Vancomycin-resistant enterococcus (VRE) – Overview

 

Overview

Vancomycin-resistant enterococcus (VRE) refers to strains of enterococcal bacteria that have developed resistance to the antibiotic vancomycin. Enterococci are bacteria that are commonly found in the human gastrointestinal tract and are also found in the environment. While most enterococcal infections can be treated with antibiotics, some strains have become resistant to multiple drugs, including vancomycin.

Vancomycin is an antibiotic that is often used to treat serious infections, particularly those caused by Gram-positive bacteria. When enterococci become resistant to vancomycin, it limits the treatment options for infections caused by these bacteria, making them more challenging to manage.

Types of VRE:

There are two main species of enterococci that are commonly associated with vancomycin resistance:

Enterococcus faecium: This species is more commonly associated with vancomycin resistance than Enterococcus faecalis. Vancomycin-resistant Enterococcus faecium (VRE) infections are often seen in healthcare settings, such as hospitals and long-term care facilities.

Enterococcus faecalis: While less common, vancomycin-resistant Enterococcus faecalis (VRE) strains have also been reported. This species is another significant cause of healthcare-associated infections.

VRE can spread from person to person, especially in healthcare settings where patients may have compromised immune systems or other underlying health conditions. Preventing the spread of VRE typically involves strict infection control measures, including proper hand hygiene, isolation precautions for infected or colonized patients, and appropriate antibiotic stewardship to prevent the development of further resistance.

Mechanism of Resistance:

Vancomycin resistance in enterococci is primarily due to the acquisition of resistance genes, such as vanA, vanB, vanC, etc. These genes encode enzymes that modify the cell wall precursors targeted by vancomycin, making the antibiotic ineffective.

Enterococci have a thick cell wall, and vancomycin is one of the few antibiotics that can effectively target and disrupt the synthesis of this cell wall. When resistance develops, it limits treatment options.

Risk Factors:

Patients with compromised immune systems, such as those undergoing chemotherapy or organ transplantation, are at higher risk of VRE infections.

Long-term hospitalization, exposure to healthcare settings, and the use of invasive medical devices (e.g., catheters) increase the risk of VRE acquisition.

Prior use of antibiotics, especially vancomycin and other broad-spectrum antibiotics, can contribute to the development of VRE.

Transmission:

VRE can be transmitted from person to person, primarily through direct contact or through contaminated surfaces and equipment.

Healthcare workers and visitors can inadvertently carry the bacteria from one patient to another.

Infections:

VRE can cause a wide range of infections, including urinary tract infections (UTIs), bloodstream infections (bacteremia), wound infections, and surgical site infections.

Infections with VRE can be more challenging to treat due to limited antibiotic options.

Diagnosis:

Diagnosis of VRE is typically confirmed through laboratory testing, including culture and susceptibility testing.

Molecular techniques may be used to detect specific resistance genes.

Treatment:

Treating VRE infections can be challenging due to limited antibiotic options. Alternative antibiotics, such as daptomycin, linezolid, tigecycline, or combination therapy, may be considered.

Antibiotic therapy should be guided by susceptibility testing to determine the most effective treatment.

Prevention:

Preventing the spread of VRE requires strict infection control measures, including proper hand hygiene, isolation precautions for infected or colonized patients, and environmental cleaning.

Antibiotic stewardship programs are important to prevent the overuse or misuse of antibiotics, which can contribute to the development of antibiotic resistance.