What is bacterial endocarditis?

Infective endocarditis (IE) [also called bacterial endocarditis (BE), or depending on acuity acute or subacute or chronic bacterial endocarditis (SBE) ] occurs when germs (usually bacteria) enter the blood stream and attach to and attack the lining of the heart valves. Infective endocarditis causes growths (vegetations) on the valves, produces toxins and enzymes which kill and break down the tissue to cause holes on the valve, and spreads outside the heart and the blood vessels. The resulting complications are embolism of material from the vegetations, leaky valve, heart block and abscesses around the valve. Without treatment, endocarditis is a fatal disease.

Normally, bacteria can be found in the mouth, on the skin, in the intestines, respiratory system, and in the urinary tract. Some of these bacteria may be able to get into the bloodstream when eating, during teeth brushing and when passing stools and cause endocarditis. Normal heart valves are very resistant to infection, but diseased valves have defects on the surface where bacteria may attach. Valve prosthesis (replacement heart valves) are more prone to infection than normal valves. The bacteria rapidly form colonies, grow vegetations and produce enzymes, destroying the surrounding tissue and opening the path for invasion.

Dental procedures (particularly tooth extractions) and endoscopic examinations are associated with bacteria in the blood, so prophylactic (preventative) antibiotics are advised for some patients with valve disease and all patients with valve replacements. Intravenous drug abusers are at high risk for developing IE.

Who is at risk for developing bacterial endocarditis?

Patients most at risk of developing bacterial endocarditis include those who have:

  • Acquired valve disease (for example, rheumatic heart disease) including mitral valve prolapse with valve regurgitation (leaking) and/or thickened valve leaflets
  • An artificial (prosthetic) heart valve, including bioprosthetic and homograft valves
  • Previous bacterial endocarditis
  • Certain congenital heart defects
  • Patients with devices, e.g. pacemakers
  • Immune suppressed patients
  • Patients who are intravenous drug abusers
  • Hypertrophic cardiomyopathy (HCM)

According to the American Heart Association, about 29,000 patients are diagnosed with endocarditis each year.

What are signs of infection?

Call your doctor if you have any of these signs of an infection:

  • Fever over 100°F(38.4°C)
  • Sweats or chills, particularly night sweats
  • Skin rash
  • Pain, tenderness, redness or swelling
  • Wound or cut that won't heal
  • Red, warm or draining sore
  • Sore throat, scratchy throat or pain when swallowing
  • Sinus drainage, nasal congestion, headaches or tenderness along upper cheekbones
  • Persistent dry or moist cough that lasts more than two days
  • White patches in your mouth or on your tongue
  • Nausea, vomiting or diarrhea

Last reviewed by a Cleveland Clinic medical professional on 04/29/2019.


  • Nishimura, RA, et. al. 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart DiseaseA Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129 (23) e521-e643. https://www.ahajournals.org/doi/full/10.1161/cir.0000000000000031 Accessed 12/2018
  • Nishimura, RA, et. al. 2017 AHA/ACC Focused Update of the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2017; 135 (25) e1159-e1195. https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000000503 Accessed 12/2018
  • Habib G, et. al. Guidelines on the prevention, diagnosis, and treatment of infective endocarditis (new version 2009) The Task Force on the Prevention, Diagnosis, and Treatment of Infective Endocarditis of the European Society of Cardiology (ESC). European Heart Journal (2009) 30, 2369–2413 doi:10.1093/eurheartj/ehp285 http://eurheartj.oxfordjournals.org/content/ehj/30/19/2369.full.pdf Accessed 12/2018
  • Wilson W, et. al. Prevention of Infective Endocarditis Guidelines From the American Heart Association A Guideline From the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. 2007;116:1736-1754 http://circ.ahajournals.org/content/116/15/1736.full.pdf Accessed 12/2018

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy