What Is Enterococcus Faecalis (E. faecalis)?

Enterococcus faecalis (E. faecalis) is a species of enterococci bacteria that normally lives in your gastrointestinal (GI) tract and can also be found in the oral cavity and vaginal tract.

Although E. faecalis usually isn't harmful to the human body, it can become an opportunistic pathogen—causing disease when a person's immune defenses are low. For this reason, E. faecalis is considered an opportunistic pathogen. Out of all the enterococci species, it is the most common cause of urinary tract infections.

This article explains the causes and symptoms of enterococcus faecalis infections, as well as how these infections are treated.

What Is Enterococcus Faecalis?

At least 50 different species of enterococci bacteria have been described in medical literature. Among them, the species Enterococcus faecalis causes the majority of infections and is a leading cause of nosocomial (hospital-acquired) infections.

E. faecalis can enter the body during surgery, through insufficiently cleaned medical devices and equipment, improper hand hygiene, or ingesting contaminated foods and fluids.

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.

Enterococcus faecalis is a tenacious species of bacteria that is growing increasingly resistant to antibiotics. The bacterium is capable of forming "microbial communities," in which it attaches to other microbial cells to form what's known as a biofilm. These biofilms are especially resistant to antibiotic therapy.

Being that it is an opportunistic pathogen, Enterococcus faecalis is harmless to most people with healthy immune systems, but it does pose a threat to the elderly as well as those who are immunocompromised (have weakened immune systems).

What Causes Enterococcus Faecalis?

Approximately 85% to 90% of Enterococci infections are caused by E. faecalis, and are typically nosocomial (originating in a hospital). Common causes of infections caused by E. faecalis include improper hand hygiene, growth on medical equipment, and contaminated food or water.

Improper Hand Hygiene

Studies of hospital-acquired infections of E. faecalis have traditionally shown transmission due to improper hand hygiene practices by healthcare workers. This is a significant cause of E. faecalis infections.

It can be transmitted from patient to patient either by direct contact or indirectly when 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.

Biofilm Formation on Medical Devices and Equipment

The use of 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.

Contaminated Foods and Liquids

E. faecalis is commonly found in soil, water, plants, and animals. Eating unwashed foods can increase the risk of infection.

Symptoms and Types of Infections

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:

• Fever and chills
• Pain or burning when you urinate
• Nausea and vomiting
• Lightheadedness or confusion
• Headache
• Pain or pressure in the lower abdomen

Urinary Tract Infections (UTIs)

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:

• Pain or a burning sensation when urinating,
• Frequent urge to urinate, but little urine passes
• Pain or pressure in the lower abdomen
• Urine that is pink/red (a sign of blood in urine) and cloudy
• Fever or nausea (a sign of kidney infection)

Bacteremia

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:

• Fever and chills
• Nausea or vomiting
• Rapid heart rate
• Lightheadedness or confusion
• Skin rashes

Endocarditis

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:

• Heart murmur (abnormal heart sound)
• High fever (typically above 102 F)
• Hematuria (blood in urine)
• Tachycardia (rapid heartbeat)
• Painless red spots on the palms and soles (Janeway lesions)
• Pain in the tip of fingers and toes (Osler's nodes)
• Chest pain
• Swelling of the legs and feet
• Heart failure (the heart cannot pump enough blood to meet the body's needs)

How Is Enterococcus Faecalis Diagnosed?

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. Those samples will be tested to see what antibiotics will or won't work to treat the infection.

Can Enterococcus Faecalis Be Cured?

Ampicillin, an antibiotic, 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.

Summary

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.

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.

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.