MOTILITY TEST

Objective:

To determine whether an organism is motile.

Test Procedure and Interpretation

1. Prepare a semisolid agar medium in a test tube.
2. Inoculate with a straight wire, making a single stab down the center of the tube to about half the depth of the medium.
3. Incubate under the conditions favoring motility.
4. Incubate at 37°C
5. Examine at intervals, e.g. after 6 h, and 1 and 2 days (depends on generation time of bacteria) . Freshly prepared medium containing 1% glucose can be used for motility tests on anaerobes.

Results: Hold the tube up to the light and look at the stab line to determine motility.

Non-motile bacteria generally give growths that are confined to the stab-line, have sharply defined margins and leave the surrounding medium clearly transparent.

Motile Bacteria typically give diffuse, hazy growths that spread throughout the medium rendering it slightly opaque.