Background: To access the accuracy and clinical usefulness of microplate identification (ID) system for the identification of Enterobacteriaceae, we compared microplate ID system with API 20E (bioMérieux, Marcy I’Etoile, France)

Methods: Ninety-two cultures of Enterobacteriaceae and one isolate of Aeromonas species were simultaneously identified by microplate ID system and the API 20E. Twenty biochemical tests used in microplate ID system were lactose, sucrose, and H₂S in Kigler’s iron agar media; indole, sucrose, raffinose, arabinose, trehalose, adonitol, dulcitol, sorbitol, cellibiose, methy-red, phenylalanine deaminase, ornithine decarboxylase, lysine decarboxylase, arginine dihydrolase, urease, and citrate in microplate; and oxidase test. The identification was obtained by considering percent likelihood (%ID), modal frequency and ID score method.

Results: Among the 92 cultures of Enterobacteriaceae and one isolate of Aeromonas species, agreement rate of identification according to the %ID between microplate ID system and API 20E were 90.3% to the species level and 97.8% to the genus level.

Conclusions: For the identification of clinical Enterobacteriaceae isolates, the microplate ID system compares favorably with API 20E in identification accuracy and have the advantage of cost-saving and easy to use. (Korean J Clin Microbiol 1999;2:135-143)