Jane Kim, MD, is board-certified in internal medicine and is currently a medical editor and writer.
Enterococcus faecalis (E. faecalis) is a species of bacteria that lives harmlessly in the digestive tract, although it can be found in the oral cavity or vaginal tract. It can be resistant to antibiotics (drugs that kill bacteria).
When people are immunocompromised (have a weakened immune system) or have an underlying disease, E. faecalis can become pathogenic (disease-causing). For this reason, E. faecalis is considered an opportunistic pathogen—one that takes advantage of the body when immune defenses are low.
E. faecalis can enter the body during surgery, insufficiently cleaned medical devices and equipment, improper hand hygiene, or ingesting contaminated foods and fluids.
Of the many species of Enterococcus, E. faecalis and Enterococcus faecium (E. faecium) are pathogenic, with E. faecalis being the most prevalent in infections.
Common E. faecalis infections include urinary tract infections (UTIs), wound infections, intra-abdominal and pelvic infections, bacteremia (infection in the blood), and endocarditis (inflammation of the heart). If these infections become systemic (widespread), they can cause serious to life-threatening symptoms.
This article discusses the causes, common infections, lab tests, and treatment options for E. faecalis infections.
Approximately 85% to 90% of Enterococci infections are caused by E. faecalis, and are typically nosocomial (hospital-acquired). Common causes of infections caused by E. faecalis include improper hand hygiene, growth on medical equipment, and contaminated food or water.
This is a significant cause of E. faecalis infections. Studies of hospital-acquired infections of E. faecalis have traditionally shown transmission due to improper hand hygiene practices by healthcare workers.
It can be transmitted from patient to patient either by direct contact or indirectly as healthcare workers don't properly wash their hands between patient encounters. Inadequate handwashing can also contribute to contamination of hospital equipment or surfaces
According to the Centers for Disease Control and Prevention (CDC), about 1 in 31 hospital patients has at least one healthcare-associated infection on a daily basis.
The use intravenous or urinary catheters, pacemakers, or heart valves increases the risk of biofilm formation (growth and adherence of bacteria communities on surfaces). Even when properly sterilized before placement they can become infected through bacteremia after they are in the body.
Biofilms have a dense 3D extracellular matrix which can be difficult to remove from surfaces. This increases their resistance to antibiotics, which can cause life-threatening infections in the body.
E. faecalis are commonly found in soil, water, plants, and animals. Eating unwashed foods can increase the risk of infection.
Common infections caused by E. faecalis include UTIs, bacteremia, and endocarditis. Symptoms of E. faecalis infections vary depending on the type of infection you have. However, common symptoms may include:
UTIs are urinary system infections of the urethra, ureters, kidneys, or bladder. They can be caused by various species of bacteria, including E. faecalis. UTIs caused by Enterococcus species account for greater than 30% of all cases in hospitalized patients.
Common symptoms of UTIs include:
Risk factors for bladder infections include previous UTI, sexual activity, older age, bladder emptying issues, an obstruction in the urinary tract (urinary stone or enlarged prostate), or use of a urinary catheter.
Bacteremia occurs when bacteria get into the blood, often from a wound site or untreated UTI. If left untreated, bacteremia can lead to life-threatening conditions, such as endocarditis, sepsis (a systemic reaction to a blood infection), and septic shock (low blood pressure in severe sepsis that can cause organ failure).
Common symptoms of bacteremia include:
Endocarditis is a rare and potentially fatal condition that involves the inflammation of the inner lining of the heart (endocardium) and its valves. E. faecalis endocarditis typically occurs as a complication of bacteremia, where bacteria in the bloodstream travels to the heart.
Enterococcus is the third most common organism to cause endocarditis and is most often seen in cases acquired in healthcare settings. Other risk factors include having an artificial heart valve, cardiac pacemaker leads, or damaged heart valves.
Common symptoms of endocarditis may develop slowly or suddenly. They include:
Endocarditis is a rare and potentially fatal condition. If you experience symptoms of endocarditis, seek immediate medical attention.
If your healthcare provider suspects that you have an infection caused by E. faecalis, bacterial culture and antibiotic sensitivity tests will be ordered. Depending on the site of infection, a sample of urine may be taken, or blood may be drawn into special bottles and sent to the lab.
In the laboratory, methods will be used to see if bacteria grow from the samples and identify that do. They will be tested to see what antibiotics will or won't work to treat the infection.
Ampicillin, an antibiotic (class of drugs that kill bacteria), is commonly used to treat E. faecalis infections. Ampicillin blocks the formation of the external cell wall of E. faecalis, causing them to die.
However, E. faecalis infections are generally very difficult to treat due to their possible resistance to several antibiotics, including vancomycin, daptomycin, aminoglycosides, and more.
For severe infections, such as endocarditis, combination antibiotics are used to increase their potency. This may include the combination of penicillin and gentamicin. That said, researchers are investigating other antibiotics that may be more effective for treating E. faecalis infections.
If the bacteria is resistant to vancomycin, healthcare providers may take extra precautions to prevent spreading it to other patients. These can include wearing a disposable gown when bathing the patient or handling soiled linens or diapers.
Standard precautions of wearing disposable gloves and handwashing before and after caring for the patient should also be followed diligently. Toilets and bed rails should be disinfected with a bleach solution.
Enterococcus faecalis is a species of bacteria that live harmlessly in the digestive tract, although some can be found in the oral cavity or vaginal tract. E. faecalis has the potential to become pathogenic (disease-causing) in people who are immunocompromised or have an underlying disease.
E. faecalis infections are typically nosocomial (hospital-acquired). Common E. faecalis infections include urinary tract infections (UTIs), bacteremia, and endocarditis. If these infections become systemic, they can cause serious to life-threatening symptoms.
Diagnostics to determine the presence of E. faecalis include common lab tests such as bacterial culture and sensitivity.
It can be very difficult to treat E. faecalis infections due to their resistance to several antibiotics. However, ampicillin is the main drug used by healthcare providers, as it is most effective against these infections. For severe infections, such as endocarditis, combination antibiotics are used.
E. faecalis infections are largely preventable through practicing good hygiene practices. This is especially important for healthcare providers who work with hospitalized patients. You are more at risk if you have a weakened immune system.
If you have been diagnosed with a vancomycin-resistant strain, extra precautions may be taken not to spread it to other vulnerable people. Be sure to discuss what you should do and any concerns with your healthcare provider.
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Anderson AC, Jonas D, Huber I, et al. Enterococcus faecalis from food, clinical specimens, and oral sites: prevalence of virulence factors in association with biofilm formation. Frontiers in Microbiology. 2016;0. doi:10.3389/fmicb.2015.01534
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National Institute of Diabetes and Digestive and Kidney Diseases. What is a bladder infection?
National Organization for Rare Diseases. Infective endocarditis.
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New York State Department of Health. Vancomycin-resistant enterococcus (VRE).
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