Dog owners are being urged not to regularly share their beds with their pets, following the spread of an "untreatable superbug."
The mcr-1 gene, which is believed to be transmitted from animals to humans, has built up a resistance to certain life-saving drugs.
It was first identified in China in 2015 and is transported from animals to humans through microscopic faecal particles.
Currently, drug-resistant infections are responsible for killing an estimated 700,000 people a year worldwide, the UN said. This number could rise to 10 million by 2050 if nothing is done.
How can the gene be transported?
A study at the University of Lisbon examined the presence of the gene in households and found where dogs had tissue infections, the gene was present in the dog and the owner.
Faecal samples of 126 healthy people living with 102 cats and dogs in 80 households were taken over two years up to February 2020.
Researchers found eight of the dogs and four humans were hosting bacteria including mcr-1.
The results also revealed three of the dogs appeared to be healthy and the others had tissue or urinary tract infections.
The findings were presented at the European Congress of Clinical Microbiology and Infectious Diseases Conference.
Experts told attendees that agricultural regions particularly in southern European countries that use colistin will be less likely to contract the mcr-1 gene.
What was said?
Dr Juliana Menezes, who led the research, said: “Colistin is used when all other antibiotics have failed, it is a crucial treatment of last resort.
“If bacteria resistant to all drugs acquire this resistance gene, they would become untreatable, and that’s a scenario we must avoid at all costs.
“We know that the overuse of antibiotics drives resistance and it is vital that they are used responsibly, not just in medicine but also in veterinary medicine and in farming.”