Drug-resistant eye infections put animal vision at risk, review says

Antibiotic-resistant eye infections are posing a growing threat to the sight of dogs, cats and horses, according to a review by researchers at the Hebrew University of Jerusalem. The review matters for veterinary care because bacterial corneal infections can damage vision within hours or days if treatment fails, the authors said.

The paper, published in Veterinary Ophthalmology, was written by Dr. Lionel Sebbag and Dr. Oren Pe'er of the Koret School of Veterinary Medicine. It examines antimicrobial resistance in veterinary ophthalmology, with a focus on bacterial keratitis, a serious infection of the cornea.

According to the review, antibiotics remain the main treatment for these infections, but evidence from several regions shows that common bacterial causes are becoming harder to treat with routinely used drugs. The authors drew on studies from North America, Europe, Asia, South America and Australia.

The researchers identified Staphylococcus pseudintermedius, beta-hemolytic streptococci and Pseudomonas aeruginosa as the bacteria most often isolated in companion-animal eye infections. They said multidrug-resistant strains are appearing more often, particularly in referral and specialty veterinary settings where severe cases are concentrated.

Prior antibiotic exposure was one of the clearest patterns across the studies reviewed, according to Sebbag and Pe'er. Animals recently treated with topical antimicrobials were more likely to carry resistant bacteria and less likely to produce positive culture results, making diagnosis and drug selection harder for veterinarians.

The authors also flagged a problem with standard laboratory testing. Antimicrobial susceptibility tests generally reflect how drugs behave when given systemically, while eye drops can create different drug concentrations on the surface of the eye, according to the review.

Because of that gap, the researchers said lab results may not reliably predict whether a topical eye treatment will work in an individual case. They recommended that veterinarians interpret test results alongside the animal's clinical signs, disease severity and treatment history.

Sebbag and Pe'er called for microbiological sampling before extensive antibiotic treatment when possible. They said earlier testing could help veterinarians choose more targeted therapies and avoid unnecessary use of broad antimicrobial treatment.

The review also placed resistant eye infections in a One Health context. Some bacteria found in animal eye infections can pass between animals and people, and the authors said veterinary clinics, equipment and households can act as places where resistant organisms circulate.

To reduce that risk, the researchers urged stronger hygiene and infection-control practices. They also called for surveillance, antimicrobial stewardship and veterinary ophthalmology guidelines tailored to eye infections.

The review outlined several antibiotic-sparing approaches that may reduce dependence on traditional antimicrobials. These include antiseptic therapies, treatments aimed at disrupting biofilms, corneal cross-linking technologies, ultraviolet-based methods and other emerging tools that could complement antibiotic care.

The authors concluded that preserving current treatments will require coordinated work across diagnostics, infection control and drug-use practices. Their review said the aim is to protect treatment reliability for future veterinary patients as well as resolve current infections.

This story draws on original reporting from Phys.org.