Healthy dogs and cats could be passing on multidrug-resistant organisms to hospitalised owners. In addition, humans could be transmitting these dangerous microbes to their pets, according to new research to be presented at the forthcoming European Congress of Clinical Microbiology & Infectious Diseases in Copenhagen. However, the researchers stressed that the risk of cross-infection is currently low.
The study of more than 2,800 hospital patients and their companion animals was carried out by Dr Carolin Hackmann from Charité University Hospital Berlin, Germany, and colleagues. “Our findings verify that the sharing of multidrug-resistant organisms between companion animals and their owners is possible,” she told the conference.
The role of pets as potential reservoirs of multidrug-resistant organisms (MDROs) – bacteria that resist treatment with more than one antibiotic – is a growing concern worldwide. It happens when infection-causing microbes evolve to become resistant to the drug designed to kill them. Estimates suggest that antimicrobial resistant infections caused almost 1.3 million deaths and were associated with nearly 5 million deaths around the world in 2019.
In order to find out whether cats and dogs play a role in spreading MDROs, researchers collected swabs from 2,891 patients hospitalised and from any dogs and cats that lived in their households.
Genetic sequencing was used to identify the species of bacteria in each sample and the presence of drug-resistant genes. Overall, 30% of hospital patients tested positive for MDROs. The rate of dog ownership was 11% and cat ownership 9% in those who tested MDRO-positive.
Pet owners were asked to send swab samples of their pets and more than 300 did so. Of these samples, 15% of dogs and 5% of cats tested positive for at least one MDRO. In four cases, these microbes were found to be of the same species and showed the same antibiotic resistance between pets and their owners.
Whole genome sequencing confirmed that only one of the matching pairs were genetically identical in a dog and its owner. “Although the level of sharing between hospital patients and their pets in our study is very low, carriers can shed bacteria into their environment for months, and they can be a source of infection for other more vulnerable people in hospital such as those with a weak immune system and the very young or old,” says Hackmann.
• This article was amended on 21 March 2023. An earlier version referred to the European Congress of Clinical Microbiology & Infectious Diseases taking place “this weekend” in Copenhagen, whereas it is scheduled for 15-18 April.
