Causes

Enterococci are normal commensal bacteria in the gastrointestinal and genitourinary tracts. It does not cause infections in healthy individuals. However, it can lead to invasive infections in the elderly, immunocompromised individuals, those with chronic underlying diseases, and patients hospitalized for invasive procedures or surgery. 

1. Pathogen
Vancomycin-Resistant Enterococci, VRE
- VRE are strains of enterococci bacteria that are resistant to the antibiotic vancomycin.
  They are normal commensal bacteria in the gastrointestinal and genitourinary tracts.
- There are six types of VRE : Van-A, Van-B, Van-C, Van-D, Van-E and Van-G.
- VRE can survive in harsh environments and be found in almost anywhere, including soil, plants, water, and food. They can also survive on dry inanimate surfaces for five days to four months.

2. Risk Factors for Colonization and Infection 
- Prior use of broad-spectrum antibiotics, particularly vancomycin and cephalosporins, or treatment for
  serious underlying conditions such as renal failure or cancer, in immunocompromised patients admitted
  to intensive care, oncology, or transplant units
- Patients with invasive devices such as central venous catheters
- Residents of long-term care facilities

3. Routes of Transmission 
- Direct contact with carriers or infected individuals
- Indirect transmission through contaminated medical devices, environmental surfaces, etc
- Transmission via the hands of healthcare workers 

Symptoms

In healthy individuals, the symptoms of vancomycin-resistant enterococci (VRE) infection are uncommon.
However, in the elderly, immunocompromised individuals, those with chronic underlying diseases, or patients who have been hospitalized in healthcare facilities for an extended period, various infections may occur, including urinary tract infections, wound infections, and bacteremia. The symptoms can vary depending on the site of infection, and they may manifest as follows.

- General symptoms: Fever, chills, and sespsis may develop in severe cases, sepsis may develop
- Urinary tract infection: Dysuria (burning during urination), fever, and lower abdominal pain
- Endocarditis: Fever, congestive heart failure, and other related symptoms
- Wound infection: Presence of pus accompanied by symptoms such as fever

Diagnosis 

Isolation and identification of vancomycin-resistant enterococci (VRE) from patient specimens
- Confirmation of vancomycin resistance in the isolated bacteria
- Detection of vancomycin resistance-specific genes (vanA or vanB) in the isolated bacteria

Preventive measures

1. Be cautious of the transmission routes
- Transmission can occur through direct or indirect contact and contaminated medical devices.
  Therefore, personal hygiene should be maintained, and thorough disinfection/sterilization of medical
  equipment is necessary.
- Maintain aseptic techniques during invasive procedures and ensure proper cleaning and disinfection of
  environmental surfaces.

2. Prudent use of antibiotics
- The use of antibiotics such as third-generation cephalosporins and vancomycin is associated with a
   higher risk of becoming a carrier of VRE, so limiting the use of these antibiotics in hospitals to only
   when absolutely necessary may help prevent the spread of VRE.

Medical Status

According to the statistical data of the Health Insurance Review and Assessment Service (Republic of Korea), 386 people were treated for vancomycin resistance (Diagnosis code, U830) in 2021. Among the age groups, those aged 80 and above accounted for 60.5% of the treated population, followed by those in their 70s with 27.5% and those in their 60s with 9.4%.