Interaction Of Group A Streptococci With Intracellular Innate Immune Defence
Funder
National Health and Medical Research Council
Funding Amount
$824,252.00
Summary
The pathogenic bacterium group A streptococcus (GAS) is estimated to cause ~700 million cases of self-limited throat or skin infection each year worldwide. GAS infections result in over 600,000 human deaths. This disease burden places GAS in the “top 10” causes of human infectious disease deaths worldwide. We have discovered a hitherto unknown mechanism by which GAS subvert the human immune system. An improved understanding of this mechanism will lead to novel ways to combat GAS infections.
Worldwide Molecular Analysis Of Streptococcus Pyogenes Scarlet Fever Outbreaks
Funder
National Health and Medical Research Council
Funding Amount
$544,041.00
Summary
The microorganism group A Streptococcus (also called GAS or Streptococcus pyogenes) ranks among the top 10 infectious disease killers of humans. Recently, outbreaks of scarlet fever have occurred in both Asia and the United Kingdom, placing a serious strain on health systems. The reasons underlying these outbreaks remain unknown. Our team will lead the global effort to characterise this rise in scarlet fever, and provide recommendations and solutions to health professionals.
Unified Model For Group A Streptococcal Invasive Disease Initiation.
Funder
National Health and Medical Research Council
Funding Amount
$605,221.00
Summary
Streptococcus pyogenes (group A streptococcus; GAS) is a bacterium that causes human skin and throat infections as well as highly invasive diseases including necrotising fasciitis and streptococcal toxic shock-like syndrome. We have recently discovered the trigger mechanism for GAS invasive disease. We hypothesise that the initial host response at the site of infection selects for a GAS invasive phenotype. We propose to examine the chain of events which result in tissue invasion in order to unde ....Streptococcus pyogenes (group A streptococcus; GAS) is a bacterium that causes human skin and throat infections as well as highly invasive diseases including necrotising fasciitis and streptococcal toxic shock-like syndrome. We have recently discovered the trigger mechanism for GAS invasive disease. We hypothesise that the initial host response at the site of infection selects for a GAS invasive phenotype. We propose to examine the chain of events which result in tissue invasion in order to understand these disease processes and allow the development of future therapeutic interventions.Read moreRead less
Role Of Bacteriophage-encoded Streptodornase In Invasive Disease Caused By Diverse Group A Streptococcal M Serotypes.
Funder
National Health and Medical Research Council
Funding Amount
$832,544.00
Summary
Streptococcus pyogenes (group A streptococcus, GAS) is estimated to cause ~700 million cases of self-limited throat or skin infection each year worldwide. Invasive GAS disease occurs in approximately 1-1000 cases, with associated mortality of 25%. We have recently discovered that a viral infection can reprogram GAS for invasive disease propensity. We will investigate whether this phenomenon is widespread, in order to understand this process and develop future therapeutics.
Characterising The Molecular Pathogenesis Of Newly Emergent Invasive Group A Streptococcus M4 Serotypes In Australia
Funder
National Health and Medical Research Council
Funding Amount
$523,756.00
Summary
Group A Streptococcus (GAS) is a human pathogen of global significance, responsible for life-threatening invasive infections such as flesh-eating disease (>650,000 cases per year), with a mortality rate of 25%. A recent outbreak of serotype M4 GAS caused severe invasive infections in Queensland Australia. The aim of this work is to determine how M4 GAS causes invasive disease. Understanding this mechanism will allow the development of new generation therapeutics, treatments and improved healt ....Group A Streptococcus (GAS) is a human pathogen of global significance, responsible for life-threatening invasive infections such as flesh-eating disease (>650,000 cases per year), with a mortality rate of 25%. A recent outbreak of serotype M4 GAS caused severe invasive infections in Queensland Australia. The aim of this work is to determine how M4 GAS causes invasive disease. Understanding this mechanism will allow the development of new generation therapeutics, treatments and improved health outcomes.Read moreRead less
Role Of The Host Fibrinolytic System In Invasive Group A Streptococcal Disease
Funder
National Health and Medical Research Council
Funding Amount
$531,444.00
Summary
The flesh-eating bacterium group A streptococcus (GAS) is estimated to cause 700 million cases of self-limiting disease, and 600,000 cases of serious invasive disease each year. Approximately 25% of invasive infections are fatal. We have shown that GAS are able to hijack the host fibrinolytoc system to cause severe invasive infections. We plan to further examine the details of how this contributes to GAS disease. This research may contribute to the future devlopment of new therapeutics.
Modelling Streptococcal Urogenital Tract Infection To Study Mechanisms Of Bacterial Colonization And Persistence
Funder
National Health and Medical Research Council
Funding Amount
$412,085.00
Summary
Colonization of the urogenital tract with bacterial pathogens is one of the most common infections in humans. In Australia millions of people are colonized in their urogenital tracts at any given time, often asymptomatically, and many such individuals require medical intervention for the treatment of consequent infections that result from persistent colonization. Bacterial colonization of the urogenital tract is associated with a variety of disease presentations including urinary tract infection ....Colonization of the urogenital tract with bacterial pathogens is one of the most common infections in humans. In Australia millions of people are colonized in their urogenital tracts at any given time, often asymptomatically, and many such individuals require medical intervention for the treatment of consequent infections that result from persistent colonization. Bacterial colonization of the urogenital tract is associated with a variety of disease presentations including urinary tract infections and neonatal infections resulting from vertical transmission of colonizing bacteria from mothers to newborns. Aside from sexually-transmitted diseases the most prominent bacterial pathogens that colonize the urogenital tract are Group B Streptococcus (GBS) and Escherichia coli. GBS in particular exist in the female urogenital tract as a persistent microbial reservoir in up to 40% of pregnant women and are transmitted to newborns in up to 72% of live births. Colonization of newborns leads to invasive disease including pneumonia, sepsis, and meningitis. While the disease presentations resulting from colonization of the urogenital tract vary the underlying basis that leads to disease is antecedent bacterial persistence in the urogenital tract despite immune system activation. The mechanisms whereby GBS evade immune responses in the urogenital tract to allow their survival are unknown. I will define the immune-evasion mechanisms and virulence traits used by GBS, as a model urogenital pathogen, to successfully colonize the urogenital tract in the face of mounting immune responses. These studies will provide a better understanding of the pathogenesis of urogenital disease in terms of bacterial colonization and immune-evasion strategies. This will shed light onto new approaches for the prevention and treatment of urogenital disease in humans such as improved vaccination, locally acting cytokines, and deliberate colonization with non-invasive strains for the prevention of disease.Read moreRead less
Investigation Of The Localisation, Transport And Vaccine Potential Of Group A Streptococcal Cell Surface Proteins.
Funder
National Health and Medical Research Council
Funding Amount
$505,523.00
Summary
Streptococcus pyogenes (group A streptococcus; GAS) is a bacterium that causes human skin and throat infections as well as highly invasive diseases including necrotising fasciitis. Additionally, serious sequeale, including rheumatic fever and acute glomerulonephritis, may result following repeated infection. We have recently examined the GAS cell wall and identified 23 proteins that are surface exposed, 20 of which are novel. We hypothesise that a number of these surface exposed proteins represe ....Streptococcus pyogenes (group A streptococcus; GAS) is a bacterium that causes human skin and throat infections as well as highly invasive diseases including necrotising fasciitis. Additionally, serious sequeale, including rheumatic fever and acute glomerulonephritis, may result following repeated infection. We have recently examined the GAS cell wall and identified 23 proteins that are surface exposed, 20 of which are novel. We hypothesise that a number of these surface exposed proteins represent candidate vaccine antigens capable of conferring protective immunity. We therefore propose to examine these surface proteins as components of experimental vaccines against GAS.Read moreRead less
Utilisation Of The Human Plasminogen Activation System By Group A Streptococci: Contribution To Virulence And Disease
Funder
National Health and Medical Research Council
Funding Amount
$254,250.00
Summary
Streptococcus pyogenes (group A streptococci; GAS) is a bacterium which causes human skin and throat infections as well as highly invasive diseases including the flesh eating disease necrotising fasciitis. Additionally, serious sequelae, including rheumatic fever and acute glomeulonephritis, may result following infection. Such diseases cause high morbidity and mortality in Aboriginal populations and are a continual significant drain on the national health fund. An important mode of invasion by ....Streptococcus pyogenes (group A streptococci; GAS) is a bacterium which causes human skin and throat infections as well as highly invasive diseases including the flesh eating disease necrotising fasciitis. Additionally, serious sequelae, including rheumatic fever and acute glomeulonephritis, may result following infection. Such diseases cause high morbidity and mortality in Aboriginal populations and are a continual significant drain on the national health fund. An important mode of invasion by GAS may be related to their ability to capture and activate host plasminogen via surface-associated or secreted plasminogen binding proteins (receptors). Plasminogen can be activated by host activators or secreted GAS streptokinase to the potent enzyme plasmin which is responsible for the degradation of tissue barriers. Thus, GAS may utilise plasmin to destroy tissue barriers and invade host tissues. The characterisation of the interaction between GAS and the plasminogen activation system would clarify the role of this system in invasive disease and provide potential targets for therapeutic intervention.Read moreRead less