Are clinical laboratories in California accurately reporting vancomycin-resistant enterococci?

Area of Science:

• Clinical Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Vancomycin-resistant enterococci (VRE) pose a significant threat in healthcare settings.
• Accurate laboratory surveillance is essential for controlling VRE outbreaks.

Purpose of the Study:

• To evaluate the accuracy of hospital-based clinical laboratories in reporting vancomycin resistance in enterococci.
• To identify challenges in VRE detection and reporting in the San Francisco Bay area.

Main Methods:

• Six characterized enterococcal strains (five VRE, one vancomycin-susceptible) were sent to 31 laboratories.
• Laboratories used their routine antimicrobial susceptibility testing methods.
• Results were analyzed based on the level of vancomycin resistance and specific enterococcal species.

Main Results:

• 100% accuracy for high-level vancomycin resistance (E. faecium, MIC 512).
• Decreased accuracy for moderate (91%) and low-level (97%, 56%) vancomycin resistance (E. faecium, E. faecalis).
• 50% accuracy for intrinsic low-level resistance (E. gallinarum, MIC 8); 100% correctly identified vancomycin-susceptible isolate.

Conclusions:

• Laboratories in the San Francisco Bay area demonstrate proficiency in detecting high-level vancomycin resistance.
• Challenges exist in accurately identifying low- to moderate-level vancomycin resistance in enterococci.
• Enhanced detection accuracy and prompt reporting are critical next steps for VRE control.