Mycoplasma gateae arthritis and tenosynovitis in cats: case report and experimental reproduction of the disease.

Polyarthritis and tenosynovitis were diagnosed in a cat. Clinical signs of 2 months' duration included swollen limbs, painful joints (sensitive to touch), lameness, and pyrexia. Laboratory test data revealed hypogammaglobulinemia, hypoalbuminemia, leukocytosis, and mild anemia. The cat was euthanatized and necropsied; there were chronic necrotizing fibrinopurulent tenosynovitis and arthritis with bone and cartilage erosions. Cultural examinations of synovia were positive for Mycoplasma gateae, but bacterial and viral cultural examinations were negative. Organisms propagated from the M gateae isolate were inoculated IV into 6 specific-pathogen-free cats--3 of these being subjected to immunosuppression induced with azathioprine. The 6 inoculated cats became lame 5 to 9 days later, and 5 became febrile. Cultural examinations of the pharynx in 4 cats were positive for M gateae and in 3 cats, the organism was isolated from various joints. Microscopically, arthritis and tenosynovitis were identified in all cats. Two specific-pathogen-free cats were used as controls (noninoculated); these did not become lame, had negative M gateae cultures, and were free of histopathologic abnormalities. Reproduction of disease with recovery of the causative agent indicates the pathogenicity of this particular isolate of M gateae in the cat when inoculated IV.