Evidence of a highly drug-resistant salmonella superbug that could infect humans and livestock has been discovered in Australia for the first time, in a domestic animal.

Key points: The salmonella strain is resistant to about 90 per cent of drugs

The salmonella strain is resistant to about 90 per cent of drugs Never discovered in an Australia domestic animal before

Never discovered in an Australia domestic animal before Easily transferrable between humans and animals

The salmonella strain, which was found in an infected cat, is resistant to carbapenems, a drug used as a life-saving defence in Australian hospitals.

Experts believe this rare and unusual resistance may pose a serious threat to public health as it does not respond to about 90 percent of antimicrobial drugs.

Murdoch University researcher Dr Sam Abraham led a study to identify the risk of the salmonella bug, along with a team of medical and veterinary researchers from Concord Hospital, Sydney University, Concord Vets and Adelaide University.

"This is the first time that a salmonella strain with resistance to most drugs has been reported in any Australian domestic animal and it is a significant concern to public health," Dr Abraham said.

Laboratory sequencing showed the superbug was a strain of regular salmonella that had picked up an antibiotic resistant piece of DNA.

"What makes this bacteria a superbug is because it has picked up a piece of DNA that gives this bacteria super powers or resistance to about nine classes of drugs that we usually use to treat humans and animals," Dr Abraham said.

"In Australia we don't such use last line drugs much at all, in animals it's not used at all - but we are seeing resistance in animals - so there are many more ecological questions to be answered in this case."

It is not known how the cat contracted the superbug. ( ABC News: Robert Koenig-Luck )

Superbug highly transferrable

The bug was discovered after a cat from a shelter was taken to Sydney vet with a serious gut infection last year.

It is not known how or where the cat, which was euthanased, contracted the superbug.

Dr Abraham says the bacteria is resistant to many drugs. ( Supplied: Murdoch University )

Another eight cats at the veterinary facility were tested, and three were also found to be carrying the bacteria, indicating that it is highly transferrable.

"Transferability is a major problem. If this drug-resistant bacteria spread outside of this facility, there would be other implications of humans and other animals exposing themselves to this bacteria," Dr Abraham said.

Australian Centre for Antimicrobial Resistance Ecology director Darren Trott said it was a "highly unusual" case.

"In a recent nationwide survey, we found no carbapenem resistance in bacteria from either companion animals or livestock," Professor Trott said.

"These strains have turned up in animals overseas, in Asia, so we certainly want to be on the lookout for them here in Australia.

"This cat was definitely very unlucky,"

The study has been accepted for publication in Scientific Reports.