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Pulmonary actinomycosis

Pulmonary actinomycosis is a rare lung infection caused by bacteria.


Pulmonary actinomycosis is caused by certain bacteria normally found in the mouth and gastrointestinal tract. The bacteria often do not cause harm. But poor dental hygiene and tooth abscess can increase your risk for lung infections caused by these bacteria.

People with the following health problems also have a higher chance of developing the infection:

The disease is rare in the United States. It may occur at any age, but is most common in people 30 to 60 years old. Men get this infection more often than women.


The infection often comes on slowly. It may be weeks or months before diagnosis is confirmed.

Symptoms may include any of the following:

Exams and Tests

The health care provider will perform a physical exam, and ask about your medical history and symptoms. Tests that may be done include:


The goal of treatment is to cure the infection. It may take a long time to get better. To be cured, you may need to receive the antibiotic penicillin through a vein (intravenously) for 4 to 6 weeks. Then you need to take penicillin by mouth for a long period. Some people need up to 18 months of antibiotic treatment.

If you cannot take penicillin, your provider will prescribe other antibiotics.

Surgery may be needed to drain fluid from the lungs and control the infection.

Outlook (Prognosis)

Most people get better after treatment with antibiotics.

Possible Complications

Complications may include:

When to Contact a Medical Professional

Call your provider if:

  • You have symptoms of pulmonary actinomycosis
  • Your symptoms get worse or do not improve with treatment
  • You develop new symptoms
  • You have a fever of 101°F (38.3°C) or higher.


Good dental hygiene may help reduce your risk for actinomycosis.

Alternative Names

Actinomycosis - pulmonary; Actinomycosis - thoracic


Brook I. Actinomycosis. In: Goldman L, Schafer AI. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 329.

Russo TA. Agents of actinomycosis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 256.

Torres A, Menendez R, Wunderink RG. Bacterial pneumonia and lung abscess. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 33.

Review Date 3/13/2016

Updated by: 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, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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