Bacterial Infection (Nocardiosis) in Cats


PetMD Editorial

Updated Aug. 24, 2022

Nocardiosis in Cats

Both dogs and cats may become exposed to the infectious, saphrophytic organism, which nourishes itself from dead or decaying matter in the soil. Also referred to as Nocardiosis, it is an uncommon infectious disease that affects several body systems, including the respiratory, musculoskeletal, and nervous systems. Typically, exposure occurs either through open wounds or via inhalation.

Symptoms and Types

Symptoms of nocardiosis are largely dependent on the site of infection. If, for example, it occurs in the pleural body cavity, which includes the lungs and surrounding membranes, symptoms can include emaciation, fever, and raspy, labored breathing (dyspnea). If it is a skin infection, symptoms can include the presence of chronic non-healing wounds and, if left untreated, draining lymph nodes. If the infection is not localized in one specific area of the body (also known as disseminated), the symptoms may include fever, weight loss, and lethargic behavior.


The infectious organism is found in the soil and can enter the cat's body through open wounds or through the respiratory tract, when it inhales. Nocardia asteroides is the most common species affecting cats. Cats are also susceptible to Nocardia brasiliensis and Proactinomyces spp.



Your veterinarian will analyze cells from the cat's thorax or abdomen to identify the causative organism. Other diagnostic procedures, such as X-rays and urine analysis, are employed to rule out other potential causes, including fungal infections and tumors.


Treatment for nocardiosis is largely dependent upon the site of infection and subsequent symptoms. If pleural effusion is apparent, hospitalization will be necessary to prevent dehydration. Surgical drainage of the fluid may even be required. Otherwise, long-term antibiotic therapy is vital for fighting off the infection.

Living and Management

Because nocardiosis frequently affects the musculoskeletal and central nervous system, it is imperative that you carefully monitor the cat for fever, weight loss, seizures, breathing difficulties, and lameness for at least one year after therapy.


General cleanliness and frequent disinfection of your cat's wounds or cuts may help prevent this type of infection, especially if your cat has a weakened immune system.

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