Nocardiosis

What is Nocardiosis?

Nocardiosis is an illness that can affect various parts of the body. It’s an infection caused by a type of bacteria called Nocardia, which are microscopic organisms that have a branch-like shape. This bacteria can commonly be found in soil, decaying plant material, and other types of organic matter. It is also present in all types of water, both fresh and saltwater. When examined under a microscope with a special dye, Nocardia is usually weakly visible, indicating its presence.

What’s notable about Nocardia is that it is pretty opportunistic – it often causes an infection in people who have a weakened immune system and can affect almost any part of the human body. This includes the skin and its structures, the lung system (including the area surrounding the lungs), or it can spread throughout the body impacting multiple organ systems.

What Causes Nocardiosis?

Pulmonary nocardiosis, and its spread-out version, usually affect people who have a low T cell-mediated immune system. This means the body’s defense system, which relies on T cells, a type of white blood cell, isn’t working as well as it should.

People who are especially vulnerable to this are those who have had solid organ or stem cell transplants, have HIV, take corticosteroids long-term, or dealing with ongoing cancer. Pulmonary nocardiosis can invade the lungs by being inhaled, while skin-based nocardiosis can occur if the bacteria gets directly introduced to the skin, say from a wound or injury.

It’s also possible for these infections to occur post-surgery if sterile equipment wasn’t used. People involved in agricultural work in rural areas are more prone to the direct contact version of the disease.

Apart from these, other risk factors for getting infected by Nocardia bacteria include alcoholism, chronic lung diseases, corticosteroids use, blood-related cancers, immune dysfunction diseases like lupus, kidney failure, bowel inflammation conditions, Whipple disease and HIV.

Risk Factors and Frequency for Nocardiosis

Nocardiosis is an infection that occurs around 500 to 1000 times per year in the United States. It affects all races equally, but men are three times more likely to get this infection than women. Although it can occur at any age, people on average get this infection in their 40s.

Signs and Symptoms of Nocardiosis

Nocardiosis is a type of infection that varies based on which body parts are affected.

Primary Cutaneous Nocardiosis is an infection of the skin that typically results from an injury that breaks the skin, often in an unclean environment. Symptoms include a red, tender, warm, and swollen area around the wound that might look like a simple skin infection. Patients may also have painful nodules or abscesses nearby, and sometimes pus drainage. In severe cases, the area can develop necrotic, or rotting, sores. This type of infection can be hard to distinguish from other bacterial diseases.

Lymphocutaneous Nocardiosis is similar to primary cutaneous nocardiosis, but in addition, inflamed lymph nodes appear and may even burst, leading to draining of necrotic material or pus in severe cases.

Pulmonary Nocardiosis happens in the lungs and can be acute or chronic. Symptoms resemble those of pneumonia and include fever, productive cough, difficulty breathing, or chest pain. In some cases, it can lead to lung cavities, abscesses, fluid buildup around the lungs, or infections of the space between the lungs and chest wall.

Disseminated Disease refers to nocardiosis that has spread to other parts of the body. Deep abscesses, or pus-filled wounds, can form at these sites. Symptoms depend on the location of the abscess but usually include fever. If the infection spreads to the central nervous system, it can cause numbness or muscle weakness corresponding to the part of the brain or spinal cord affected. In some cases, patients may show signs of meningitis, including headache, stiff neck, or changes in mental state.

Testing for Nocardiosis

If your doctor suspects that you might have a bacterial infection caused by Nocardia, they will need to carry out several tests. They would take samples of any infected areas, which might include a skin biopsy, collecting discharge from a wound, taking sputum (mucus) from your lungs, and samples from deep inside any infected areas, such as abscesses or pleural (lung) aspirates. Nocardia bacteria grow slowly, so your samples may need to be kept in the lab for a few days to give the bacteria enough time to grow. If there’s a possibility that the infection has spread to your blood or lungs, your doctor will also take some blood cultures.

Imaging scans can also help identify if and where the infection has spread. For lung infections, your doctor might order an X-ray or a computed tomography (CT) scan of your chest. The images might not show classical signs of nocardiosis, but they could show irregular growths or nodules, cavities in your lung tissue, widespread pulmonary infiltrates (which means that your lungs are full of cells, fluid, and bacteria), a lung abscess, or fluid in your pleural cavity (the space between your lungs and chest wall).

If they suspect that the infection might have spread to your brain, they would also arrange for a CT or magnetic resonance imaging (MRI) scan of your brain. If you’re showing signs of meningitis (an infection in the protective membranes that surround your brain and spinal cord), your doctor might also organize a lumbar puncture. This is a procedure where a sample of your cerebrospinal fluid (the fluid that surrounds and protects your brain and spinal cord) is collected for examination in a lab.

Treatment Options for Nocardiosis

The main treatment for nocardiosis, a bacterial infection, typically lasts for a minimum of six months. This treatment should continue for at least a month after infection symptoms have gone away with the help of antibiotics. If the infection is on the skin and the patient has a healthy immune system, it could be managed with a single antibiotic treatment. However, if the infection spreads to the lungs or throughout the body, the initial treatment should include 2 to 3 different types of antibiotics.

Because no particular treatment has been proven to be more effective than others for this disease, doctors recommend using antibiotics based on lab test results that identify the specific type of bacteria causing the infection, and the most effective drugs to treat it. Possible antibiotics that may be used in the treatment include trimethoprim/sulfamethoxazole, amikacin, imipenem, meropenem, third-generation cephalosporins, minocycline, moxifloxacin, linezolid, tigecycline, dapsone, and clarithromycin.

Sulfonamides, a group of drugs including sulfadiazine, are normally the first choice of treatment, particularly because sulfadiazine is good at reaching the brain. The combination of trimethoprim and sulfamethoxazole is also preferred by some doctors. If the disease is severe, doctors typically recommend a combination of different drugs for treatment.

If the infection results in an abscess, a pocket of pus, surgery may be needed to open it up and drain the pus. For brain abscesses, surgery is necessary if the abscess is large or does not improve after two weeks of antibiotic therapy.

It’s vital for patients to follow up with their doctors for up to a year after stopping antibiotics to make sure the infection hasn’t come back. Regular radiographic studies (scans and X-rays) and lab tests will be needed to monitor the patient’s progress.

What else can Nocardiosis be?

Nocardiosis is a medical condition that can sometimes be confused with several other kinds of illness. It can look like a range of bacterial, viral, or fungal infections, and even certain types of cancer. It’s crucial for healthcare professionals to accurately identify it and distinguish it from these other conditions. Some of the conditions that nocardiosis might be mistaken for include:

• Bacterial pneumonia
• Cellulitis
• Community-acquired pneumonia
• Fungal pneumonia
• Glioblastoma multiforme (a type of brain cancer)
• Histoplasmosis (a type of fungal infection)
• Kaposi sarcoma (a type of cancer)
• Lung abscess
• Mycobacterium avium complex (a type of bacterial infection)
• Non-Hodgkin lymphoma (a type of cancer)
• Parapneumonic pleural effusions (fluid around the lungs due to pneumonia)
• Empyema thoracis (a condition where pus accumulates in the pleural space)
• Pneumocystis jiroveci pneumonia (a type of fungal pneumonia)
• Sporotrichosis (a type of fungal infection)
• Tuberculosis
• Viral pneumonia

What to expect with Nocardiosis

The outcome of nocardiosis, a type of infection, can differ from person to person. The result can be influenced by factors like which organ is infected, how long the person has been sick, the person’s immune system health, and how severe the infection is.

People often have a better recovery when the infection is in the skin or soft tissue compared to when it impacts the lungs or spreads throughout the body, provided they receive the right treatment. Most individuals with skin nocardiosis can be fully treated if care is provided swiftly.

However, in people with a nocardiosis infection that’s resulted in a brain abscess (an infected, pus-filled area in the brain), the success rate of treatment is less than 60%.

Possible Complications When Diagnosed with Nocardiosis

• Lung infection, also known as empyema
• Brain abscess, a pocket of infection in the brain
• Meningitis, an inflammation of the membranes around the brain and spinal cord
• Osteomyelitis, which is an infection in a bone

Recovery from Nocardiosis

Nocardiosis, a kind of infection, should be treated for at least six months. For people who have weaker immune systems, the treatment needs to continue until all symptoms have gone away.

Preventing Nocardiosis

Some research suggests that taking a medication called trimethoprim-sulfamethoxazole could help protect people with AIDS who have low CD4 counts from getting an infection called nocardiosis. CD4 cells are a type of white blood cell that fights infection, and people with AIDS have lower numbers of these. Nocardiosis is a rare but potentially serious infection caused by a type of bacteria found in soil and water. The medication might help to reduce their risk of getting this infection.