Study shows healthy dogs and cats can transmit dangerous germs to humans – and vice versa
Healthy dogs and cats can transmit multidrug-resistant (MDR) organisms to their hospitalized owners, while humans can also transmit these microbes to their pets, according to a study to be presented at the European Congress of Clinical Microbiology and Infectious Diseases. The study highlights the potential transmission of antibiotic-resistant bacteria between pets and humans.
Multidrug-resistant organisms can be transmitted between healthy dogs and cats and their hospitalized owners.
Fortunately, only a small number of cases have been found indicating that pets are not the main source of antibiotic-resistant infections in hospital patients.
Healthy dogs and cats can transmit multidrug-resistant organisms (MROs; bacteria that are resistant to treatment with more than one antibiotic) to their hospitalized owners, and similarly, humans can transmit these dangerous microbes to their pets, according to new research. at this year’s European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) in Copenhagen, Denmark (April 15-18).
The study of more than 2,800 hospital patients and their pets is being conducted by Dr. Caroline Hackmann of the Charité University Hospital in Berlin, Germany, and her colleagues.
“Our results confirm that the sharing of multidrug-resistant organisms between companion animals and their owners is possible,” says Dr. Hackmann. “However, we have identified only a few cases suggesting that neither cat nor dog is an important risk factor for colonization of multidrug-resistant organisms in patients in hospitals.”
The role of pets as potential reservoirs of MPO is a growing concern around the world. Antimicrobial resistance occurs when infection-causing microbes (such as bacteria, viruses, or fungi) evolve to become resistant to the drug designed to kill them. In 2019, antimicrobial resistant infections were estimated to cause nearly 1.3 million deaths and were associated with almost 5 million deaths worldwide (1).
In this case-control study, the investigators wanted to find out if pets (i.e., cats and dogs) play a role in infecting MMRO hospital patients.
They focused on the most common superbugs in hospital patients — methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE), cephalosporin-resistant 3rd generation enterobacteria (3GCRE), and carbapenem-resistant enterobacteria (CRE), which are resistant to several antibiotics, including penicillin and cephalosporins.
Between June 2019 and September 2022, nasal and rectal swabs were taken from 2891 patients admitted to the Charité University Hospital Berlin (1184 patients with previous colonization or colonization on admission and 1707 newly admitted patients as controls ), as well as any dogs and cats that lived in their households.
Genetic sequencing was used to identify both the bacterial species in each sample and the presence of drug resistance genes. Whole genome sequencing has been used to confirm the possible sharing of resistant bacteria.
Participants were also asked about known risk factors for MPRO (eg, recent MPRO infection or use of antibiotics, recent hospital stay, presence of a urinary or central venous catheter), as well as information on the number of pets in the household, proximity of contacts, and pet health.
Overall, 30% (871/2891) of hospital patients tested positive for MDRO and 70% (2020/2891) tested negative. The proportion of dog owners was 11% (93/871) and cats 9% (80/871) for those who tested positive for MDRO and 13% (267/2020 and 253/2020, respectively) for those who were negative for MDRO.
All 626 pet owners were asked to send throat and stool samples from their pets. Overall, 300 pet owners submitted samples from 400 pets. Of these samples, 15% (30/203) of dogs and 5% (9/197) of cats tested positive for at least one MDRO. In four cases, MPOs were phenotypically matched (MPOs were of the same species and showed the same resistance to antibiotics) between pets and their owners.
Whole genome sequencing confirmed that only one of the matched pairs was genetically identical in dog and owner. A suitable pathogen was Escherichia coli 3GCR (common in the intestines of healthy humans and animals).
“While the rate of exchange between hospital patients and their pets in our study is very low, carriers can shed bacteria into the environment for months, and they can be a source of infection for other more vulnerable people in the hospital, such as people with weak immune systems. and very young or old,” says Dr. Hackmann.
This observational study cannot prove that close contact with pets causes MDRO colonization, but only suggests the possibility of co-carrying, while the direction of transmission is unclear. The authors point out several limitations, including possible underreporting of MDRO colonization in pets due to problems with swab sampling, which were done by pet owners themselves. Finally, the results of the study are applicable to patient hospitalization settings in urban areas and therefore may not be applicable to the general population or high-risk MDRO groups such as livestock keepers.
Link:
“Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis,” by Collaborators Antimicrobial Resistance, January 19, 2022, The Lancet.
DOI: 10.1016/S0140-6736(21)02724-0
Meeting: European Society for Clinical Microbiology and Infectious Diseases (ECCMID), 2023
