A New Class Of Inhibitors For The Treatment Of Tuberculosis
Funder
National Health and Medical Research Council
Funding Amount
$720,691.00
Summary
Tuberculosis (TB) remains a major cause of mortality and morbidity worldwide, with 1.3 million deaths annually. Some strains of the TB bacterium are resistant to all available drugs. We have identified novel chemical structures that display potent and specific activity against pathogenic mycobacteria. In this proposal we will develop optimised derivatives with more potent activity against mycobacteria, assess their stability and toxicity and determine their mode of action.
Efflux Mediated Multidrug Resistance In Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$738,056.00
Summary
Strains of the pathogenic bacterium Staphylococcus aureus (Golden Staph), resistant to almost all available anti-staphylococcal agents, are responsible for serious infections among patients; in some hospitals such outbreaks reach epidemic proportions. In these bacteria, resistance has emerged to all classes of antimicrobial agents, including antibiotics and antiseptics-disinfectants commonly used in the hospital environment, largely due to the acquisition of resistance determinants. These determ ....Strains of the pathogenic bacterium Staphylococcus aureus (Golden Staph), resistant to almost all available anti-staphylococcal agents, are responsible for serious infections among patients; in some hospitals such outbreaks reach epidemic proportions. In these bacteria, resistance has emerged to all classes of antimicrobial agents, including antibiotics and antiseptics-disinfectants commonly used in the hospital environment, largely due to the acquisition of resistance determinants. These determinants encode proteins that provide the bacterial cell with a range of different biochemical mechanisms to evade antibiotic chemotherapy. Specifically, this project seeks to increase our understanding of proteins that confer resistance by pumping structurally-dissimilar antimicrobials out of the cell. The importance of these proteins in the biology of organisms is implied by the fact that an overwhelming majority of the drug targets are membrane proteins. Proteins which recognise such a broad spectrum of compounds are called multidrug resistance (MDR) proteins and present a disturbing clinical threat since the acquisition of one such system by a cell may simultaneously decrease its susceptibility to a number of antimicrobials. Similar MDR pumps are widespread in nature and are credited for resistance to antibiotics and other chemotherapeutic drugs in many pathogenic organisms and in human cancer cells. In this project, we aim to characterise the QacA MDR protein which is involved in pumping many different antimicrobial compounds from staphylococcal cells. We will identify the regions of the QacA MDR protein which bind the compounds and examine how the protein expels them to give resistance. These studies are a prerequisite for the design of more effective antibacterial compounds able to bypass these drug resistance pumps and will also provide fundamental knowledge applicable to the problem of MDR in other infectious diseases and cancer.Read moreRead less
Molecular Mechanisms Of Low-level Vancomycin Resistance In Clinical Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$437,916.00
Summary
The common bacteria Staphylococcus aureus causes many infections in humans, and is becoming more resistant to antibiotic treatments, especially in hospitals. This project will determine how this bacteria is developing resistance to some of our last available antibiotics. This will provide an important basis for detecting and preventing this antibiotic resistance problem in future.
Mechanisms Of Stable Gene Inheritance In Multiresistant Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$620,357.00
Summary
Strains of Golden Staph bacteria resistant to many antibiotics are a major cause of serious hospital-acquired, and increasingly community-acquired, infections in Australia and around the world. The bacteria have mechanisms that cause efficient inheritance of resistance genes, even when antibiotics are no longer being used. This project will elucidate key aspects of such mechanisms so that treatments can be devised that interfere with the development and maintenance of resistance.
Horizontal And Vertical Transmission Mechanisms Of Staphylococcus Aureus Multiresistance Plasmids
Funder
National Health and Medical Research Council
Funding Amount
$408,993.00
Summary
Strains of Golden Staph bacteria resistant to many antibiotics are a major cause of serious hospital-acquired, and increasingly community-acquired, infections. The bacteria have mechanisms that cause efficient transmission of resistance genes to their offspring as well as to other strains. This project aims to elucidate key features of these mechanisms so that treatments can be devised that disrupt the maintenance and transfer of resistance, so as to prolong the effectiveness of antibiotics.
Redefining Antibiotic Resistance Plasmid Transfer In Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$735,585.00
Summary
Multidrug-resistant Golden Staph bacteria are a major health problem. Resistance develops rapidly because bacteria efficiently acquire/share resistance genes. Our discoveries suggest DNA transfer mechanisms are far more diverse and widespread than previously expected and this has wide-reaching implications for numerous pathogenic organisms. This project aims to define the prevalence and key features of each mechanism so treatments can be devised to disrupt the evolution and spread of resistance.
Molecular Genetics And Evolution Of Antibiotic Resistant Staphylococci
Funder
National Health and Medical Research Council
Funding Amount
$432,750.00
Summary
Potentially life-threatening 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 h ....Potentially life-threatening 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. 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 staphylococcal multiresistance plasmids efficiently replicate in the host cell and are stably maintained in growing bacterial populations or when acquired by a new host after transfer; such mechanisms may well provide novel drug targets. The results will also lead to the development of improved methods for the characterisation of clinical strains and the monitoring of antibiotic resistance, and will be of broad relevance to the problem of antimicrobial resistance in bacterial pathogens. Most importantly, the application of knowledge arising from these studies to the design and implementation of rational antibiotic usage policies has the potential to extend the efficacy of existing and future anti-staphylococcal therapies.Read moreRead less
An Ace Up Their Sleeve: Characterisation Of A Novel Family Of Drug Efflux Systems Represented By The Acinetobacter AceI Exporter
Funder
National Health and Medical Research Council
Funding Amount
$400,286.00
Summary
Chlorhexidine is widely used as an antiseptic in products such as skin washes, soaps, mouthwashes, disinfectants and preservatives. We have recently discovered a novel bacterial protein which pumps chlorhexidine out of bacterial cells to make them resistant to this antiseptic agent. This proposal aims to understand this resistance mechanism and to find inhibitors which could be applied in clinical settings to augment the activity of chlorhexidine.
Reversing Antibiotic Resistance With Efflux Pump Inhibitors
Funder
National Health and Medical Research Council
Funding Amount
$494,174.00
Summary
Antibiotic resistance in dangerous pathogens is one of the greatest threats to human health of the 21st century. The main cause of multidrug resistance is the presence of drug efflux pumps, which remove antibiotics from the bacterial cell thereby lowering the antibiotic concentration inside the cells to sub-toxic levels. We will use our expertise on these efflux pumps and on how to inhibit them to develop compounds that could reverse resistance and restore the activity of antibiotics.
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