Molecular And Genetic Basis Of Colistin Resistance In Acinetobacter Baumannii
Funder
National Health and Medical Research Council
Funding Amount
$526,878.00
Summary
Acinetobacter baumannii is a bacterium that causes hospital acquired infections which have become difficult to treat due to the bacteria developing resistance to most antibiotics in routine use. Colistin is now widely used as 'salvage' therapy in patients with these infections. Colistin resistance is currently low but is an emerging problem. As a first step in combating this problem this project will identify how this bacterium becomes resistant to colistin.
QacA-mediated Multidrug Resistance And Export In Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$497,250.00
Summary
Strains of the pathogenic bacterium Staphylococcus aureus (Golden Staph) which are resistant to almost all available anti-staphylococcal agents are responsible for serious infections among hospitalised 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 deter ....Strains of the pathogenic bacterium Staphylococcus aureus (Golden Staph) which are resistant to almost all available anti-staphylococcal agents are responsible for serious infections among hospitalised 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 for proteins which 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 which confer resistance by pumping a variety of structurally-dissimilar antimicrobials out of the bacterial cell. Proteins which recognise such a broad spectrum of compounds are called multidrug resistance 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 multidrug pumps are widespread in nature and are credited for resistance to antibiotics and other chemotherapeutic drugs in many pathogenic organisms, such as the bacteria responsible for tuberculosis, and in human cancer cells. In this project, we aim to characterise the QacA multidrug resistance protein which is involved in pumping many different antimicrobial compounds from staphylococcal cells. We will identify the regions of the QacA multidrug resistance 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 or block these drug resistance pumps, and will also provide fundamental knowledge applicable to the problem of multidrug resistance in other infectious diseases and cancer.Read moreRead less
QacA-mediated Multidrug Resistance And Export In Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$437,545.00
Summary
Strains of the pathogenic bacterium Staphylococcus aureus (Golden Staph) which are resistant to almost all available anti-staphylococcal agents are responsible for serious infections among hospitalised 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 deter ....Strains of the pathogenic bacterium Staphylococcus aureus (Golden Staph) which are resistant to almost all available anti-staphylococcal agents are responsible for serious infections among hospitalised 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 for proteins which 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 which confer resistance by pumping a variety of structurally-dissimilar antimicrobials out of the bacterial cell. Proteins which recognise such a broad spectrum of compounds are called multidrug resistance 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 multidrug pumps are widespread in nature and are credited for resistance to antibiotics and other chemotherapeutic drugs in many pathogenic organisms, such as the bacteria responsible for tuberculosis, and in human cancer cells. In this project, we aim to characterise the QacA multidrug resistance protein which is involved in pumping many different antimicrobial compounds from staphylococcal cells. We will identify the regions of the QacA multidrug resistance 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 multidrug resistance in other infectious diseases and cancer.Read moreRead less
Multidrug Resistance Regulatory Protein QacR From Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$459,750.00
Summary
One of the most significant mechanisms of drug resistance is the export of antibiotics and other chemotherapeutic drugs from the cell. Drug export systems are an important medical problem due to their frequent occurrence in bacteria and parasites which cause human disease, and in human cancer cells. Proteins which recognise and export a broad range of drugs from a cell are called multidrug efflux pumps. These multidrug efflux systems present a serious threat to patient care and to successful the ....One of the most significant mechanisms of drug resistance is the export of antibiotics and other chemotherapeutic drugs from the cell. Drug export systems are an important medical problem due to their frequent occurrence in bacteria and parasites which cause human disease, and in human cancer cells. Proteins which recognise and export a broad range of drugs from a cell are called multidrug efflux pumps. These multidrug efflux systems present a serious threat to patient care and to successful therapy, since the ability to produce a single protein simultaneously renders the cell or organism resistant to several different drugs. Strains of the bacterial pathogen Staphylococcus aureus or Golden Staph, which are endemic in hospitals world-wide, contain an example of such a multidrug exporter, the QacA multidrug efflux pump. QacA exports at least 30 different antimicrobial compounds, including antiseptics and disinfectants. Production of this protein is regulated by a sensor protein, QacR, which detects the presence of a number of these antimicrobial compounds. To understand how the QacR sensor protein can recognise such a wide variety of compounds, we will identify and structurally characterise the regions of the QacR multidrug regulatory protein which bind these compounds. Additionally, we will examine the means by which QacR regulates the production of the QacA pump protein. This project will provide fundamental knowledge that will not only help with understanding the important process of multidrug resistance but will also enable the rational design of more effective antibacterial compounds that either block or evade these multidrug efflux systems.Read moreRead less
Novel Therapeutic Strategy Against Multidrug-resistant Gram-negative Bacteria
Funder
National Health and Medical Research Council
Funding Amount
$349,823.00
Summary
In the past two decades, there has been a marked decline in discovery and development of new antibiotics while there has been a remarkable increase in resistance to the currently available antibiotics. The growth in the number of resistant bacteria and lack of antibiotics available for treatment is very significant with gram-negative bacteria, such as Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia. Colistin, an old antibiotic that has been used little over the l ....In the past two decades, there has been a marked decline in discovery and development of new antibiotics while there has been a remarkable increase in resistance to the currently available antibiotics. The growth in the number of resistant bacteria and lack of antibiotics available for treatment is very significant with gram-negative bacteria, such as Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia. Colistin, an old antibiotic that has been used little over the last 40-50 years, has been 'taken off the shelf' and is now being used as a last line of defence to treat people with infections caused by these bacteria. Clearly, doctors and their infected patients will be in an even more precarious position than currently exists if resistance to colistin increases. We have discovered a novel therapeutic strategy that is able to reverse colistin resistance in P. aeruginosa. The studies proposed in this project will investigate this novel strategy across a range of multidrug-resistant bacteria and provide the information essential for rational use in patients. We propose that such a novel therapeutic strategy will provide a powerful weapon for the war on these 'superbugs'.Read moreRead less
Multidrug Resistance Regulatory Protein QacR From Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$196,527.00
Summary
One of the most significant mechanisms of drug resistance is the export of antibiotics and other chemotherapeutic drugs from the cell. Drug export systems are an important medical problem due to their frequent occurrence in bacteria and parasites which cause human disease and in human cancer cells. Proteins which recognise and export a broad range of drugs from a cell are called multidrug efflux pumps. These multidrug efflux systems present a serious threat to patient care and to successful ther ....One of the most significant mechanisms of drug resistance is the export of antibiotics and other chemotherapeutic drugs from the cell. Drug export systems are an important medical problem due to their frequent occurrence in bacteria and parasites which cause human disease and in human cancer cells. Proteins which recognise and export a broad range of drugs from a cell are called multidrug efflux pumps. These multidrug efflux systems present a serious threat to patient care and to successful therapy, since the ability to produce a single protein simultaneously renders the cell or organism resistant to several different drugs. Strains of the bacterial pathogen Staphylococcus aureus or Golden Staph, which are endemic in hospitals world-wide, contain an example of such a multidrug exporter, the QacA multidrug efflux pump, which exports at least 30 different antimicrobial compounds, including antiseptics and disinfectants. Production of this protein is regulated by a sensor protein, QacR, which detects the presence of a number of these antimicrobial compounds. To understand how the QacR sensor protein can recognise such a wide variety of compounds, we will identify and structurally characterise the regions of the QacR multidrug regulatory protein which bind these compounds. Additionally, we will examine the means by which QacR regulates the production of the QacA pump protein. This project will provide fundamental knowledge that will not only help with understanding the important process of multidrug resistance but will also enable the rational design of more effective antibacterial compounds that either block or evade these multidrug efflux systems.Read moreRead less
Targeting Polymyxin-resistant Gram-negative Superbugs: Development Of Novel Antimicrobial Lipopeptides
Funder
National Health and Medical Research Council
Funding Amount
$661,069.00
Summary
Prevalence of resistance to antibiotics among Gram-negative 'superbugs' is a major global medical challenge, which is highlighted by the Bad Bugs, No Drugs campaign of the Infectious Diseases Society of America. There are virtually no new antibiotics in the current drug development pipeline for these dangerous pathogens. In this project, novel lipopeptides will be designed, synthesised and evaluated against these 'superbugs'. Information obtained will be crucial for further drug development.
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
Towards Reducing Resistance And Haematological Toxicity Of Linezolid
Funder
National Health and Medical Research Council
Funding Amount
$135,825.00
Summary
Multi-drug resistance in bacteria is increasing at an alarming rate. We have diminishing therapeutic options, and there are few antibiotics in the drug development pipeline that offer much hope. It is therefore important that we look towards ways of further optimising the use of antibiotics that we currently have available. An important last line of defense drug, linezolid, has been available in Australia for less than 2 years and already resistance is occuring. In addition, with broader use of ....Multi-drug resistance in bacteria is increasing at an alarming rate. We have diminishing therapeutic options, and there are few antibiotics in the drug development pipeline that offer much hope. It is therefore important that we look towards ways of further optimising the use of antibiotics that we currently have available. An important last line of defense drug, linezolid, has been available in Australia for less than 2 years and already resistance is occuring. In addition, with broader use of this drug outside clinical trials, there has been an increasing concern over its toxicity to important blood cells. We seek to better understand the determinants of linezolid resistance and toxicity, so that novel dosing strategies may be developed to optimise its use (reduce toxicity and enhance efficacy) thereby extending the usefulness of this last line of defense antibiotic.Read moreRead less