Vancomycin-Resistant Enterococci (VRE) are bacteria that have developed resistance to vancomycin, a powerful antibiotic often used for serious infections. Enterococci normally inhabit the human digestive and female genital tracts. Resistance means that when these bacteria cause an infection, the primary antibiotic used to treat them is ineffective, making VRE a significant concern, particularly in healthcare settings.
What is Vancomycin-Resistant Enterococci?
Enterococci are Gram-positive bacteria that naturally live in the human gastrointestinal and female genital tracts. Resistance develops when enterococci are exposed to vancomycin, leading to a genetic change that prevents the antibiotic from interfering with the bacteria’s cell wall construction. This acquired defense mechanism allows the bacteria to survive and multiply even in the presence of the medication.
The resistance gene in VRE can potentially be transferred to other types of bacteria, compounding the problem of antimicrobial resistance. It is important to distinguish between VRE colonization and VRE infection. Colonization means a person is carrying the VRE bacteria in their body (such as in the gut or on the skin) without experiencing symptoms or illness. An infection occurs when the VRE bacteria cause disease, leading to noticeable symptoms that require medical attention.
How VRE Infections Manifest
VRE infections are opportunistic, meaning they typically cause disease only when a person’s immune system is weak or when the bacteria enter a part of the body where they do not belong. Symptoms depend on the specific site of the infection. VRE commonly causes infections in the urinary tract, the bloodstream, and surgical wounds.
One frequent manifestation is a Urinary Tract Infection (UTI), presenting with symptoms such as a burning sensation during urination, increased frequency, or pain in the back or lower abdomen. If VRE enters the bloodstream, it causes bacteremia, which is often the most serious complication. Symptoms of a bloodstream infection include high fever, severe chills, and a general feeling of being unwell.
VRE wound infections typically occur at surgical sites or around medical devices like catheters. Signs of a localized wound infection include increased redness, swelling, and pain at the site, often accompanied by the drainage of pus. Diagnosis relies on laboratory testing of a sample from the affected area.
Acquisition and High-Risk Settings
Acquisition of VRE is linked to contact with the bacteria, often occurring in healthcare environments where risk factors are concentrated. The bacteria spread indirectly from person to person, primarily on the hands of healthcare staff or through contact with contaminated equipment and environmental surfaces like bed rails and doorknobs. VRE can survive on these surfaces for extended periods, increasing transmission risk.
The risk of acquiring a VRE infection involves factors that compromise the body’s natural defenses or expose it to the bacteria. Patients with a history of long-term or repeated treatment with antibiotics, especially vancomycin, are at higher risk. This antibiotic use eliminates competing, non-resistant bacteria, creating an environment where VRE can thrive.
Prolonged hospital stays, particularly in Intensive Care Units or oncology wards, are risk factors due to the concentration of ill patients and frequent procedures. Patients with weakened immune systems, such as those with cancer or organ transplant recipients, are more susceptible to VRE infection following colonization. Invasive medical devices, including urinary catheters, central intravenous lines, or feeding tubes, also provide a pathway for the bacteria to enter the body and cause infection.
Medical Management and Treatment Protocols
Management of a VRE infection begins with laboratory testing to determine the specific antibiotics that can successfully treat the strain. Since vancomycin is ineffective, treatment relies on alternative antimicrobial agents. For patients who are only colonized with VRE and show no symptoms, antibiotic treatment is usually not necessary, as unnecessary use promotes further resistance.
When an active infection is present, the choice of antibiotic depends on the site of the infection and the organism’s specific drug susceptibility. For severe, systemic VRE infections like bacteremia, doctors often use drugs such as Linezolid or Daptomycin. Linezolid is effective for VRE infections, and high-dose Daptomycin is frequently used for bloodstream infections, sometimes combined with other drugs.
For VRE UTIs, antibiotics that concentrate well in the urine, such as Fosfomycin or Nitrofurantoin, may be used for uncomplicated cases. The removal of the indwelling catheter is often necessary for catheter-associated VRE UTIs, as this can help resolve the infection. Supportive care, including managing fever, maintaining hydration, and addressing underlying medical conditions, is an important component of the overall treatment plan.
Preventing the Spread of VRE
Limiting the spread of VRE focuses on rigorous infection control practices, particularly in high-risk healthcare environments. The simplest measure is meticulous hand hygiene for both staff and visitors. Healthcare personnel must wash their hands with soap and water or use an alcohol-based hand sanitizer before and after every patient interaction and after removing gloves.
Hospitals utilize Contact Isolation protocols for patients known to be infected or colonized with VRE to prevent transmission. These protocols involve placing the patient in a private room or cohorting them with other VRE-positive patients. Healthcare workers must wear gowns and gloves when entering the room and remove them before leaving to avoid carrying the bacteria elsewhere.
Beyond personal protective equipment, environmental cleaning plays a significant role in containment. VRE can contaminate surfaces near the patient, requiring rigorous cleaning and disinfection of frequently touched objects, such as bed rails, medical equipment, and bathroom fixtures. Adhering to these protocols helps healthcare facilities reduce the risk of VRE transmission and protect vulnerable patients.