EVALUATION OF THE VITEK-2 SYSTEM FOR RAPID IDENTIFICATION OF MEDICALLY RELEVANT GRAM-NEGATIVE RODS

The new VITEK 2 system (bioMerieux) was evaluated at two independent s ites with the identification card for gram-negative bacilli (ID-GNB ca rd). Of the 845 strains tested, which represented 70 different taxa be longing to either the family Enterobacteriaceae or the nonenteric baci lli, 716 (84.7%) were correctly identified at the species level. Thirt y-two (3.8%) additional strains were identified to the species level a fter the performance of simple, rapid manual tests (oxidase, hemolysis , indole reaction, motility, and pigmentation). For 80 (9.5%) strains, these additional tests did not lead to an identification at the speci es level but the correct species identification was given among the or ganisms listed. Only 7 (0.8%) strains were misidentified, and 10 (1.2% ) were not identified. Mistakes were randomly distributed over differe nt taxa. Due to the new, more sensitive fluorescence-based technology of the VITEK 2 system, final results were available after 3 h, Since o ur evaluation was mainly a stress test, it is predicted that the VITEK 2 system in conjunction with the ID-GNB card would perform well under conditions of a routine clinical laboratory in identifying members of the family Enterobacteriaceae and selected species of nonenteric bact eria. This system is a promising, highly automated new tool for the ra pid identification of gram-negative bacilli from human clinical specim ens.