Nocardiosis Infection in Cats

Nocardial infections are uncommon but can prove problematic to treat due to the bacteria's resistant nature and its effect on all of the organs of the body. Continual care is necessary in order to recover from nocardiosis.

Nocardiosis is a serious bacterial infection that is caused by exposure to the bacteria Nocardia. The bacteria is infectious and is commonly found in decaying vegetation and compost, where it feeds off of the dead matter. Cats become exposed to the bacteria through inhalation or through an open wound on their body.

Symptoms of the bacterial infection vary and depend on the site where the bacteria entered the body.

• Poor appetite (all sites)
• Lethargy (all sites)
• Fever (all sites)
• Weight loss (all sites)
• Skin lesions (skin site)
• Swollen lymph nodes (skin site)
• Swollen tissue (skin site)
• Non-healing cuts (skin site)
• Swelling and inflammation of gums (mouth site)
• Mouth ulcers (mouth site)
• Bad breath (mouth site)
• Labored breathing (pleural body cavity site)
• Productive cough (pleural body cavity site)

Cats may be exposed to the infectious bacteria through inhalation, ingestion or contact:

• Inhaling the Nocardia bacteria
• Eating compost that contains the Nocardia bacteria
• Walking in or playing in dirt or mulch that contains the Nocardia bacteria, followed by normal grooming

A correct diagnosis of nocardiosis is critical, as a misdiagnosis can lead to the disease becoming chronic, refractory and extensive. In order to get the proper diagnosis, the veterinarian will have to run several labs to correctly identify the type of bacteria and determine the best way to treat it.

The veterinarian will ask for the cat's complete health history and will need details about the cat's symptoms and when symptoms first began. Next, the veterinarian will gently examine the cat, listening for any breathing problems and feeling for swollen lymph nodes.

In order to rule out other problems, such as viruses, fungal infections or tumors, x-rays, a urinalysis and blood work will be performed. The urinalysis and blood work will help to identify other possible causes and also give the veterinarian an idea how the organs of the body are functioning. A sample of the cells from the infected site will be taken. The cells will then be sent to an outside lab that will identify the cells and the medication that will best treat them.

Medication: Depending on the identification of bacteria, an antibiotic will be prescribed for the cat in order to eliminate the bacteria. These antibiotics must be taken for at least three months in order to be effective. After the three months, the cat will need to be re-tested to ensure that the bacteria has been eliminated. If swelling in the tissues is severe, corticosteroids may also be prescribed to reduce the inflammation. If the bacteria entered through an open wound or scratch, topical antibiotics may be given to reduce pain and swelling at the site.

Hospitalization: If the bacteria was inhaled and has caused pleural effusion, the cat will need to be hospitalized. During pleural effusion, fluid accumulates in the pleural sac that surrounds the lungs, compromising the function of the heart and lungs. The cat will be given fluids in order to prevent dehydration while the proper antibiotics are started. Oxygen therapy may also be necessary.

Surgical Drainage: Fluid build-up from effusion may make it necessary to surgically drain the fluid in order for the cat's heart and lungs to function at their best. This procedure is called thoracentesis. The veterinarian will carefully guide a needle into the lower part of the lungs and drain the pleural cavity of the excess fluid. The cat will be given a tranquilizer or ultrashort anesthesia so that no pain is experienced during the procedure. 

Nocardiosis is a serious infection that can cause long-term complications. Antibiotics must be continued long-term until the cat has been tested and found to be cleared of the bacteria. Relapse is common and may require further treatment. Following up with the veterinarian to get the cat tested for the bacteria will ensure that the antibiotics are working and will help the veterinarian to know if any additional treatments are necessary. Any cuts or scratches the cat receives should be washed immediately with soap and water to prevent re-infection from occurring at a different site. 

Living in areas with temperate, tropical or subtropical temperatures, or keeping a compost pile or decaying vegetation in areas the cat frequents can increase the risk of exposure.