Mycological Aspects of Action of Griseofulvin Against Dermatophytes

Aytoun, R. S. C.

doi:10.1001/archderm.1960.03730050006002

Cited by 42 publications

(6 citation statements)

References 4 publications

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“…This value can be encumbered, as we found, with too serious errors due to a series of antibiotic dilutions, by the magnitude of the inoculum, by cultivation time as well as by other factors. In our expeniments only the difference in the number of spores in the suspension used for inoculation caused a diffepence from 5 to 8 pg GF/ml in the determination of m. i. c. The influence of the magnitude of the inoculum and of cultivation temperature in the determination of m. i. c. of GF has also been reported by AYTOUN et al (1960), the influence of pH of the medium has been demonstrated by IWATA (1960). In biological assays the application of the ED 50 mean efficient dose as a measure of efficiency or of sensitivity (ROTH et al 1962) is theoretically and practically justified.…”

Section: L?i S C U S S I O Nsupporting

confidence: 67%

Determination of Griseofulvin Sensitivity by Mycelial Growth Test

Lenhart

1968

Mycoses

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Section: L?i S C U S S I O Nsupporting

confidence: 67%

Determination of Griseofulvin Sensitivity by Mycelial Growth Test

Lenhart

1968

Mycoses

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“…Aytoun et al. 17 isolated six strains of M. canis resistant to griseofulvin with MIC values of 8, 32 and 64 μ g ml −1 and one strain of T. rubrum with MIC of 8 μ g ml −1 by layer plate method. They believe that these strains possess, in their ability to destroy griseofulvin, a potential mechanism for attaining resistance and also other dermatophyte species may have this ability to become resistant.…”

Section: Discussionmentioning

confidence: 99%

In vitro evaluation of griseofulvin against clinical isolates of dermatophytes from Isfahan

Chadeganipour

Nilipour

Havaei

2004

Mycoses

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Fifty dermatophyte isolates, recently obtained from clinical materials, belonging to Trichophyton mentagrophytes, T. verrucosum, Microsporum canis and Epidermophyton floccosum were examined for their susceptibility to griseofulvin. The minimum inhibitory concentration (MIC) values were obtained using the modified microdilution method. All 100% tested isolates had MIC geometric mean at a concentration between 0.43 and 0.95 microg ml(-1) The MIC(90)s and MIC(50)s were 8 microg ml(-1) and <0.25-1 microg ml(-1) respectively. From all isolates, 12% including three T. verrucosum, one M. canis and two T. mentagrophytes isolates had MIC values out of the standardized range, therefore, they were considered as relatively griseofulvin-resistant. At least some of the isolates tested might be difficult to eradicate in clinical terms with griseofulvin treatment in Isfahan.

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“…Griseofulvin is most active against stationary phase dermatophytes even though protein synthesis is required for its uptake [7]. This is probably due to destruction of the compound in actively growing cells [1]. Whether a similar mechanism is responsible for the phenotypic resistance of growing C. parapsilosis to ambruticin is not known.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of growth and uptake of amino acids in the yeast,Candida parapsilosis, by ambruticin

Simpkin

1985

Med Mycol

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The antifungal antibiotic, ambruticin, inhibits growth of Candida parapsilosis and reduces its ability to take up amino acids. Increasing growth temperature from 30°C to 390C leads to a 100-fold decrease in the minimum growth inhibitory concentration. Ambruticin is 20 times more effective at pH 5 than at pH 8 and exponentially growing cultures are much less susceptible than stationary phase cells. The activity of ambruticin is also dependent on the presence of certain exogenous nutrients. When acetate or succinate (10 mM) are included in the incubation medium, ambruticin has little effect on amino acid uptake. Glucose, mannose and glycerol do not decrease the efficacy of ambruticin. Ambruticin probably inhibits growth by reducing the utilization of exogenous and intracellular carbohydrates. This leads to a fall in energy production within the cell which can be monitored as a reduction in the activity of energy-dependent transport systems.Ambruticin is an antibiotic of novel structure produced by the myxobacterium, Polyangium cellulosum var.fulvum [14]. It is a cyclopropyl-polyene-pyran-acid and its absolute configuration has been determined by X-ray crystallography and partial chiral synthesis [2,9]. Ambruticin possesses very little antibacterial activity but is active in vitro and in vivo against dermatophytes [13,15]. It inhibits the growth of Histoplasma capsulatum, Blastomyces dermatitidis, Coccidioides immitis and Candida parapsilosis but has little effect on Paracoccidioides brasiliensis, Cryptococcus neoforroans or C. albicans [11,13].Ambruticin is fungicidal to Microsporum fulvum at 370C but not 4°C and is more active against spores than pregrown hyphae. It does not cause leakage of intracellular material but decreases the incorporation of exogenous uridine and leucine into macromolecules [13]. This paper reports the results of an investigation into the effects of ambruticin on growth and amino acid uptake in C. parapsilosis. This organism was chosen in preference to filamentous dermatophytes because of its ability to grow rapidly and homogeneously in defined liquid media.Correspondence address: 100 Rampton Road, Willingham, Cambridge CB4 5JQ, U.K. 425Med Mycol Downloaded from informahealthcare.com by University of Alberta on 11/26/14For personal use only.

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Mycological Aspects of Action of Griseofulvin Against Dermatophytes

Cited by 42 publications

References 4 publications

Determination of Griseofulvin Sensitivity by Mycelial Growth Test

Determination of Griseofulvin Sensitivity by Mycelial Growth Test

In vitro evaluation of griseofulvin against clinical isolates of dermatophytes from Isfahan

Inhibition of growth and uptake of amino acids in the yeast,Candida parapsilosis, by ambruticin

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