Recombinant Bacteria Expressing Oligosaccharide Receptor Mimics For Prevention Of Enteric Infections
Funder
National Health and Medical Research Council
Funding Amount
$451,056.00
Summary
Gastrointestinal infectious diseases kill more than 3 million people each year. The principal microbial pathogens responsible for these infections are known to exploit oligosaccharides on the surface of host cells as receptors for ahesins or toxins. We have developed (and patented) a novel anti-infective strategy, based on mimicry of oligosaccharide receptors for toxins and adhesins produced by enteric pathogens on the surface of harmless carrier bacteria. Oral administration of such recombinant ....Gastrointestinal infectious diseases kill more than 3 million people each year. The principal microbial pathogens responsible for these infections are known to exploit oligosaccharides on the surface of host cells as receptors for ahesins or toxins. We have developed (and patented) a novel anti-infective strategy, based on mimicry of oligosaccharide receptors for toxins and adhesins produced by enteric pathogens on the surface of harmless carrier bacteria. Oral administration of such recombinant probiotics has the potential to prevent enteric infections by binding and neutralizing toxins in the gut lumen and by blocking adherence of the pathogen to intestinal epithelial cells. As a prototypic example, we have developed a bacterium capable of preventing the serious consequences of Shiga toxigenic Escherichia coli (STEC) infections; this agent binds Shiga toxin with very high efficiency and is 100% protective in animal models. The strategy has very broad applications, however, and receptors for virtually any pathogen can be mimicked by expression of appropriate glycosyl transferases in a suitable harmless host bacterium. This proposal involves extension of our existing work to develop therapeutic agents for other important life threatening diarrhoeal diseases including cholera, travellers' diarrhoea, dysentery, antibiotic-associated colitis, rotavirus, etc.Read moreRead less
Global Regulation Of Toxin Production In Clostridium Perfringens
Funder
National Health and Medical Research Council
Funding Amount
$389,860.00
Summary
This project involves an investigation of how the bacteria that cause an often fatal wound infection control the production of the toxic proteins that are essential elements of the disease process. In all pathogenic bacteria there are specific genes that encode the virulence factors that are involved in the disease. The expression of these genes is generally controlled by the products of other genes known as regulatory genes. The function of these regulatory networks is generally responsive to e ....This project involves an investigation of how the bacteria that cause an often fatal wound infection control the production of the toxic proteins that are essential elements of the disease process. In all pathogenic bacteria there are specific genes that encode the virulence factors that are involved in the disease. The expression of these genes is generally controlled by the products of other genes known as regulatory genes. The function of these regulatory networks is generally responsive to environmental stimuli. This project involves the detailed functional analysis of a regulatory network that was first identified in this laboratory and which controls the expression of extracellular toxins that have been implicated in gas gangrene. The overall objectives of the project are to develop a detailed understanding of the mechanisms involved in this regulatory process. Specifically, the project aims to determine the functional components of the regulatory proteins that interact with the environmental signal or which bind to the genes encoding the bacterial toxins, to determine the nature of the target sites to which the regulatory proteins bind, and to examine the hypothesis that there is another regulatory gene that is involved in this process. The project will make a major contribution to our knowledge of the complex interactions that occur between an invading bacterium and the host tissues. If we are to fully comprehend how bacteria cause disease then it is critical that we understand how bacteria control the production of the toxic products that are an integral part of the disease process.Read moreRead less
Role Of Regulatory Genes In The Gastrointestinal Pathogen, Clostridium Difficile
Funder
National Health and Medical Research Council
Funding Amount
$287,036.00
Summary
When patients are treated in hospital with antibiotics they sometimes develop chronic diarrhoea or colitis syndromes that are very difficult and expensive to treat. This project involves the analysis of the bacterium that generally causes these gastrointestinal diseases. We know that this microorganism is present in the hospital environment and that it produces potent protein toxins that are responsible for these diseases but we know little about the actual disease process. In most bacteria that ....When patients are treated in hospital with antibiotics they sometimes develop chronic diarrhoea or colitis syndromes that are very difficult and expensive to treat. This project involves the analysis of the bacterium that generally causes these gastrointestinal diseases. We know that this microorganism is present in the hospital environment and that it produces potent protein toxins that are responsible for these diseases but we know little about the actual disease process. In most bacteria that cause disease there are regulatory networks that control the expression of the genes responsible for the disease process. In this project, we aim to develop an understanding of how these regulatory networks operate in this particular bacterium. The latest techniques of molecular biology will be used to investigate several specific regulatory genes at the functional level. Since the entire DNA sequence of this bacterium is now known we will also use a broader research approach that makes use of this knowledge to examine all of potential regulatory networks that exist in this bacterium. Finally, we will develop new methods for the genetic analysis of the causative bacterium so that we will be better able to elucidate the role of specific genes in the disease process. By understanding how this bacterium controls the production of the proteins that interact with human intestinal cells to cause disease we hope to be able to prevent such diseases from occurring. The successful completion of the project therefore will make a major contribution to the development of improved methods for the control and treatment of these chromic diarrhoea and colitis syndromes.Read moreRead less
Virulence Mechanisms In Hypervirulent Epidemic Strains Of Clostridium Difficile.
Funder
National Health and Medical Research Council
Funding Amount
$499,135.00
Summary
The bacterium Clostridium difficile is the major cause of nosocomial diarrhoea in many countries, including Australia. More virulent isolates have emerged since 2000, leading to increased incidence and severity of disease in many countries and resulting in epidemics. This project will make a major contribution to our understanding of how these bacteria cause disease and may help to prevent outbreaks of the hypervirulent strains in Australia by identifying potential new vaccine candidates.