- Research at the ithree institute, UTS provides a route to better detection and tracking of antibiotic resistance, in health and biosecurity management.
- Mobile gene elements provide a reservoir of antibiotic-resistant genes in non-pathogenic bacteria.
- Next generation sequencing and advanced bioinformatics being used to understand mechanism for transfer of large mobile elements carrying antibiotic resistance.
Advancing the understanding about how genes responsible for antibiotic resistance move between ‘good’ and ‘bad’ (disease-causing) bacteria, and the link between animals, the environment and humans is now providing a vital route to improved tracking — and hence control — of drug resistant infections, say Australian scientists in a new report published today.
A review published in a special issue of Frontiers in Microbiology, dedicated to Antimicrobials, Resistance and Chemotherapy by Professor Steve Djordjevic and Dr Piklu Chowdhury from the University of Technology’s ithree institute provides a vital insight into how mobile genetic elements — first discovered by the team at ithree in 1995, provide a reservoir of genes that confer multi drug resistance (MDR) in commensal (‘good’) bacteria, and how these genes are transferred to pathogenic (‘bad’) bacteria.
Importantly, the review highlights the route of transfer between animals, the environment and humans, and how the widespread use of antibiotics in animal production for food is now manifesting itself in the increasingly widespread problem of antibiotic-resistant bacteria in hospitals.
Professor Ian Charles, Director of the ithree institute put the research at ithree in context explaining that, “The human body contains ten times more cells that are non-human — mostly bacteria — than it does human cells. These bacteria live with us and have a vital role in healthy life balance”.
“These bacteria in the human body are exposed not only to antibiotics that we consume to treat infections, but also to any antibiotics in the environment” he said. “They contain genetic elements that confer resistance to antibiotics — important for their survival and function. The problem comes when these resistance genes are transferred to pathogenic bacteria generating infections that are impossible to treat.” This so called lateral gene transfer explains how the same resistance gene is commonly present in otherwise very distant and unrelated bacterial species.
“The heaviest use of antibiotics is not in humans, but is in animal production and agriculture more broadly” explained lead author, Professor Steve Djordevic. This practice is leading to a build-up of antimicrobial residues as environmental pollutants he said.
“Whilst reducing the use of antibiotics in food production is of course essential, what we need right now is better detection and surveillance so that we can get a handle on where the reservoirs of MDR genes are ‘hiding’ in the environment, to help us understand how to better manage healthcare and animal husbandry in order to curtail the problem of antibiotic resistance” said Prof Djordevic.
The research team at the ithree institute is using its pioneering research with mobile genetic elements, together with new technologies in bioinformatics and next generation sequencing to develop novel assays that can track the transfer of drug resistance genes at a higher level of accuracy that current PCR-based methods.
World-leading research in this area that could lead to more effective bacterial diagnostics is being conducted by co-author Dr Chowdhury in conjunction with scientists at the Department of Primary Industry, NSW.
Reference: Mobile elements, zoonotic pathogens and commensal bacteria: conduits for the delivery of resistance genes into humans, production animals and soil microbiota, Djordjevic SP, Stokes HW, Roy Chowdhury P. Front Microbiol. 2013 Apr 30;4:86. doi: 10.3389/fmicb.2013.00086. Print 2013.