Bacterial endocarditis is an infection of the inner lining of the heart that most often attacks one or several heart valves. As its name suggests, bacteria in the bloodstream are the cause of this infectious illness.

Although this infection is rare, its consequences are extremely serious and can be fatal.

For many years, medical institutions around the world have been ruling on the prevention of this passage of bacteria in the blood called bacteremia. Recommendations are dictated by the presence of an abnormality in the cardiac structure and procedures that allow bacteria to enter the bloodstream.

We now know that the current use of antibiotics is not without risk; in fact, the resistance of these bacteria to be neutralized could occur.

The assessment of this risk versus benefit should be taken into account. In which cases is it really necessary to resort to a state-of-the-art treatment with antibiotics and, above all, before which procedures is it justified?

This article bears on the issues raised above for better knowledge and understanding of prevention against bacterial endocarditis.


Bacterial Infection

Bacterial endocarditis is an infectious disease caused by one or more bacteria.

Bacteria are most often found on one or several cardiac valves.

They can also attach to any damaged areas in the heart structure.


A Very Rare Condition, but Potentially Fatal

It is a very rare disease that can unfortunately result in a serious medical condition and be deadly. Its hospital mortality rate is estimated at nearly 1 in 5 or 20%!



The use of antibiotics in the prevention of potential infection is called antibiotic prophylaxis.


Understanding Prevention

To fully understand the meaning of prevention of such an infectious complication, we have to consider patient-specific characteristics to identify the people who are more at risk.

The use of antibiotics as a preventive measure has been recommended since the 50s with a progressively better understanding of why, for whom, and how to prevent that medical condition.



Prescribing antibiotics was done for many years in any procedure where bacteria could be introduced into the blood of patients who were considered at risk for bacterial endocarditis.

Scientific studies and clinical expertise eventually challenged that therapy.



Human beings are covered in bacteria all over their skin, inside their mouth, and their entire digestive tract. However, those organs are not infectious because of where they are located in the body. They protect people from particularly virulent forms of bacteria.

The points of access for bacteria to enter the bloodstream are as follows, in descending order:  the skin, teeth and mouth, intestines, and the urogenital system, i.e., the organs and functions of excretion and reproduction.

Various surgical procedures and other invasive interventions create openings for bacteria to enter the bloodstream transiently but in large quantities. 


Pay Attention to Ordinary, but Recurrent Situations

We now know that there are other openings from where bacteria can enter the bloodstream on a recurring or even daily basis, but in a lesser quantity.

These two phenomena were therefore considered as follows: significant and punctual access vs. less frequent but repeatedly. Animal studies revealed that frequent low-density bacterial seedings could cause bacterial endocarditis as well.


Bacteria Enter the Bloodstream Daily

For example, here are daily gestures likely to have this consequence: brushing your teeth and chewing food. Antibiotics cannot prevent these daily entries of bacteria.

This is why, over the years, we have been giving particular importance to personal, oral, and dental hygiene.


Body, Oral, and Dental Hygiene

The first rule to go by, particularly in the case of people with diabetes, is to take meticulous care of their feet. People who have foot sores should promptly get a medical diagnosis and apply treatment as directed. They should look out also for tinea pedis, better known as Athlete's Foot, and get proper medical care.

The second rule recommends visiting a dental health professional regularly. Brushing teeth at least twice a day, and using dental floss and mouthwash should be part of a regular dental care routine. Mouthwash helps in averting gingivitis.  

Those two basic rules alone are at the root of preventing bacterial endocarditis and, in most cases, they are the only rules to follow.


Development of the Recommendations

The continuous development of bacterial prevention recommendations was made gradually over time. Special consideration was given to the natural history of endocarditis, the risk factors involved and the research done on animals, among others.

It also takes into account the impact of a large spectrum antibiotic therapy, of the emergence of some resistance to those bacteria, and of the danger of causing infections that could be even more serious. In other words, reckless use of antibiotics can do more harm than good.


Current Recommendations

It is now recommended to reduce the potential causes of bacteremia compared to neutralizing bacteria by antibiotic prophylaxis.


Basic Rule

The basic rule remains regular body, oral and dental hygiene habits, as stated above.

The addition of an antibiotic prophylaxis treatment depends on a preexisting cardiac condition and on the type of procedure to be performed.

The following patients are concerned:

  • who had a heart valve replacement or repair, regardless of the method used,
  • who already had bacterial endocarditis,
  • who had a heart transplant and then developed cardiac valve dysfunction,
  • who had a cardiac abnormality at birth, including:
  1. any cyanotic heart defect that is partially or not repaired. This abnormality impairs normal blood flow;

  2. during the first 6 months of a complete repair, regardless of the material involved.



The following conditions are not subject to antibiotic prophylaxis:

  • aorta coronary bypass,
  • presence of coronary stents,
  • heart pacemaker,
  • mitral prolapse without thickening or valve failure,
  • Interatrial Communication,  
  • 6 months after closing Interatrial Communication,
  • 6 months after closing the left atrial appendage,
  • valvular insufficiency or stenosis,
  • preexisting rheumatic fever with or without the associated valvular disease.


Procedures Requiring Prophylaxis in At-risk Patients

The medical procedures requiring prophylaxis in specifically at-risk patients are the following:

  • any cardiac surgery,
  • mouth, pharynx, or larynx surgery,
  • bronchoscopy with biopsy,
  • oral procedures that include teeth cleaning, dental extraction, or any other treatment that requires surgery.


Cutaneous and musculoskeletal procedures do not require any prophylaxis even when infectious elements are present. This applies as well in the case of gastrointestinal and genitourinary tract infection interventions.

The above guidelines are from the American Heart Association. Last update: 2017.

Your healthcare provider should keep an eye out for any changes in the aforementioned recommendations.