Erysipeloid lesions caused by Erysipelothrix rhusiopathiae in a dog: clinical and histopathological findings, molecular diagnosis and treatment.

Erysipelothrix rhusiopathiae is a widespread Gram-positive, nonsporulating rod bacterium predominantly associated with skin disease in swine and cetaceans. Cutaneous lesions have yet to be described in dogs.To describe the clinical presentation, molecular and histopathological diagnosis, and treatment of a case of erysipeloid caused by E. rhusiopathiae in a dog.A 6-month-old spayed female standard poodle dog presented with lethargy, fever, vomiting and diarrhoea. Skin lesions appeared 20 days post first examination.Complete blood count, serum chemistry profile, urinalysis, urine culture, blood culture, computed topography, forelimb radiography, joint and cerebrospinal fluid aspiration were performed; samples were collected for skin cytological evaluation, culture and histopathological analysis.Blood cultures yielded Gram-positive, catalase-negative bacilli. Histopathological evaluation of skin biopsies revealed lymphoplasmacytic, neutrophilic and histiocytic perivascular and periadnexal dermatitis, and vasculitis. Cutaneous and blood PCR and sequencing of 16S rRNA identified the bacteria as E. rhusiopathiae. Clinical resolution was observed following the use of of amoxicillin/clavulanic acid and ciprofloxacin therapies.To the best of the authors' knowledge, this is the first confirmed case of erysipeloid caused by E. rhusiopathiae in a dog. Clinical resolution was attained with the extended use of antibiotics. After 13 months, no clinical signs had returned.