Hello everyone, I am currently troubleshooting a bacterial contamination in my mammalian cell culture. Based on MaldiTOF analysis the contaminant seems to be Sphingomonas paucimobilis. However, according to google pictures it might be Achromobacter species as well.
We recently received HEK293T cells directly from ATCC. Initially, the cells grew very well. We froze aliquots following the ATCC recommended protocol. However, after thawing the cells, we noticed an issue: the cells grow normally for about 5–7 days, sometimes 3-5 days, but afterward, signs of bacterial contamination appear. The culture medium becomes blurry, and the cells start detaching from the surface. We thawed 3 cryovials in the past 3 weeks. We suspect the contaminant might be either Sphingomonas paucimobilis or Achromobacter.
DMEM F-12; Anti-anti (PS) antibiotic; FBS Gibco and L-glutamine. Has anyone experienced similar delayed contamination after thawing ATCC cells? Could you suggest how to distinguish between these two bacterial genera, or share your thoughts on possible sources and solutions? First time facing this type of contamination. Thank you in advance for your help!
I think those images do not allow to identify what bacteria are contaminating the cell line. I don't see any bacteria in those photos. Have you tried to cultivate them in bacteriological media like BHI agar?
Hey Jakub! I have attached zoomed pictures below. I hope they help. By the way, I forgot to mention that they were moving in the media, so it is not cell debris, etc.
Hi Saya,
We are currently facing a similar problem with mouse germline stem cell culture. The pattern of contamination looks very much like what you described—it usually appears between day 4–5, often after passaging the cells. We are using PS/PSA, but so far we have not been able to resolve the issue. Initially, small black dots appear, and later the medium changes color.
Please have a look at the images attached below.
Have you found any solution to this? If yes, could you please share it with me?
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