On Thu, 04 Jun 1998 23:46:35 -0700, Phil <jorge2 at earthlink.net> wrote:
>sandra wrote:
>>>> I am looking for the formule of a selective media for cryptococcus
>> neoformans of saprophytic origin, it is called Niger seed agar or Guizotia
>> abyssinica medium. I will also welcome any other alternative and selective
>> media for this organism. many thanks.
>>>> Sandra
>>Sandra:
>>Are you sure the seed extract agar is selective? I think it may be
>differential. You might just go with Mycosel or antibiotic BHI or PDA.
The Guizotia Abyssinica in the medium adds to the selectivity of the
medium by allowing C. Neoformans to form a brown pigment (melanin) by
which you can distinguish their colonies from others by their
chocolate-like colour.
You might want to read:
http://vega.crbm.cnrs-mop.fr/bioscience/1997/v2/e/william/e99-107.htm
Currently I am doing some research into C. Neoformans here at the
Medical Microbiology Dept. of the AMC-Hospital (Academical Medical
Centre) in Amsterdam.
Here we use the following recipe:
Grind G.A. seed in blender
Cook for 30 min. (50 gr./liter)
Filter through gauze
Filter through tea towel
Add water to original volume.
Sterilize for 15 min. at 121 Celsius
Add:
Creatinine 1 gr./l. (Sigma Chemical Co. - St. Louis)
Glucose 1 gr./l.
KH2PO4 1 gr./l. (potassium-di-hydrogen-phosphate)
Methylviolet 2 mg./l. (Brocades - Amsterdam) to inhibit yeast growth
Bacto Agar 15 gr./l. (Difco Laboratories - Detroit)
Sterilize 15 min. at 115 Celsius
Add:
20 E/ml. penicilline
0,1 mg./ml. gentamycine
0,01-0,1% biphenyl to inhibit mould growth. the lower concentration
gives more mould growth but the higher also gives some growth
inhibition of C. Neoformans.
Success!
I also have a question.
Here we used a chemoluminescent DNA-probe (Accu-Probe from Gen-Probe)
to identify C. Neoformans but unfortunately they have taken this out
of production.
Does anyone know of a similar probe-kit and where we could obtain
this?
If you do, lots of thanks.
Ben Muller
