Contamination. Help needed!

[Cindy GRANDJENETTE]

Dear all, 

We have problems of contamination in several of our cell lines. Cell viability is pretty good, however, cell morphology is affected whatever the cell line. In addition and importantly, we observe a lot of small particles in the medium. Their number increase over time.

Mycoplasma tests were negative. We also sent our samples to 2 microbiological labs. Nevertheless, they were not able to identify the source of our contamination. We are wondering whether these contaminations are due to (myco)bacteria, viruses, or even yeast.

You may find attached movies showing how these particles "appear". The morphology of this cell line is normally homogeneous with round cells.

https://www.dropbox.com/s/n1p711dwfxnzxgy/150724%20tf1%202h30%20mes%205%20min%202%28converti%29.mov?dl=0

https://www.dropbox.com/s/ggbt1u8i3piau0q/150724%20tf1%202h30%20mes%205%20min.avi?dl=0

https://www.dropbox.com/s/sp2ncal7szl2kkr/150726%20tf1%202%20min%20mes%20100ms.mov?dl=0

https://www.dropbox.com/s/c0okt4k3twgzg4z/150726%20tf1%204h%205%20min.avi?dl=0

https://www.dropbox.com/s/6ngjhzcy9fejzjn/TF-1%20big%20cell.avi?dl=0

Does somebody have an idea concerning this contamination ? 

Thanks for your help,

Cindy