Chloramphenicol and Fungi - (Dec/08/2004 )

Hi y'all,
We've had a problem with contamination of fungal plates in my lab and have since started adding chloramphenicol to the growth media: 0.1 g CP/ 1 L media. The chloramphenicol seems to have little affect on the growth rate of C. herbarum: within 48 hours there's a nice overgrowth. However, A. niger is EXTREMELY slow to sporulate. After 48 hours there is a slight ring of sporulation around the outer edge. After about 5-7 days, the rest of the plate begins to sporulate. However, the lawn never looks quite as healthy as when I grew it up on media without ABs. Anyone have any suggestions for how to improve A. niger sporulation yet reduce chance of bacterial contamination, ie medias, alternative ABs, etc. ?

Thanks in advance

Suggest aseptic technique is your answer - antibiotics as protection v. lab contamination are crutch for the careless. Wonder what microbes you're using the chloramphenicol to control. Concentrations (greater than used here) do inhibit fungi by inhibiting mitochondrial function and CAP has been used to treat fungal disease in frogs.

I agree with George,

aseptic technique would do it. A.niger is growing rapidly and usually outcompeting a lot of other microbes on agar plates (by growing fast and e.g. by producing a lot of citric acid which inhibits some bacteria).

And as far as I am aware it is usually 4 day to a week until you can harvest a good number of spores form single spore isolates of A. niger....but maybe your isolate is sporulating very well?

Cladosporium species are very well protected against different antibiotics.....esp. the ones from the herbarum- and spaerospermum group can be isolated easy from all kinds of substrates and air given that the medium has a high osmotic potential (like DG18-plates with glycerin in it).....and they wont care much about antibiotics.

But I think recently there was a issue of "Studies in Mycology" dedicated to Cladosporium and one for Aspergillus, you can find them free on the CBS-web-page. I would be not suprised if the Dutch collegues have made some tests with antibiotics....so maybe you can find some information there

gebirgsziege

came across a paper reporting Cladosporium contamination (presume growth) in 45-50% glycerol.

So high concentrations are new to me will have a look....but we use a medium containing 18% Glycerol to isolate Cladosproium sp.

But I think fungi cannot suprise me anymore, even if they can read or write
we had a Penicillium growing in our Acridine Orange stock solution....looking a little bit weired but still alive and it recovered quickly on agar plates......

Appl micro 21:363 '71 and Mycologia 80:732 '98

for a chapter I've written on app of Aw for product quality