COLLABORATIVE EVALUATION OF THE RADIOMETER SENSITITRE-AP80 FOR IDENTIFICATION OF GRAM-NEGATIVE BACILLI

A multicenter trial of the Sensititre AP80 panel read on the Sensititr e AutoReader (Radiometer America, Westlake, Ohio) for the automated id entification of gram-negative bacilli was conducted with 1,023 clinica l isolates (879 members of the family Enterobacteriaceae plus 144 none nteric organisms). Assignment of taxa was based on the computer-assist ed interpretation of the results of a series of reactions with fluorog enic enzyme substrates after 5 h of incubation, with an incubation int erval of approximately 18 h used when indicated. Accuracy was determin ed initially by comparison with the results obtained with the API 20E or Rapid NFT system (Analytab Products, Plainview, N.Y.). Isolates sho wing discrepancies were identified by using conventional biochemical p rofiles. Identifications were available after 5 h of incubation for 91 8 isolates (90%). Agreements with reference results for members of the family Enterobacteriaceae were 95.3 and 92.5% at the genus and specie s levels, respectively, and for the nonmembers of the family Enterobac teriaceae, the agreements with reference results were 95.1 and 84.7%, respectively. The Sensititre AP80 panel was found to be simple and con venient to use, allowed for the testing of three isolates per panel, r equired minimal supplementary testing for completion of identification , performed in a reproducible fashion, and demonstrated an accuracy of same-day identification comparable to that reported for other automat ed systems. The AP80 panel appears well suited for routine use in the clinical microbiology laboratory as an automated means of identifying both members of the family Enterobacteriaceae and nonenteric gram-nega tive bacilli.