Definition of Nocardia infection:

Nocardia infection is a rare 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.

While individuals with normal immune systems can get this infection, the main risk factors for getting nocardiosis are a weakened immune system or chronic lung disease. People on long-term steroid therapy, those with cancer, organ or bone marrow transplants, or HIV/AIDS are at higher risk.