Selective Agar for Pathogenic Fungi

Selective Agar for Pathogenic Fungi

EMD Cat. No. 1.05467.0500

500 g

For the isolation of pathogenic fungi, particularly dermato- phytes, from heavily contaminated sample material.

Additives

EMD Cat. No.	Product	Pack Size
EMD Biosciences	Gentamicin solution	10 ml

Mode of Action	Preparation
Experimental Procedure and Evaluation	Quality Control
Typical Composition (g/liter)	Literature
Picture/Image

Mode of Action
Cycloheximide is used to select for dermatophytes (GEORG 1953; GEORG et al. 1954). Choramphenicol largely suppresses bacteria. Certain pathogenic fungi may also sometimes be inhibited, therefore a culture medium devoid of inhibitors should be inoculated as well. TAPLIN (1965) recommends addition of 40 mg gentamicin sulfate/liter (e.g. 0.5 ml gentamicin solution/liter), to suppress chloramphenicol-resistant bacteria, which are occasionally present.

Preparation
Suspend 33 g/liter completely, pour plates.
pH: 6.9 ± 0.2 at 25 °C.
The plates are clear and yellowish-brown.
Do not autoclave, do not overheat. Avoid reliquefication.

Experimental Procedure and Evaluation
Obtain the sample material by an appropriate method and inoculate on the surface of the culture medium.

Incubation: up to 3 weeks at approximately 28 °C (room temperature); if endomycoses are suspected to be present,
at 35 °C as well.

Any fungal colonies which develop can be identified as such (MCDONOUGH et al. 1960) or can be inoculated on media which do not contain inhibitors (e.g. SABOURAUD media) for further differentiation.

Quality control

Test strains	Growth
Trichophyton mentagrophytes	good / very good
Trichophyton rubrum	fair / good
Microsporum gallinae ATCC 12108	fair / good
Trichophyton ajelloi	fair / good
Microsporum canis	good / very good
Geotrichum candidum DSM 1240	good / very good
Candida albicans ATCC 10231	good / very good
Aspergillus niger	none / poor
Penicillium spp.	none / poor
Bacillus cereus ATCC 11778	none

Typical Composition (g/liter)
Peptone from soymeal 10.0; D(+)glucose 10.0; cycloheximide 0.4; chloramphenicol 0.05; agar-agar 12.5.

Literature

AHEARN, D.G.: Systematics of Yeasts of Medical Interest (Pan American Health Organization: International Symposium on Mycoses). - 205; 54-70 (1970).
GEORG, L.K.: Use of cycloheximide medium for isolation of dermatophytes from clinical materials. - Arch. Dermat. Syphil., 67; 355-361 (1953).
GEORG, L.K., AJELLO, D. a. PAPAGEORGE, C.: Use of cycloheximide in the selective isolation of fungi pathogenic to man. - J. Lab. Clin. Med., 44; 422-428 (1954).
HALEY, L.D.: Laboratory Methods in Systematic Mycoses (C.D.C. Course 8170-C, Atlanta, 1969).
MCDONOUGH, E.S., GEORG, L.K., AJELLO, L., a. BRINKMAN, S.: Growth of dimorphic human pathogenic fungi on media containing cycloheximide and chloramphenicol. - Mycopath. Mycol. Appl., 13; 113-120 (1960).
TAPLIN, D.: The use of gentamicin in mycology. - J. Invest. Dermat., 45; 549-550 (1965).

Microsporum spp.