Evaluation of VITEK 2 for analysis of Enterobacteriaceae using the Advanced Expert System (AES) versus interpretive susceptibility guidelines used at Dynacare Kasper Medical Laboratories, Edmonton, Alberta.

OBJECTIVE: To evaluate the applicability and adaptability of the bioMérieux VITEK 2 Advanced Expert System (AES) to the customized interpretive susceptibility guidelines used at Dynacare Kasper Medical Laboratories (DKML).
METHODS: Three hundred isolates of Enterobacteriaceae (not more than 30% Escherichia coli) were tested on the VITEK 2 system and the API 20E for identification. Susceptibility testing for these isolates was performed on the VITEK 2 system and the Pasco broth microdilution panels. Minimal inhibitory concentrations (MICs) and interpreted results according to the AES and DKML antimicrobial susceptibility guidelines were compared.
RESULTS: Of 300 isolates tested for susceptibility, 13 did not give AES interpretations. Of the remaining 287 isolates, interpretations between AES and DKML guidelines were compared for 10 antibiotics. The overall correlation between the AES and DKML interpretations was 96.2%.
CONCLUSION: This study demonstrated the benefits and limitations of the bioMérieux AES. Automated knowledge-based systems provide a useful laboratory tool for the interpretation of susceptibility results.