Superbugs resistant to all antibiotics have spread to Europe for the first time - and they could already be in New Zealand, a senior Kiwi scientist warns.
The news comes the day after it was revealed a patient in Denmark has become infected with an untreatable form of salmonella.
Danish scientists also discovered untreatable bacteria in five samples of chicken imported from China via Germany.
Experts fear it is the start of a global epidemic of untreatable infections.
Dr Richard Doehring, a medical microbiologist in Christchurch, said he would be "very surprised" if the bacteria - found in a gene called MCR-1 - wasn't already here.
"It is only a matter of time before it shows up," he told the Herald on Sunday. "We import a lot of farmed meat and seafood and this is where superbugs would generally be found."
The announcement in Denmark comes three weeks after Chinese academics discovered superbugs had breached the last line of antibiotic defences for the first time, the Daily Mail reported.
Colistin - a drug classed as "critical" to human medicine - was until recently the only antibiotic to work after all others had failed. But the Chinese team identified the first germs to become resistant to the drugs and warned of the "inevitable" spread of superbugs.
Dr Doehring said Kiwi scientists had been expecting new strains of superbugs like MCR-1 to appear because Colistin is widely used in farming, particularly overseas. The more that antibiotics are used - in humans or animals - the greater the selection for bacteria resistant to them.
"The developments in China and now Europe means the genie is now well and truly out of the bottle," he said. "If you look for this bug in New Zealand, no doubt you will find it."
Dr Doehring said those most at risk of falling ill were people already on antibiotics, particularly the elderly.
He said an option would be to treat patients with a combination of powerful antibiotics at the same time but there was no guarantee it would work.