Man’s best friend is just as vulnerable to drug-resistant superbugs as their owners and can even catch such germs from humans, and possibly vice versa, according to new research recently published in the American Society for Microbiology’s journal mBio. Health experts in Canada fear the spread of pet superbugs could make the human superbug problem worse, and blame the growing number of animal infections on the overuse of pet antibiotics, which are often available over the counter and don’t require a prescription.

"If we need to use an antibiotic, we need to use it right -- which means getting the right diagnosis," Scott Weese, an infectious disease expert at the University of Guelph’s Ontario Veterinary College, told CBC News. "We need to use the right drug, right duration. All of these things can go wrong if people access the drugs in a wrong way.” 

Recent outbreaks in the U.S. among humans of a deadly bacterium known as carbapenem-resistant Enterobacteriaceae, or CRE, have highlighted the unintended consequences of overused antibiotics. Health physicians in the U.S. write an estimated 11.4 million needless antibiotic prescriptions every year, a trend that has given rise to drug-resistant superbugs that no longer respond to conventional antibiotic treatments.

One such superbug, methicillin-resistant Staphylococcus aureus, commonly known as MRSA, has been spreading in human populations for years now, but has more recently been seen in animals as well. "This demonstrates how the use of antibiotics in both human and animal medicine can alter the population of a bacteria that can cause infections in both," Ewan Harrison, a research associate with the University of Cambridge in the U.K. and one of the study’s co-authors, told HealthDay. "Infectious diseases in humans and animals are intrinsically linked and should be seen as a single problem to be addressed jointly by human and veterinary medicine.”

Previous research has supported the idea that pets can carry drug-resistant superbugs. Last year, University of Cambridge researchers found that 1 in every 100 cats and 2 to 9 in every 100 dogs in the U.K. were infected with MRSA. They discovered that the strain infecting pets was from the same family as the human MRSA bug, suggesting the infection can be passed between species, according to the BBC.