International researchers warn of risks of microbe spread

A group of international researchers, including Professor Michael Gillings from Macquarie University, has voiced concerns in the journal Science, that modern travel, agriculture, trade and transport systems are enabling the spread of bacteria with potentially hazardous consequences for human health, and has called for urgent action to monitor and model the changes being made to the microbial world and improve waste water and manure treatments to reduce the spread of microbes and resistance genes.

According to the article, some microbes are winners, spreading around the world into new ecological niches we’ve created. Others are losing, and might face extinction. These changes are invisible, but the article suggests that human survival may depend on these microbial winner and losers.

“The oxygen we breathe is largely made by photosynthetic bacteria in the oceans (and not by rainforests, as is commonly believed),” explains Macquarie University biologist Michael Gillings.

“Over 95 per cent of the faeces in the world comes from humans and the animals we farm. And our poo is travelling around the world with a billion tourists, spreading microbes and antibiotic resistance genes.”

Modern agricultural practices, transport systems and other trade practices are also contributing to the problem.

“Until 100 years ago all the nitrogen in our food came from bacteria we nurtured in our crops. Now more than half comes from artificial fertilisers,” says Professor Gillings.

“We’re moving trillions of ocean microbes around the world in ballast water. Some one hundred million tonnes of ballast water – carried in ships to help improve stability – is dumped in US waters each year. We know they’re introducing foreign starfish, sea snails, and seaweed. But we don’t know what invisible changes they’re making to ocean microbes as well.”

“Microbes usually perform their essential ecosystem services invisibly, but we ignore them at our peril. Current models which track the movement of genes through microbial communities are unable to do this with an overarching global perspective, leaving us open to potentially dangerous microbes that could impact human health – an issue that molecular and environmental scientists need to keenly focus on in the near future,” concludes Gillings.

The international team who authored the article consists of researchers from Macquarie University, Australia; the Chinese Academy of Sciences, China; Universite de Lyon, France; University of Nottingham and University of Leeds, UK; and CSIC/CREAF, Barcelona, Spain.

The article is available at

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