actinomycetes & filamentous fungi

Colin Davidson c.davidson at
Wed Feb 23 12:11:39 EST 2000

Sarah Davies <noone at> wrote in message
news:88v389$e29$1 at
> Hi,  I am trying to do my microbiology homework & one question is still
> puzzling me:
> How can you differentiate between sctinomycetes & filamentous fungi?
> I have searched the web & read all the recommended texts, but they seem
> similar & I haven't found anything that differentiates them.
> If anyone could help with me with this problem I would be very grateful.

One give away is the smell.   If you have a Petri dish with  Streptomyces
culture then you get a distinctive "wet earth" smell.

If you take a scraping and look under a microscope, the cell sizes are
vastly different  (the filaments of streptomyces are only a few micometers
across, whereas fungal filaments are much, much bigger).

Once you've handled actinomycetes and fungi for a short while, the
differences become apparent.   It isn't hard to distinguish the two by eye.

Colin A. B. Davidson,
Institute of Biotechnology,
University of Cambridge.

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