Comparison of AMS-Vitek, MicroScan, and Autobac Series II for the identification of gram-negative bacilli

Identification of Gram-negative bacilli by AMS-Vitek, MicroScan, and Autobac Series II was evaluated with 434 clinical isolates comprising glucose fermenters and glucose nonfermenters. The organisms were tested in each of the three systems (the AMS Vitek GNI card, the MicroScan Combo Plus Panel, and the Autobac 18 chamber cuvette). API 20E was used as the primary reference system. MicroScan and Vitek correctly identified 96.1% and 95.6% of the organisms, respectively. The Autobac Series II identified 82.3% of the organisms correctly. Results with MicroScan, Vitek, and Autobac were available in 24-48 hours, 4-18 hours, and 3-8 hours, respectively.