [DOI: 10.1007/s11908-012-0263-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Liu M, Zhu H, Li J, Garcia CC, Feng W, Kirpotina LN, Hilmer J, Tavares LP, Layton AW, Quinn MT, Bothner B, Teixeira MM, Lei B. Group A Streptococcus secreted esterase hydrolyzes platelet-activating factor to impede neutrophil recruitment and facilitate innate immune evasion. PLoS Pathog 2012; 8:e1002624. [PMID: 22496650 PMCID: PMC3320582 DOI: 10.1371/journal.ppat.1002624] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 02/21/2012] [Indexed: 11/19/2022] Open
Abstract
The innate immune system is the first line of host defense against invading organisms. Thus, pathogens have developed virulence mechanisms to evade the innate immune system. Here, we report a novel means for inhibition of neutrophil recruitment by Group A Streptococcus (GAS). Deletion of the secreted esterase gene (designated sse) in M1T1 GAS strains with (MGAS5005) and without (MGAS2221) a null covS mutation enhances neutrophil ingress to infection sites in the skin of mice. In trans expression of SsE in MGAS2221 reduces neutrophil recruitment and enhances skin invasion. The sse deletion mutant of MGAS5005 (ΔsseMGAS5005) is more efficiently cleared from skin than the parent strain. SsE hydrolyzes the sn-2 ester bond of platelet-activating factor (PAF), converting biologically active PAF into inactive lyso-PAF. KM and kcat of SsE for hydrolysis of 2-thio-PAF were similar to those of the human plasma PAF acetylhydrolase. Treatment of PAF with SsE abolishes the capacity of PAF to induce activation and chemotaxis of human neutrophils. More importantly, PAF receptor-deficient mice significantly reduce neutrophil infiltration to the site of ΔsseMGAS5005 infection. These findings identify the first secreted PAF acetylhydrolase of bacterial pathogens and support a novel GAS evasion mechanism that reduces phagocyte recruitment to sites of infection by inactivating PAF, providing a new paradigm for bacterial evasion of neutrophil responses. GAS is a major human pathogen causing a variety of infections, including pharyngitis and necrotizing fasciitis. GAS pathogenesis is mediated by a large array of secreted and cell-surface virulence factors. However, the functions of many GAS virulence factors are poorly understood. Recently, we reported that the esterase secreted by GAS (SsE) is a CovRS (the control of virulence two component regulatory system)-regulated protective antigen and is critical for spreading in the skin and systemic dissemination of GAS in a mouse model of necrotizing fasciitis. This report presents three major findings regarding the function and functional mechanism of SsE: 1) SsE contributes to GAS inhibition of neutrophil recruitment; 2) SsE is a potent PAF acetylhydrolase and the first secreted bacterial PAF acetylhydrolase identified so far; and 3) the PAF receptor significantly contributes to neutrophil recruitment in skin GAS infection. These findings support a novel mechanism for evasion of the innate immune system by GAS that may be relevant to other infections.
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Affiliation(s)
- Mengyao Liu
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Hui Zhu
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- Department of Physiology, Harbin Medical University, Harbin, People's Republic of China
| | - Jinquan Li
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Cristiana C. Garcia
- Laboratory of Immunopharmacology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Wenchao Feng
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Liliya N. Kirpotina
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Jonathan Hilmer
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Luciana P. Tavares
- Laboratory of Immunopharmacology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Arthur W. Layton
- Montana Veterinary Diagnostic Laboratory, Bozeman, Montana, United States of America
| | - Mark T. Quinn
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Mauro M. Teixeira
- Laboratory of Immunopharmacology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Benfang Lei
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- * E-mail:
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Streptococcus pneumoniae can utilize multiple sources of hyaluronic acid for growth. Infect Immun 2012; 80:1390-8. [PMID: 22311922 DOI: 10.1128/iai.05756-11] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The mechanisms by which Streptococcus pneumoniae obtains carbohydrates for growth during airway colonization remain to be elucidated. The low concentration of free carbohydrates in the normal human airway suggests that pneumococci must utilize complex glycan structures for growth. The glycosaminoglycan hyaluronic acid is present on the apical surface of airway epithelial cells. As pneumococci express a hyaluronate lyase (Hyl) that cleaves hyaluronic acid into disaccharides, we hypothesized that during colonization pneumococci utilize the released carbohydrates for growth. Hyaluronic acid supported significant pneumococcal growth in an hyl-dependent manner. A phosphoenolpyruvate-dependent phosphotransferase system (PTS) and an unsaturated glucuronyl hydrolase (Ugl) encoded downstream of hyl are also essential for growth on hyaluronic acid. This genomic arrangement is present in several other organisms, suggesting conservation of the utilization mechanism between species. In vivo experiments support the hypothesis that S. pneumoniae utilizes hyaluronic acid as a carbon source during colonization. We also demonstrate that pneumococci can utilize the hyaluronic acid capsule of other bacterial species for growth, suggesting an alternative carbohydrate source for pneumococcal growth. Together, these data support a novel function for pneumococcal degradation of hyaluronic acid in vivo and provide mechanistic details of growth on this glycosaminoglycan.
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Bazaka K, Jacob MV, Crawford RJ, Ivanova EP. Plasma-assisted surface modification of organic biopolymers to prevent bacterial attachment. Acta Biomater 2011; 7:2015-28. [PMID: 21194574 DOI: 10.1016/j.actbio.2010.12.024] [Citation(s) in RCA: 220] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 12/01/2010] [Accepted: 12/20/2010] [Indexed: 12/30/2022]
Abstract
Despite many synthetic biomaterials having physical properties that are comparable or even superior to those of natural body tissues, they frequently fail due to the adverse physiological reactions they cause within the human body, such as infection and inflammation. The surface modification of biomaterials is an economical and effective method by which biocompatibility and biofunctionality can be achieved while preserving the favorable bulk characteristics of the biomaterial, such as strength and inertness. Amongst the numerous surface modification techniques available, plasma surface modification affords device manufacturers a flexible and environmentally friendly process that enables tailoring of the surface morphology, structure, composition, and properties of the material to a specific need. There are a vast range of possible applications of plasma modification in biomaterial applications, however, the focus of this review paper is on processes that can be used to develop surface morphologies and chemical structures for the prevention of adhesion and proliferation of pathogenic bacteria on the surfaces of in-dwelling medical devices. As such, the fundamental principles of bacterial cell attachment and biofilm formation are also discussed. Functional organic plasma polymerised coatings are also discussed for their potential as biosensitive interfaces, connecting inorganic/metallic electronic devices with their physiological environments.
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Affiliation(s)
- Kateryna Bazaka
- Electronic Materials Research Laboratory, School of Engineering and Physical Sciences, James Cook University, Townsville, Queensland, Australia
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Bacterial Extracellular Polysaccharides. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 715:213-26. [DOI: 10.1007/978-94-007-0940-9_13] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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36
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Skinner JM, Caro-Aguilar IC, Payne AM, Indrawati L, Fontenot J, Heinrichs JH. Comparison of rhesus and cynomolgus macaques in a Streptococcus pyogenes infection model for vaccine evaluation. Microb Pathog 2010; 50:39-47. [PMID: 21035535 DOI: 10.1016/j.micpath.2010.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 10/20/2010] [Accepted: 10/21/2010] [Indexed: 11/29/2022]
Abstract
Animal models predictive of human disease are generally difficult to establish and reproduce. In the case of the Group A Streptococcus (GAS) bacterium, which is predominantly a human pathogen, virulence assessment in animal models is problematic. We compared a monkey colonization and pharyngitis model of infection in two macaque species to determine the optimal model for vaccine candidate evaluation. Rhesus and cynomolgus macaques were intranasally infected with a streptomycin resistant (Str(r)) GAS strain. Monkeys were monitored for body weight and temperature changes, throat swabs and sera were collected, and clinical observations were noted throughout the study. Both species exhibited oropharyngeal colonization by GAS, with rhesus macaques demonstrating a more sustained colonization through day 28 post-challenge. Veterinary observations revealed no significant differences between GAS-infected rhesus and cynomolgus macaques. Mock-infected monkeys did not exhibit clinical symptoms or GAS colonization throughout the study. ELISA results demonstrated that both rhesus and cynomolgus macaques developed anti-streptolysin-O antibody titers, with cynomolgus generating higher titers. Sera from infected monkeys produced opsonophagocytic killing and bound to the bacterium in an immunofluorescence assay. Both rhesus and cynomolgus macaques can be used for colonization studies with this GAS M3 strain, yet only mild clinical signs of pharyngitis and tonsillitis were observed.
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Affiliation(s)
- Julie M Skinner
- Merck & Co., Inc., Vaccines Research, 770 Sumneytown Pike, P.O. Box 4, WP43T-1, West Point, PA 19486, USA.
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Abstract
Group A Streptococcus (GAS) is a human-specific pathogen that is highly prevalent throughout the world. The vast majority of GAS infections lead to a mild disease involving the epithelial surfaces of either the throat or skin. The concept of distinct sets of 'throat' and 'skin' strains of GAS has long been conceived. From an ecological standpoint, the epithelium of the throat and skin are important because it is where the organism is most successful in reproducing and transmitting to new hosts. This article examines key features of the epidemiology, population biology and molecular pathogenesis that underlie the tissue site preferences for infection exhibited by GAS, with an emphasis on work from our laboratory on skin tropisms. Recombinational replacement with orthologous gene forms, following interspecies transfer, appears to be an important genetic step leading up to the exploitation of new niches by GAS.
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Affiliation(s)
- Debra E Bessen
- Department of Microbiology & Immunology, New York Medical College, Valhalla, NY 10573, USA, Tel.: +1 914 594 4193, Fax: +1 914 594 4176
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Functional dissection of Streptococcus pyogenes M5 protein: the hypervariable region is essential for virulence. PLoS One 2009; 4:e7279. [PMID: 19794915 PMCID: PMC2749438 DOI: 10.1371/journal.pone.0007279] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 09/06/2009] [Indexed: 11/22/2022] Open
Abstract
The surface-localized M protein of Streptococcus pyogenes is a major virulence factor that inhibits phagocytosis, as determined ex vivo. Because little is known about the role of M protein in vivo we analyzed the contribution of different M protein regions to virulence, using the fibrinogen (Fg)-binding M5 protein and a mouse model of acute invasive infection. This model was suitable, because M5 is required for mouse virulence and binds mouse and human Fg equally well, as shown here. Mixed infection experiments with wild type bacteria demonstrated that mutants lacking the N-terminal hypervariable region (HVR) or the Fg-binding B-repeat region were strongly attenuated, while a mutant lacking the conserved C-repeats was only slightly attenuated. Because the HVR of M5 is not required for phagocytosis resistance, our data imply that this HVR plays a major but unknown role during acute infection. The B-repeat region is required for phagocytosis resistance and specifically binds Fg, suggesting that it promotes virulence by binding Fg. However, B-repeat mutants were attenuated even in Fg-deficient mice, implying that the B-repeats may have a second function, in addition to Fg-binding. These data demonstrate that two distinct M5 regions, including the HVR, are essential to virulence during the early stages of an infection. In particular, our data provide the first in vivo evidence that the HVR of an M protein plays a major role in virulence, focusing interest on the molecular role of this region.
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Churchward G, Bates C, Gusa AA, Stringer V, Scott JR. Regulation of streptokinase expression by CovR/S in Streptococcus pyogenes: CovR acts through a single high-affinity binding site. MICROBIOLOGY-SGM 2009; 155:566-575. [PMID: 19202105 DOI: 10.1099/mic.0.024620-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The important human pathogen Streptococcus pyogenes (the group A streptococcus or GAS) produces many virulence factors that are regulated by the two-component signal transduction system CovRS (CsrRS). Dissemination of GAS infection originating at the skin has been shown to require production of streptokinase, whose transcription is repressed by CovR. In this work we have studied the interaction of CovR and phosphorylated CovR (CovR-P) with the promoter for streptokinase, Pska. We found that, in contrast to the other CovR-repressed promoters, Pska regulation by CovR occurs through binding at a single ATTARA consensus binding sequence (CB) that overlaps the -10 region of the promoter. Binding of CovR to other nearby consensus sequences occurs upon phosphorylation of the protein, but these other CBs do not contribute to the regulation of Pska by CovR. Thus, binding at a specific site does not necessarily indicate that the site is involved in regulation by CovR. In addition, at Pska, CovR binding to the different sites does not appear to involve cooperative interactions, which simplifies the analysis of CovR binding and gives us insight into the modes of interaction that occur between CovR and its specific DNA-binding sites. Finally, the observation that regulation of transcription from Pska occurs at a very low concentration of phosphorylated CovR may have important implications for the regulation of virulence gene expression during GAS infection.
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Affiliation(s)
- Gordon Churchward
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Christopher Bates
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Asiya A Gusa
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Virginia Stringer
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - June R Scott
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA
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Roberts S, Scott JR, Husmann LK, Zurawski CA. Murine models of Streptococcus pyogenes infection. ACTA ACUST UNITED AC 2008; Chapter 9:Unit 9D.5. [PMID: 18770596 DOI: 10.1002/9780471729259.mc09d05s02] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This unit describes procedures for testing virulence of Streptococcus pyogenes in mice. S. pyogenes is an important human pathogen and causes one of the most common childhood diseases. The syndromes that result from S. pyogenes infection are diverse, ranging from mild, superficial throat or skin infection to severe, invasive disea/se that is often lethal. Thus, a greater understanding of the virulence factors of this bacterium and development of modalities to prevent or relieve the infections it causes are important. Since S. pyogenes is a strictly human pathogen (with the exception of a single strain), the value of all animal models is limited. This unit describes a model for long-term throat colonization following the natural route of infection (inhalation), one for pneumonia and systemic dissemination following intratracheal inoculation, and one for systemic dissemination following the more natural route of skin infection. In addition, methods are presented for culturing S. pyogenes from tissues of the infected animal.
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Gryllos I, Grifantini R, Colaprico A, Cary ME, Hakansson A, Carey DW, Suarez-Chavez M, Kalish LA, Mitchell PD, White GL, Wessels MR. PerR confers phagocytic killing resistance and allows pharyngeal colonization by group A Streptococcus. PLoS Pathog 2008; 4:e1000145. [PMID: 18773116 PMCID: PMC2518855 DOI: 10.1371/journal.ppat.1000145] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Accepted: 08/07/2008] [Indexed: 01/24/2023] Open
Abstract
The peroxide response transcriptional regulator, PerR, is thought to contribute to virulence of group A Streptococcus (GAS); however, the specific mechanism through which it enhances adaptation for survival in the human host remains unknown. Here, we identify a critical role of PerR-regulated gene expression in GAS phagocytosis resistance and in virulence during pharyngeal infection. Deletion of perR in M-type 3 strain 003Sm was associated with reduced resistance to phagocytic killing in human blood and by murine macrophages in vitro. The increased phagocytic killing of the perR mutant was abrogated in the presence of the general oxidative burst inhibitor diphenyleneiodonium chloride (DPI), a result that suggests PerR-dependent gene expression counteracts the phagocyte oxidative burst. Moreover, an isogenic perR mutant was severely attenuated in a baboon model of GAS pharyngitis. In competitive infection experiments, the perR mutant was cleared from two animals at 24 h and from four of five animals by day 14, in sharp contrast to wild-type bacteria that persisted in the same five animals for 28 to 42 d. GAS genomic microarrays were used to compare wild-type and perR mutant transcriptomes in order to characterize the PerR regulon of GAS. These studies identified 42 PerR-dependent loci, the majority of which had not been previously recognized. Surprisingly, a large proportion of these loci are involved in sugar utilization and transport, in addition to oxidative stress adaptive responses and virulence. This finding suggests a novel role for PerR in mediating sugar uptake and utilization that, together with phagocytic killing resistance, may contribute to GAS fitness in the infected host. We conclude that PerR controls expression of a diverse regulon that enhances GAS resistance to phagocytic killing and allows adaptation for survival in the pharynx.
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Affiliation(s)
- Ioannis Gryllos
- Division of Infectious Diseases, Children's Hospital Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
| | | | | | - Max E. Cary
- Department of Pathology and Comparative Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Anders Hakansson
- Division of Infectious Diseases, Children's Hospital Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - David W. Carey
- Department of Pathology and Comparative Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Maria Suarez-Chavez
- Department of Pathology and Comparative Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Leslie A. Kalish
- Division of Infectious Diseases, Children's Hospital Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- Clinical Research Program, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Paul D. Mitchell
- Division of Infectious Diseases, Children's Hospital Boston, Massachusetts, United States of America
- Clinical Research Program, Children's Hospital Boston, Boston, Massachusetts, United States of America
| | - Gary L. White
- Department of Pathology and Comparative Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Michael R. Wessels
- Division of Infectious Diseases, Children's Hospital Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
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42
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Luo F, Lizano S, Banik S, Zhang H, Bessen DE. Role of Mga in group A streptococcal infection at the skin epithelium. Microb Pathog 2008; 45:217-24. [PMID: 18588968 PMCID: PMC2593622 DOI: 10.1016/j.micpath.2008.05.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 05/26/2008] [Accepted: 05/27/2008] [Indexed: 01/26/2023]
Abstract
Group A streptococci (GAS) primarily cause infection at epithelial tissue sites of its human host. The role of the transcriptional regulator Mga in a humanized mouse model for superficial skin infection was investigated. Inactivation of mga in a skin strain (Alab49) led to loss of virulence. The Deltamga mutant displayed >100-fold decrease in emm (pam) transcript levels, and loss of bacterial-bound plasmin activity. A slight decrease in speB transcription, accompanied by a partial decrease in cysteine protease activity but no change in PrtF2 degradation, was also observed. Mga had no effect on transcription of nra, Nra-regulated pilus genes (cpa, fctA) or other FCT-region genes (msmR, prtF2). Combined with findings on other Alab49 mutants, data show that several essential virulence genes are regulated by Mga or Nra, but not both, implying that any coordinated response during skin infection likely operates at a higher level of transcriptional control. Mga was required for bacterial autoaggregation and biofilm-like growth on an abiotic surface; however, aggregation and biofilm formation have only partial overlap with the skin virulence phenotype. Findings on numerous phenotypes for 7 mutants constructed on the same genetic background yield a detailed, integrated model for GAS pathogenesis at the skin.
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Affiliation(s)
- Feng Luo
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, USA
| | - Sergio Lizano
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, USA
| | - Sukalyani Banik
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, USA
| | - Hong Zhang
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, USA
| | - Debra E. Bessen
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, USA
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43
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Olsen RJ, Shelburne SA, Musser JM. Molecular mechanisms underlying group A streptococcal pathogenesis. Cell Microbiol 2008; 11:1-12. [PMID: 18710460 DOI: 10.1111/j.1462-5822.2008.01225.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Group A Streptococcus (GAS) is a versatile human pathogen causing diseases ranging from uncomplicated mucosal infections to life-threatening invasive disease. The development of human-relevant animal models of GAS infection and introduction of new technologies have markedly accelerated the pace of discoveries related to GAS host-pathogen interactions. For example, recently investigators have identified pili on the GAS cell surface and learned that they are key components for adherence to eukaryotic cell surfaces. Similarly, the recent development of a transgenic mouse expressing human plasminogen has resulted in new understanding of the molecular processes contributing to invasive infection. Improved understanding of the molecular mechanisms underlying the pathogenesis of GAS pharyngeal, invasive and other infections holds the promise of assisting with the development of novel preventive or therapeutic agents for this prevalent human pathogen.
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Affiliation(s)
- Randall J Olsen
- Center for Molecular and Translational Human Infectious Disease Research, The Methodist Hospital Research Institute, Houston, TX 77030, USA
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44
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Stollerman G, Dale J. The Importance of the Group AStreptococcusCapsule in the Pathogenesis of Human Infections: A Historical Perspective. Clin Infect Dis 2008; 46:1038-45. [DOI: 10.1086/529194] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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45
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Oliver MA, García-Rey C, Bosch R, Albertí S. Evaluation of the ability of erythromycin-resistant and -susceptible pharyngeal group A Streptococcus isolates from Spain to enter and persist in human keratinocytes. J Med Microbiol 2008; 56:1485-1489. [PMID: 17965349 DOI: 10.1099/jmm.0.47203-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The macrolide-resistance rate among group A Streptococcus (GAS) isolates has increased in some European countries. To investigate the reasons for this increase, the ability of 60 erythromycin-resistant and 61 erythromycin-susceptible, genetically unrelated, pharyngeal GAS isolates from Spain to enter and persist within human keratinocytes was evaluated. It was observed that erythromycin resistance was associated with the presence of prtF1, a gene related to invasiveness, whereas no association was observed with the ability to enter human keratinocytes. However, the ability to enter human keratinocytes was not associated with the presence of prtF1 or with the emm type, suggesting that interaction with keratinocytes depends on several characteristics of the isolate. Almost all strains (95.9 %) were capable of persisting within human keratinocytes. However, most of them (91.7 %) exhibited a decline in viability over time. Interestingly, the ability to persist within keratinocytes protected from the action of the beta-lactams was higher among erythromycin-resistant isolates and correlated with their ability to avoid the induction of cellular lysis. These observations suggest that if the carrier state results from intracellular GAS survival, the association between erythromycin resistance and intracellular persistence may represent a serious problem for the eradication of these isolates.
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Affiliation(s)
- Maria A Oliver
- Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Universitat de les Illes Balears (UIB), Palma de Mallorca, Spain
| | - César García-Rey
- Departamento Médico, GlaxoSmithKline SA, Tres Cantos, Madrid, Spain
| | - Rafael Bosch
- Área de Microbiología, Departamento de Biologia, Universitat de les Illes Balears (UIB), Palma de Mallorca, Spain
| | - Sebastián Albertí
- Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Universitat de les Illes Balears (UIB), Palma de Mallorca, Spain
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46
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A non-human primate model of acute group a Streptococcus pharyngitis. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2008; 431:255-67. [PMID: 18287762 DOI: 10.1007/978-1-60327-032-8_20] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
This chapter describes methods for using non-human primates as a model of group A streptococcal (GAS) pharyngitis. This model has been used successfully to study host-pathogen interactions occurring during pharyngeal GAS infections. The protocol as described will compare two different GAS strains for their ability to cause clinical symptoms of pharyngitis.
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47
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Roberts SA, Scott JR. RivR and the small RNA RivX: the missing links between the CovR regulatory cascade and the Mga regulon. Mol Microbiol 2007; 66:1506-22. [PMID: 18005100 DOI: 10.1111/j.1365-2958.2007.06015.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The CovR/S two-component system regulates the transcription of many genes that are crucial for the virulence of Streptococcus pyogenes (group A Streptococcus, GAS). Previously, we demonstrated that one gene repressed directly by CovR is rivR, which encodes a member of the RofA-like family of transcriptional regulators. In this study, we deleted rivR and its downstream gene rivX in a DeltacovR background. Microarray analysis revealed that the products of the rivRX locus exert positive control over the transcription of members of the Mga regulon. Using mutational analysis, we established that rivX encodes a small regulatory RNA. We found that RivR enhances transcriptional activation by Mga in vivo and in vitro. An M1 DeltacovRDeltarivRX strain is attenuated for virulence in a murine model of invasive soft tissue infection and this attenuation is complemented by rivRX expressed from a plasmid, demonstrating the importance of the rivRX locus in pathogenesis. This study provides the first link between the CovR and Mga regulatory networks. By integrating the signals received through these two global regulators, GAS is able to select from its repertoire different combinations of specific virulence factors to express in response to a broad spectrum of environmental conditions.
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Affiliation(s)
- Samantha A Roberts
- Department of Microbiology and Immunology, School of Medicine, Emory University, Atlanta, GA 30322, USA
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48
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Dinkla K, Sastalla I, Godehardt AW, Janze N, Chhatwal GS, Rohde M, Medina E. Upregulation of capsule enables Streptococcus pyogenes to evade immune recognition by antigen-specific antibodies directed to the G-related α2-macroglobulin-binding protein GRAB located on the bacterial surface. Microbes Infect 2007; 9:922-31. [PMID: 17544803 DOI: 10.1016/j.micinf.2007.03.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 03/07/2007] [Accepted: 03/16/2007] [Indexed: 11/24/2022]
Abstract
One of the major problems associated with the development of a vaccine against Streptococcus pyogenes is the ability of this pathogen to escape recognition by antibodies directed against conserved surface-associated determinants and to establish infection in the setting of an acquired immune response. Identification of the mechanism(s) used by S. pyogenes to avoid recognition by antigen-specific antibodies and escape killing in blood was the focus of this study. We showed here that S. pyogenes was capable of surviving in human blood containing high levels of antibodies directed against the G-related alpha2-macroglobulin-binding protein GRAB, a highly conserved bacterial surface protein. S. pyogenes upregulated the hyaluronic acid capsule production during incubation with human blood, suggesting that the capsule may structurally minimize antibody access to protein GRAB. This hypothesis was confirmed by the ability of anti-GRAB antibodies to promote opsonophagocytosis of a capsule-deficient mutant of S. pyogenes but not of the encapsulated wild-type strain. Capsule upregulation and protection of S. pyogenes from opsonophagocytosis in the presence of anti-GRAB antibodies was also observed in a murine model of streptococcal infection. Thus, masking of surface immunogenic determinants by the hyaluronic acid capsule may constitute a novel mechanism of S. pyogenes for evasion of antigen-specific antibodies.
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Affiliation(s)
- Katrin Dinkla
- Department of Microbial Pathogenicity, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany.
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49
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Tart AH, Walker MJ, Musser JM. New understanding of the group A Streptococcus pathogenesis cycle. Trends Microbiol 2007; 15:318-25. [PMID: 17524649 DOI: 10.1016/j.tim.2007.05.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 03/26/2007] [Accepted: 05/09/2007] [Indexed: 10/23/2022]
Abstract
Group A Streptococcus (GAS) has long been recognized as a human pathogen causing an exceptionally broad range of infections. Despite intense research, however, the molecular mechanisms of GAS disease remain unclear. Recently, many important discoveries have been made that shed light on GAS pathogenesis and open exciting avenues for future research. Advances in genome sequencing, microarray technology and proteomic analysis, in combination with the development of more suitable animal models, have markedly increased our knowledge of the mechanisms underlying GAS pathogenesis. The information gained from these studies will translate into improved diagnostics and new targets for therapeutic drugs and vaccines.
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Affiliation(s)
- Anne H Tart
- Center for Molecular and Translational Human Infectious Diseases Research, The Methodist Hospital Research Institute, and Department of Pathology, The Methodist Hospital, 6565 Fannin Street B490, Houston, TX 77030, USA
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50
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Düzgün N, Duman T, Haydardedeoğlu FE, Tutkak H. The lack of genetic association of the Toll-like receptor 2 (TLR2) Arg753Gln and Arg677Trp polymorphisms with rheumatic heart disease. Clin Rheumatol 2006; 26:915-9. [PMID: 17096074 DOI: 10.1007/s10067-006-0432-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 08/28/2006] [Accepted: 08/31/2006] [Indexed: 10/23/2022]
Abstract
UNLABELLED Acute rheumatic fever (ARF) is a non-suppurative inflammatory disease after group A, beta haemolytic streptococcal pharyngitis. Certain individuals can develop ARF. This finding implies variability in host predisposition to ARF. A variety of studies have linked specific genetic markers with ARF or rheumatic heart disease (RHD) as a sequelae of ARF. For this purpose, we aimed to search the role of polymorphisms in Toll-like receptor-2 and -4 (TLR2 and TLR4) gene in Turkish patients with RHD. This study included a total 84 patients with RHD, ages ranging between 18 and 65, 25 male and 59 female, fulfilling the revised classification criteria of Jones. One hundred forty healthy unrelated persons were selected as a control group. Genotype analysis: DNA was extracted from whole blood. TLR4 gene (Asp 299Gly and Thr399Ile) and TLR2 gene (Arg753Gln and Arg677Trp) polymorphisms were genotyped by the previously reported method. STATISTICAL ANALYSIS binary logistic regression models were used. Results were expressed as odds ratios (OR) with corresponding 95% confidence intervals (95% CI). Significant level was predefined at 0.05. There was a significant difference for carrying Ile allele in the 399 position in the patients compared to healthy controls (OR = 5.26, 95% CI, 1.40-19.73, p = 0.014). In the TLR4 gene, Asp 299Gly polymorphism did not reach to a statistically significant value (OR = 3.02). We found no Arg753Gln polymorphism of the TLR2 gene in the patient group. There were three heterozygote samples in the healthy group. We did not detect Arg677Trp polymorphism of the TLR2 gene in both patient and control groups.
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Affiliation(s)
- Nurşen Düzgün
- Department of Clinical Immunology and Rheumatology, Ankara University School of Medicine, Ankara, Turkey.
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