Pulmonary Actinomycosis

What Is Pulmonary Actinomycosis?

Pulmonary actinomycosis is a rare bacterial lung infection. It is also known as thoracic actinomycosis. It is not contagious.

This condition mainly affects people between 30 and 60 years old. It occurs more often in men than in women.

Treatment is generally successful, but it can be a lengthy process.

What Causes Pulmonary Actinomycosis?

This condition is caused by bacteria from the genus Actinomyces. These bacteria normally live in your mouth and gastrointestinal tract. Most of the time they are harmless. However, they can cause an infection if tissue becomes damaged.

Infection usually occurs after illness or injury, such as a tooth abscess or gum disease. The damaged tissue makes it possible for bacteria to move to your lungs or other parts of your body. There it can cause harm.

In most cases, pulmonary actinomycosis occurs when a mixture of food and bacteria accidentally ends up in the lungs instead of the stomach. Inhaling food instead of swallowing it is called aspiration.

Who Is at Risk for Pulmonary Actinomycosis?

Risk factors for this condition include:

  • dental abscess
  • not taking care of your teeth and gums
  • emphysema (a type of lung infection)
  • scarred lungs from bronchiectasis
  • heavy drinking

Long-term alcohol use may weaken your immune system. Heavy drinkers are also more likely to aspirate vomit.

According to a recent study published in Mayo Clinic Proceedings, another risk factor may be hiatal hernia. This is a condition where part of your stomach pushes up into your chest (Adreani, et al., 2009). However, research is still preliminary.

What Are the Symptoms of Pulmonary Actinomycosis?

Symptoms of pulmonary actinomycosis generally start slowly. Common signs include:

  • fever at or above 100.4 F
  • fatigue
  • shortness of breath
  • weight loss
  • chest pain when inhaling deeply
  • night sweats
  • appetite loss
  • dry cough with or without blood
  • a cough with phlegm that might contain blood

How Serious Is Pulmonary Actinomycosis?

Without treatment, pulmonary actinomycosis can destroy parts of your lungs. You could also develop a brain abscess or a brain infection called meningitis. This is potentially life-threatening.

Other complications include emphysema and a bone infection called osteomyelitis.

How Is Pulmonary Actinomycosis Diagnosed?

Symptoms of pulmonary actinomycosis are similar to those of other conditions. Therefore, your doctor might have to perform several tests to confirm the diagnosis. These include:

  • lung biopsy: a small piece of lung tissue is removed and checked for signs of damage or infection
  • bronchoscopy: a thin tube is used to see inside your lungs
  • complete blood count: this blood test will reveal signs of infection
  • chest computed tomography (CT) scan: X-rays are used to make an image of your chest. This helps find abnormalities in your lungs.
  • chest X-rays
  • sputum culture: to check for bacteria
  • thoracentesis: fluid is removed from your lungs for testing. Too much fluid can indicate infection.

How Is Pulmonary Actinomycosis Treated?


Penicillin is the most common antibiotic treatment. Its usually given as injections for two to six weeks. Then oral penicillin is used for six to 12 months. It can take up to 18 months of treatment for a cure.

If youre allergic to penicillin, your doctor might prescribe other antibiotics like tetracycline or clindamycin.


You might need to have fluid surgically drained from your lungs. Excess fluid can lead to pulmonary edema. This condition is potentially life-threatening.

Surgery can also repair tissue damage in your lungs.

How Can Pulmonary Actinomycosis Be Prevented?

Good dental hygiene can help lower your risk. Keep your teeth and gums in good shape. This helps prevent bacteria from spreading to other parts of your body. To do this:

  • Brush and floss your teeth twice a day.
  • Get regular dental cleanings and exams.
  • Eat fewer sugary foods. Sugary foods can increase your risk for tooth decay.