151
|
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
| |
Collapse
|
152
|
Virulence Role of the GlcNAc Side Chain of the Lancefield Cell Wall Carbohydrate Antigen in Non-M1-Serotype Group A Streptococcus. mBio 2018; 9:mBio.02294-17. [PMID: 29382733 PMCID: PMC5790915 DOI: 10.1128/mbio.02294-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Classification of streptococci is based upon expression of unique cell wall carbohydrate antigens. All serotypes of group A Streptococcus (GAS; Streptococcus pyogenes), a leading cause of infection-related mortality worldwide, express the group A carbohydrate (GAC). GAC, the classical Lancefield antigen, is comprised of a polyrhamnose backbone with N-acetylglucosamine (GlcNAc) side chains. The immunodominant GlcNAc epitope of GAC is the basis of all rapid diagnostic testing for GAS infection. We previously identified the 12-gene GAC biosynthesis gene cluster and determined that the glycosyltransferase GacI was required for addition of the GlcNAc side chain to the polyrhamnose core. Loss of the GAC GlcNAc epitope in serotype M1 GAS resulted in attenuated virulence in two animal infection models and increased GAS sensitivity to killing by whole human blood, serum, neutrophils, and antimicrobial peptides. Here, we report that the GAC biosynthesis gene cluster is ubiquitous among 520 GAS isolates from global sources, representing 105 GAS emm serotypes. Isogenic ΔgacI mutants were constructed in M2, M3, M4, M28, and M89 backgrounds and displayed an array of phenotypes in susceptibility to killing by whole human blood, baby rabbit serum, human platelet releasate, human neutrophils, and antimicrobial peptide LL-37. The contribution of the GlcNAc side chain to GAS survival in vivo also varied by strain, demonstrating that it is not a prerequisite for virulence in the murine infection model. Thus, the relative contribution of GAC to virulence in non-M1 serotypes appears to depend on the quorum of other virulence factors that each strain possesses.IMPORTANCE The Lancefield group A carbohydrate (GAC) is the species-defining antigen for group A Streptococcus (GAS), comprising ~50% of the cell wall of this major human pathogen. We previously showed that the GlcNAc side chain of GAC contributes to the innate immune resistance and animal virulence phenotypes of the globally disseminated strain of serotype M1 GAS. Here, we use isogenic mutagenesis to examine the role of GAC GlcNAc in five additional medically relevant GAS serotypes. Overall, the GlcNAc side chain of GAC contributes to the innate immune resistance of GAS, but the relative contribution varies among individual strains. Moreover, the GAC GlcNAc side chain is not a universal prerequisite for GAS virulence in the animal model.
Collapse
|
153
|
Pal'chun VT, Gurov AV, Guseva OA. [The specific pathogenetic features of the development of chronic tonsillar pathology]. Vestn Otorinolaringol 2018; 83:30-33. [PMID: 29697651 DOI: 10.17116/otorino201883230-33] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The authors discuss the mechanisms underlying the development of chronic tonsillar pathology confirmed by the methods of histological, autoradiographic, and bacteriological diagnostics. The new aspects of vital activity of microorganisms in the parenchymal tissue of the palatine tonsils are highlighted that account for the low effectiveness of the conservative therapy of chronic tonsillitis and give evidence of the necessity of the surgical treatment of this condition.
Collapse
Affiliation(s)
- V T Pal'chun
- N.I. Pirogov Russian National Research Medical University, Ministry of Health of the Russian Federation, Moscow, Russia, 117997; L.I. Sverzhevskiy Research Institute of Clinical Otorhinolaryngology, Moscow Health Department, Moscow, Russia, 117152
| | - A V Gurov
- N.I. Pirogov Russian National Research Medical University, Ministry of Health of the Russian Federation, Moscow, Russia, 117997; L.I. Sverzhevskiy Research Institute of Clinical Otorhinolaryngology, Moscow Health Department, Moscow, Russia, 117152
| | - O A Guseva
- N.I. Pirogov Russian National Research Medical University, Ministry of Health of the Russian Federation, Moscow, Russia, 117997
| |
Collapse
|
154
|
Abstract
Group A Streptococcus (GAS) is a leading human bacterial pathogen with diverse clinical manifestations. Macrophages constitute a critical first line of host defense against GAS infection, using numerous surface and intracellular receptors such as Toll-like receptors and inflammasomes for pathogen recognition and activation of inflammatory signaling pathways. Depending on the intensity of the GAS infection, activation of these signaling cascades may provide a beneficial early alarm for effective immune clearance, or conversely, may cause hyperinflammation and tissue injury during severe invasive infection. Although traditionally considered an extracellular pathogen, GAS can invade and replicate within macrophages using specific molecular mechanisms to resist phagolysosomal and xenophagic killing. Unraveling GAS-macrophage encounters may reveal new treatment options for this leading agent of infection-associated mortality. [Formula: see text].
Collapse
Affiliation(s)
- J Andrés Valderrama
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Victor Nizet
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA.,Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| |
Collapse
|
155
|
Katzenellenbogen JM, Ralph AP, Wyber R, Carapetis JR. Rheumatic heart disease: infectious disease origin, chronic care approach. BMC Health Serv Res 2017; 17:793. [PMID: 29187184 PMCID: PMC5708129 DOI: 10.1186/s12913-017-2747-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 11/20/2017] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Rheumatic heart disease (RHD) is a chronic cardiac condition with an infectious aetiology, causing high disease burden in low-income settings. Affected individuals are young and associated morbidity is high. However, RHD is relatively neglected due to the populations involved and its lower incidence relative to other heart diseases. METHODS AND RESULTS In this narrative review, we describe how RHD care can be informed by and integrated with models of care developed for priority non-communicable diseases (coronary heart disease), and high-burden communicable diseases (tuberculosis). Examining the four-level prevention model (primordial through tertiary prevention) suggests primordial and primary prevention of RHD can leverage off existing tuberculosis control efforts, given shared risk factors. Successes in coronary heart disease control provide inspiration for similarly bold initiatives for RHD. Further, we illustrate how the Chronic Care Model (CCM), developed for use in non-communicable diseases, offers a relevant framework to approach RHD care. Systems strengthening through greater integration of services can improve RHD programs. CONCLUSION Strengthening of systems through integration/linkages with other well-performing and resourced services in conjunction with policies to adopt the CCM framework for the secondary and tertiary prevention of RHD in settings with limited resources, has the potential to significantly reduce the burden of RHD globally. More research is required to provide evidence-based recommendations for policy and service design.
Collapse
Affiliation(s)
- Judith M Katzenellenbogen
- Telethon Kids Institute, The University of Western Australia, Perth, Western, Australia.
- School of Population and Global Health, The University of Western Australia, Perth, Western, Australia.
| | - Anna P Ralph
- Global and Tropical Health, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Division of Medicine, Royal Darwin Hospital, Darwin, NT, Australia
| | - Rosemary Wyber
- Telethon Kids Institute, The University of Western Australia, Perth, Western, Australia
| | - Jonathan R Carapetis
- Telethon Kids Institute, The University of Western Australia, Perth, Western, Australia
- Princess Margaret Hospital for Children, Perth, Western, Australia
| |
Collapse
|
156
|
Beres SB, Olsen RJ, Ojeda Saavedra M, Ure R, Reynolds A, Lindsay DSJ, Smith AJ, Musser JM. Genome sequence analysis of emm89 Streptococcus pyogenes strains causing infections in Scotland, 2010-2016. J Med Microbiol 2017; 66:1765-1773. [PMID: 29099690 PMCID: PMC5845742 DOI: 10.1099/jmm.0.000622] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose Strains of type emm89 Streptococcus pyogenes have recently increased in frequency as a cause of human infections in several countries in Europe and North America. This increase has been molecular epidemiologically linked with the emergence of a new genetically distinct clone, designated clade 3. We sought to extend our understanding of this epidemic behavior by the genetic characterization of type emm89 strains responsible in recent years for an increased frequency of infections in Scotland. Methodology We sequenced the genomes of a retrospective cohort of 122 emm89 strains recovered from patients with invasive and noninvasive infections throughout Scotland during 2010 to 2016. Results All but one of the 122 emm89 infection isolates are of the recently emerged epidemic clade 3 clonal lineage. The Scotland isolates are closely related to and not genetically distinct from recent emm89 strains from England, they constitute a single genetic population. Conclusions The clade 3 clone causes virtually all-contemporary emm89 infections in Scotland. These findings add Scotland to a growing list of countries of Europe and North America where, by whole genome sequencing, emm89 clade 3 strains have been demonstrated to be the cause of an ongoing epidemic of invasive infections and to be genetically related due to descent from a recent common progenitor.
Collapse
Affiliation(s)
- Stephen B Beres
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, and Houston Methodist Hospital, Houston, TX 77030, USA
| | - Randall J Olsen
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, and Houston Methodist Hospital, Houston, TX 77030, USA.,Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, NY 10021, USA
| | - Matthew Ojeda Saavedra
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, and Houston Methodist Hospital, Houston, TX 77030, USA
| | - Roisin Ure
- Scottish Haemophilus Legionella Meningococcus Pneumococcus Reference Laboratory, New Lister Building, Glasgow, G31 2ER, Scotland, UK
| | - Arlene Reynolds
- Scottish Haemophilus Legionella Meningococcus Pneumococcus Reference Laboratory, New Lister Building, Glasgow, G31 2ER, Scotland, UK
| | - Diane S J Lindsay
- Scottish Haemophilus Legionella Meningococcus Pneumococcus Reference Laboratory, New Lister Building, Glasgow, G31 2ER, Scotland, UK
| | - Andrew J Smith
- Scottish Haemophilus Legionella Meningococcus Pneumococcus Reference Laboratory, New Lister Building, Glasgow, G31 2ER, Scotland, UK.,College of Medical, Veterinary and Life Sciences, Glasgow Dental Hospital and School, University of Glasgow, 378 Sauchiehall Street, Glasgow, G2 3JZ, Scotland, UK
| | - James M Musser
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, and Houston Methodist Hospital, Houston, TX 77030, USA.,Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, NY 10021, USA
| |
Collapse
|
157
|
Tagini F, Greub G. Bacterial genome sequencing in clinical microbiology: a pathogen-oriented review. Eur J Clin Microbiol Infect Dis 2017; 36:2007-2020. [PMID: 28639162 PMCID: PMC5653721 DOI: 10.1007/s10096-017-3024-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/22/2017] [Indexed: 12/11/2022]
Abstract
In recent years, whole-genome sequencing (WGS) has been perceived as a technology with the potential to revolutionise clinical microbiology. Herein, we reviewed the literature on the use of WGS for the most commonly encountered pathogens in clinical microbiology laboratories: Escherichia coli and other Enterobacteriaceae, Staphylococcus aureus and coagulase-negative staphylococci, streptococci and enterococci, mycobacteria and Chlamydia trachomatis. For each pathogen group, we focused on five different aspects: the genome characteristics, the most common genomic approaches and the clinical uses of WGS for (i) typing and outbreak analysis, (ii) virulence investigation and (iii) in silico antimicrobial susceptibility testing. Of all the clinical usages, the most frequent and straightforward usage was to type bacteria and to trace outbreaks back. A next step toward standardisation was made thanks to the development of several new genome-wide multi-locus sequence typing systems based on WGS data. Although virulence characterisation could help in various particular clinical settings, it was done mainly to describe outbreak strains. An increasing number of studies compared genotypic to phenotypic antibiotic susceptibility testing, with mostly promising results. However, routine implementation will preferentially be done in the workflow of particular pathogens, such as mycobacteria, rather than as a broadly applicable generic tool. Overall, concrete uses of WGS in routine clinical microbiology or infection control laboratories were done, but the next big challenges will be the standardisation and validation of the procedures and bioinformatics pipelines in order to reach clinical standards.
Collapse
Affiliation(s)
- F Tagini
- Institute of Microbiology, Department of Laboratory, University of Lausanne & University Hospital, Lausanne, Switzerland
| | - G Greub
- Institute of Microbiology, Department of Laboratory, University of Lausanne & University Hospital, Lausanne, Switzerland.
| |
Collapse
|
158
|
Speers DJ, Levy A, Gichamo A, Eastwood A, Leung MJ. M protein gene (emm type) analysis of group A Streptococcus isolates recovered during an acute glomerulonephritis outbreak in northern Western Australia. Pathology 2017; 49:765-769. [PMID: 29079005 DOI: 10.1016/j.pathol.2017.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 08/15/2017] [Accepted: 09/05/2017] [Indexed: 11/26/2022]
Abstract
Certain M protein types of group A streptococcus (GAS) are known to cause acute post-streptococcal glomerulonephritis (APSGN). Outbreaks of APSGN can occur regularly in tropical regions but the emm types responsible are geographically and temporally diverse. GAS isolates from Western Australia (WA) were analysed for emm type and emm cluster during the period of increased APSGN activity in the tropical northern Kimberley region of WA. Although emm types 49, 75 and 108 and corresponding emm clusters E3, E6 and D4 were more common in WA during the outbreak there was no predominant circulating emm type or cluster found to correspond to the APSGN activity. This is consistent with the high diversity of GAS strains found during APSGN outbreaks in other countries. Potential vaccine coverage of the new 30-valent M-protein GAS vaccine was 70%.
Collapse
Affiliation(s)
- David J Speers
- Department of Microbiology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, Hospital Avenue, Nedlands, Australia; School of Medicine and Pharmacology, University of Western Australia, Crawley, Australia.
| | - Avram Levy
- Department of Microbiology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, Hospital Avenue, Nedlands, Australia; School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Australia
| | - Adanech Gichamo
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Australia
| | - Ashley Eastwood
- WA Country Health Service, Kimberley Population Health Unit, Department of Health, Broome, WA, Australia
| | - Michael J Leung
- Department of Microbiology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, Hospital Avenue, Nedlands, Australia; School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Australia
| |
Collapse
|
159
|
Incremental Contributions of FbaA and Other Impetigo-Associated Surface Proteins to Fitness and Virulence of a Classical Group A Streptococcal Skin Strain. Infect Immun 2017; 85:IAI.00374-17. [PMID: 28808160 DOI: 10.1128/iai.00374-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 08/08/2017] [Indexed: 12/26/2022] Open
Abstract
Group A streptococci (GAS) are highly prevalent human pathogens whose primary ecological niche is the superficial epithelial layers of the throat and/or skin. Many GAS strains with a strong tendency to cause pharyngitis are distinct from strains that tend to cause impetigo; thus, genetic differences between them may confer host tissue-specific virulence. In this study, the FbaA surface protein gene was found to be present in most skin specialist strains but largely absent from a genetically related subset of pharyngitis isolates. In an ΔfbaA mutant constructed in the impetigo strain Alab49, loss of FbaA resulted in a slight but significant decrease in GAS fitness in a humanized mouse model of impetigo; the ΔfbaA mutant also exhibited decreased survival in whole human blood due to phagocytosis. In assays with highly sensitive outcome measures, Alab49ΔfbaA was compared to other isogenic mutants lacking virulence genes known to be disproportionately associated with classical skin strains. FbaA and PAM (i.e., the M53 protein) had additive effects in promoting GAS survival in whole blood. The pilus adhesin tip protein Cpa promoted Alab49 survival in whole blood and appears to fully account for the antiphagocytic effect attributable to pili. The finding that numerous skin strain-associated virulence factors make slight but significant contributions to virulence underscores the incremental contributions to fitness of individual surface protein genes and the multifactorial nature of GAS-host interactions.
Collapse
|
160
|
Rajkumari R, Jose JM, Brahmadathan KN. Genetic Diversity and Allelic Variation in South Indian Isolates of Group A Streptococci Causing Invasive Disease. Indian J Med Microbiol 2017; 35:575-579. [DOI: 10.4103/ijmm.ijmm_17_298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
161
|
Population and Whole Genome Sequence Based Characterization of Invasive Group A Streptococci Recovered in the United States during 2015. mBio 2017; 8:mBio.01422-17. [PMID: 28928212 PMCID: PMC5605940 DOI: 10.1128/mbio.01422-17] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Group A streptococci (GAS) are genetically diverse. Determination of strain features can reveal associations with disease and resistance and assist in vaccine formulation. We employed whole-genome sequence (WGS)-based characterization of 1,454 invasive GAS isolates recovered in 2015 by Active Bacterial Core Surveillance and performed conventional antimicrobial susceptibility testing. Predictions were made for genotype, GAS carbohydrate, antimicrobial resistance, surface proteins (M family, fibronectin binding, T, R28), secreted virulence proteins (Sda1, Sic, exotoxins), hyaluronate capsule, and an upregulated nga operon (encodes NADase and streptolysin O) promoter (Pnga3). Sixty-four M protein gene (emm) types were identified among 69 clonal complexes (CCs), including one CC of Streptococcus dysgalactiae subsp. equisimilis. emm types predicted the presence or absence of active sof determinants and were segregated into sof-positive or sof-negative genetic complexes. Only one “emm type switch” between strains was apparent. sof-negative strains showed a propensity to cause infections in the first quarter of the year, while sof+ strain infections were more likely in summer. Of 1,454 isolates, 808 (55.6%) were Pnga3 positive and 637 (78.9%) were accounted for by types emm1, emm89, and emm12. Theoretical coverage of a 30-valent M vaccine combined with an M-related protein (Mrp) vaccine encompassed 98% of the isolates. WGS data predicted that 15.3, 13.8, 12.7, and 0.6% of the isolates were nonsusceptible to tetracycline, erythromycin plus clindamycin, erythromycin, and fluoroquinolones, respectively, with only 19 discordant phenotypic results. Close phylogenetic clustering of emm59 isolates was consistent with recent regional emergence. This study revealed strain traits informative for GAS disease incidence tracking, outbreak detection, vaccine strategy, and antimicrobial therapy. The current population-based WGS data from GAS strains causing invasive disease in the United States provide insights important for prevention and control strategies. Strain distribution data support recently proposed multivalent M type-specific and conserved M-like protein vaccine formulations that could potentially protect against nearly all invasive U.S. strains. The three most prevalent clonal complexes share key polymorphisms in the nga operon encoding two secreted virulence factors (NADase and streptolysin O) that have been previously associated with high strain virulence and transmissibility. We find that Streptococcus pyogenes is phylogenetically subdivided into loosely defined multilocus sequence type-based clusters consisting of solely sof-negative or sof-positive strains; with sof-negative strains demonstrating differential seasonal preference for infection, consistent with the recently demonstrated differential seasonal preference based on phylogenetic clustering of full-length M proteins. This might relate to the differences in GAS strain compositions found in different geographic settings and could further inform prevention strategies.
Collapse
|
162
|
Shocking superantigens promote establishment of bacterial infection. Proc Natl Acad Sci U S A 2017; 114:10000-10002. [PMID: 28900005 DOI: 10.1073/pnas.1713451114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
163
|
Ghosh P. Variation, Indispensability, and Masking in the M protein. Trends Microbiol 2017; 26:132-144. [PMID: 28867148 DOI: 10.1016/j.tim.2017.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 07/26/2017] [Accepted: 08/08/2017] [Indexed: 11/17/2022]
Abstract
The M protein is the major surface-associated virulence factor of group A Streptococcus (GAS) and an antigenically variable target of host immunity. How selection pressures to escape immune recognition, maintain indispensable functions, and mask vulnerabilities have shaped the sequences of the >220M protein types is unclear. Recent experiments have shed light on this question by showing that, hidden within the antigenic variability of many M protein types, are sequence patterns conserved for recruiting human C4b-binding protein (C4BP). Other host factors may be recruited in a similar manner by conserved but hidden sequence patterns in the M protein. The identification of such patterns may be applicable to the development of a GAS vaccine.
Collapse
Affiliation(s)
- Partho Ghosh
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.
| |
Collapse
|
164
|
Multi-functional mechanisms of immune evasion by the streptococcal complement inhibitor C5a peptidase. PLoS Pathog 2017; 13:e1006493. [PMID: 28806402 PMCID: PMC5555575 DOI: 10.1371/journal.ppat.1006493] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/27/2017] [Indexed: 11/19/2022] Open
Abstract
The complement cascade is crucial for clearance and control of invading pathogens, and as such is a key target for pathogen mediated host modulation. C3 is the central molecule of the complement cascade, and plays a vital role in opsonization of bacteria and recruitment of neutrophils to the site of infection. Streptococcal species have evolved multiple mechanisms to disrupt complement-mediated innate immunity, among which ScpA (C5a peptidase), a C5a inactivating enzyme, is widely conserved. Here we demonstrate for the first time that pyogenic streptococcal species are capable of cleaving C3, and identify C3 and C3a as novel substrates for the streptococcal ScpA, which are functionally inactivated as a result of cleavage 7 amino acids upstream of the natural C3 convertase. Cleavage of C3a by ScpA resulted in disruption of human neutrophil activation, phagocytosis and chemotaxis, while cleavage of C3 generated abnormally-sized C3a and C3b moieties with impaired function, in particular reducing C3 deposition on the bacterial surface. Despite clear effects on human complement, expression of ScpA reduced clearance of group A streptococci in vivo in wildtype and C5 deficient mice, and promoted systemic bacterial dissemination in mice that lacked both C3 and C5, suggesting an additional complement-independent role for ScpA in streptococcal pathogenesis. ScpA was shown to mediate streptococcal adhesion to both human epithelial and endothelial cells, consistent with a role in promoting bacterial invasion within the host. Taken together, these data show that ScpA is a multi-functional virulence factor with both complement-dependent and independent roles in streptococcal pathogenesis. The complement pathway is critical in the innate immune response to bacterial pathogens. It consists of a self-perpetuating proteolytic cascade initiated via three distinct pathways that converge at the central complement protein, C3. Pathogens must evade complement-mediated immunity to cause disease, and inactivation of the C3 protein can dampen all effectors of this pathway. Streptococcal species are the causative agents of an array of infections ranging from the benign to lethal. Using the human pathogen Group A Streptococcus as a representative species, we show that the enzyme ScpA, which is conserved amongst the pyogenic streptococci, cleaves human C3a and also C3, releasing abnormally sized and functionally-impaired fragments. As a result, invading streptococci were less well opsonized and host immune cells not properly activated, reducing bacterial phagocytosis and clearance. Despite manifest in vitro activity against complement factors and human neutrophils, ScpA was still able to contribute to systemic bacterial spread in mice lacking C3 and C5. ScpA was also demonstrated to mediate streptococcal adhesion to both epithelial and endothelial cells, which may enhance bacterial systemic spread. Our study highlights the likely importance of both complement-independent and complement-dependent roles for ScpA in streptococcal pathogenesis.
Collapse
|
165
|
Group A streptococcal M protein activates the NLRP3 inflammasome. Nat Microbiol 2017; 2:1425-1434. [PMID: 28784982 DOI: 10.1038/s41564-017-0005-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 07/04/2017] [Indexed: 12/17/2022]
Abstract
Group A Streptococcus (GAS) is among the top ten causes of infection-related mortality in humans. M protein is the most abundant GAS surface protein, and M1 serotype GAS strains are associated with invasive infections, including necrotizing fasciitis and toxic shock syndrome. Here, we report that released, soluble M1 protein triggers programmed cell death in macrophages (Mϕ). M1 served as a second signal for caspase-1-dependent NLRP3 inflammasome activation, inducing maturation and release of proinflammatory cytokine interleukin-1β (IL-1β) and macrophage pyroptosis. The structurally dynamic B-repeat domain of M1 was critical for inflammasome activation, which involved K+ efflux and M1 protein internalization by clathrin-mediated endocytosis. Mouse intraperitoneal challenge showed that soluble M1 was sufficient and specific for IL-1β activation, which may represent an early warning to activate host immunity against the pathogen. Conversely, in systemic infection, hyperinflammation associated with M1-mediated pyroptosis and IL-1β release could aggravate tissue injury.
Collapse
|
166
|
Lu B, Fang Y, Fan Y, Chen X, Wang J, Zeng J, Li Y, Zhang Z, Huang L, Li H, Li D, Zhu F, Cui Y, Wang D. High Prevalence of Macrolide-resistance and Molecular Characterization of Streptococcus pyogenes Isolates Circulating in China from 2009 to 2016. Front Microbiol 2017. [PMID: 28642756 PMCID: PMC5463034 DOI: 10.3389/fmicb.2017.01052] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Streptococcus pyogenes, or group A Streptococcus, is a pathogen responsible for a wide range of clinical manifestations, from mild skin and soft tissue infections and pharyngitis to severe diseases. Its epidemiological characteristics should be comprehensively under surveillance for regulating the national prevention and treatment practice. Herein, a total of 140 S. pyogenes, including 38 invasive and 102 noninvasive isolates, were collected from infected patients in 10 tertiary general hospitals from 7 cities/provinces in China during the years 2009–2016. All strains were characterized by classical and molecular techniques for its emm types/subtypes, virulent factors and antibiotic resistance profiling. Of 140 isolates, 15 distinct emm types and 31 subtypes were detected, dominated by emm12 (60 isolates, 42.9%), emm1(43, 30.7%), and emm89 (10, 7.1%), and 8 new emm variant subtypes were identified. All strains, invasive or not, harbored the superantigenic genes, speB and slo. The other virulence genes, smeZ, speF, and speC accounted for 96.4, 91.4, and 87.1% of collected isolates, respectively. Further multilocus sequence typing (MLST) placed all strains into 22 individual sequence types (STs), including 4 newly-identified STs (11, 7.9%). All isolates were phenotypically susceptible to penicillin, ampicillin, cefotaxime, and vancomycin, whereas 131(93.5%), 132(94.2%), and 121(86.4%) were resistant to erythromycin, clindamycin, and tetracycline, respectively. Our study highlights high genotypic diversity and high prevalence of macrolide resistance of S. pyogenes among clinical isolates circulating in China.
Collapse
Affiliation(s)
- Binghuai Lu
- Department of Laboratory Medicine, Civil Aviation General Hospital, Peking University Civil Aviation School of Clinical MedicineBeijing, China
| | - Yujie Fang
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Centre for Disease Control and Prevention, National Institute for Communicable Disease Control and PreventionBeijing, China.,Collaborative Innovation Centre for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
| | - Yanyan Fan
- Laboratory of Clinical Microbiology and Infectious Diseases, Department of Pulmonary and Critical Care Medicine, China-Japan Friendship HospitalBeijing, China
| | - Xingchun Chen
- Department of Laboratory Medicine, People's Hospital of Guangxi Zhuang Autonomous RegionNanning, China
| | - Junrui Wang
- Department of Clinical Laboratory, Affiliated Hospital of Inner Mongolia Medical UniversityHohhot, China
| | - Ji Zeng
- Department of Laboratory Medicine, Wuhan Pu Ai Hospital of Huazhong, University of Science and TechnologyWuhan, China
| | - Yi Li
- Department of Laboratory Medicine, Henan Provincial People's HospitalZhengzhou, China
| | - Zhijun Zhang
- Department of Laboratory Medicine, Tai'an City Central Hospital (Tai'an)Shandong, China
| | - Lei Huang
- Department of Laboratory Medicine, First Hospital, Peking UniversityBeijing, China
| | - Hongxia Li
- Department of Laboratory Medicine, Chengdu First People's Hospital (Chengdu)Sichuan, China
| | - Dong Li
- Department of Laboratory Medicine, Civil Aviation General Hospital, Peking University Civil Aviation School of Clinical MedicineBeijing, China
| | - Fengxia Zhu
- Department of Laboratory Medicine, Civil Aviation General Hospital, Peking University Civil Aviation School of Clinical MedicineBeijing, China
| | - Yanchao Cui
- Department of Laboratory Medicine, Civil Aviation General Hospital, Peking University Civil Aviation School of Clinical MedicineBeijing, China
| | - Duochun Wang
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Centre for Disease Control and Prevention, National Institute for Communicable Disease Control and PreventionBeijing, China.,Collaborative Innovation Centre for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
| |
Collapse
|
167
|
Ly AT, Noto JP, Walwyn OL, Tanz RR, Shulman ST, Kabat W, Bessen DE. Differences in SpeB protease activity among group A streptococci associated with superficial, invasive, and autoimmune disease. PLoS One 2017; 12:e0177784. [PMID: 28545045 PMCID: PMC5435240 DOI: 10.1371/journal.pone.0177784] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 05/03/2017] [Indexed: 11/19/2022] Open
Abstract
The secreted cysteine proteinase SpeB is an important virulence factor of group A streptococci (GAS), whereby SpeB activity varies widely among strains. To establish the degree to which SpeB activity correlates with disease, GAS organisms were recovered from patients with pharyngitis, impetigo, invasive disease or acute rheumatic fever (ARF), and selected for analysis using rigorous sampling criteria; >300 GAS isolates were tested for SpeB activity by casein digestion assays, and each GAS isolate was scored as a SpeB-producer or non-producer. Highly significant statistical differences (p < 0.01) in SpeB production are observed between GAS recovered from patients with ARF (41.5% SpeB-non-producers) compared to pharyngitis (20.5%), invasive disease (16.7%), and impetigo (5.5%). SpeB activity differences between pharyngitis and impetigo isolates are also significant, whereas pharyngitis versus invasive isolates show no significant difference. The disproportionately greater number of SpeB-non-producers among ARF-associated isolates may indicate an altered transcriptional program for many rheumatogenic strains and/or a protective role for SpeB in GAS-triggered autoimmunity.
Collapse
Affiliation(s)
- Anhphan T. Ly
- Department of Microbiology and Immunology, New York Medical College, Valhalla, New York, United States of America
| | - John P. Noto
- Department of Microbiology and Immunology, New York Medical College, Valhalla, New York, United States of America
| | - Odaelys L. Walwyn
- Department of Microbiology and Immunology, New York Medical College, Valhalla, New York, United States of America
| | - Robert R. Tanz
- Department of Pediatrics, Northwestern University Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital, Chicago, Illinois, United States of America
| | - Stanford T. Shulman
- Department of Pediatrics, Northwestern University Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital, Chicago, Illinois, United States of America
| | - William Kabat
- Department of Pediatrics, Northwestern University Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital, Chicago, Illinois, United States of America
| | - Debra E. Bessen
- Department of Microbiology and Immunology, New York Medical College, Valhalla, New York, United States of America
| |
Collapse
|
168
|
Kapatai G, Coelho J, Platt S, Chalker VJ. Whole genome sequencing of group A Streptococcus: development and evaluation of an automated pipeline for emmgene typing. PeerJ 2017; 5:e3226. [PMID: 28462035 PMCID: PMC5410157 DOI: 10.7717/peerj.3226] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 03/24/2017] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pyogenes group A Streptococcus (GAS) is the most common cause of bacterial throat infections, and can cause mild to severe skin and soft tissue infections, including impetigo, erysipelas, necrotizing fasciitis, as well as systemic and fatal infections including septicaemia and meningitis. Estimated annual incidence for invasive group A streptococcal infection (iGAS) in industrialised countries is approximately three per 100,000 per year. Typing is currently used in England and Wales to monitor bacterial strains of S. pyogenes causing invasive infections and those isolated from patients and healthcare/care workers in cluster and outbreak situations. Sequence analysis of the emm gene is the currently accepted gold standard methodology for GAS typing. A comprehensive database of emm types observed from superficial and invasive GAS strains from England and Wales informs outbreak control teams during investigations. Each year the Bacterial Reference Department, Public Health England (PHE) receives approximately 3,000 GAS isolates from England and Wales. In April 2014 the Bacterial Reference Department, PHE began genomic sequencing of referred S. pyogenes isolates and those pertaining to selected elderly/nursing care or maternity clusters from 2010 to inform future reference services and outbreak analysis (n = 3, 047). In line with the modernizing strategy of PHE, we developed a novel bioinformatics pipeline that can predict emmtypes using whole genome sequence (WGS) data. The efficiency of this method was measured by comparing the emmtype assigned by this method against the result from the current gold standard methodology; concordance to emmsubtype level was observed in 93.8% (2,852/3,040) of our cases, whereas in 2.4% (n = 72) of our cases concordance was observed to emm type level. The remaining 3.8% (n = 117) of our cases corresponded to novel types/subtypes, contamination, laboratory sample transcription errors or problems arising from high sequence similarity of the allele sequence or low mapping coverage. De novo assembly analysis was performed in the two latter groups (n = 72 + 117) and was able to diagnose the problem and where possible resolve the discordance (60/72 and 20/117, respectively). Overall, we have demonstrated that our WGS emm-typing pipeline is a reliable and robust system that can be implemented to determine emm type for the routine service.
Collapse
Affiliation(s)
- Georgia Kapatai
- Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom
| | - Juliana Coelho
- Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom
| | - Steven Platt
- Infectious Disease Informatics, Public Health England, London, United Kingdom
| | - Victoria J Chalker
- Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom
| |
Collapse
|
169
|
Gandhi GD, Krishnamoorthy N, Motal UMA, Yacoub M. Towards developing a vaccine for rheumatic heart disease. Glob Cardiol Sci Pract 2017; 2017:e201704. [PMID: 28971103 PMCID: PMC5621712 DOI: 10.21542/gcsp.2017.4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Rheumatic heart disease (RHD) is the most serious manifestations of rheumatic fever, which is caused by group A Streptococcus (GAS or Streptococcus pyogenes) infection. RHD is an auto immune sequelae of GAS pharyngitis, rather than the direct bacterial infection of the heart, which leads to chronic heart valve damage. Although antibiotics like penicillin are effective against GAS infection, improper medical care such as poor patient compliance, overcrowding, poverty, and repeated exposure to GAS, leads to acute rheumatic fever and RHD. Thus, efforts have been put forth towards developing a vaccine. However, a potential global vaccine is yet to be identified due to the widespread diversity of S. pyogenes strains and cross reactivity of streptococcal proteins with host tissues. In this review, we discuss the available vaccine targets of S. pyogenes and the significance of in silico approaches in designing a vaccine for RHD.
Collapse
Affiliation(s)
- Geethanjali Devadoss Gandhi
- Division of Cardiovascular Research, Sidra Medical and Research Center, Qatar Foundation, Doha, Qatar.,Division of Experimental Genetics, Sidra Medical and Research Center, Doha, Qatar
| | - Navaneethakrishnan Krishnamoorthy
- Division of Cardiovascular Research, Sidra Medical and Research Center, Qatar Foundation, Doha, Qatar.,Division of Experimental Genetics, Sidra Medical and Research Center, Doha, Qatar.,Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Ussama M Abdel Motal
- Division of Cardiovascular Research, Sidra Medical and Research Center, Qatar Foundation, Doha, Qatar
| | - Magdi Yacoub
- Division of Cardiovascular Research, Sidra Medical and Research Center, Qatar Foundation, Doha, Qatar.,Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| |
Collapse
|
170
|
Kuo CF, Tsao N, Hsieh IC, Lin YS, Wu JJ, Hung YT. Immunization with a streptococcal multiple-epitope recombinant protein protects mice against invasive group A streptococcal infection. PLoS One 2017; 12:e0174464. [PMID: 28355251 PMCID: PMC5371370 DOI: 10.1371/journal.pone.0174464] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 03/09/2017] [Indexed: 12/11/2022] Open
Abstract
Streptococcus pyogenes (group A Streptococcus; GAS) causes clinical diseases, including pharyngitis, scarlet fever, impetigo, necrotizing fasciitis and streptococcal toxic shock syndrome. A number of group A streptococcus vaccine candidates have been developed, but only one 26-valent recombinant M protein vaccine has entered clinical trials. Differing from the design of a 26-valent recombinant M protein vaccine, we provide here a vaccination using the polyvalence epitope recombinant FSBM protein (rFSBM), which contains four different epitopes, including the fibronectin-binding repeats domain of streptococcal fibronectin binding protein Sfb1, the C-terminal immunogenic segment of streptolysin S, the C3-binding motif of streptococcal pyrogenic exotoxin B, and the C-terminal conserved segment of M protein. Vaccination with the rFSBM protein successfully prevented mortality and skin lesions caused by several emm strains of GAS infection. Anti-FSBM antibodies collected from the rFSBM-immunized mice were able to opsonize at least six emm strains and can neutralize the hemolytic activity of streptolysin S. Furthermore, the internalization of GAS into nonphagocytic cells is also reduced by anti-FSBM serum. These findings suggest that rFSBM can be applied as a vaccine candidate to prevent different emm strains of GAS infection.
Collapse
Affiliation(s)
- Chih-Feng Kuo
- Department of Nursing, College of Medicine, I-Shou University, Kaohsiung, Taiwan
| | - Nina Tsao
- Department of Biological Science and Technology, College of Medicine, I-Shou University, Kaohsiung, Taiwan
| | - I-Chen Hsieh
- Department of Biological Science and Technology, College of Medicine, I-Shou University, Kaohsiung, Taiwan
| | - Yee-Shin Lin
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jiunn-Jong Wu
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Department of Biotechnology and Laboratory Science in Medicine, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Ting Hung
- Department of Biological Science and Technology, College of Medicine, I-Shou University, Kaohsiung, Taiwan
| |
Collapse
|
171
|
Group A Streptococcus, Acute Rheumatic Fever and Rheumatic Heart Disease: Epidemiology and Clinical Considerations. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2017; 19:15. [PMID: 28285457 PMCID: PMC5346434 DOI: 10.1007/s11936-017-0513-y] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OPINION STATEMENT Early recognition of group A streptococcal pharyngitis and appropriate management with benzathine penicillin using local clinical prediction rules together with validated rapi-strep testing when available should be incorporated in primary health care. A directed approach to the differential diagnosis of acute rheumatic fever now includes the concept of low-risk versus medium-to-high risk populations. Initiation of secondary prophylaxis and the establishment of early medium to long-term care plans is a key aspect of the management of ARF. It is a requirement to identify high-risk individuals with RHD such as those with heart failure, pregnant women, and those with severe disease and multiple valve involvement. As penicillin is the mainstay of primary and secondary prevention, further research into penicillin supply chains, alternate preparations and modes of delivery is required.
Collapse
|
172
|
Swe PM, Christian LD, Lu HC, Sriprakash KS, Fischer K. Complement inhibition by Sarcoptes scabiei protects Streptococcus pyogenes - An in vitro study to unravel the molecular mechanisms behind the poorly understood predilection of S. pyogenes to infect mite-induced skin lesions. PLoS Negl Trop Dis 2017; 11:e0005437. [PMID: 28278252 PMCID: PMC5360341 DOI: 10.1371/journal.pntd.0005437] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/21/2017] [Accepted: 02/25/2017] [Indexed: 02/01/2023] Open
Abstract
Background On a global scale scabies is one of the most common dermatological conditions, imposing a considerable economic burden on individuals, communities and health systems. There is substantial epidemiological evidence that in tropical regions scabies is often causing pyoderma and subsequently serious illness due to invasion by opportunistic bacteria. The health burden due to complicated scabies causing cellulitis, bacteraemia and sepsis, heart and kidney diseases in resource-poor communities is extreme. Co-infections of group A streptococcus (GAS) and scabies mites is a common phenomenon in the tropics. Both pathogens produce multiple complement inhibitors to overcome the host innate defence. We investigated the relative role of classical (CP), lectin (LP) and alternative pathways (AP) towards a pyodermic GAS isolate 88/30 in the presence of a scabies mite complement inhibitor, SMSB4. Methodology/Principal findings Opsonophagocytosis assays in fresh blood showed baseline immunity towards GAS. The role of innate immunity was investigated by deposition of the first complement components of each pathway, specifically C1q, FB and MBL from normal human serum on GAS. C1q deposition was the highest followed by FB deposition while MBL deposition was undetectable, suggesting that CP and AP may be mainly activated by GAS. We confirmed this result using sera depleted of either C1q or FB, and serum deficient in MBL. Recombinant SMSB4 was produced and purified from Pichia pastoris. SMSB4 reduced the baseline immunity against GAS by decreasing the formation of CP- and AP-C3 convertases, subsequently affecting opsonisation and the release of anaphylatoxin. Conclusions/Significance Our results indicate that the complement-inhibitory function of SMSB4 promotes the survival of GAS in vitro and inferably in the microenvironment of the mite-infested skin. Understanding the tripartite interactions between host, parasite and microbial pathogens at a molecular level may serve as a basis to develop improved intervention strategies targeting scabies and associated bacterial infections. The molecular mechanisms that underpin the link between scabies and bacterial pathogens were unknown. We proposed that scabies mites play a role in the establishment, proliferation and transmission of opportunistic pathogens. We investigated here the synergy between mites and one of the most recognised mite associated pathogens, Streptococcus pyogenes. As part of the innate immune response mammals have a pre-programmed ability to recognise and immediately act against substances derived from fungal and bacterial microorganisms. This is mediated through a sequential biochemical cascade involving over 30 different proteins (complement system) which as a result of signal amplification triggers a rapid killing response. The complement cascade produces peptides that attract immune cells, increases vascular permeability, coats (opsonises) the surfaces of a pathogen, marking it for destruction, and directly disrupts foreign plasma membranes. To prevent complement mediated damage of their gut cells, scabies mites secrete several classes of complement inhibiting proteins into the mite gut and excrete them into the epidermal mite burrows. Furthermore, these inhibitors also provide protection for S. pyogenes. We verified here specifically the impact of the mite complement inhibitor SMSB4, to identify the molecular mechanisms behind the long recognised tendency of S. pyogenes to infect mite-induced skin lesions.
Collapse
Affiliation(s)
- Pearl M. Swe
- QIMR Berghofer Medical Research Institute, Infectious Diseases Department, Herston, Brisbane, Australia
| | - Lindsay D. Christian
- QIMR Berghofer Medical Research Institute, Infectious Diseases Department, Herston, Brisbane, Australia
| | - Hieng C. Lu
- QIMR Berghofer Medical Research Institute, Infectious Diseases Department, Herston, Brisbane, Australia
| | - Kadaba S. Sriprakash
- QIMR Berghofer Medical Research Institute, Infectious Diseases Department, Herston, Brisbane, Australia
| | - Katja Fischer
- QIMR Berghofer Medical Research Institute, Infectious Diseases Department, Herston, Brisbane, Australia
- * E-mail:
| |
Collapse
|
173
|
Beye M, El Karkouri K, Labas N, Raoult D, Fournier PE. Genomic analysis of a Streptococcus pyogenes strain causing endocarditis in a child. New Microbes New Infect 2017; 17:1-6. [PMID: 28239478 PMCID: PMC5318540 DOI: 10.1016/j.nmni.2017.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/03/2017] [Accepted: 01/11/2017] [Indexed: 11/16/2022] Open
Abstract
We sequenced the genome of Streptococcus pyogenes strain G773 that caused an infective endocarditis in a 4-year-old boy suffering from acute endocarditis. The 1.9-Mb genome exhibited a specific combination of virulence factors including a complete integrative and conjugative element, sp2905, previously described as incomplete in S. pyogenes, and five bacteriocin-coding genes. However, strain G773 lacked a CRISPR-Cas system.
Collapse
Affiliation(s)
- M Beye
- URMITE, UM63, CNRS7278, IRD198, Inserm1095, Institut Hospitalo-Universitaire Méditerranée-infection, Aix-Marseille Université, Faculté de Médecine, Marseille, France
| | - K El Karkouri
- URMITE, UM63, CNRS7278, IRD198, Inserm1095, Institut Hospitalo-Universitaire Méditerranée-infection, Aix-Marseille Université, Faculté de Médecine, Marseille, France
| | - N Labas
- URMITE, UM63, CNRS7278, IRD198, Inserm1095, Institut Hospitalo-Universitaire Méditerranée-infection, Aix-Marseille Université, Faculté de Médecine, Marseille, France
| | - D Raoult
- URMITE, UM63, CNRS7278, IRD198, Inserm1095, Institut Hospitalo-Universitaire Méditerranée-infection, Aix-Marseille Université, Faculté de Médecine, Marseille, France; Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdul Aziz University, Jeddah, Saudi Arabia
| | - P-E Fournier
- URMITE, UM63, CNRS7278, IRD198, Inserm1095, Institut Hospitalo-Universitaire Méditerranée-infection, Aix-Marseille Université, Faculté de Médecine, Marseille, France
| |
Collapse
|
174
|
Disorazoles Block Group A Streptococcal Invasion into Epithelial Cells Via Interference with the Host Factor Ezrin. Cell Chem Biol 2017; 24:159-170. [DOI: 10.1016/j.chembiol.2016.12.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/07/2016] [Accepted: 12/15/2016] [Indexed: 12/22/2022]
|
175
|
Huish S, Thelwell C, Longstaff C. Activity Regulation by Fibrinogen and Fibrin of Streptokinase from Streptococcus Pyogenes. PLoS One 2017; 12:e0170936. [PMID: 28125743 PMCID: PMC5268773 DOI: 10.1371/journal.pone.0170936] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/12/2017] [Indexed: 01/26/2023] Open
Abstract
Streptokinase is a virulence factor of streptococci and acts as a plasminogen activator to generate the serine protease plasmin which promotes bacterial metastasis. Streptokinase isolated from group C streptococci has been used therapeutically as a thrombolytic agent for many years and its mechanism of action has been extensively studied. However, group A streptococci are associated with invasive and potentially fatal infections, but less detail is available on the mechanism of action of streptokinase from these bacteria. We have expressed recombinant streptokinase from a group C strain to investigate the therapeutic molecule (here termed rSK-H46A) and a molecule isolated from a cluster 2a strain from group A (rSK-M1GAS) which is known to produce the fibrinogen binding, M1 protein, and is associated with life-threatening disease. Detailed enzyme kinetic models have been prepared which show how fibrinogen-streptokinase-plasminogen complexes regulate plasmin generation, and also the effect of fibrin interactions. As is the case with rSK-H46A our data with rSK-M1GAS support a "trigger and bullet" mechanism requiring the initial formation of SK•plasminogen complexes which are replaced by more active SK•plasmin as plasmin becomes available. This model includes the important fibrinogen interactions that stimulate plasmin generation. In a fibrin matrix rSK-M1GAS has a 24 fold higher specific activity than the fibrin-specific thrombolytic agent, tissue plasminogen activator, and 15 fold higher specific activity than rSK-H46A. However, in vivo fibrin specificity would be undermined by fibrinogen stimulation. Given the observed importance of M1 surface receptors or released M1 protein to virulence of cluster 2a strain streptococci, studies on streptokinase activity regulation by fibrin and fibrinogen may provide additional routes to addressing bacterial invasion and infectious diseases.
Collapse
Affiliation(s)
- Sian Huish
- Component development laboratory, NHS Blood and Transplant, Cambridge Donor Centre, Cambridge, United Kingdom
| | - Craig Thelwell
- Biotherapeutics Section, National Institute for Biological Standard and Control, South Mimms, Herts, United Kingdom
| | - Colin Longstaff
- Biotherapeutics Section, National Institute for Biological Standard and Control, South Mimms, Herts, United Kingdom
- * E-mail:
| |
Collapse
|
176
|
Blood Group Antigen Recognition via the Group A Streptococcal M Protein Mediates Host Colonization. mBio 2017; 8:mBio.02237-16. [PMID: 28119471 PMCID: PMC5263248 DOI: 10.1128/mbio.02237-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Streptococcus pyogenes (group A streptococcus [GAS]) is responsible for over 500,000 deaths worldwide each year. The highly virulent M1T1 GAS clone is one of the most frequently isolated serotypes from streptococcal pharyngitis and invasive disease. The oral epithelial tract is a niche highly abundant in glycosylated structures, particularly those of the ABO(H) blood group antigen family. Using a high-throughput approach, we determined that a strain representative of the globally disseminated M1T1 GAS clone 5448 interacts with numerous, structurally diverse glycans. Preeminent among GAS virulence factors is the surface-expressed M protein. M1 protein showed high affinity for several terminal galactose blood group antigen structures. Deletion mutagenesis shows that M1 protein mediates glycan binding via its B repeat domains. Association of M1T1 GAS with oral epithelial cells varied significantly as a result of phenotypic differences in blood group antigen expression, with significantly higher adherence to those cells expressing H antigen structures compared to cells expressing A, B, or AB antigen structures. These data suggest a novel mechanism for GAS attachment to host cells and propose a link between host blood group antigen expression and M1T1 GAS colonization. IMPORTANCE There has been a resurgence in group A streptococcal (GAS) invasive disease, which has been paralleled by the emergence of the highly virulent M1T1 GAS clone. Intensive research has focused on mechanisms that contribute to the invasive nature of this serotype, while the mechanisms that contribute to host susceptibility to disease and bacterial colonization and persistence are still poorly understood. The M1T1 GAS clone is frequently isolated from the throat, an environment highly abundant in blood group antigen structures. This work examined the interaction of the M1 protein, the preeminent GAS surface protein, against a wide range of host-expressed glycan structures. Our data suggest that susceptibility to infection by GAS in the oral tract may correlate with phenotypic differences in host blood group antigen expression. Thus, variations in host blood group antigen expression may serve as a selective pressure contributing to the dissemination and overrepresentation of M1T1 GAS.
Collapse
|
177
|
Efstratiou A, Lamagni T, Turner CE. Streptococci and Enterococci. Infect Dis (Lond) 2017. [DOI: 10.1016/b978-0-7020-6285-8.00177-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
|
178
|
Ibrahim J, Eisen JA, Jospin G, Coil DA, Khazen G, Tokajian S. Genome Analysis of Streptococcus pyogenes Associated with Pharyngitis and Skin Infections. PLoS One 2016; 11:e0168177. [PMID: 27977735 PMCID: PMC5158041 DOI: 10.1371/journal.pone.0168177] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 11/25/2016] [Indexed: 12/12/2022] Open
Abstract
Streptococcus pyogenes is a very important human pathogen, commonly associated with skin or throat infections but can also cause life-threatening situations including sepsis, streptococcal toxic shock syndrome, and necrotizing fasciitis. Various studies involving typing and molecular characterization of S. pyogenes have been published to date; however next-generation sequencing (NGS) studies provide a comprehensive collection of an organism’s genetic variation. In this study, the genomes of nine S. pyogenes isolates associated with pharyngitis and skin infection were sequenced and studied for the presence of virulence genes, resistance elements, prophages, genomic recombination, and other genomic features. Additionally, a comparative phylogenetic analysis of the isolates with global clones highlighted their possible evolutionary lineage and their site of infection. The genomes were found to also house a multitude of features including gene regulation systems, virulence factors and antimicrobial resistance mechanisms.
Collapse
Affiliation(s)
- Joe Ibrahim
- Department of Natural Sciences, Lebanese American University, School of Arts and Sciences, Byblos, Lebanon
| | - Jonathan A. Eisen
- University of California Davis Genome Center, Davis, California, United States of America
| | - Guillaume Jospin
- University of California Davis Genome Center, Davis, California, United States of America
| | - David A. Coil
- University of California Davis Genome Center, Davis, California, United States of America
| | - Georges Khazen
- Department of Computer Science and Mathematics, Lebanese American University, School of Arts and Sciences, Byblos, Lebanon
| | - Sima Tokajian
- Department of Natural Sciences, Lebanese American University, School of Arts and Sciences, Byblos, Lebanon
- * E-mail:
| |
Collapse
|
179
|
Dale JB, Smeesters PR, Courtney HS, Penfound TA, Hohn CM, Smith JC, Baudry JY. Structure-based design of broadly protective group a streptococcal M protein-based vaccines. Vaccine 2016; 35:19-26. [PMID: 27890396 DOI: 10.1016/j.vaccine.2016.11.065] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 11/10/2016] [Accepted: 11/17/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND A major obstacle to the development of broadly protective M protein-based group A streptococcal (GAS) vaccines is the variability within the N-terminal epitopes that evoke potent bactericidal antibodies. The concept of M type-specific protective immune responses has recently been challenged based on the observation that multivalent M protein vaccines elicited cross-reactive bactericidal antibodies against a number of non-vaccine M types of GAS. Additionally, a new "cluster-based" typing system of 175M proteins identified a limited number of clusters containing closely related M proteins. In the current study, we used the emm cluster typing system, in combination with computational structure-based peptide modeling, as a novel approach to the design of potentially broadly protective M protein-based vaccines. METHODS M protein sequences (AA 16-50) from the E4 cluster containing 17 emm types of GAS were analyzed using de novo 3-D structure prediction tools and the resulting structures subjected to chemical diversity analysis to identify sequences that were the most representative of the 3-D physicochemical properties of the M peptides in the cluster. Five peptides that spanned the range of physicochemical attributes of all 17 peptides were used to formulate synthetic and recombinant vaccines. Rabbit antisera were assayed for antibodies that cross-reacted with E4 peptides and whole bacteria by ELISA and for bactericidal activity against all E4GAS. RESULTS The synthetic vaccine rabbit antisera reacted with all 17 E4M peptides and demonstrated bactericidal activity against 15/17 E4GAS. A recombinant hybrid vaccine containing the same E4 peptides also elicited antibodies that cross-reacted with all E4M peptides. CONCLUSIONS Comprehensive studies using structure-based design may result in a broadly protective M peptide vaccine that will elicit cluster-specific and emm type-specific antibody responses against the majority of clinically relevant emm types of GAS.
Collapse
Affiliation(s)
- James B Dale
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, United States; Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States; Department of Veterans Affairs Medical Center, Memphis, TN, United States.
| | - Pierre R Smeesters
- Department of Pediatrics, Academic Children Hospital Queen Fabiola, Université Libre de Bruxelles, Brussels, Belgium; Molecular Bacteriology Laboratory, Université Libre de Bruxelles, Brussels, Belgium; Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Melbourne, Australia; Centre for International Child Health, University of Melbourne, Melbourne, Australia
| | - Harry S Courtney
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Thomas A Penfound
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Claudia M Hohn
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Jeremy C Smith
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Oak Ridge, TN, United States; University of Tennessee/Oak Ridge National Laboratory Center for Molecular Biophysics, Oak Ridge, TN, United States
| | - Jerome Y Baudry
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Oak Ridge, TN, United States; University of Tennessee/Oak Ridge National Laboratory Center for Molecular Biophysics, Oak Ridge, TN, United States
| |
Collapse
|
180
|
Tsai JYC, Loh JMS, Clow F, Lorenz N, Proft T. The Group A Streptococcus serotype M2 pilus plays a role in host cell adhesion and immune evasion. Mol Microbiol 2016; 103:282-298. [PMID: 27741558 DOI: 10.1111/mmi.13556] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2016] [Indexed: 01/22/2023]
Abstract
Group A Streptococcus (GAS), or Streptococcus pyogenes, is a human pathogen that causes diseases ranging from skin and soft tissue infections to severe invasive diseases, such as toxic shock syndrome. Each GAS strain carries a particular pilus type encoded in the variable fibronectin-binding, collagen-binding, T antigen (FCT) genomic region. Here, we describe the functional analysis of the serotype M2 pilus encoded in the FCT-6 region. We found that, in contrast to other investigated GAS pili, the ancillary pilin 1 lacks adhesive properties. Instead, the backbone pilin is important for host cell adhesion and binds several host factors, including fibronectin and fibrinogen. Using a panel of recombinant pilus proteins, GAS gene deletion mutants and Lactococcus lactis gain-of-function mutants we show that, unlike other GAS pili, the FCT-6 pilus also contributes to immune evasion. This was demonstrated by a delay in blood clotting, increased intracellular survival of the bacteria in macrophages, higher bacterial survival rates in human whole blood and greater virulence in a Galleria mellonella infection model in the presence of fully assembled FCT-6 pili.
Collapse
Affiliation(s)
- Jia-Yun C Tsai
- Department of Molecular Medicine & Pathology, School of Medical Sciences.,Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand
| | - Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences.,Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand
| | - Fiona Clow
- Department of Molecular Medicine & Pathology, School of Medical Sciences
| | - Natalie Lorenz
- Department of Molecular Medicine & Pathology, School of Medical Sciences
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences.,Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
181
|
Kilsgård O, Karlsson C, Malmström E, Malmström J. Differential compartmentalization of Streptococcus pyogenes virulence factors and host protein binding properties as a mechanism for host adaptation. Int J Med Microbiol 2016; 306:504-516. [DOI: 10.1016/j.ijmm.2016.06.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/28/2016] [Accepted: 06/28/2016] [Indexed: 10/21/2022] Open
|
182
|
Lindahl G, Persson JJ. Structural biology: Variability without change. Nat Microbiol 2016; 1:16218. [PMID: 27782137 DOI: 10.1038/nmicrobiol.2016.218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Gunnar Lindahl
- Department of Veterinary Disease Biology, University of Copenhagen, 1870 Frederiksberg C, Denmark
| | - Jenny J Persson
- Department of Experimental Medical Science, Lund University, SE-221 84 Lund, Sweden
| |
Collapse
|
183
|
Seale AC, Davies MR, Anampiu K, Morpeth SC, Nyongesa S, Mwarumba S, Smeesters PR, Efstratiou A, Karugutu R, Mturi N, Williams TN, Scott JAG, Kariuki S, Dougan G, Berkley JA. Invasive Group A Streptococcus Infection among Children, Rural Kenya. Emerg Infect Dis 2016; 22:224-32. [PMID: 26811918 PMCID: PMC4734542 DOI: 10.3201/eid2202.151358] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
These infections cause serious illness, especially in neonates. To determine the extent of group A Streptococcus (GAS) infections in sub-Saharan Africa and the serotypes that cause disease, we analyzed surveillance data for 64,741 hospital admissions in Kilifi, Kenya, during 1998–2011. We evaluated incidence, clinical presentations, and emm types that cause invasive GAS infection. We detected 370 cases; of the 369 for which we had data, most were skin and soft tissue infections (70%), severe pneumonia (23%), and primary bacteremia (14%). Overall case-fatality risk was 12%. Incidence of invasive GAS infection was 0.6 cases/1,000 live births among neonates, 101/100,000 person-years among children <1 year of age, and 35/100,000 among children <5 years of age. Genome sequencing identified 88 emm types. GAS causes serious disease in children in rural Kenya, especially neonates, and the causative organisms have considerable genotypic diversity. Benefit from the most advanced GAS type–specific vaccines may be limited, and efforts must be directed to protect against disease in regions of high incidence.
Collapse
|
184
|
Comparative M-protein analysis of Streptococcus pyogenes from pharyngitis and skin infections in New Zealand: Implications for vaccine development. BMC Infect Dis 2016; 16:561. [PMID: 27733129 PMCID: PMC5062888 DOI: 10.1186/s12879-016-1891-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 10/01/2016] [Indexed: 02/04/2023] Open
Abstract
Background Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) are responsible for a significant disease burden amongst Māori and Pacific populations in New Zealand (NZ). However, contemporary data are lacking regarding circulating group A Streptococcal (GAS) strains in NZ. Such information is important in guiding vaccine development. Methods GAS isolates from April to June 2015 were recovered from skin and pharyngeal samples from children living in areas of high social deprivation in Auckland, NZ, a significant proportion of which are Māori or Pacific. These children are among the highest risk group for developing ARF. Isolates were compared to concurrently collected pharyngeal isolates from Dunedin, NZ, where both the proportion of Māori and Pacific children and risk of developing ARF is low. Emm typing, emm cluster typing and theoretical coverage of the 30-valent vaccine candidate were undertaken as previously described. Results A high diversity of emm types and a high proportion of emm-pattern D and cluster D4 isolates were detected amongst both skin and pharyngeal isolates in children at high risk of ARF. Pharyngeal isolates from children at low risk of ARF within the same country were significantly less diverse, less likely to be emm pattern D, and more likely to be theoretically covered by the 30-valent M protein vaccine. Conclusions The high proportion of emm pattern D GAS strains amongst skin and pharyngeal isolates from children at high risk of ARF raises further questions about the role of skin infection in ARF pathogenesis. Emm types and emm clusters differed considerably between ARF endemic and non-endemic settings, even within the same country. This difference should be taken into account for vaccine development. Electronic supplementary material The online version of this article (doi:10.1186/s12879-016-1891-6) contains supplementary material, which is available to authorized users.
Collapse
|
185
|
Conserved patterns hidden within group A Streptococcus M protein hypervariability recognize human C4b-binding protein. Nat Microbiol 2016; 1:16155. [PMID: 27595425 PMCID: PMC5014329 DOI: 10.1038/nmicrobiol.2016.155] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 07/22/2016] [Indexed: 12/24/2022]
Abstract
No vaccine exists against group A Streptococcus (GAS), a leading cause of worldwide morbidity and mortality. A severe hurdle is the hypervariability of its major antigen, the M protein, with >200 different M types known. Neutralizing antibodies typically recognize M protein hypervariable regions (HVRs) and confer narrow protection. In stark contrast, human C4b-binding protein (C4BP), which is recruited to the GAS surface to block phagocytic killing, interacts with a remarkably large number of M protein HVRs (apparently ∼90%). Such broad recognition is rare, and we discovered a unique mechanism for this through the structure determination of four sequence-diverse M proteins in complexes with C4BP. The structures revealed a uniform and tolerant 'reading head' in C4BP, which detected conserved sequence patterns hidden within hypervariability. Our results open up possibilities for rational therapies that target the M-C4BP interaction, and also inform a path towards vaccine design.
Collapse
|
186
|
Wu S, Peng X, Yang Z, Ma C, Zhang D, Wang Q, Yang P. Estimated burden of group a streptococcal pharyngitis among children in Beijing, China. BMC Infect Dis 2016; 16:452. [PMID: 27566251 PMCID: PMC5002216 DOI: 10.1186/s12879-016-1775-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 08/11/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Burden of Group A streptococcus (GAS) pharyngitis is scarce in developing countries, still unknown in China. The objective of this study was to determine the incidence of clinical cases of pharyngitis and GAS culture-positive pharyngitis, and their outpatient visits among children aged 0-14 years in Beijing, the capital of China. METHODS Multiplier model was used to estimate the numbers of pharyngitis cases, based on reported numbers of clinical cases and GAS culture-positive rates from GAS surveillances in Beijing, consultation rate, population coverage of GAS surveillances, sampling success rate, and test sensitivity of GAS culture from previous studies, surveys and surveillances. RESULTS An average of 29804.6 (95 % CI: 28333.2-31276.0) clinical cases of pharyngitis per 100,000 person-years occurred among children aged 0-14 years, resulting in correspondingly 19519.0 (95 % CI: 18516.7-20521.2) outpatient visits per 100,000 person-years from 2012 to 2014 in Beijing. On average, there were 2685.1 (95 % CI: 2039.6-3330.6) GAS culture-positive cases of pharyngitis and 1652.7 (95 % CI: 1256.5-2049.0) outpatient visits per 100,000 person-years during the same period. The estimated burden of GAS pharyngitis was significantly higher than that of scarlet fever. Children aged 5-14 years had a higher burden of GAS pharyngitis than those aged 0-4 years. CONCLUSIONS The present data suggests that GAS pharyngitis is very common in children in China. Further studies and surveillances are needed to monitor trends and the effectiveness of control measures.
Collapse
Affiliation(s)
- Shuangsheng Wu
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, No. 16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China.,School of Public Health, Captial Medical University, Beijing, China
| | - Xiaomin Peng
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, No. 16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China.,School of Public Health, Captial Medical University, Beijing, China
| | - Zuyao Yang
- Division of Epidemiology, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, SAR China
| | - Chunna Ma
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, No. 16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China.,School of Public Health, Captial Medical University, Beijing, China
| | - Daitao Zhang
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, No. 16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China.,School of Public Health, Captial Medical University, Beijing, China
| | - Quanyi Wang
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, No. 16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China.,School of Public Health, Captial Medical University, Beijing, China
| | - Peng Yang
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, No. 16 Hepingli Middle Street, Dongcheng District, Beijing, 100013, China. .,School of Public Health, Captial Medical University, Beijing, China.
| |
Collapse
|
187
|
Affiliation(s)
- Manisha Pandey
- Institute for Glycomics, Griffith University, Gold Coast, Australia
| | - Michael F Good
- Institute for Glycomics, Griffith University, Gold Coast, Australia
| |
Collapse
|
188
|
Raynes JM, Frost HRC, Williamson DA, Young PG, Baker EN, Steemson JD, Loh JM, Proft T, Dunbar PR, Atatoa Carr PE, Bell A, Moreland NJ. Serological Evidence of Immune Priming by Group A Streptococci in Patients with Acute Rheumatic Fever. Front Microbiol 2016; 7:1119. [PMID: 27499748 PMCID: PMC4957554 DOI: 10.3389/fmicb.2016.01119] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 07/05/2016] [Indexed: 01/08/2023] Open
Abstract
Acute rheumatic fever (ARF) is an autoimmune response to Group A Streptococcus (GAS) infection. Repeated GAS exposures are proposed to ‘prime’ the immune system for autoimmunity. This notion of immune-priming by multiple GAS infections was first postulated in the 1960s, but direct experimental evidence to support the hypothesis has been lacking. Here, we present novel methodology, based on antibody responses to GAS T-antigens, that enables previous GAS exposures to be mapped in patient sera. T-antigens are surface expressed, type specific antigens and GAS strains fall into 18 major clades or T-types. A panel of recombinant T-antigens was generated and immunoassays were performed in parallel with serum depletion experiments allowing type-specific T-antigen antibodies to be distinguished from cross-reactive antibodies. At least two distinct GAS exposures were detected in each of the ARF sera tested. Furthermore, no two sera had the same T-antigen reactivity profile suggesting that each patient was exposed to a unique series of GAS T-types prior to developing ARF. The methods have provided much-needed experimental evidence to substantiate the immune-priming hypothesis, and will facilitate further serological profiling studies that explore the multifaceted interactions between GAS and the host.
Collapse
Affiliation(s)
- Jeremy M Raynes
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
| | - Hannah R C Frost
- School of Biological Sciences, University of Auckland Auckland, New Zealand
| | - Deborah A Williamson
- Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand; Institute of Environmental Science and ResearchWellington, New Zealand; The Peter Doherty Institute, University of MelbourneMelbourne, Australia
| | - Paul G Young
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
| | - Edward N Baker
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
| | - John D Steemson
- School of Biological Sciences, University of Auckland Auckland, New Zealand
| | - Jacelyn M Loh
- Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand; School of Medical Sciences, University of AucklandAuckland, New Zealand
| | - Thomas Proft
- Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand; School of Medical Sciences, University of AucklandAuckland, New Zealand
| | - P R Dunbar
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
| | | | - Anita Bell
- Waikato District Health Board Hamilton, New Zealand
| | - Nicole J Moreland
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
| |
Collapse
|
189
|
Brouwer S, Barnett TC, Rivera-Hernandez T, Rohde M, Walker MJ. Streptococcus pyogenes adhesion and colonization. FEBS Lett 2016; 590:3739-3757. [PMID: 27312939 DOI: 10.1002/1873-3468.12254] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 06/10/2016] [Accepted: 06/13/2016] [Indexed: 12/19/2022]
Abstract
Streptococcus pyogenes (group A Streptococcus, GAS) is a human-adapted pathogen responsible for a wide spectrum of disease. GAS can cause relatively mild illnesses, such as strep throat or impetigo, and less frequent but severe life-threatening diseases such as necrotizing fasciitis and streptococcal toxic shock syndrome. GAS is an important public health problem causing significant morbidity and mortality worldwide. The main route of GAS transmission between humans is through close or direct physical contact, and particularly via respiratory droplets. The upper respiratory tract and skin are major reservoirs for GAS infections. The ability of GAS to establish an infection in the new host at these anatomical sites primarily results from two distinct physiological processes, namely bacterial adhesion and colonization. These fundamental aspects of pathogenesis rely upon a variety of GAS virulence factors, which are usually under strict transcriptional regulation. Considerable progress has been made in better understanding these initial infection steps. This review summarizes our current knowledge of the molecular mechanisms of GAS adhesion and colonization.
Collapse
Affiliation(s)
- Stephan Brouwer
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Timothy C Barnett
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Tania Rivera-Hernandez
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre For Infection Research, Braunschweig, Germany
| | - Mark J Walker
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| |
Collapse
|
190
|
McNeilly C, Cosh S, Vu T, Nichols J, Henningham A, Hofmann A, Fane A, Smeesters PR, Rush CM, Hafner LM, Ketheesan N, Sriprakash KS, McMillan DJ. Predicted Coverage and Immuno-Safety of a Recombinant C-Repeat Region Based Streptococcus pyogenes Vaccine Candidate. PLoS One 2016; 11:e0156639. [PMID: 27310707 PMCID: PMC4911098 DOI: 10.1371/journal.pone.0156639] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/17/2016] [Indexed: 12/14/2022] Open
Abstract
The C-terminal region of the M-protein of Streptococcus pyogenes is a major target for vaccine development. The major feature is the C-repeat region, consisting of 35–42 amino acid repeat units that display high but not perfect identity. SV1 is a S. pyogenes vaccine candidate that incorporates five 14mer amino acid sequences (called J14i variants) from differing C-repeat units in a single recombinant construct. Here we show that the J14i variants chosen for inclusion in SV1 are the most common variants in a dataset of 176 unique M-proteins. Murine antibodies raised against SV1 were shown to bind to each of the J14i variants present in SV1, as well as variants not present in the vaccine. Antibodies raised to the individual J14i variants were also shown to bind to multiple but different combinations of J14i variants, supporting the underlying rationale for the design of SV1. A Lewis Rat Model of valvulitis was then used to assess the capacity of SV1 to induce deleterious immune response associated with rheumatic heart disease. In this model, both SV1 and the M5 positive control protein were immunogenic. Neither of these antibodies were cross-reactive with cardiac myosin or collagen. Splenic T cells from SV1/CFA and SV1/alum immunized rats did not proliferate in response to cardiac myosin or collagen. Subsequent histological examination of heart tissue showed that 4 of 5 mice from the M5/CFA group had valvulitis and inflammatory cell infiltration into valvular tissue, whereas mice immunised with SV1/CFA, SV1/alum showed no sign of valvulitis. These results suggest that SV1 is a safe vaccine candidate that will elicit antibodies that recognise the vast majority of circulating GAS M-types.
Collapse
Affiliation(s)
- Celia McNeilly
- Bacterial Pathogenesis Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, QLD, 4006, Australia
| | - Samantha Cosh
- Bacterial Pathogenesis Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, QLD, 4006, Australia
| | - Therese Vu
- Bacterial Pathogenesis Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, QLD, 4006, Australia
| | - Jemma Nichols
- Inflammation and Healing Research Cluster, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, QLD, 4558, Australia
| | - Anna Henningham
- Australian Infectious Disease Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Andreas Hofmann
- Structural Chemistry Program, Eskitis Institute for Cell and Molecular Therapies, Griffith University, Nathan, and Queensland Tropical Health Alliance, Smithfield, QLD, Australia
| | - Anne Fane
- Australian Institute of Tropical Medicine, James Cook University, Townsville, QLD, 4811, Australia
| | - Pierre R Smeesters
- Laboratoire de Génétique et Physiologie Bactérienne, Institut de Biologie et de Médecine Moléculaires, Faculté des Sciences, Université Libre de Bruxelles, Gosselies, Belgium, and Murdoch Children Research Institute, Melbourne, VIC, 3052, Australia
| | - Catherine M Rush
- Australian Institute of Tropical Medicine, James Cook University, Townsville, QLD, 4811, Australia
| | - Louise M Hafner
- School of Biomedical Sciences, Faculty of Health & Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, QLD, 4001, Australia
| | - Natkuman Ketheesan
- Australian Institute of Tropical Medicine, James Cook University, Townsville, QLD, 4811, Australia
| | - Kadaba S Sriprakash
- Bacterial Pathogenesis Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, QLD, 4006, Australia
| | - David J McMillan
- Bacterial Pathogenesis Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, QLD, 4006, Australia.,Inflammation and Healing Research Cluster, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, QLD, 4558, Australia
| |
Collapse
|
191
|
Imperi M, Pittiglio V, D'Avenio G, Gherardi G, Ciammaruconi A, Lista F, Pourcel C, Baldassarri L, Creti R. A new genotyping scheme based on MLVA for inter-laboratory surveillance of Streptococcus pyogenes. J Microbiol Methods 2016; 127:176-181. [PMID: 27302039 DOI: 10.1016/j.mimet.2016.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 11/24/2022]
Abstract
A newly developed MLVA seven-loci scheme for Streptococcus pyogenes is described. The method can be successfully applied by using both agarose gel with visual inspections of bands and Lab on Chip technology. The potential of the present MLVA has been tested on a collection of 100 clinical GAS strains representing the most common emm types found in high-income countries plus 18 published gap-free genomes, in comparison to PFGE and MLST. The MLVA analysis defined 30 MLVA types with ten out of the considered 15 emm types exhibiting multiple and specific MLVA types. In only one occasion the same MLVA profile was shared between isolates belonging to two different emm types. A robust congruency between the methods was observed, with MLVA discriminating within clonal complexes as defined by PFGE or MLST. This new MLVA scheme can be adopted as a quick, low-cost and reliable typing method to track the short-term diffusion of GAS clones in inter-laboratory-based surveillance.
Collapse
Affiliation(s)
- Monica Imperi
- Dept. of Infectious, Parasitic and Immune-mediated Disease, Istituto Superiore di Sanità, Rome, Italy
| | - Valentina Pittiglio
- Health Corps Italian Army, Department of Molecular Biology, Immunology and Experimental Medicine, Army Medical and Veterinary Research Center, Rome, Italy
| | - Giuseppe D'Avenio
- Dept. of Technology and Health, Istituto Superiore di Sanità, Rome, Italy
| | | | - Andrea Ciammaruconi
- Health Corps Italian Army, Department of Molecular Biology, Immunology and Experimental Medicine, Army Medical and Veterinary Research Center, Rome, Italy
| | - Florigio Lista
- Health Corps Italian Army, Department of Molecular Biology, Immunology and Experimental Medicine, Army Medical and Veterinary Research Center, Rome, Italy
| | - Christine Pourcel
- I2BC, CNRS, Université Paris Sud, Université Paris-Saclay, Orsay, France
| | - Lucilla Baldassarri
- Dept. of Infectious, Parasitic and Immune-mediated Disease, Istituto Superiore di Sanità, Rome, Italy
| | - Roberta Creti
- Dept. of Infectious, Parasitic and Immune-mediated Disease, Istituto Superiore di Sanità, Rome, Italy.
| |
Collapse
|
192
|
Bessen DE. Tissue tropisms in group A Streptococcus: what virulence factors distinguish pharyngitis from impetigo strains? Curr Opin Infect Dis 2016; 29:295-303. [PMID: 26895573 PMCID: PMC5373551 DOI: 10.1097/qco.0000000000000262] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE OF REVIEW Group A streptococci (GAS) are a common cause of pharyngitis and impetigo, and distinct throat strains and skin strains have been long recognized. This review aims to describe recent advances in molecular differences between throat and skin strains, and the pathogenic mechanisms used by virulence factors that may distinguish between these two groups. RECENT FINDINGS Recent findings include a new typing scheme for GAS strains based on sequence clusters of genes encoding the entire surface-exposed portion of M protein; correlations between emm-based typing schemes, clinical disease and surface adhesins; covalent bond formation mediated by GAS pili and other adhesins in binding to host ligands; a key role for superantigens in oropharyngeal infection via binding major histocompatibility complex class II antigen; and migration of GAS-specific Th17 cells from the upper respiratory tract to the brain, which may be relevant to autoimmune sequelae. SUMMARY The gap between molecular markers of disease (correlation) and virulence mechanisms (causation) in the establishment of tissue tropisms for GAS infection currently remains wide, but the gap also continues to narrow. Whole genome sequencing combined with mutant construction and improvements in animal models for oropharyngeal infection by GAS may help pave the way for new discoveries.
Collapse
Affiliation(s)
- Debra E Bessen
- Department of Microbiology and Immunology, New York Medical College, New York, USA
| |
Collapse
|
193
|
Tuerlinckx D, Gueulette E, Loens K, Goossens H, Smeesters PR. Group A streptococcal meningitis: emm type distribution and theoretical vaccine coverage in children. Acta Clin Belg 2016; 71:138-41. [PMID: 26319426 DOI: 10.1179/2295333715y.0000000066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
As group A Streptococcus (GAS) meningitis is seldom reported in children, emm-type distribution data are scare. We report eight cases of GAS meningitis in Belgium (2008-2013) and compare molecular characteristics of our strains with a further 55 cases previously reported with their corresponding emm-types. emm1 type was the most frequent (24%) followed by emm6 (11%), emm12 (11%) and emm3 (6%). Together these four emm-types accounted for 52% of the cases, while the rest of the cases are due to 24 different emm-types. These 28 emm-types associated with GAS meningitis belonged to 16 different emm-clusters suggesting that there is no propensity for particular emm-types or emm-cluster to cause meningitis. Theoretical coverage of the 30-valent vaccine candidate would be 77.8% (49/63 isolates) among children with GAS meningitis.
Collapse
Affiliation(s)
- David Tuerlinckx
- a CHU Dinant-Godinne , Service de Pédiatrie, Université Catholique de Louvain , Yvoir , Belgium
| | | | - Katherine Loens
- c Department of Microbiology , University Hospital Antwerp , Belgium
| | - Herman Goossens
- c Department of Microbiology , University Hospital Antwerp , Belgium
| | - Pierre Robert Smeesters
- d Group A Streptococcus Research Group , Murdoch Childrens Research Institute , Melbourne , VIC , Australia
- e Centre for International Child Health , University of Melbourne , VIC , Australia
| |
Collapse
|
194
|
Status of research and development of vaccines for Streptococcus pyogenes. Vaccine 2016; 34:2953-2958. [DOI: 10.1016/j.vaccine.2016.03.073] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 03/09/2016] [Indexed: 11/23/2022]
|
195
|
Abstract
There is concern of global resurgence of invasive group A Streptococcus (iGAS) infections. We compared the clinical and molecular epidemiology of patients admitted with iGAS over two time periods, 2008 and 2010, in Western Sydney, Australia. The annual incidence was 19 cases per 100,000 admissions in 2008, compared to 33 per 100,000 in 2010. An increasing proportion of patients died (0% versus 13%), had an APACHE II score ≥30 (0% versus 19%), and had no known risk-factors (12% versus 25%). A potential skin source was identified as a trigger in fewer cases in 2010 (36% versus 11%). In total, there were 27 different emm types and 11 different emm clusters. There were some new emm types/clusters in 2010 that were not present in 2008. However, the study was not adequately powered to detect statistically significant differences in the distribution of emm types (p = 0.06) and emm clusters (p = 0.16) between the two years. There were also no clear associations between emm types/clusters and severity and clinical manifestations of iGAS infections. Although the proposed 30-valent M protein vaccine encompasses only 47% of our isolates, it will likely provide coverage for at least 71% of iGAS infections due to cross-opsonisation.
Collapse
|
196
|
Characterization of Streptococcus pyogenes isolates responsible for adult meningitis in France from 2003 to 2013. Diagn Microbiol Infect Dis 2016; 84:350-2. [DOI: 10.1016/j.diagmicrobio.2015.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 12/01/2015] [Accepted: 12/14/2015] [Indexed: 11/22/2022]
|
197
|
Identifying protective Streptococcus pyogenes vaccine antigens recognized by both B and T cells in human adults and children. Sci Rep 2016; 6:22030. [PMID: 26911649 PMCID: PMC4766568 DOI: 10.1038/srep22030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/04/2016] [Indexed: 01/01/2023] Open
Abstract
No commercial vaccine exists against Group A streptococci (GAS; Streptococcus pyogenes) and only little is known about anti-GAS protective immunity. In our effort to discover new protective vaccine candidates, we selected 21 antigens based on an in silico evaluation. These were all well-conserved among different GAS strains, upregulated in host-pathogen interaction studies, and predicted to be extracellular or associated with the surface of the bacteria. The antigens were tested for both antibody recognition and T cell responses in human adults and children. The antigenicity of a selected group of antigens was further validated using a high-density peptide array technology that also identified the linear epitopes. Based on immunological recognition, four targets were selected and tested for protective capabilities in an experimental GAS infection model in mice. Shown for the first time, three of these targets (spy0469, spy1228 and spy1801) conferred significant protection whereas one (spy1643) did not.
Collapse
|
198
|
Development of a multicomponent vaccine for Streptococcus pyogenes based on the antigenic targets of IVIG. J Infect 2016; 72:450-9. [PMID: 26880087 PMCID: PMC4796040 DOI: 10.1016/j.jinf.2016.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 01/14/2016] [Accepted: 02/06/2016] [Indexed: 01/22/2023]
Abstract
Objectives Despite over a century of research and the careful scrutiny of many promising targets, there is currently no vaccine available for the prevention of Streptococcus pyogenes infection. Through analysis of the protective, anti-streptococcal components of pooled human immunoglobulin, we previously identified ten highly conserved and invariant S. pyogenes antigens that contribute to anti-streptococcal immunity in the adult population. We sought to emulate population immunity to S. pyogenes through a process of active vaccination, using the antigens targeted by pooled human immunoglobulin. Methods Seven targets were produced recombinantly and mixed to form a multicomponent vaccine (Spy7). Vaccinated mice were challenged with S. pyogenes isolates representing four globally relevant serotypes (M1, M3, M12 and M89) using an established model of invasive disease. Results Vaccination with Spy7 stimulated the production of anti-streptococcal antibodies, and limited systemic dissemination of M1 and M3 S. pyogenes from an intramuscular infection focus. Vaccination additionally attenuated disease severity due to M1 S. pyogenes as evidenced by reduction in weight loss, and modulated cytokine release. Conclusion Spy7 vaccination successfully stimulated the generation of protective anti-streptococcal immunity in vivo. Identification of reactive antigens using pooled human immunoglobulin may represent a novel route to vaccine discovery for extracellular bacteria. Targets of population level immunity to Streptococcus pyogenes can be identified using pooled IVIG. Seven conserved targets were combined to form a new vaccine (Spy7). Vaccine antigen components were individually immunogenic. Vaccination with Spy7 reduced dissemination of invasive M1 and M3 S. pyogenes. The immuno-proteomic approach to vaccine discovery may be applicable to other pathogens.
Collapse
|
199
|
Frost HR, Tsoi SK, Baker CA, Laho D, Sanderson-Smith ML, Steer AC, Smeesters PR. Validation of an automated colony counting system for group A Streptococcus. BMC Res Notes 2016; 9:72. [PMID: 26856815 PMCID: PMC4745170 DOI: 10.1186/s13104-016-1875-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 01/19/2016] [Indexed: 01/06/2023] Open
Abstract
Background The practice of counting bacterial colony forming units on agar plates has long been used as a method to estimate the concentration of live bacteria in culture. However, due to the laborious and potentially error prone nature of this measurement technique, an alternative method is desirable. Recent technologic advancements have facilitated the development of automated colony counting systems, which reduce errors introduced during the manual counting process and recording of information. An additional benefit is the significant reduction in time taken to analyse colony counting data. Whilst automated counting procedures have been validated for a number of microorganisms, the process has not been successful for all bacteria due to the requirement for a relatively high contrast between bacterial colonies and growth medium. The purpose of this study was to validate an automated counting system for use with group A Streptococcus (GAS). Results Methods: Twenty-one different GAS strains, representative of major emm-types, were selected for assessment. In order to introduce the required contrast for automated counting, 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) dye was added to Todd–Hewitt broth with yeast extract (THY) agar. Growth on THY agar with TTC was compared with growth on blood agar and THY agar to ensure the dye was not detrimental to bacterial growth. Automated colony counts using a ProtoCOL 3 instrument were compared with manual counting to confirm accuracy over the stages of the growth cycle (latent, mid-log and stationary phases) and in a number of different assays. The average percentage differences between plating and counting methods were analysed using the Bland–Altman method. Conclusions Results: A percentage difference of ±10 % was determined as the cut-off for a critical difference between plating and counting methods. All strains measured had an average difference of less than 10 % when plated on THY agar with TTC. This consistency was also observed over all phases of the growth cycle and when plated in blood following bactericidal assays. Agreement between these methods suggest the use of an automated colony counting technique for GAS will significantly reduce time spent counting bacteria to enable a more efficient and accurate measurement of bacteria concentration in culture. Electronic supplementary material The online version of this article (doi:10.1186/s13104-016-1875-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- H R Frost
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia. .,Laboratoire de Bactériologie Moléculaire, Université Libre de Bruxelles, Brussels, Belgium.
| | - S K Tsoi
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia.
| | - C A Baker
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia.
| | - D Laho
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia.
| | - M L Sanderson-Smith
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Wollongong, Australia.
| | - A C Steer
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia. .,Centre for International Child Health, University of Melbourne, Melbourne, Australia. .,Department of General Medicine, Royal Children's Hospital Melbourne, Melbourne, Australia.
| | - P R Smeesters
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia. .,Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Wollongong, Australia. .,Department of General Medicine, Royal Children's Hospital Melbourne, Melbourne, Australia.
| |
Collapse
|
200
|
Abstract
Epidemiological data regarding group A streptococcal (GAS) infections in South East Asia are scarce with no information from Laos. We characterized emm types, emm clusters and the antibiotic resistance profile of 124 GAS isolates recovered in Laos during 2004-2013. Most strains were recovered from skin and invasive infections (76% and 19%, respectively). Thirty-four emm types were identified as belonging to 12 emm clusters and no novel emm types were identified. No significant differences were observed in the distribution of emm types or emm clusters according to age or site of recovery (skin or invasive infections). There was moderate strain diversity in this country but considerable differences in emm-type distribution between Laos, Thailand and Cambodia. Vaccine coverage was high for the J8 vaccine candidate. The theoretical coverage for the 30-valent vaccine candidate needs further investigation. Antibiotic resistance was moderate to erythromycin and chloramphenicol (8% and 7%, respectively) and low to ofloxacin (<1%).
Collapse
|