Hello, I’m currently suffering a problem with my cells. The cells in question were recently transduced with lentivirus to obtain cells stably expressing a construct. After several weeks of selection with antibiotics, I was ready to start with experiments but from one day to the next the media became cloudy and clusters of cells were dying. The cells that still were adherent looked healthy and were able to proliferate. We initially suspected a bacterial contamination, but the cultivating medium was unaffected. There we’re also no signs of yeast or fungal infection. Next, I’ve performed a test for mycoplasma which was positive, but normally mycoplasmas don’t cause turbid media so I’m doubting whether this is the only explanation for my problems. Is there anyone else that come up with an explanation? Many thanks in advance!
Dear Anneleen,
Regardless of the identity of the contaminant, my advise is to throw away EVERYTHING, clean up and decontaminate twice (and this goes also for your laboratory coat and the incubators, microscopes and all surfaces in the lab) and start all over again this time controlling every step. I attach a very useful booklet pulished by Conrning.
Feeling very sorry for you,
Agnieszka
If you use an electronic pipettor you should also check the filter. This item is missed many times in the hunt for possible cell culture contaminants. Have discovered that even with the use of serological (filtered) pipettes the contaminant can sometimes get into cultures.
Hi Anneleen.
In our laboratory we have got a problem with bacterial contamination, which presumedly was caused minimal contamination of laboratory plastic.
We always used medium without antibiotics, therefore contamination was found almost immediately after beginning using. But for a long time we found contaminated reagents, freesed cells etc.
For identification nidus we did some actions, which are the imitation of the usual operation with plastic, and included contact with media, and after that media was incubated for 2-5 days. Thus was identifed the most probable nidus. We tested 3-4 samples of each plastic units in each lot.
Only orderly execution of this tests may help you to find the nidus. If you have contamination in 2 and all the more in 3 lots, you will come to a conclusion, that the nidus is in the instruments, air, furniture etc.
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