Evaluation of the VITEK 2 gram positive (GP) microbial identification test card: collaborative study

Area of Science:

• Clinical Microbiology
• Bacteriology
• Diagnostic Technology

Background:

• Accurate identification of Gram-positive bacteria is crucial for effective patient treatment.
• The VITEK 2 system offers automated microbial identification.
• The VITEK 2 Gram Positive (GP) card is designed for identifying specific Gram-positive organisms.

Purpose of the Study:

• To evaluate the performance of the VITEK 2 GP identification card.
• To assess its accuracy in identifying Gram-positive bacteria in a collaborative study.

Main Methods:

• A multi-laboratory study involving 20 laboratories across the United States.
• Analysis of 720 Gram-positive bacterial isolates using the VITEK 2 GP card.
• Screening of 120 non-Gram-positive strains to assess specificity.

Main Results:

• The VITEK 2 GP card correctly identified 714 out of 720 Gram-positive isolates.
• Zero misidentifications and zero unidentified results were recorded for Gram-positive organisms.
• Gram stain screening showed 14 inaccuracies, impacting VITEK 2 GP analysis.

Conclusions:

• The VITEK 2 GP identification method is an acceptable automated tool.
• It provides rapid and accurate identification of selected Gram-positive bacteria.
• The system shows high inclusivity and specificity for targeted organisms.