MIO Medium is primarily used in microbiology for the identification and differentiation of motile bacteria, especially members of the Enterobacteriaceae family. It is particularly useful in detecting bacterial motility, indole production, and ornithine decarboxylase activity—all three in a single test, making it efficient for biochemical profiling.

The medium supports the assessment of motility by allowing observation of bacterial spread through a soft agar matrix. Indole production is determined by adding Kovac’s reagent after incubation, where a red ring indicates a positive result. Ornithine decarboxylase activity is detected through a pH change that turns the medium purple, indicating the organism’s ability to ferment amino acids.

MIO Medium is commonly used in clinical labs to help differentiate similar-looking Gram-negative rods, such as distinguishing between Salmonella, Shigella, and other enteric pathogens. Its ability to provide three test results from one inoculation saves time and resources in diagnostic workflows.