Accuracy of Micro-ID for Identification of Salmonella and Other Enterobacteriaceae from Clinical and Food Sources

The accuracy of a new 4-h Enterobacteriaceae identification kit, not previously tested with food isolates, was evaluated by using 265 known bacterial cultures. These clinical and food isolates represented 11 genera of Enterobacteriaceae ; about 10% were atypical strains. Micro-ID test strips were inoculated from 24-h brain heart infusion agar slants and then incubated at 37 C for 4 h. With initial tests, 251 of the 265 cultures (95%) were correctly identified to species. When cultures initially misidentified were re-inoculated into Micro-ID, accuracy of identification increased to 98%. In tests to determine whether this multitest system would perform efficiently if incubated overnight at a lower temperature. 100 cultures of Enterobacteriaceae were inoculated into Micro-ID strips and incubated at 22 C for 16 h. Under these conditions, the system correctly identified 86 cultures to genus and 78 to species. Most of the misidentifications involved Enterobacter agglomerans . The degree of accuracy of Micro-ID at 22 C for 16 h was comparable to that at 37 C for 4 h, i.e., 95%, for identification to genus of the following: Arizona , Citrobacter , Edwardsiella , Escherichia , Klebsiella , Proteus , Salmonella , Serratia , Shigella and Yersinia .