Evaluation of the automicrobic system gram-positive identification card for species identification of coagulase-negative staphylococci.

The AutoMicrobic system Gram-Positive Identification Card (Vitek Systems, Inc., Hazelwood, Mo.) was evaluated for identification of a group of 150 isolates of coagulase-negative staphylococci. Identifications obtained with the Gram-Positive Identification Card were compared with reference identifications derived from 15 conventional biochemical tests. The AutoMicrobic system correctly identified only 67.3% (101 of 150) of the test isolates. The greatest accuracy was achieved with Staphylococcus epidermidis isolates (95.7%), whereas Staphylococcus hominis isolates were least often correctly identified (26.7%).