Superbugs in Canine Poop: More Than 50% of Pet Dogs With Diarrhea Carry Antibiotic-Resistant E. coli Bacteria

Escherichia coli (E. coli) is a ubiquitous member of the intestinal microbiome. With the widespread use of antimicrobial products, multi-drug-resistant E. coli has posed a significant threat to the health of humans and companion animals.

Rise of the Superbugs

In a recent study, a team of Chinese scientists has found that more than half of pet dogs carry antibiotic-resistant E. coli in their diarrhea. Their investigation results are discussed in the paper "Characteristics of MDR E. coli strains isolated from Pet Dogs with clinic diarrhea: A pool of antibiotic resistance genes and virulence-associated genes."

Over the past decade, antibiotics to fight bacterial infections have become less effective as bacteria become more resistant. As a result, experts have begun looking for other drugs or therapies that can replace those that no longer work. They also look into the factors that may be contributing to this resistance.

For this research, the team led by Yu Yuan explored the possibility of cohabiting animals as part of the health problem. To test this theory, they tested a host of stool samples from pet dogs with diarrhea since this disease is often linked to E. coli infections. The researchers specifically looked for drug-resistant E. coli strains. They excluded dogs that had taken antimicrobial drugs of any kind in the past three months to ensure they were getting an unaltered look at their bacterial contents.

After gathering 185 fecal samples, Yuan and colleagues discovered 135 strains of E. coli. Several batches of each strain were collected and grouped, exposing them to different antibacterial drugs to see their response.

It was found that more than 87% of the strains tested were resistant to at least one of the drugs.

Specifically, 59% of the samples were found to be resistant to sulfonamides, 64% to tetracyclines, and 76% to beta-lactams, which include penicillin and ampicillin. Genomic analysis of the resistant bacteria revealed genes previously linked to antibiotic resistance.

The research team also noted that E. coli is a commercial microbe. This means many of its strains safely reside in the gut without making humans sick or causing diarrhea. However, it was also found that many resistant strains were closely related to variants known to infect other parts of the human body, like the urinary tract.

Threat From Dog Infection

According to the World Health Organization, superbugs can kill over one million people every year. The organization even warned that our planet is heading for a 'post-antibiotic' era. A 2019 large-scale study has found that almost half of multidrug-resistant infections are acquired in hospital settings.

Based on a recent study, scientists conclude that the overwhelming presence of superbugs among companion animals can help accelerate the emergence of new drug-resistant diseases in humans.

Harmful bacteria are killed off when a pet dog or human is treated with an antibiotic. However, the drug may not kill 100% of them. Those that remain can because they possess specific genetic variants that protect them from antibiotics.

When these microbes survive, their resistance genes are passed on to their offspring. Aside from this, bacteria can also share genetic material, giving each other resistance genes without even reproducing.