Origins And Relationships Of Shigella And Enteroinvasive Escherichia Coli
Funder
National Health and Medical Research Council
Funding Amount
$377,310.00
Summary
Shigella is a well known highly infectious human pathogen with as few as 10 cells allowing effective spread by infected food or water, and also by person to person contact. Shigellosis is a particularly significant disease for children due to lack of pre-existing immunity and greater chance of transfer by fecal-oral route. One group of E. coli called Enteroinvasive E. coli (EIEC) resembles Shigella in many aspects from disease symptoms to biochemical properties. EIEC is a major cause of diarrhoe ....Shigella is a well known highly infectious human pathogen with as few as 10 cells allowing effective spread by infected food or water, and also by person to person contact. Shigellosis is a particularly significant disease for children due to lack of pre-existing immunity and greater chance of transfer by fecal-oral route. One group of E. coli called Enteroinvasive E. coli (EIEC) resembles Shigella in many aspects from disease symptoms to biochemical properties. EIEC is a major cause of diarrhoea in less developed countries and has also caused large outbreaks in developed countries. It is now clear that Shigella and E. coli are really one species. EIEC and Shigella strains are variants of E. coli with humans as the only host. However separation of the two in all records and most studies means that there is no integrated understanding of the forms. We aim to study the relationships of Shigella and EIEC and expect significant insights into the origins of Shigella-EIEC. This will facilitate diagnosis and understanding of the disease(s) and lead to a far better classification . EIEC-Shigella strains have arisen from other E. coli independently. This has happened seven times in the derivation of Shigella and we expect more such events with EIEC. An interesting phenomenon during this process is that strains tend to lose metabolic functions. In this study we will look at what, why and how functions are lost. O antigens are important in evading the host immune system. Shigella strains obtained many O antigens, the majority apparently from other species. This is quite likely the key to its success. We will look at how Shigella obtained new O antigens. This project will be significant in the understanding of Shigell-EIEC, a very significant human pathogen, and in general for understanding emergence of new pathogens.Read moreRead less
Some of the world's most important diseases, including important diseases of indigenous chilren and the hospitalised elderly are caused by bacteria that carry a surface coating called a capsule. It is not clear how this capsule is retained by bacteria. Resolution of this question could lead to the development of new disinfectants that will stop hospital-acquired infections, to new reagents that can be incoporated into medical devices where bacteria frequently grow, and new antibiotics.
Molecular Basis Of O-antigen Modification And Genomics Of Serotype-converting Bacteriophages Of Shigella Flexneri
Funder
National Health and Medical Research Council
Funding Amount
$268,264.00
Summary
There are approximately 165 million cases of shigellosis world wide annually, resulting in 1.1 million deaths. The majority of cases occur in developing countries and most deaths occur in children under 5 years of age. Shigellosis is mainly caused by the bacterium Shigella flexneri. There are 13 different serotypes of S. flexneri determined by bacterial cell-surface polysaccharides called O-antigens. Bacterial viruses (bacteriophages) carry the genes which confer O-antigen variation. Infection a ....There are approximately 165 million cases of shigellosis world wide annually, resulting in 1.1 million deaths. The majority of cases occur in developing countries and most deaths occur in children under 5 years of age. Shigellosis is mainly caused by the bacterium Shigella flexneri. There are 13 different serotypes of S. flexneri determined by bacterial cell-surface polysaccharides called O-antigens. Bacterial viruses (bacteriophages) carry the genes which confer O-antigen variation. Infection and subsequent incorporation of the virus into the genetic material of the bacterial cell result in modification of the bacterial O-antigen. This phage-mediated O-antigen modification gives rise to different serotypes. The project will address fundamental processes related to the O-antigen modification. This will be achieved by studying structure and function of the enzymes encoded by the O-antigen modification gene cluster. We have isolated several serotype-converting bacteriophages from S. flexneri and we plan to compare and characterise their genomic information to increase understanding of their origin and relationship with the bacterial host.Read moreRead less
Structural Investigations Of Bacterial Evasion Of IgA Mucosal And Systemic Immunity
Funder
National Health and Medical Research Council
Funding Amount
$488,812.00
Summary
Nose, throat and skin infections are often caused by streptococcal and staphylococcal bacteria, known as Strep Throat and Golden Staph. Infections can be life-threatening in newborns, the elderly or individuals with weak immune systems. These bacteria make proteins bind and inactivate immune proteins. Our research examines the structural basis for bacterial interactions with a key immune system protein (an antibody called IgA) and may lead to new prevention and treatment strategies.
DNA Segregation In Multiresistant Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$306,592.00
Summary
Strains of Golden Staph bacteria resistant to many antibiotics are a major cause of hospital-acquired, and increasingly community-acquired, infections in Australia and around the world. Bacterial growth depends on the faithful inheritance of genetic material, which is facilitated by active DNA segregation. This project will elucidate key aspects of segregation processes so that treatments can be devised that interfere with the growth of this important pathogen and the development of resistance.
Molecular Mechanisms Of Plasmid Maintenance In Multiply-resistant Staphylococci
Funder
National Health and Medical Research Council
Funding Amount
$543,778.00
Summary
Serious infections caused by Staphylococcus aureus bacteria, commonly known as Golden Staph, often arise as complications in patients within hospitals. These infections compromise the health of the patient and jeopardise their recovery from the condition for which they were initially admitted, which significantly increases healthcare costs. Golden Staph is a major cause of hospital-acquired infections in Australia and globally. The problem is largely due to the presence in hospitals of strains t ....Serious infections caused by Staphylococcus aureus bacteria, commonly known as Golden Staph, often arise as complications in patients within hospitals. These infections compromise the health of the patient and jeopardise their recovery from the condition for which they were initially admitted, which significantly increases healthcare costs. Golden Staph is a major cause of hospital-acquired infections in Australia and globally. The problem is largely due to the presence in hospitals of strains that are resistant to most clinically-useful antibiotics and are therefore very difficult to eradicate; the recent isolation of strains highly-resistant to one of the last resort anti-staphylococcal antibiotics, vancomycin, is particularly worrying, as is the emergence of resistant strains that cause infections in the wider community. The emergence of these multiresistant strains is primarily attributable to the acquisition of pre-existing resistance determinants by cell-to-cell gene transfer, a process in which plasmids, extra-chromosomal DNA elements, play a prominent role. Staphylococcal multiresistance plasmids carry genes that can confer resistance to up to 20 antimicrobial agents and are themselves capable of transfer between bacterial cells. In this project, we will define the molecular mechanisms by which multiresistance plasmids efficiently replicate in the host cell and are stably maintained in bacterial populations. This information will identify targets for agents that can promote the loss of plasmids and hence combat the development of resistance; the activity of one type of agent will be determined in this project. The application of knowledge arising from these studies to has the potential to extend the efficacy of existing and future antimicrobial therapies.Read moreRead less
Urinary tract infections (UTI) are among the most common infectious diseases of humans and a major cause of morbidity and mortality. In the USA, UTI accounts for >$1.6 billion in medical expenses each year. It is estimated that 50% of women will develop a UTI in their lifetime. This research aims to understand the processes by which bacteria colonize the human bladder. The work has implications for the development of new approaches to prevent and treat UTI.
The Team brings together a unique grouping of people with backgrounds in molecular biology, medical microbiology, microbiology, marine ecology and immunology to tackle a significant health problem infections caused by bacteria. Using a novel approach, based on understanding how marine organisms specifically interfere with bacterial colonisation, the Team over the past seven years has identified a group of compounds that represent a novel group of antibiotics. Publications and patenting by the Te ....The Team brings together a unique grouping of people with backgrounds in molecular biology, medical microbiology, microbiology, marine ecology and immunology to tackle a significant health problem infections caused by bacteria. Using a novel approach, based on understanding how marine organisms specifically interfere with bacterial colonisation, the Team over the past seven years has identified a group of compounds that represent a novel group of antibiotics. Publications and patenting by the Team has demonstrated that the Team is at the forefront of research in this area. The novel antibiotics work by preventing bacteria sticking to surfaces and by preventing the bacteria from releasing toxins. The studies will concentrate on those bacteria that produce infections in the lungs (acute pneumonia), eyes (corneal infection), ear (middle ear disease), and abscesses.Read moreRead less
Identifying The Physiological Conditions That Promote Lateral Gene Transfer And Evolution Of New Streptococcal Pathovars
Funder
National Health and Medical Research Council
Funding Amount
$415,907.00
Summary
In the last few decades, the diseases caused by the three human pathogens, groups A, B and G streptococcus have undergone a transformation. The exchange of DNA between these species is speculated to play a role in this changing disease association. In this proposal we will identify the specific physiological and growth conditions that promote DNA transfer. Such information may help in our understanding of how new pathogenic strains of streptococci arise.
Pathogenomics: New Ways To Exploit Genome Sequence Data From Pathogenic Bacteria.
Funder
National Health and Medical Research Council
Funding Amount
$547,372.00
Summary
Bacterial pathogens are locked in an evolutionary battle of survival with their eukaryote hosts. The rapidly evolving genes of medically-important pathogens are generally those required for adaptation to the human host. This project aims to exploit the abundance of available bacterial genome sequences to predict rapid evolution in bacterial pathogens using computational methods. The protein products of such genes offer novel targets for therapeutic intervention.