Vancomycin-resistant Enterococcus

Vancomycin-resistant Enterococcus (VRE) refers to strains of the genus Enterococcus that have acquired resistance to the antibiotic vancomycin, which is often used to treat infections caused by enterococci. The emergence of VRE is a significant concern in healthcare settings due to the limited options for effective antibiotics against these resistant strains. VRE infections can range from urinary tract infections to more severe cases such as bacteremia, endocarditis, and infections of surgical sites.

Epidemiology

VRE is primarily found in the hospital environment, where the heavy use of antibiotics selects for resistant strains. The prevalence of VRE has been increasing worldwide, making it a notable pathogen in nosocomial (hospital-acquired) infections. Patients at higher risk for VRE colonization or infection include those with prolonged hospital stays, individuals receiving antibiotic therapy, patients with compromised immune systems, and those with invasive devices such as catheters or surgical drains.

Mechanism of Resistance

The resistance of Enterococcus species to vancomycin is primarily due to the acquisition of genes that alter the target site of the antibiotic. The most common mechanism involves the synthesis of a modified peptidoglycan precursor with decreased affinity for vancomycin, thus preventing the antibiotic from inhibiting cell wall synthesis. These genetic changes are often mediated by mobile genetic elements, such as plasmids and transposons, which facilitate the spread of resistance genes among enterococci and other bacteria.

Clinical Significance

The clinical significance of VRE lies in its ability to cause difficult-to-treat infections, particularly in vulnerable patient populations. VRE infections are associated with increased morbidity, mortality, and healthcare costs. The limited treatment options for VRE infections necessitate the use of alternative antibiotics, which may be less effective, more toxic, or both.

Prevention and Control

Prevention and control of VRE transmission in healthcare settings involve a combination of infection control measures, including hand hygiene, the use of personal protective equipment, environmental cleaning, and the judicious use of antibiotics. Screening and isolation of colonized or infected patients may also be employed to prevent the spread of VRE.

Treatment

Treatment of VRE infections involves the use of antibiotics to which the organism is susceptible. Options may include linezolid, daptomycin, and tigecycline, among others. The choice of antibiotic depends on the site and severity of the infection, as well as the susceptibility profile of the isolate. Consultation with an infectious disease specialist is often recommended for the management of VRE infections.

See Also

• Antibiotic resistance
• Nosocomial infection
• Infectious disease

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