Hello Louise Piilgaard Petersen ,

Based on your description and the figures, the amphotericin B did not cause either growth inhibition of apoptosis of the component in your culture medium, and the component seems in the different layer other then cells, which I observed that was out of focus in the microscopic image, I suggest this contamination suspects is an artificial object such as polypropylene fiber from the tips of pipette. Therefore, there should be no contamination in your cell sample.

Best

Hi Mu-Shen

It’s floating at the very top of our cell cultures as funghi would do with their hyphae and mycelia, which we would like to identify as the strain may be resistent to amp B. So as much as I would like it to be polypropylene fibers I unfortunately don’t think so, but I could be wrong.

Hello Louise Piilgaard Petersen,

From what I can see, it looks like the contamination might be fungal. You could try testing with Amphotericin B, Nystatin, or Thiabendazole. If things don’t improve, it might be best to take a fresh culture so you're not wasting time, effort, or resources. Hope this helps!