Dear bacteria and cell culture specialists,
Recently we encountered this bacteria during cell culture, please see the attached images.
These bacteria doesn't change the PH of the culture media (color of the media remains the same no matter how much the bacteria grow),
the growth of these bacteria can be almost 70% suppressed by P/S/G but these combination of antibiotics can't kill these bacteria.
Can anyone identify what are these bacteria, and what could be the possible reasons to see it, and how to get rid of it ?
Thank you in advance.
Dear Doaa,
Looks like some Bacillus. Have you done 16s rRNA analysis. Anyway, the easiest way to get rid of this contamination is to do serial dillutions of the mixed culture up unt. -8, until you get single colonies of your strain and then to inoculate it into liquid as a new "pure" clone.
Hi,
I assume you intend to culture eukaryotic cells and the bacteria got there due to an accidental contamination? Generally, the best approach to deal with contaminations is to thoroughly clean your working environment (especially laminar flow hood, water baths and incubators), discard all already opened media and supplements, ensure that your cyrostocks are contamination-free (incubate in antibiotic-free medium for several days) and start fresh. If your stocks are already contaminated, get fresh cell stocks, e.g. from a cell bank such as ATCC.
However, if you are working with irreplacable lines, you may try decontamination, if standard antibiotics (P/S) don't work, there are several alternatives with other mechanisms of action, maybe take a look at this information sheet from Sigma: https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma-Aldrich/Brochure/1/biofiles_v7_n1.pdf
Best regards
Hi,
Standard procedure in my lab would be to dispose of the culture by autoclave, especially if it is resistant to anti microbial agents. Clean the flow bench with 70% ethanol, biocidal and run a UV cycle. Also clean the incubators and check other cell cultures in the same incubator, so basically what Patrick suggested. If you absolutely need to keep the cells, you could isolate the bacteria and ask your microbiology department to identify it so you could target treatment more effectively. I’m not sure what you’re planning to do with the cells downstream but you need to assess the reliability of the results particularly if you need to use a lot of antibiotics, cell stress from constant media changes and exposure to different compounds for example could alter expression profiles. I hope this helps.
Hayley.
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