Investigation of an outbreak of vancomycin-resistant Enterococcus faecium by random amplified polymorphic DNA (RAPD)...

Area of Science:

• Medical Microbiology
• Infectious Diseases Epidemiology
• Molecular Typing

Background:

• Vancomycin-resistant Enterococcus faecium (VREF) poses a significant healthcare challenge.
• Understanding VREF transmission dynamics is crucial for infection control.
• Previous epidemiological studies on VREF in London teaching hospitals are limited.

Purpose of the Study:

• To characterize VREF isolates from a London teaching hospital over a four-year period.
• To investigate the genetic diversity and transmission patterns of VREF strains.
• To evaluate the utility of Random Amplified Polymorphic DNA (RAPD) typing in VREF outbreak investigations.

Main Methods:

• Collection and vancomycin susceptibility testing of 122 VREF isolates from 103 patients.
• Molecular typing of VREF isolates using Random Amplified Polymorphic DNA (RAPD) with a single primer.
• Analysis of temporal and spatial clustering of identified RAPD types.

Main Results:

• All 122 VREF isolates demonstrated high-level resistance to vancomycin and teicoplanin.
• Nine distinct RAPD types were identified among the VREF isolates.
• Significant temporal and spatial clustering of specific RAPD types was observed, suggesting cross-infection.

Conclusions:

• Multiple VREF strains contributed to the observed outbreaks in the hospital.
• Cross-infection with specific VREF types occurred on certain hospital wards.
• RAPD typing is an effective method for elucidating VREF epidemiology and guiding infection control strategies.