External sources of vancomycin-resistant enterococci for intensive care units

Area of Science:

• Infectious Diseases
• Critical Care Medicine
• Microbiology

Background:

• Vancomycin-resistant enterococci (VRE) colonization and infection rates have significantly increased in recent years, particularly within intensive care units (ICUs).
• VRE colonization is a known risk factor for subsequent VRE infection.

Purpose of the Study:

• To investigate the prevalence and sources of vancomycin-resistant enterococci (VRE) colonization among patients admitted to a medical intensive care unit (MICU) where VRE colonization is endemic.
• To identify risk factors associated with VRE colonization on admission to the MICU.

Main Methods:

• Prospective, descriptive analysis of 301 consecutively admitted patients to a public hospital's MICU.
• Rectal swabs were collected on admission for VRE detection.
• VRE isolates underwent genetic fingerprinting using pulsed-field gel electrophoresis (PFGE) to identify strain types.

Main Results:

• 14% (43/301) of patients were colonized with VRE upon MICU admission.
• Risk factors for VRE colonization included longer hospital stays prior to MICU admission (OR 4.65 for ≥3 days) and prior in-hospital antibiotic use.
• Of 22 recognized VRE PFGE strain types, 18% were introduced by community-admitted patients and 45% by patients from other hospital wards.

Conclusions:

• While ICUs are recognized as hubs for antibiotic resistance, this study highlights that a majority of VRE strain types in the MICU originated from sources outside the unit, such as other hospital wards.
• Interventions to control VRE spread should consider transmission dynamics across different hospital units, not solely focusing on community-acquired VRE.