Simple scheme for identification of common species of enterobacteriaceae.

We propose a simple scheme for the identification of enterobacteriaceae species which routinely necessitates numerous biochemical tests and prolonged time span. In the scheme, family enterobacteriaceae is initially divided into four major groups depending on two important biochemical reactions viz. Lactose fermentation (L) and Methyl red test (MR). Each of the four groups, Group I (L + MR+), Group II (L + MR-), Group III (L- MR-), Group IV (L- MR+) can further be differentiated by using few tests. Eleven genera and 23 species can be identified by this scheme using limited biochemical tests. As many as 990 strains of enterobacteriaceae were subjected to standard biochemical tests and proposed simple scheme for identification. The discrepancy was observed only with 8 atypical strains of E. coli.