Exploitation Of Bacterial Transcription Initiation As A Target For New Antimicrobials
Funder
National Health and Medical Research Council
Funding Amount
$540,356.00
Summary
Antibiotic resistant infections from 'superbugs' are a major health problem. We will exploit information we have gathered on the machinery that copies genetic information into a message to discover chemical compounds that can be used for the development of new antibiotics with a novel mechanism of action.
Multidrug Recognition And Resistance In Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$598,978.00
Summary
Strains of 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. Resistance has emerged to all classes of antimicrobial agents. We will increase our understanding of proteins that confer resistance by pumping multiple antimicrobials out of the cell to ultimately design more effective antibacterials able to bypass such drug pumps.
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.
Structural Studies Of Bacterial Pore-forming Protein Toxins
Funder
National Health and Medical Research Council
Funding Amount
$509,017.00
Summary
In this project the three-dimensional structures of proteins that form pores in membrane cell walls will be determined. These proteins are bacterial toxins and knowledge of their structure may prove useful in the design of new antibiotics. This project will focus on a class of toxins called the cholesterol-dependent cytolysins which are released by Gram positive bacteria such as Clostridia and Streptococcus and which cause a variety of nasty infectious diseases such as gas gangrene, pneumonia an ....In this project the three-dimensional structures of proteins that form pores in membrane cell walls will be determined. These proteins are bacterial toxins and knowledge of their structure may prove useful in the design of new antibiotics. This project will focus on a class of toxins called the cholesterol-dependent cytolysins which are released by Gram positive bacteria such as Clostridia and Streptococcus and which cause a variety of nasty infectious diseases such as gas gangrene, pneumonia and meningitis. The three-dimensional structures will be elucidated using X-ray crystallography. Protein crystallography is the study of three-dimensional shapes of proteins at near atomic resolution. In this method proteins are made to form crystals. X-ray beams are then shone on the crystals causing the X-rays to scatter in a pattern which is characteristic of the protein's three-dimensional shape. Knowledge of the structure of proteins is necessary for the complete understanding of their biological activity and is also very useful for the rational design of new drugs that may alter their activity.Read moreRead less
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
Novel Perspectives On The Function Of AB5 Toxin B Subunits
Funder
National Health and Medical Research Council
Funding Amount
$1,041,896.00
Summary
AB5 toxins are important virulence factors of pathogenic bacteria. They comprise pentameric B subunits that bind to target cell surfaces and catalytic A subunits that damage host cell functions. This proposal examines a new paradigm wherein the B subunits are significant contributors to cell damage. We will characterize the cytopathic properties of diverse B subunits, particularly those of emerging toxins. This will provide novel insights into pathogenesis and inform development of therapeutics.
Genome Wide Investigations Of Mycobacterium Tuberculosis To Reveal Processes Of Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$396,341.00
Summary
Tuberculosis remains a global health burden of staggering proportions. Around 1 in 3 people are infected with Mycobacteria tuberculosis, the organism responsible for the disease, which kills 2 million people annually. The emergence of strains now resistant to almost all of our front line drugs has placed extra pressure on researchers who are attempting to develop new protective vaccines and the critical antibiotics required to eradicate the disease. Furthermore the current global HIV pandemic is ....Tuberculosis remains a global health burden of staggering proportions. Around 1 in 3 people are infected with Mycobacteria tuberculosis, the organism responsible for the disease, which kills 2 million people annually. The emergence of strains now resistant to almost all of our front line drugs has placed extra pressure on researchers who are attempting to develop new protective vaccines and the critical antibiotics required to eradicate the disease. Furthermore the current global HIV pandemic is making the situation far worse as HIV kills the very cells of the body that protect us from tuberculosis. This research project will fill the significant gaps in our knowledge of M. tuberculosis infection, specifically identify the genes of the organism which allow it to invade and spread throughout the body. M. tuberculosis infection consists of 3 characteristic stages, i.e. colonisation, spread and long term survival in specialised structures called granulomas. It is from these granulomas that the bacterium can emerge after long periods of inactivity to cause clinical tuberculosis. Using a mouse model of infection I will define the genes needed by the bacterium to survive at these 3 key stages of disease thereby providing for a better knowledge base from which to design new vaccine strategies and to create effective drugs.Read moreRead less
Characterization Of The Type IX Secretion System In Porphyromonas Gingivalis
Funder
National Health and Medical Research Council
Funding Amount
$831,656.00
Summary
Periodontitis is associated with the keystone pathogen Porphyromonas gingivalis. We have identified a novel protein secretion machine comprised of at least 12 components in P. gingivalis which transports the bacterium's major virulence factors to the cell surface and attaches them to the outer membrane. We aim to determine the spatial arrangement and specific role of each of these 12 components and thereby provide targets for future treatments against this disease.
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.
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.