Superbugs threaten vision in animals – and can jump to humans, Israeli researchers warn

Israeli veterinary experts say antimicrobial resistance is making certain eye infections increasingly difficult to treat, posing a growing threat worldwide to vision in both animals and humans.

The peer-reviewed research was led by veterinary doctors Lionel Sebbag and Oren Pe’er of the Koret School of Veterinary Medicine at the Hebrew University of Jerusalem.

“These bacteria can spread from animals with eye infections or skin infections to humans and vice versa,” Sebbag told The Times of Israel in a video call. “This is a serious concern.”

He said that in 10 years, “it will become much more challenging to treat even common eye infections and there will be a greater chance of blindness in both humans and animals.”

The research, which appeared in Veterinary Ophthalmology, calls for more targeted antibiotic use, stronger infection control measures, and increased awareness.

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“We need to switch the way we think about antibiotics,” Sebbag said.

One Health: Humans, animals, and a shared environment

Sebbag said that his approach to eye infections is part of a holistic strategy known as the global “One Health” framework, which states that human health, animal health, and the shared environment are deeply interconnected.

“Bacteria and their resistance genes can spread between animals and humans,” said Sebbag. “Many of these bacteria are not limited to a single host, so resistant bacteria can spread between people, animals, and the environment.”

He stressed that the “inappropriate” use of antibiotics drives antimicrobial resistance.

“This makes infections more difficult to treat,” Sebbag explained, “increasing the risk of complications and affecting both animal and human health.”

Overuse of antibiotics

The study examines bacterial keratitis, a serious infection of the cornea, which is among the most urgent emergencies in veterinary eye care.

Without prompt and appropriate treatment, bacterial keratitis can rapidly progress, leading to permanent vision loss or even loss of the eye.

The researchers found mounting evidence that many of the bacteria responsible for these infections are becoming increasingly resistant to commonly used antibiotics.

“Like with humans, antibiotics have been over-prescribed in animals, and this is creating the multi-resistant bacteria,” Sebbag said. “Maybe the right antibiotic isn’t selected, or we don’t use it often enough, or not long enough. Antibiotics are misused in animals the same way that they’re misused among people.”

In a longitudinal study published in 2020, Sebbag and colleagues found that multidrug resistance among ocular bacterial isolates increased from approximately five percent to more than 30% within five years.

“That trend may continue to rise,” he said, “and this is very concerning.”

Eye infections

Primary care veterinarians are usually the first to see most animals with eye problems, Sebbag said.

While these doctors manage a wide range of medical conditions, they are not eye specialists.

For example, dogs are very prone to allergies, whether environmental or food-related.

“Many cases of red, goopy eyes in dogs are actually caused by allergies or other non-bacterial conditions,” Sebbag said. The owner takes the pet to the veterinarian, who may incorrectly guess there is a bacterial infection and prescribe antibiotics.

Horses, which are “quite popular in Israel, whether as pets or used for sports or competitions, also get nasty eye infections,” Sebbag said. “Owners should understand that not every red eye requires antibiotics, and appropriate diagnosis is essential before treatment is started.”

He stressed that antimicrobial stewardship does not mean avoiding antibiotics.

“It means using the right antibiotic only when it is truly needed, at the right dose, for the right duration,” Sebbag said.

Another important way to reduce the spread of these resistant bacteria is through better cleaning and infection-control protocols in veterinary clinics, he said.

“We use a lot of instruments to examine animals,” Sebbag said. “We examine one animal, then touch instruments, tables, and other surfaces. Animals are also moved between different areas of the hospital, just like in a human hospital. We know these bacteria can survive on hard surfaces and equipment, so other animals, or people, can be exposed.”

‘Microbes do not have any borders’

“The review article from Dr. Lionel Sebbag represents an excellent summary of the fundamental knowledge of antibiotics, antimicrobial use and resistance, especially in cases of bacterial keratitis in dogs, cats, and horses,” Franck Ollivier, founder of Ophtamo Vétérinaire Inc., in Montreal, Canada, told The Times of Israel.

Ollivier was not involved in the study.

Antimicrobial resistance is a “huge issue in human medicine as well as in veterinary medicine and thus worldwide because microbes do not have any borders,” he said.

The study’s One Health perspective suggests how veterinary ophthalmologists and veterinarians in general should diagnose and treat bacterial infections.

“This seems to be the essential key to preserving the efficacy of antimicrobial agents,” Ollivier said.

Sebbag and colleagues from the veterinary school’s ophthalmology department recently presented numerous studies at the European Conference of Veterinary Ophthalmologists. He said this “reflects the growing international contribution of Israeli veterinary ophthalmology research.”

While there, Sebbag also helped establish a global task force to develop antimicrobial stewardship guidelines that veterinarians can follow.

“This is an important international initiative,” he said. “Public awareness of antimicrobial resistance is still limited, and we’re trying to change that.”