This microbiological analysis employs a specialized agar medium containing three sugars (glucose, lactose, and sucrose) and ferrous sulfate. The medium is inoculated with the target bacterium via a stab and streak method and then incubated. Observed changes in the agar’s color, along with gas production, indicate the organism’s ability to ferment specific sugars and produce hydrogen sulfide. For example, a yellow slant and butt signify fermentation of glucose, lactose, and/or sucrose, while a red slant and yellow butt suggest only glucose fermentation. Blackening of the medium indicates hydrogen sulfide production.
Distinguishing among enteric bacteria, a group often involved in human disease, is a key application of this method. Developed as a differential medium, it allows rapid preliminary identification of various genera based on distinct biochemical properties, expediting diagnosis and appropriate treatment strategies. This information is critical in public health, food safety, and environmental monitoring, where rapid and accurate bacterial identification is paramount.
