Pets have a low risk of transmitting multi-drug resistant bugs to owners, study finds

By Angela Betsaida B. Laguipo, BSNApr 21 2020

Zoonoses are diseases that are transmitted from animals to humans. About 75 percent of emerging infectious diseases are zoonoses, just like the coronavirus disease (COVID-19) that’s caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Domesticated animals such as pets can carry parasites and other pathogens to people. However, a new study suggests that pets are not a significant source of transmission to humans.

The researchers from Hygiene and Environmental Medicine, Charite-University Hospital in Berlin, Germany, aimed to determine the relevance of pet husbandry in the colonization of multidrug-resistant organisms (MRROs) of hospital patients. The exact role of pets in MDROs is still unclear. The study, which will be presented at the European Congress of Clinical Microbiology and Infectious Diseases, highlights the importance of pet care in the infection of hospital patients with multi-drug resistant organisms.

Genetic relationship

Over one hundred diseases are capable of being transmitted from animals to humans. Included are domestic animals such as cats, dogs, horses, birds, sheep, cows, goats, and rabbits, among others. Basic hand washing and proper hygiene are simple measures but can prevent these potential diseases.

In the study, the team focused more on MDROs in pet owners, particularly Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE), third-generation cephalosporin-resistant Enterobacterales (3GCRE), and carbapenem-resistant Enterobacterales (CRE).

Methicillin-resistant Staphylococcus aureus (MRSA) - 3d rendering. Image Credit: Shutterstock

To determine and study the contact to household pets as a risk factor for the colonization of the pathogens mentioned, the team performed an exploratory unmatched case-control-study. The team asked pet owners specific questions about risk factors and their contact with cats and dogs, including data about the number of pets in their home, the diseases and treatments of their pets, and their closeness to these animals.

The team also assessed the genetic relationship between humans and pet MDROs. To arrive at their findings, they collected rectal and nasal swabs of the pet owners in the hospital and their pets to see if they harbor MDROs. The team conducted phenotypical matching in the samples of the participants and their pets, and they were screened for genetic relationships utilizing whole-genome sequencing (WGS).

Of the 1,500 patients tested, about 33 percent or 495 participants tested positive for MDROs. Also, 20 percent of all the participants in the study owned at least one pet, while 38 percent tested positive for MDROs.

“This analysis of preliminary data showed no significant difference in pet care or closeness of contact to pets between MDRO-positive and MDRO-negative hospital patients. A transmission of MDROs between humans and animals was confirmed in only 1.8 percent of 112 pet owners and their respective pets. So far, the preliminary data does not indicate pet care as a significant risk factor for MDRO colonization in hospital patients,” the researchers concluded in the study,

The research reveals that though pets can transmit pathogens to pet owners, they are not major reservoir and host for multi-drug resistant pathogens.

What is zoonosis?

Zoonosis or zoonotic disease is a condition wherein pathogens, which are microbes that cause illness, are spread between animals and humans. Zoonotic diseases may be caused by a multitude of microorganisms, such as bacteria, viruses, fungi, and parasites.

Though some diseases are common, some diseases may be severe and potentially fatal. Some of the common zoonotic diseases include animal flu, anthrax, coronavirus disease (COVID-19), SARS, MERS, bovine tuberculosis, bird flu, Ebola, dengue fever, malaria, leptospirosis, listeria, Lyme disease, bacterial infections such as Salmonella, E. coli, and streptococcal sepsis, among others. These pathogens can jump from animals to humans through the air, by eating contaminated meat or produce, touching a contaminated area or surface, close contact with an infected animal, and through insect bites.