Healthy pet dogs and cats could be passing on antibiotic-resistant bacteria as well as genes that play a key role in bacterial resistance to their owners, a joint Portuguese-UK study suggests.
The role of companion animals as potential reservoirs of antimicrobial-resistant bacteria is a growing concern worldwide. Escherichia coli (E. coli) bacteria are common in the intestines of healthy people and animals.
There are a number of different types and, while the majority are harmless, some can cause serious food poisoning and life-threatening infections, including blood poisoning, with more than 40,000 cases each year in England alone.
Particularly important are infections caused by highly resistant strains with ESBL and AmpC-producing Enterobacteriaceae (AmpC-E) and Carbapenemase-producing Enterobacterales (CPE), which are resistant to multiple antibiotics including penicillin and cephalosporins.
The health of companion animals was evaluated by vets at the Small Animal Veterinary Teaching Hospital at the University of Lisbon and the Royal Veterinary College Small Animal Veterinary Referral Service.
Only animals and their owners who had not experienced bacterial infections or taken antibiotics in the three months prior to the start of the study were recruited.
Stool samples were collected from 58 healthy people and the 18 cats and 40 dogs that lived with them from 41 households in Portugal, and from 56 healthy people and 45 dogs from 42 households in the UK.
Samples were collected at monthly intervals for four months, and genetic sequencing was used to identify both the species of bacteria in each sample and the presence of drug resistance genes.
“Even before the Covid-19 pandemic, antibiotic resistance was one of the biggest threats to public health because it can make conditions like pneumonia, sepsis, urinary tract and wound infections untreatable," said Dr Juliana Menezes from the University of Lisbon.
"Although the level of sharing from the households we have studied is low, healthy carriers can shed bacteria into their environment for months, and they can be a source of infection for other more vulnerable people and animals such as the elderly and pregnant women.
"Our findings reinforce the need for people to practice good hygiene around their pets and to reduce the use of unnecessary antibiotics in companion animals and people."
The research will be presented at the European Congress of Clinical Microbiology & Infectious Diseases in Lisbon later this month.