In 1936, Tittsler and Sandholzer reported using a semisolid agar for the detection of bacterial motility.1 Tubed Motility Medium Test Agar is a modification of this formulation. Bacterial motility is observed macroscopically by a diffuse zone of growth spreading from the line of inoculation. Certain species of motile bacteria will show diffuse growth throughout the entire medium, while others may show diffusion from one or two points appearing as nodular outgrowths along the stab. Tittsler and Sandholzer reported tubes incubated for one day gave identical results with the hanging drop method, and incubation for two days permitted demonstration of motility in an additional 4% of cultures tested.1 Motility Test Agar is recommended for the detection of microbial motility in food and dairy standard methods.2-4 The nitrogen, carbon, and vitamin sources are provided by enzymatic digest of gelatin and beef extract in Motility Test Agar. Sodium chloride maintains the osmotic environment. Agar is the solidifying agent used at a low concentration.
1. Tittsler, R. P, and L. A. Sandholzer. 1936. The use of semi-solid agar for the detection of bacterial motility. J. Bacteriol. 31:575-cc c580.9;;;;;;;;
2. Harmon, S. M., D. A. Kautter, D. A. Golden, and E. J. Rhodehamel. 1995. Bacteriological analytical manual, 8th ed. AOAC International, Arlington, VA.
3. Marshall, R. T. (ed.). 1992. Standard methods for the examination of dairy products, 16th ed. American Public Health Association, Washington, D.C.
4. Vanderzant, C., and D. F. Splittstoesser (eds.). 1992. Compendium of methods for the microbiological examination of foods, 3rd ed. American Public Health Association, Washington, D.C.
5. MacFaddin, J. D. 1985. Media for isolation-cultivation-identification-maintenance of medical bacteria, vol. 1, p. 110-114. Williams & Wilkins, Baltimore, MD.