Something is happening in my lab. Cells were not split for a long time and then saw all flask are turbid and then some black tiny structures are overcrowded in all the flask. Next day, changed media and replated in new flask. After two days, not too crowded black structures. But, saw long filaments and have refractlie surfaces. Some looks like comma shaped. Cells even not too healthy. After growing on agar plate, nothing came up. I suspect this is contamination. But after putting in new flask, they should grow rapidly, but these are not growing rapidly. Although, in between cells, those filamentous structure are very well visible.
To me this is some sort of contamination. What do you think? Is it worth growing these cells or should I just throw them out?
Thanks.
Dear Monika,
If you see filamentous structures, turbid media and no growth on agar plate then this might be the contamination from Fungi. Fungal contaminants may or may not cause a change in the pH of the medium and can be distinguished from bacteria by checking for the presence of filamentous structures (by naked eye) in the suspension. Generally fungal contamination can be identified and confirmed by doing the following simple steps:
1. Cloudy/dark media solution
2. “Garbage” smell
3. Dead/poorly spread cell cultures
4. fuzz or thread morphology of contaminant under microscope
5. Inoculate and incubate Sabouraud broth/agar or YM broth/agar which supports fungal growth at 20-25°C and observe for 3 weeks
6. staining for fungus with lactophenol cotton blue and observe under microscope
7. Inoculate blood agar/ thioglycollate broth/ BHI broth to rule out the possibility of bacterial contamination since some fastidious bacteria may not grow on simple ordinary nutrient agar.
Once the contamination has been identified and confirmed then you can find out the root cause for sources of contamination.
Hi Monika
I think this is fungal contamination. It would be better to start with fresh culture. Check your media for contamination...
good luck!!!
Sounds like fungi indeed. The problem is, they may form airborne spores even before becoming visible to the naked eye, and easily contaminate other cultures in the same incubator, especially if the cells were in dishes rather than flasks. Dispose of the affected cultures and decontaminate the incubator thoroughly!
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