Comparison of enteric identification systems.

An evaluation of methods for identification of Enterobacteriaceae was made employing the new commercial Micro-Media Enteric System (MMES) with that of the Analytab Products Incorporated (API) and the Conventional tube media schema as suggested by the Center for Disease Control (CDS). The MMES system employed 20 biochemical tests, the API 21, and the CDC procedure 25. Sixteen of these were identical biochemical tests. Two hundred clinical isolates of Enterobacteriaceae were tested employing procedures recommended by the manufacturers of MMES and API, and methods suggested by CDC. Among the sixteen identical biochemical tests the agreement was 98.0% (Conventional), 98.2% (API), and 97.98% (MMES). Bacteria misidentified by the API system totaled 5 (2.5%), 12 (6%) for the Conventional, and 13 (6.5%) for the MMES. Five of the bacteria misidentified with the MMES procedure were due to false positive citrate tests. This problem was subsequently eliminated. The results of this study indicated that the new MMES method for identification of Enterobacteriaceae compared favorably with both the API and Conventional procedures. However, significant advantages of the MMES method were evident in initial purchase price, utilization of technology time, and less tedium performing the test.