Identification of Enterobacteriaceae in frozen microdilution trays prepared by Micro-Media Systems

Abstract

Frozen microdilution trays with 20 different biochemical test media for identification of Enterobactericeae were evaluated. The test panels were those provided by Micro-Media Systems (MMS), who also provided a code book for interpretation of the test results. The interpretations of the MMS test system and of the Analytab API-20E test system were compared with those obtained from tests with conventional media. Tests with 468 Enterobacteriaceae demonstrated nearly comparable results with the 2 commercial systems. About 6% (API) and 7% (MMS) of the isolates could not be identified without additional tests, and another 3% (MMS) to 4% (API) of the isolates gave test patterns that were not found in the code books. Of the isolates, 1-3% were misidentified. The MMS Enteric Quad Panels provide an efficient, relatively inexpensive and reasonably accurate method for identification of the Enterobacteriaceae.