What is the best method for determining motility in a bacterial cell?

Question

I know there are lots of ways, but what is best?

Answer 1

You're right.  There are several way, but I would say that the best is a hanging drop slide.  It is a slide with a dip in the middle, into which you put a drop of the liquid with the bacterial sample in.  You use a sm. amt. of vaseline to attach the slide cover and view under oil immersion.  (These have to be live bacteria, by the way).  Then, simply, you watch and see if they move.  Be careful to check for real movement rather than vibration or movement of the fluid.  

Using motility mediums in tubes, etc., is less reliable, as a non-motile bacteria and an anaerobic motile one can appear similar.  

Answer 2

You could try my method: Once you know which bacteria it is, look up whether it is motile or not.  lol.  It works for me.  Only a problem when they ask you what test you used to determine it.   Then you say, "hanging drop"!  or, "motility media"!

Answer 3

The most common is probably to use motility media.

Bacteria can swim through this less dense agar, so you just inoculate a single spot and measure the distance they move.

They are problems with it, but it is very simple and easy.