Understanding The Complex Relationship Between Host, Pathogen And Antibiotic Factors On Treatment Outcome In Serious Bacterial Infections
Funder
National Health and Medical Research Council
Funding Amount
$380,945.00
Summary
Millions of people still die every year from bacterial infections despite the availability of antibiotics. The same bacterial infection in one person can behave very differently in another person, so infections can range from trivial to life-threatening or fatal. Understanding the relationship between the patient, the infecting bacteria and the antibiotic treatment given will ultimately help to predict and improve outcomes for patients with serious bacterial infections.
Beta-lactamase Mediated Antibiotic Resistance In Gram-negative Pathogens: How Does Genotype Relate To Phenotype?
Funder
National Health and Medical Research Council
Funding Amount
$397,869.00
Summary
Unfortunately, one of the consequences of antibiotic usage (and in particular over-use and mis-use) is the development of resistance; if a small proportion of bacteria survive treatment, they can grow and replace the previous population of sensitive bacteria. In addition, the genes that confer resistance can be transferred between different bacterial lineages, thus facilitating the dissemination of resistant bacteria. The most important mechanism of penicillin resistance is through the expressio ....Unfortunately, one of the consequences of antibiotic usage (and in particular over-use and mis-use) is the development of resistance; if a small proportion of bacteria survive treatment, they can grow and replace the previous population of sensitive bacteria. In addition, the genes that confer resistance can be transferred between different bacterial lineages, thus facilitating the dissemination of resistant bacteria. The most important mechanism of penicillin resistance is through the expression of an enzyme called a beta-lactamase. This enzyme breaks down the penicillin. Beta-lactamase enzymes come in many different varieties, and new varieties appear quite frequently. Remarkably, when new kinds of penicillin are invented to circumvent resistance, the appearance of new beta-lactamases that can break down these new penicillins follows shortly thereafter. The objectives of our research are twofold. Firstly, it is now clear that the relationship between the beta-lactamase genes in a bacterium and the resulting pattern of resistance can be very complex. It can involve both the broad nature of the genes, the numbers of duplicates of the genes inside the cell, and very minor changes to the gene sequences. We will probe the relationship between the gene and resistance so as to understand it at a deeper level. Secondly, we will use this information to develop very efficient and cost affective methods for keeping track of the spread of the different varieties of beta-lactamase genes. These methods will be designed to be carried out on real-time PCR machines. These high-tech devices are general purpose gene analyzers that can carry out many different kinds of genetic assay. They are rapidly becoming ubiquitous in clinical microbiology laboratories. The use of these methods will provide much hard information that will be used to minimise the dissemination of antibiotic resistance.Read moreRead less
Functional Biology Of Large Serine Recombinases From Mobile Antibiotic Resistance Elements
Funder
National Health and Medical Research Council
Funding Amount
$436,328.00
Summary
In recent years there has been increasing concern about the emergence of multiply antibiotic resistant strains of many common bacterial pathogens. The development of multiple resistance phenotypes has already led to compromises in the ability to successfully treat infected patients and to increased treatment costs. The emergence of these resistant bacteria is the result of excessive or inappropriate use of antibiotics and the ability of antibiotic resistance genes to be transferred from resistan ....In recent years there has been increasing concern about the emergence of multiply antibiotic resistant strains of many common bacterial pathogens. The development of multiple resistance phenotypes has already led to compromises in the ability to successfully treat infected patients and to increased treatment costs. The emergence of these resistant bacteria is the result of excessive or inappropriate use of antibiotics and the ability of antibiotic resistance genes to be transferred from resistant to susceptible bacteria, either within or between bacterial species. The movement of resistance elements that are integrated into the bacterial genome often involves their excision from their existing site and their subsequent integration into another site in the same or a different genome. This project centres on the analysis of this process in resistant bacteria that cause major disease problems in our hospitals. The research project will focus on MRSA (Multiply Resistant Staphylococcus aureus) which has been a serious problem in our hospitals for many years, and Clostridium difficile, an emerging pathogen of increasing importance and which causes a very serious and chronic form of colitis in hospital patients. By studying the biochemical processes by which enzymes called recombinases excise and subsequently integrate antibiotic resistance elements from these bacteria and by determining the three dimensional structure of such enzymes we aim to determine the mechanism of action of members of this important enzyme family. The major outcomes of the project will be an increased understanding of one of the major processes by which antibiotic resistance determinants can spread both within and between bacterial pathogens of importance in the hospital environment. These studies will contribute towards the development of improved methods for controlling the spread of resistant pathogens and resistance genes in the hospital environment, with concomitant benefits to human health.Read moreRead less