Motility Test medium Semi-solid Motility Test medium may also be used to detect motility. When a nonmotile organism is stabbed into Motility Test medium, growth occurs only along the line of inoculation . Growth along the stab line is very sharp and defined . When motile organisms are stabbed into the soft agar, they swim away from the stab line. Growth along the stab line appears much more cloud-like as it moves away from the stab .
Bacterial metabolism reduces the TTC producing formazan which is red in color.
The more bacteria present at any location, the darker red the growth appears. Flagella staining If we assume that bacterial flagella confer motility, flagella staining can then be used indirectly to denote bacterial motility. This is a delicate staining procedure and will not be attempted here. We will, however look at several demonstration flagella stains. Observe the dark-field microscopy demonstration of motile Pseudomonas aeruginosa .