methylotrophic bacteria culture contamination - (Aug/13/2009 )

I growed many many times of a pure bacteria called methyloversatilis universalis (dry cells purchased from ATCC). But every time it was contaminated just one or two times inoculations. I can see weild cells moving very fast under microscope, with the similar size and shape of my bacteria.

Does anyone have an idea how to prevent it from contamination? methyloversatilis universalis is a heterotrophic denitrifying bacteria

The only way to prevent contamination is to use good technique. Find a book on culturing techniques and follow their advice.