First case of a rare bacterium causing conjunctivitis in dogs

Moraxella canis (M. canis) is a rare, zoonotic bacterium. It has been isolated from various human tissues, including the lymph node of a patient with alcoholism, a foot ulcer of a patient with diabetes and the septic joint cavity of a patient with multiple myelomas. The first reported case of keratoconjunctivitis caused by M. canis in animals was found in a camel herd in 2010. The pathogenicity of M. canis in dogs and cats is still unclear. However, recent studies suggest that M. canis is a commensal bacterium present in the oral cavities of dogs and cats.

In a recent study in China, M. canis was isolated from a canine corneal ulcer. Treatment was based on the results of antimicrobial susceptibility testing, and conjunctival flap surgery was also performed.

The case presented in a 5-year-old neutered male bulldog, who was diagnosed with a corneal ulcer accompanied by conjunctival oedema and hyperemia. Veterinarians performed an ophthalmological examination and microbiological analysis, and the bacteria were found to be gram-negative and globular. The isolate was identified as Moraxella canis. Antimicrobial susceptibility testing showed that the bacteria were sensitive to tetracycline and chloramphenicol, but resistant to levofloxacin and ciprofloxacin. After placement of a conjunctival flap, tobramycin ophthalmic solution and 5% sodium hyaluronate were administered. After surgery, the ulcer was effectively controlled and, after 3 weeks, the cornea healed.

The authors state that “this is the first case report of canine corneal ulceration associated with M. canis, which should be considered in suspected corneal ulceration or keratitis”.