Group A streptococci are model extracellular gram-positive pathogens responsible for pharyngitis, impetigo, rheumatic fever, and acute glomerulonephritis. A resurgence of invasive streptococcal diseases and rheumatic fever has appeared in outbreaks over the past 10 years, with a predominant M1 serotype as well as others identified with the outbreaks. emm (M protein) gene sequencing has changed serotyping, and new virulence genes and new virulence regulatory networks have been defined. The emm gene superfamily has expanded to include antiphagocytic molecules and immunoglobulin-binding proteins with common structural features. At least nine superantigens have been characterized, all of which may contribute to toxic streptococcal syndrome. An emerging theme is the dichotomy between skin and throat strains in their epidemiology and genetic makeup. Eleven adhesins have been reported, and surface plasmin-binding proteins have been defined. The strong resistance of the group A streptococcus to phagocytosis is related to factor H and fibrinogen binding by M protein and to disarming complement component C5a by the C5a peptidase. Molecular mimicry appears to play a role in autoimmune mechanisms involved in rheumatic fever, while nephritis strain-associated proteins may lead to immune-mediated acute glomerulonephritis. Vaccine strategies have focused on recombinant M protein and C5a peptidase vaccines, and mucosal vaccine delivery systems are under investigation.

Pathogenesis of Group A Streptococcal Infections

Group A Streptococcus (GAS; Streptococcus pyogenes) is a human pathogen which causes significant morbidity and mortality globally. GAS typically infects the throat and skin of the host, causing mild infections such as pharyngitis and impetigo, in addition to life threatening conditions including necrotizing fasciitis, streptococcal toxic shock syndrome (STSS), and bacteremia. Repeated infection with GAS may result in the non-suppurative sequelae, acute rheumatic fever, and acute glomerulonephritis. GAS remains sensitive to the antibiotic penicillin which can be administered as a means to treat infection or as prophylaxis. However, issues with patient compliance and a growing concern over the possible emergence of resistant GAS strains may limit the usefulness of antibiotics in the future. A vaccine capable of preventing GAS infection may be the only effective way to control and eliminate GAS infection and disease.

Pathogenesis of group A streptococcal infections.

The efficacy and safety of high-dose intravenous polyspecific immunoglobulin G (IVIG) as adjunctive therapy in streptococcal toxic shock syndrome (STSS) were evaluated in a multicenter, randomized, double-blind, placebo-controlled trial. The trial was prematurely terminated because of slow patient recruitment, and results were obtained from 21 enrolled patients (10 IVIG recipients and 11 placebo recipients). The primary end point was mortality at 28 days, and a 3.6-fold higher mortality rate was found in the placebo group. A significant decrease in the sepsis-related organ failure assessment score at days 2 (P = .02) and 3 (P = .04) was noted in the IVIG group. Furthermore, a significant increase in plasma neutralizing activity against superantigens expressed by autologous isolates was noted in the IVIG group after treatment (P = .03). Although statistical significance was not reached in the primary end point, the trial provides further support for IVIG as an efficacious adjunctive therapy in STSS.

/pdf/intravenous-immunoglobulin-g-therapy-in-streptococcal-toxic-qb4066nqae.pdf

Intravenous Immunoglobulin G Therapy in Streptococcal Toxic Shock Syndrome: A European Randomized, Double-Blind, Placebo-Controlled Trial

Twenty-one consecutive patients with streptococcal toxic shock syndrome (TSS) between December 1994 and April 1995 were treated with a median dose of 2 g of intravenous immunoglobulin (IVIG)/kg (cases) and were compared with 32 patients with streptococcal TSS between 1992 and 1995 who did not receive IVIG therapy (controls). The outcome measure was 30-day survival. Patient plasma was tested for its ability to inhibit T cell activation induced by the infecting strain. The proportion of cases with 30-day survival was higher than that of the controls with 30-day survival (67% vs. 34%, respectively; P = .02). Multivariate analysis revealed that IVIG administration and a lower Acute Physiology and Chronic Health Evaluation II score were associated with survival; the odds ratio for survival associated with IVIG therapy was 8.1 (95% confidence interval, 1.6-45; P = .009). IVIG therapy enhanced the ability of patient plasma to neutralize bacterial mitogenicity and reduced T cell production of interleukin-6 and tumor necrosis factor alpha. IVIG may be an effective adjunctive therapy for streptococcal TSS, possibly because of its ability to neutralize bacterial exotoxins.

/pdf/intravenous-immunoglobulin-therapy-for-streptococcal-toxic-3ynu6y5vbo.pdf

Intravenous Immunoglobulin Therapy for Streptococcal Toxic Shock Syndrome—A Comparative Observational Study

The past 2 decades have brought worrying increases in severe Streptococcus pyogenes diseases globally To investigate and compare the epidemiological patterns of these diseases within Europe, data were collected through a European Union FP-5-funded program (Strep-EURO) Prospective population-based surveillance of severe S pyogenes infection diagnosed during 2003 and 2004 was undertaken in 11 countries across Europe (Cyprus, the Czech Republic, Denmark, Finland, France, Germany, Greece, Italy, Romania, Sweden, and the United Kingdom) using a standardized case definition A total of 5,522 cases were identified across the 11 countries during this period Rates of reported infection varied, reaching 3/100,000 population in the northern European countries Seasonal patterns of infection showed remarkable congruence between countries The risk of infection was highest among the elderly, and rates were higher in males than in females in most countries Skin lesions/wounds were the most common predisposing factor, reported in 25% of cases; 21% had no predisposing factors reported Skin and soft tissue were the most common foci of infection, with 32% of patients having cellulitis and 8% necrotizing fasciitis The overall 7-day case fatality rate was 19%; it was 44% among patients who developed streptococcal toxic shock syndrome The findings from Strep-EURO confirm a high incidence of severe S pyogenes disease in Europe Furthermore, these results have identified targets for public health intervention, as well as raising awareness of severe S pyogenes disease across Europe

https://www.julkari.fi/bitstream/handle/10024/78076/2008a28.pdf?sequence=1

Epidemiology of Severe Streptococcus pyogenes Disease in Europe

GROUP A streptococcus (Streptococcus pyogenes) may cause a variety of illnesses ranging from very common, usually clinically mild conditions such as pharyngitis and impetigo to less common severe infections including septicemia and pneumonia. In 1987, Cone et al1described two patients with severe group A streptococcal infections having clinical features similar to the staphylococcal toxic shock syndrome. This syndrome, designated the "streptococcal toxic shock—like syndrome" or the "toxic streptococcal syndrome,"2was further characterized by Stevens et al3in a series of 20 patients. Most patients included in this series were less than 50 years old and otherwise healthy. All had invasive group A streptococcal infections characterized by signs including shock, multi—organ system involvement, and rapidly progressive, destructive soft-tissue infection (necrotizing fasciitis). The case-fatality rate was 30% even though most patients received appropriate antimicrobial therapy, supportive care, and, where necessary, surgical debridement. Ten available isolates were serotyped and

https://jamanetwork.com/journals/jama/articlepdf/402846/jama_269_3_038.pdf

Defining the Group A Streptococcal Toxic Shock Syndrome: Rationale and Consensus Definition

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Barry M. Gray

Author Tools

Chat about Author

Papers

Defining the Group A Streptococcal Toxic Shock Syndrome: Rationale and Consensus Definition