Nocardia infection is a disorder affecting the lungs, brain, or skin. It occurs mainly in people with weakened immune systems.
Causes, incidence, and risk factors
Nocardia infection is a bacterial infection that usually starts in the lungs. It may spread to other organ systems -- most often the brain and the skin. It may also involve the kidneys, joints, heart, eyes, and bones.
Nocardia bacteria are found in soil around the world. You can get the disease by inhaling contaminated dust or if soil containing nocardia bacteria gets into an open wound.
You are more likely to get this infection if you have chronic lung disease or a weakened immune system, which can occur with transplants, cancer, HIV/AIDs, and long-term use of steroids.
Symptoms vary and depend on the organs involved.
Lungs (pulmonary nocardiosis):
Chest pain when breathing (may occur suddenly or slowly)
Coughing up blood
Brain (cerebral nocardiosis):
May become chronically infected (mycetoma) and develop draining tracts
Ulcers or nodules with infection sometimes spreading along lymph nodes
Some people with nocardia infection have no symptoms.
Signs and tests
Nocardia infection should be suspected in people with lung, brain, or skin symptoms if they also have a condition or conditions that weaken the immune system.
Nocardiosis is diagnosed using tests that identify the bacteria. Depending on the part of the body infected, testing may involve taking a tissue sample by:
Treatment involves antibiotic therapy (usually with sulfonamides) for 6 months to a year or longer. Sometimes, more than one antibiotic is given.
You may also need long-term, low-dose antibiotic therapy.
Surgery may be done to drain an abscess.
How well a person does depends on your overall health and the parts of the body involved. Widespread infection (disseminated nocardiosis) has a significant death rate.
Complications of nocardial infections depend on how much of the body is involved.
Certain lung infections may lead to scarring and chronic shortness of breath.
Skin infections may lead to scarring or disfigurement.
Brain abscesses may lead to loss of neurological function.
Calling your health care provider
Tell your doctor or nurse if you have any symptoms of this infection. They are nonspecific symptoms that can have many other causes.
Sorrell TC, Mitchell DH, Iredell JR, Chen SC-A. Nocardia species. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone;2009:chap 254.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.