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
Molecular Genetics And Evolution Of Antibiotic Resistant Staphylococci
Funder
National Health and Medical Research Council
Funding Amount
$437,545.00
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. Hospital-acquired infections caused by Golden Staph are a major problem in Australia and globally. The problem is largely due to the pre ....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. Hospital-acquired infections caused by Golden Staph are a major problem in Australia and globally. The problem is largely due to the presence in hospitals of strains that have become resistant to most clinically-useful antibiotics and are therefore very difficult to eradicate. This research project will reveal detailed information about strains of Golden Staph that are currently prevalent in hospitals in Australia, USA, Europe, and South East Asia. It will also provide important insights into the mechanisms that enable this organism to become resistant so readily, and identify factors that promote the development of resistant strains. The results of this research project will lead to improved methods for the characterisation of clinical strains and the monitoring of antibiotic resistance. The findings will also be of relevance to other types of antibiotic resistant bacteria. Most importantly, the application of knowledge arising from these studies has potential to minimise the emergence of strains that are even more resistant, thereby extending the effectiveness of existing and future antibiotics. The design and implementation of strategies to limit the proliferation of resistant bacteria are essential if we are to avoid a scenario similar to that prior to the introduction of antibiotics, when serious infectious diseases were often untreatable.Read moreRead less
Plasmids are additional mini-chromosomes carried by many bacteria. They carry information that enables their hosts to prosper in otherwise hostile environments. Plasmids spread rapidly between bacteria, efficiently disseminating plasmid-borne information throughout bacterial populations. Many plasmids carry information that increases the virulence of their host. The emergence of multi-drug resistant bacteria and the rapid spread of the information enabling bacteria to withstand most antibiotics ....Plasmids are additional mini-chromosomes carried by many bacteria. They carry information that enables their hosts to prosper in otherwise hostile environments. Plasmids spread rapidly between bacteria, efficiently disseminating plasmid-borne information throughout bacterial populations. Many plasmids carry information that increases the virulence of their host. The emergence of multi-drug resistant bacteria and the rapid spread of the information enabling bacteria to withstand most antibiotics available today, were mediated by plasmids. Plasmids also carry information that ensures their own survival. Consequently, their hosts retain the plasmids even when it is no longer beneficial for them to do so. For example, plasmids mediating resistance to antibiotics are not lost when bacterial hosts are grown in the absence of those antibiotics. That is because plasmids have control systems, which ensure both that replication of the plasmid keeps pace with that of its host, and that the plasmid does not produce so many copies of itself that it overwhelms its host or places it at a competitive disadvantage amongst other bacteria. This project examines the intricate regulatory system that enables two groups of antibiotic-resistance plasmids to ensure that, on average, each plasmid molecule is replicated once per bacterial cell cycle. This system uses a tertiary RNA structure as a molecular switch, an antisense RNA as the regulator of this switch, and a protein that interacts with DNA sequences on the plasmid and with a bacterial protein, to initiate replication. Information gained from studies of plasmid systems is essential to the development of treatments for the elimination of antibiotic-resistance and virulence-contributing plasmids from populations of pathogenic bacteria. Antisense RNAs are not only a powerful research tool, but are also being developed for therapeutic use. Understanding how these RNAs interact with their targets will increase their effectiveness.Read moreRead less
Some of the world's most important diseases, including important diseases of indigenous chilren and the hospitalised elderly are caused by bacteria that carry a surface coating called a capsule. It is not clear how this capsule is retained by bacteria. Resolution of this question could lead to the development of new disinfectants that will stop hospital-acquired infections, to new reagents that can be incoporated into medical devices where bacteria frequently grow, and new antibiotics.