Motility Test: Click Here to View a Video
The motility test is used to determine the presence of flagella (external
appendages used for movement). Bacteria that are motile have flagella,
where as non-motile bacteria do not.
Tips for Success:
Be sure that the microscope is located on a solid surface free from
vibration. It is helpful to reduce the illumination, and increase contrast to
help view the bacteria, as they are not stained in this procedure. Motility by
direct microscopic observation can be difficult for the amateur
microbiologist. Always run positive and negative controls from known
cultures. Do not mistake Brownian motion, or fluid movement under the
cover slip for motility. Motility agar may be used as an alternative to this
procedure.
Procedure:
The motility test is used to determine the presence of flagella (external
appendages used for movement). Bacteria that are motile have flagella,
where as non-motile bacteria do not.
Tips for Success:
Be sure that the microscope is located on a solid surface free from
vibration. It is helpful to reduce the illumination, and increase contrast to
help view the bacteria, as they are not stained in this procedure. Motility by
direct microscopic observation can be difficult for the amateur
microbiologist. Always run positive and negative controls from known
cultures. Do not mistake Brownian motion, or fluid movement under the
cover slip for motility. Motility agar may be used as an alternative to this
procedure.
Procedure:
- Inoculate an isolated colony into tryptic soy broth or brain heart
infusion broth. - Incubate the culture for 24 hours
- Place a drop of the broth onto a clean microscope slide, and cover
with a cover slip. - Observe microscopically for the presence of motility.
- A positive test result is indicated by individual bacterial cells moving
in random directions.
| Motility Procedure For The Identification of Bacteria |
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