Enterococcus faecalis is a gram-positive bacterium commonly present in the gastrointestinal tracts, oral cavity, and vaginal tract of healthy individuals. As a natural inhabitant of the human gut, it is normally a harmless member of the body’s microbial ecosystem. Some strains are even used in probiotic supplements due to their lack of genes associated with disease.
The Dual Nature of Enterococcus Faecalis
While Enterococcus faecalis is a standard resident of the human gut, it is also an opportunistic pathogen. This means the bacterium can transition from harmless to harmful under specific circumstances. The opportunity for infection arises when it spreads outside of its usual intestinal environment to other parts of the body.
This transition is not due to a change in the bacterium, but rather a change in its location or the host’s condition. For instance, if it enters the urinary tract, bloodstream, or a surgical wound, it can establish an infection. Individuals with weakened immune systems are particularly susceptible. The bacterium’s resilience allows it to survive in various environments, including those with high salt concentrations or acidity.
Associated Infections and High-Risk Groups
Enterococcus faecalis is linked to various infections, particularly in healthcare settings. Urinary tract infections (UTIs) are among the most common, occurring when the bacterium enters the urinary system. Patients with urinary catheters are at an elevated risk because the device allows bacteria to form a protective biofilm. Symptoms of a UTI often include a painful or burning sensation during urination.
When E. faecalis enters the bloodstream, it causes a condition called bacteremia. One of the most serious complications is endocarditis, an infection of the inner lining of the heart chambers and valves. This condition is more likely in individuals with pre-existing heart damage or artificial heart valves. General symptoms of a spreading infection include fever, chills, and fatigue.
The bacterium is also a frequent cause of infections in surgical sites and wounds. Individuals in hospitals, especially those with recent surgery or indwelling medical devices, are at the greatest risk for these hospital-acquired infections. Other high-risk groups include the elderly, people receiving kidney dialysis, and those with compromised immune systems.
Antibiotic Resistance and Treatment Difficulties
Treating Enterococcus faecalis infections is challenging due to its resistance to many antibiotics. It possesses intrinsic, or natural, resistance to several classes of antimicrobial drugs, including most cephalosporins. This inherent durability means many common antibiotics are ineffective, limiting treatment options.
Further complicating treatment is the bacterium’s ability to acquire resistance to other antibiotics. Through the transfer of genetic material, it can develop defenses against drugs that were once effective. This has led to the emergence of strains resistant to vancomycin, an antibiotic for serious infections. These strains are known as Vancomycin-Resistant Enterococci (VRE) and are a concern in healthcare facilities.
The combination of intrinsic and acquired resistance makes E. faecalis a difficult pathogen to eradicate. Infections involving VRE may require treatment with a combination of specific antibiotics. The bacterium’s ability to form biofilms also contributes to treatment difficulty, as this protective matrix shields it from both antibiotics and the body’s immune response.
Infection Prevention Strategies
Preventing the spread of Enterococcus faecalis is important in hospital environments where infection risk is highest. Hand hygiene by healthcare workers, patients, and visitors is a primary prevention measure. Because the bacterium is found in feces, it can be transmitted if people do not wash their hands properly after using the restroom.
Proper management of medical devices is also necessary for preventing infections. This includes the sterile insertion and careful maintenance of urinary catheters and intravenous lines. The surfaces of these devices can harbor E. faecalis, so minimizing their use and duration is an important strategy for risk reduction.
Thorough environmental cleaning and disinfection in healthcare settings help reduce the bacterium on surfaces like bed rails and toilets. Additionally, antibiotic stewardship programs aid in prevention. These programs optimize the use of antibiotics to improve patient outcomes and limit the development of drug-resistant organisms like VRE.