Susceptibility testing and resistance phenotypes detection in bacterial pathogens using the VITEK 2 System.

A set of well characterized strains, collected in Polish hospitals, including Gram-negative (n = 93) and Gram-positive (n = 90) isolates was used in the study. The VITEK 2 AST-cards were used in the analysis according to the manufacturer's recommendations. Comparison of the susceptibility data obtained by the standard method and by VITEK 2 cards proved concordant in 99% of cases. Clinically important mechanisms were revealed by the VITEK 2 AES with >95% agreement with reference data including methicillin resistance in staphylococci (98%), high-level aminoglycoside resistance in enterococci (100%), VanA and VanB phenotypes in enterococci (100%), and ESBLs in Enterobacteriaceae (93.8%). The VITEK 2 AES System appears a reliable tool for the detection and interpretive reading of clinically important mechanisms of resistance and can be recommended for routine work.