Motility Test Medium (Edwards and Ewing)

Motility Test Medium (Edwards and Ewing) is recommended for testing motility of enteric bacteria. This medium is the modification of the original formulation as per Edwards and Ewing and is used for testing motility of Enterobacteriaceae. Motility can be visualized as a diffused zone of growth flaring out from the line of inoculation. Bacterial motility can be observed directly by examination of the tubes following incubation. Inoculation is done by stabbing through the centre of the medium. Incubate at appropriate temperature for 18 to 40 hours. Non-motile organisms grow only along the line of inoculation whereas motile organisms grow away from the line of inoculation or may show growth even throughout the medium. All weak or equivocal motility results should be confirmed by flagellum stain or by direct wet microscopy (hanging drop).