Macquarie biological sciences researchers find antibiotic resistance spreading to wildlife

5 August 2015

Researchers have found antibiotic resistance genes are spreading to bacteria of Australian wildlife, including captive sea lions and rock wallabies, and the little penguins of Sydney Harbour.
Dr Michelle Power, from the Macquarie Department of Biological Sciences, presented the findings at the International Conference of the Wildlife Disease Association, held in Queensland on the Sunshine Coast from July 26 – 30.

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Captive Australian sea lions have been found to carry bacteria with antibiotic resistance genes, ultimately derived from bacteria of humans (Photo credit: Prof Rob Harcourt)

“Antibiotic resistance is one of the world’s most pressing health issues. The spread of antibiotic resistance is commonly attributed to overuse of antibiotics in both human health and animal production,” said Dr Power.
“It is worrying that we are seeing antibiotic resistance in bacteria of wild animals that have never been treated with antibiotics. Resistance genes from bacteria in humans and domestic animals are being spread through the environment to the naturally occurring bacteria of those wild animals,” she said.
Dr Power said one way the transfer of genetic resistance genes was happening was through naturally occurring mobile genetic elements called integrons, which were first discovered by Australian researchers in the late 1990s.
Integrons are able to pass genes between different species of bacteria, and can be spread through water, allowing antibiotic resistance to spread from land to marine environments. They are not deactivated by normal sewage treatment processes.
“We found the closer the contact between the wildlife with humans, the more animals within a population were carrying the antibiotic resistant bacteria. Some animals even in wild populations were carrying antibiotic resistant bacteria, a case being the little penguins of Sydney Harbour,” she said.
The Macquarie biological sciences professor said the research findings meant that if we continue to see antibiotic resistance spreading into wildlife, that antibiotic treatment of sick wild animals may not work as well.
She said there were wider implications of the research that were of concern.
“We know that the normal bacterial flora of an animal can influence its growth, development, behaviour, and even mate selection. What we don’t know is what impact we are having on wildlife through the introduction of antibiotic resistance genes to their bacteria. We also need to be asking what else wildlife is picking up from human and domestic animals in terms of bacteria or other disease agents, and if that is hurting our efforts to conserve biodiversity,” she said.
Dr Power said her research was a great illustration of the One-Health concept—that the health of humans, domestic animals and wildlife is interconnected.
She said efforts to reduce the overuse of antibiotics in humans and domestic animals were important and must be continued.

Macquarie University Department of Biological Sciences

The Macquarie Department of Biological Sciences is a department of integrative biology that integrates research and teaching across all levels of biological organisation as well as across a diversity of taxa. The department’s work links structure with function and processes that influence the evolution and ecology of organisms, using models ranging from microbes through to fungi, plants and animals. They offer comprehensive undergraduate and postgraduate education in the full range of biological disciplines, from molecules to ecosystems and the biosphere.

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