Role Of Novel Mobile Elements In The Infiltration Of Antibiotic Resistance Genes Into Clinical Isolates.
Funder
National Health and Medical Research Council
Funding Amount
$421,650.00
Summary
Bacteria have a remarkable ability to capture and spread antibiotic resistance genes. This phenomenon is a particular problem in our hospitals and in the community as multi-drug resistant pathogenic organisms have been selected over time as a result of the use of antibitoics. Moreover the incidence of resistance appears to be on the increase. Once resistant strains appear they can greatly complicate the treatment of infections and the eradication of such pathogens from a hospital is both difficu ....Bacteria have a remarkable ability to capture and spread antibiotic resistance genes. This phenomenon is a particular problem in our hospitals and in the community as multi-drug resistant pathogenic organisms have been selected over time as a result of the use of antibitoics. Moreover the incidence of resistance appears to be on the increase. Once resistant strains appear they can greatly complicate the treatment of infections and the eradication of such pathogens from a hospital is both difficult and costly. We have been working on the problem of how antibiotic resistance genes are spread for a number of years and have identified a novel genetic element that can capture resistance genes by a process of site-specific recombination. This element, the integron, is common in mutli-drug resistant clinical isolates. To be captured by an integron, an antibiotic resistance gene has to be part of a mobile element known as a gene cassette. Although the application of antibiotics acts to amplify pathogens that are resistant and favours their persistance in hospitals, it is generally recognized that neither the gene cassette nor the drug resistance gene evolve in the hospital. Rather, these genes make their way into human pathogens from bacteria that normally reside in other environments, for example soil or water. In this project, we will investigate one route by which drug resistance genes and integrons might find their way into clinically relevant strains and what the sources of the resistance genes and gene cassettes might be. A greater understanding of these processes will help in developing strategies to limit the spread of drug resistant bacteria into and around hospitals.Read moreRead less
A remarkable feature of bacterial cells though is that they can share genes. In so doing bacteria have the ability to acquire completely new characteristics. One example of this spreading of genes is the rapid dissemination of antibiotic resistance in pathogenic bacteria and the creation of multi-resistant superbugs. This process contributes greatly to the problem of hospiatal acquired infeections and results in many patient deaths annually. The other aspect of this sharing of genes is that in a ....A remarkable feature of bacterial cells though is that they can share genes. In so doing bacteria have the ability to acquire completely new characteristics. One example of this spreading of genes is the rapid dissemination of antibiotic resistance in pathogenic bacteria and the creation of multi-resistant superbugs. This process contributes greatly to the problem of hospiatal acquired infeections and results in many patient deaths annually. The other aspect of this sharing of genes is that in a population some cells will lack genes that others have. Some of these shared genes apart from antibiotic resistance can be a concern and include traits that make some bacteria pathogenic. Thus, two cells of the same species may have very different abilities to cause disease based on what additional genes they carry. Genomics is becoming one of the great scientific revolutions of the 21st century. Over 160 microbial genomes have been sequenced to date and from these studies we have also learned many important things including how some bacteria cause disease. Mobile DNA presents unique challenges to microbial genomics however since different individuals in a species can have many different genes. Thus genomics on even many individuals of a species may miss bacterial genes important to us. Here we will be applying genomics in a way that specifically targets those genes that are shared. This will have many benefits. We will be able to greatly increase our rate of discovery of medically important and other genes in way that is targeted. This approach will allow us to discover these shared genes in a way that is much more cost effective and faster than conventional whole cell genomics. It will also allow us to gain an understanding of how benign bacteria associated with humans may act as reservoirs for passing on harmful genes to bacteria that cause hospital infections.Read moreRead less
Gentamicin Vestibulotoxicity: Detection And Prevention
Funder
National Health and Medical Research Council
Funding Amount
$205,500.00
Summary
A powerful, life-saving and cheap antibiotic, gentamicin, has one potential serious permanent side-effect: loss of balance due to damage to the balance organs of the inner ears. Detected early, the inner ear damage can be reversed by stopping gentamicin. Until now there has been no way of monitoring inner ear balance at the bedside. We have now developed such a method and want to show that by monitoring inner ear balance of patients needing gentamicin we can detect damage at such an early stage ....A powerful, life-saving and cheap antibiotic, gentamicin, has one potential serious permanent side-effect: loss of balance due to damage to the balance organs of the inner ears. Detected early, the inner ear damage can be reversed by stopping gentamicin. Until now there has been no way of monitoring inner ear balance at the bedside. We have now developed such a method and want to show that by monitoring inner ear balance of patients needing gentamicin we can detect damage at such an early stage that stopping the drug and using another instead will allow the balance organs to recover by themselves.Read moreRead less
Asthma causes a unique type of inflammation in the airways. Until recently, the cell responsible for this inflammation was thought to be the eosinophil. Eosinophils are evaluated in sputum samples from the airways and are commonly reported in increased levels from people with asthma. Recent work has identified that some people have symptoms of asthma but their eosinophil levels remain normal. Those with non-eosinophilic asthmatics may account for up to 50% of all asthma reported. Our study will ....Asthma causes a unique type of inflammation in the airways. Until recently, the cell responsible for this inflammation was thought to be the eosinophil. Eosinophils are evaluated in sputum samples from the airways and are commonly reported in increased levels from people with asthma. Recent work has identified that some people have symptoms of asthma but their eosinophil levels remain normal. Those with non-eosinophilic asthmatics may account for up to 50% of all asthma reported. Our study will investigate the cells present in the sputum of people that have non-eosinophilic asthma. It has been speculated that neutrophils (another cell causing inflammation in the lungs) may be responsible. Neutrophils are known to cause inflammation and release many chemical mediators, which are capable of destroying lung tissue. We will focus on the neutrophil and the chemicals that cause neutrophils to move into the lungs and then destroy tissue. By comparing the levels of neutrophils and its mediators between the eosinophilic and non-eosinophilic asthma populations it may be possible to understand the mechanism behind non-eosinophilic asthma. Current asthma treatments-preventers focus essentially on controlling the inflammation caused by eosinophils. By understanding what is causing the inflammation in people without eosinophils in their sputum, we can begin to investigate and design new treatments. One possible treatment is the use of macrolide antibiotics. These medicines have been shown to be useful in reducing inflammation in other chronic inflammatory diseases. We plan to investigate the usefulness of a macrolide antibiotic (erythromycin) in reducing inflammation in non-eosinophilic asthma by a randomised-controlled trial. Armed with more information about non-eosinophilic asthma we will be able to more effectively diagnose and treat this group in the community.Read moreRead less
Management Of Burn Injury: Fluid Dynamics And Antibiotic Pharmacokinetics
Funder
National Health and Medical Research Council
Funding Amount
$342,375.00
Summary
It is well known that major burns, as well as being relatively common injuries, are notoriously difficult to manage. Patients exhibit significant variability due to a combination of anatomic, physiologic, hormonal and immunologic alterations occurring both at the wound site and, more importantly, in other body compartments and vital organ systems. Skin burn injury results in the release of multiple inflammatory mediators in addition to significant fluid loss. The distribution of inflammatory med ....It is well known that major burns, as well as being relatively common injuries, are notoriously difficult to manage. Patients exhibit significant variability due to a combination of anatomic, physiologic, hormonal and immunologic alterations occurring both at the wound site and, more importantly, in other body compartments and vital organ systems. Skin burn injury results in the release of multiple inflammatory mediators in addition to significant fluid loss. The distribution of inflammatory mediators and wound bacteria to central organs can cause complex physiological changes that may lead to multiple organ failure, with serious infections occurring in around 50% of patients with serious burns. Antibiotic distribution kinetics, such as bioavailability, clearance, volume of distribution, elimination half-life and unbound fraction in plasma can be significantly altered in burn patients. Without detailed knowledge of changes and relationships between factors such as wound pH, tissue oxygenation, protein concentrations of fluid leaked from the local wound microvasculature, tissue binding, oedema and changes in burned and non-burned tissue induced by resuscitation therapies, the optimisation of both local and systemic infection contriol therapies can hardly be expected to advance. This project aims to determine how changes the physiology of burn patients, in particular in the burn wound environment, affect antibiotic penetration and distribution into tissues. We also believe that these changes will vary between patients and are aiming to determine whether certain parameters can be used to give an indication of the best antibiotic dosing regimens for individual patients.Read moreRead less
A Randomised Controlled Trial Of Alternative Treatments To Intramuscular Penicillin For Impetigo In Aboriginal Children
Funder
National Health and Medical Research Council
Funding Amount
$1,326,182.00
Summary
We will conduct clinical trials to find an effective, simple and cheap oral alternative to injected penicillin for skin sores which could become the universal standard of care whether the patient is in Melbourne or Milingimbi. It would also likely be adopted by the World Health Organization as a standard of care for developing countries. This would lead directly to a reduced burden of skin sores and their complications. It would also open the way for studies to explore even simpler regimens.
Antibiotic Loading Of Bone Allografts For The Prevention Of Peri-operative Infection
Funder
National Health and Medical Research Council
Funding Amount
$300,847.00
Summary
Bone is the second most often transplanted tissue after blood, with thousands of grafts done every year in Australia. Allograft bone (taken from another person) is used to replace bone removed due to cancer, but is prone to infection. Infected grafts must be removed, and can lead to amputation. We are developing a process to put antibiotics into allograft bone, to prevent infections from taking hold. Reducing infections can increase the success of limb salvage surgery for cancer patients.
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
Structure, Formation And Evolution Of Multiple Antibiotic And Mercury Resistance Regions In Gram-negative Bacteria
Funder
National Health and Medical Research Council
Funding Amount
$550,500.00
Summary
Antibiotic resistance and particularly resistance to several different antibiotics simultaneously is becoming alarmingly common in bacteria that cause infectious diseases in humans and animals. New antibiotics are proving slow to appear and the most obvious way to increase the effectiveness and the useful lifetime of existing antibiotics is though attempting to reduce the prevalence of resistant bacteria. This can only be done using good surveillance that allows the places where resistant bacter ....Antibiotic resistance and particularly resistance to several different antibiotics simultaneously is becoming alarmingly common in bacteria that cause infectious diseases in humans and animals. New antibiotics are proving slow to appear and the most obvious way to increase the effectiveness and the useful lifetime of existing antibiotics is though attempting to reduce the prevalence of resistant bacteria. This can only be done using good surveillance that allows the places where resistant bacteria and resistance genes are present in large numbers, e.g. in food-production animals, in hospitals, in the human gut or in the environment, to be identified. Very little data of this type is available internationally and even less for the Australian situation. Using recent knowledge of resistance genes and modern molecular techniques the work will identify which resistance genes and combinations of resistance genes confering resistance to antibbiotics used either in the clinic or administered to food-producing animals or both are found in Australian isolates. By examining multiply antibiotic resistant isolates from these two and other sources the flow of resistance genes and resistant bacteria between these two reservoirs will be tracked accurately. This will allow the sources relevant to difficult to treat or untreatable infections acquired in the hospital setting to be identified and appropriate action taken.Read moreRead less