Researchers say ‘eye-opening’ findings that 20% of silver gulls nationwide carry pathogenic bacteria should be a wake-up call

This article is more than 1 year old

This article is more than 1 year old

Australian gulls are carrying superbugs resistant to antibiotics, raising fears that disease-causing bacteria may spread from the birds to humans, livestock and pets.

A team of scientists led by researchers at Perth’s Murdoch University found more than 20% of silver gulls nationwide were carrying pathogenic bacteria, such as E coli, that are resistant to drugs. E coli can cause urinary tract infections, life-threatening sepsis and meningitis.

Dr Sam Abraham, a lecturer in veterinary and medical infectious diseases at the university, said the “eye-opening” study should be a wake-up call for Australian governments.

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“What we found was, regardless of the state, the gull population in Australia are carriers of superbugs, or antimicrobial resistant bacteria, that cause infection in humans,” Abraham said. “These are the ones that are resistant to drugs of importance to human health, that is where our initial concerns are.”

Globally, antimicrobial resistance has risen to “dangerously high levels” and it is one of the biggest threats to health and food security, according to the World Health Organisation and the Australian federal government.

The bacteria can spread to humans if they accidentally ingest them after touching seagull faeces.

A Murdoch University veterinary virologist, Mark O’Dea, said children could be exposed if they touched their mouths or ate after playing on grass or rocks where seagulls had been, but the risk could be eliminated by hand washing,

Abraham said: “The birds are a potential for this to move and we don’t know exactly how it’s going to move.”

Some gull faeces in the study contained bugs resistant to last-resort medicines, such as carbapenems, which are used to treat antimicrobial-resistant infections. One bird at Cottesloe Beach in Perth was found to be resistant to the drug colistin, which is the last antibiotic treatment option after all else has failed.

A spokesman from the federal health department said gulls were not part of existing antibiotic-resistance monitoring because the risk of transmission from the birds to humans had not been established.

“The department in general is concerned about the spread of bacteria resistant to antimicrobial agents, no matter the mechanism,” the spokesman said.

“However, the specific mechanism of seagulls acting as a reservoir for bacteria resistant to antimicrobial agents after feeding on human household waste is a matter for other government sectors including state, territory and local government authorities.

Antibiotic-resistant bacteria have been found in gulls and other birds in several countries, which in some cases have implicated the link with household waste.

In 2010, Portuguese researchers found yellow-legged caspian gulls carrying bugs resistant to the common antibiotic vancomycin. Since then, resistant bacteria have been found in gull species in France, Russia, Greenland, Siberia and Alaska, and in 2016 colistin resistant pathogens were found in pig intestines.

Resistance to colistin has never before been seen in Australian wildlife.

The Murdoch study, which involved government agriculture scientists and examined the droppings of 562 silver gulls at densely populated coastal areas between 2015 and 2017, was published on Wednesday in the Journal of Antimicrobial Chemotherapy.

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Gulls range as far as 1,600km from their hatchery, and O’Dea said it was feared superbugs might “leapfrog” through other bird species that would then travel to farming regions.

“The other thing that we are worried about and that we want to investigate more is the potential of gulls to spread superbugs to areas where they haven’t previously been,” he said.

“What we wouldn’t like to see happen is these types of bacteria move into food animals or pets. We don’t have any proof that it is being moved into anything else by the gulls, but it is certainly something that needs to be looked at.”

Despite typically feeding from the ocean, gulls living in cities were picking up the superbugs as they scavenged at waste treatment plants and through bins and tips filled with soiled nappies and incontinence pads, Abraham said.

Australia uses 3.75m disposable nappies every day – making up a significant proportion of household waste going to landfill.

“I think that it is a wake-up call for all government and various agencies, like water treatment and big councils that manage waste, to properly work collaboratively to tackle this issue,” Abraham said.

The Local Government Association said the issue of birds and disease was handled according to environmental policy.

“Management plans are in place to minimise these risks ... and can include covering the waste or implementing bird-scaring mechanisms to keep them away,” said the president of the WA Local Government Association, Lynne Craigie.