Growth Of Dermatophytes Research Articles

Effect of Inulaviscosa extract on chitin synthesis in dermatophytes and Candidaalbicans

An antimycotic effect of an extract from Inula viscosa leaves was demonstrated affecting chitin synthesis in dermatophytes and Candida albicans. The antimycotic effect was compared to the effect caused by miconazole nitrate — an antifungal drug. The inhibition effect on chitin synthesis was not correlated to the extent of growth inhibition caused by the antifungal agents: both miconazole nitrate and the I. viscosa extract inhibited the growth of dermatophytes and C. albicans. Miconazole nitrate did not affect chitin synthesis — except for M. canis — whereas I. viscosa extract caused a significant decline in chitin content.

Azole Antifungal Agents Related to Naftifine and Butenafine

The methyl group of naftifine (1) and butenafine (2) was replaced by an azolic nucleus to obtain the new compounds 3—8 which exhibit the characteristics of both allylamine (or benzylamine) and azole antifungals. The title compounds were evaluated in vitro against several pathogenic fungi responsible for human disease. Among these, compounds 5, 6, and 8 were found to inhibit the growth of dermatophytes with a potency comparable to that of naftifine. The synthetic sequence includes the preparation of aminoazole Schiff bases, reduction, and alkylation of the corresponding secondary amines.

Azole Antifungal Agents Related to Naftifine and Butenafine

The methyl group of naftifine (1) and butenafine (2) was replaced by an azolic nucleus to obtain the new compounds 3-8 which exhibit the characteristics of both allylamine (or benzylamine) and azole antifungals. The title compounds were evaluated in vitro against several pathogenic fungi responsible for human disease. Among these, compounds 5, 6, and 8 were found to inhibit the growth of dermatophytes with a potency comparable to that of naftifine. The synthetic sequence includes the preparation of aminoazole Schiff bases, reduction, and alkylation of the corresponding secondary amines.

REGRANEX — A topical growth factor for the treatment of chronic wounds

Background: The ratio of fungicidal to fungistatic activity of two new antifungal agents, itraconazole and terbinafine, against the causative organisms in onychomycosis may have clinical relevance. Objective: This study compared the fungistatic and fungicidal activity of terbinafine and itraconazole against clinical isolates of dermatophytes and Candida species causing onychomycosis. Methods: The antifungal agent was added to suspensions of dermatophyte conidia and hyphal fragments (5 × 103 to 5 × 104 fungal elements/ml) that had been preincubated to allow hyphal formation. Cell suspensions of Candida species (1 to 5 × 103 cells/ml) were not preincubated before drug exposure. Macrobroth and macrobroth dilution assays were used to test antifungal susceptibility of dermatophytes and yeasts, respectively. An agent was considered fungicidal if the minimal fungicidal concentration (MFC) to minimal inhibitory concentration (MIC) ratio was ≤ 4 and fungistatic if the ratio was > 4. Cell death was also visualized by a vital stain. Results: For both itraconazole and terbinafine, the MIC for dermatophytes was low. The MFCs and MFC/MIC ratios for terbinafine against dermatophytes were lower than for itraconazole; the fungicidal activity of terbinafine was excellent and initiated rapidly (by 7 hours) and that of itraconazole was poor (fungicidal activity was not evident until 10 to 12 hours). For yeasts, the MICs were higher than for dermatophytes, and the differences between itraconazole and terbinafine were less pronounced. Conclusion: Both itraconazole and terbinafine inhibit growth of dermatophytes. The more rapid fungicidal activity of terbinafine may have clinical relevance in the treatment of onychomycosis. (J Am Acad Dermatol 1998;38:S37-41.)

Fungicidal versus fungistatic activity of terbinafine and itraconazole: An in vitro comparison

Background: The ratio of fungicidal to fungistatic activity of two new antifungal agents, itraconazole and terbinafine, against the causative organisms in onychomycosis may have clinical relevance. Objective: This study compared the fungistatic and fungicidal activity of terbinafine and itraconazole against clinical isolates of dermatophytes and Candida species causing onychomycosis. Methods: The antifungal agent was added to suspensions of dermatophyte conidia and hyphal fragments (5 × 10 3 to 5 × 10 4 fungal elements/ml) that had been preincubated to allow hyphal formation. Cell suspensions of Candida species (1 to 5 × 10 3 cells/ml) were not preincubated before drug exposure. Macrobroth and macrobroth dilution assays were used to test antifungal susceptibility of dermatophytes and yeasts, respectively. An agent was considered fungicidal if the minimal fungicidal concentration (MFC) to minimal inhibitory concentration (MIC) ratio was ≤ 4 and fungistatic if the ratio was > 4. Cell death was also visualized by a vital stain. Results: For both itraconazole and terbinafine, the MIC for dermatophytes was low. The MFCs and MFC/MIC ratios for terbinafine against dermatophytes were lower than for itraconazole; the fungicidal activity of terbinafine was excellent and initiated rapidly (by 7 hours) and that of itraconazole was poor (fungicidal activity was not evident until 10 to 12 hours). For yeasts, the MICs were higher than for dermatophytes, and the differences between itraconazole and terbinafine were less pronounced. Conclusion: Both itraconazole and terbinafine inhibit growth of dermatophytes. The more rapid fungicidal activity of terbinafine may have clinical relevance in the treatment of onychomycosis. (J Am Acad Dermatol 1998;38:S37-41.)

Butenafine.

Butenafine is a new antifungal agent with primary fungicidal activity against dermatophytes such as Trichophyton mentagrophytes, Microsporum canis and Trichophyton rubrum which cause tinea infections. 14C-labelled butenafine (approximately 30 micrograms/g tissue) was found within guinea-pig dorsal skin 24 hours after topical application. Most of the drug was distributed into the epidermis including the horny layer. Small amounts were found in the dermis, probably transported via sebaceous glands and hair follicles. In vitro, the minimum concentration that completely inhibited growth of dermatophytes (MIC) and the minimum fungicidal concentrations (MFC) for butenafine against T. mentagrophytes and M. canis were similar (0.012 to 0.05 mg/L) and were 4 to 130 times lower than those for naftifine, tolnaftate, clotrimazole and bifonazole. It also has greater activity against T. rubrum, M. gypseum and Epidermophyton floccosum when compared with naftifine, tolnaftate and clotrimazole; comparisons with bifonazole against these strains were not available. Assessment after 1 week's treatment in patients with tinea pedis revealed that mycological cure rates were greater in those who received twice-daily butenafine for 1 week or once-daily butenafine for 4 weeks than in placebo recipients. Mycological and overall cure rates were either further increased or maintained up to 5 weeks after treatment cessation compared with end-of-treatment values. In patients with tinea cruris or tinea corporis who received once-daily butenafine 1% for 2 weeks, the mycological and overall cure rates continued to increase for up to 4 weeks after treatment cessation.

Dicarboxylic acids affect the growth of dermatophytes in vitro.

Azelaic acid is a dicarboxylic acid with known antimycotic activity. In this study we have used an agar dilution technique to test the effect of six other dicarboxylic acids (sebacic, undecanedioic, dodecanedioic, tridecanedioic, tetradecanedioic and hexadecanedioic acid, 10(-4)-10(-2) mol/l, pH 5.5) on in vitro growth of Trichophyton (T.) rubrum, T. mentagrophytes and Microsporum (M.) canis. Furthermore, the fungicidal activity of 10(-2) mol/l undecanedioic and sebacic acid was tested using a T. rubrum growth assay. Undecanedioic acid proved fungistatic at 10(-2) mol/l for all species and fungicidal for T. rubrum. A minor fungistatic effect on T. rubrum and T. mentagrophytes was also seen with the other acids at this concentration. M. canis was inhibited only by high concentrations of four acids, whereas low concentrations of all six agents resulted in enlarged thallus diameters. We conclude that among dicarboxylic acids fungistatic activity is not limited to azelaic acid. Undecanedioic acid appears promising for further investigations.

Azelaic acid has antimycotic properties in vitro.

Azelaic acid is a therapeutic agent with well-known antibacterial properties, but its antimycotic effect has not yet been investigated systematically. In this study we have used an agar dilution technique to test the inhibitory effect of azelaic acid upon common dermatophytes, Scopulariopsis brevicaulis, Candida albicans, Candida glabrata and Pityrosporum ovale. As a result, the growth of dermatophytes and S. brevicaulis was suppressed by 0.56% azelaic acid and that of P. ovale by 1%. By 4% azelaic acid C. glabrata was inhibited completely, but C. albicans still maintained some growth. The antimycotic effect of azelaic acid occurred at pH values between 4.8 and 5.5, whereas its disodium salt had no such effect at pH 6.1. Considering the favorable pharmacological data of azelaic acid, our results give reason to investigate the antimycotic effect of this agent in vivo.

The effect of selected human steroid hormones upon the growth of dermatophytes with different adaptation to man.

The inhibitory effect exerted by steroid hormones on the in vitro growth characteristics of dermatophytes is poorly understood. As a hypothesis this inhibition could result from fungal adaptation to the human host. Therefore, in this study the susceptibility of representative anthropophilic, zoophilic and geophilic dermatophytes to hormonal inhibition was compared. As a result, in agar dilution assays progesterone, testosterone, and estradiol proved to reduce fungal growth, whereas hydrocortisone had no such effect. In general, anthropophilic dermatophytes were shown to be more responsive to steroid hormones than geophilic species, suggesting a correlation of steroid susceptibility with adaptation to human skin. However, since fungal response to hormones consisted of growth inhibition and occurred only at steroid concentrations much higher than present in human skin, it cannot be assumed to contribute to this adaptation.

Inhibition of growth of dermatophytes by Indian hair oils.

A survey on the use of hair oils for hair dressings by the Indian population revealed that mustard oil is preferred by males and coconut oil by females. Amla oil is used equally by both. These oils contain different percentages of various saturated and unsaturated fatty acids which largely determine their toxicity against dermatophytes. For Microsporum canis, M. gypseum and Trichophyton rubrum, amla oil was most toxic, followed by cantharidine and coconut oil, while Trichophyton mentagrophytes was most susceptible to coconut oil followed by amla and cantharidine oil. Mustard oil showed least toxicity to all four test species. The rarity of tinea capitis in India has been concluded to be due to the common use of hair oils by the Indian population.

Biochemical and morphological effects of polyamine biosynthesis inhibitors onTrichophytonandMicrosporum

The minimum inhibitory concentrations (MICs) of three known irreversible inhibitors of polyamine synthesis, alpha-difluoromethylornithine (DFMO) and monofluoromethyldehydroornithine methylester (MFMOme), inhibitors of ornithine decarboxylase (ODC) and alpha-difluoromethylarginine (DFMA), an inhibitor of arginine decarboxylase (ADC), were determined for 10 species of dermatophytic fungi. Trichophyton species were generally more sensitive to these inhibitors than Microsporum species. Both genera produced arginase, and treatment of members of either genus with DFMO or DFMA resulted in an inhibition of ODC activity and a depletion of cellular polyamines. However, conversion of labelled DFMA to DFMO, either in vivo or in vitro, could not be demonstrated in spite of both genera producing arginase. The ultrastructure of cells cultured in the presence of either DFMO or DFMA was similar, and revealed disruption of calcium metabolism, an increase in mitochondrial number and alterations to membrane systems. DFMA and DFMO also inhibited sporulation in Microsporum gypseum. Our findings indicate that DFMO limits the growth of dermatophytes by direct inhibition of ODC and lowering of cellular polyamine levels; in contrast, DFMA inhibits polyamine synthesis in an unspecified manner as ADC activity was undetected.

Athlete's foot caused by pseudomonas aeruginosa

An enzymatically active pigment-producing clinical isolate of Pseudomonas aeruginosa was found to produce a diffusible antifungal product that was shown to be inhibitory to the growth of several dermatophytes, specifically, Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum gypseum, and Microsporum audouini. In this study, Trichophyton rubrum was used as the test organism. The antifungal product was partially purified by Sephadex column chromatography and was found to be stable at 5°, 25°, and 37° C. Several investigators have alluded to the fact that as asymptomatic cases of dermatophytosis simplex progress to symptomatic dermatophytosis complex, the bacterial profile changes from a gram-positive bacterial ecosystem to a gram-negative bacterial overgrowth. The primary event in the pathogenesis of interdigital athlete's foot is the invasion of the horny layer by dermatophytes. This presents as a mild to moderate scaly lesion and is asymptomatic. As a result of predisposing factors, such as hyperhidrosis, occlusion by tight shoes, minute abrasions due to friction, and fungal-infected skin surfaces, dynamic overgrowth of opportunistic gram-negative bacilli prevails. As the gram-negative population increases, the recovery of dermatophytes dramatically diminishes, until a point is reached when no dermatophytes can be recovered from clinically symptomatic tinea pedis. Pseudomonas aeruginosa is inhibiting its fungal competitor Trichophyton rubrum by producing a diffusible antifungal agent into the infectious environment of the intertriginous foot lesion. Clinically, the patient is diagnosed as having tinea pedis; laboratory culture for fungus and KOH are negative, and what was a paradox just a few years ago can currently be identified and treated appropriately as gram-negative athlete's foot.

Restoration ofTrichophyton mentagrophytesgrowth in medium depleted of metals by chelation: Importance of iron

The present study examined the requirement of Trichophyton mentagrophytes ATCC-18748 for iron. Nutrient broth depleted of iron by the chelating cation exchange resin Chelex-100 did not support the growth of T. mentagrophytes beyond germ tube formation. The soluble chelate of iron, ferric ammonium citrate, restored the capacity of the chelated medium to support fungal growth in proportion to the amount of iron added. Ferric chloride, which rapidly becomes insoluble at neutral pH, was not effective in the medium. The soluble salts of cobalt, chromium, copper, manganese, nickel, and zinc individually did not replace the requirement for iron. A method for defining the iron requirement based upon utilization of iron from ferric ammonium citrate is described. These data indicate that the growth of T. mentagrophytes ATCC-18748 is iron-dependent, which is consistent with the hypothesis that serum transferrin inhibits dermatophyte growth by the mechanism of iron deprivation.

Improved methods for office fungal culture.

A new screening culture method which can be used as an office fungal culture involves a microculture, where a selective medium (DTM) is used for coating a thin transparent plastic slide. Sampling is performed with a transparent adhesive tape which is pressed on to the surface of the agar and allows daily microscopic examination of the culture. Identification of the fungus is based on its micromorphologic features and possible color change of the substrate. Growth of dermatophytes and candida usually can be detected and registered within 48 hours. The screening method is simple to handle and read and may be monitored by inexperienced personnel with virtually no microbiologic knowledge.

Dermatophyte infection of the penis. Association with a particular undergarment.

Penile involvement was seen in 19.5% of 261 patients, aged 11 to 30 years, with tinea cruris. It was more common in patients under the age of 20 years (p less than 0.05). The increased incidence is probably related to the use of langota, a semiocclusive undergarment that may favor the growth of dermatophytes.

The effect of aqueous garlic extract on the growth of dermatophytes.

ABSTRACT: The effect of aqueous garlic extract on the growth of different medically important dermatophytes was studied. The extract proved to have an inhibitory effect on the growth of Microsporum gypseum, Trichophyton verrucosum, Trichophyton violaceum, Trichophyton rubrum, Trichophyton schoenleini, Trichophyton mentagrophytes and Epidermophyton floccosum. The inhibitory concentration ranged from 130‐200 mg/1. Experimental infection was induced in guinea pigs and rabbits. Treatment of the produced lesions included topical application or injection of the extract. The topical treatment was very effective, producing complete healing in 14 to 17 days following twice daily application of the extract for one week.

Interactions of Trichophyton mentagrophytes and Micrococci on Skin Culture

Scanning electron microscopy was used to search for local or limited synthesis of antibiotics by a strain of Trichophyton mentagrophytes. Micrococcus luteus, which was susceptible to penicillin and to the dermatophyte when both were cultured on agar media, displayed morphological alterations of flattened walls, invagination, enlargement, and collapse in skin cultures with the fungus. Penicillinase did not neutralize these effects. A control strain of Staphylococcus spp with poor sensitivity to penicillin was resistant to the dermatophyte in all test systems. T. mentagrophytes showed positive tropism to the bacteria. Regional variation in fungal germination and antibiotic production, the limited yield of antibiotics, and the pattern of dermatophyte growth and alteration of bacterial morphology demonstrated the significant influence of microenvironment on antibiosis.

Onychomycosis caused byAspergillus terreus

Four cases of onychomycosis caused by Aspergillus terreus are presented. The clinical characteristics consisted of spotted and striated leuconychia, dark spots and fragility of the nails. The mycology is described, and is shown that A. terreus has an inhibitory effect on the growth of dermatophytes and Scopulariopis brevicaulis. Topical treatment with 1% Pimafucin in a mixture of 60% dimethylsulfoxide (DMSO) and 40% water as well as 9% aqueous solution of sodium benzoate were both effective. The literature concerning onychomycosis caused by A. terreus is summarized.

Identification of carbon dioxide as a dermatophyte inhibitory factor produced by Candida albicans

A factor produced by Candida albicans, which inhibits dermatophyte growth and induces arthrospore formation is characterized and identified. Candida dermatophyte inhibitory factor (CDIF) is volatile and fungistatic. Analysis of volatile materials produced by C. albicans was subsequently identified as carbon dioxide. The involvement of carbon dioxide in the inhibition of dermatophytes was demonstrated by: (1) utilization of commercial carbon dioxide to produce dermatophyte inhibition as well as arthrospore formation, and (2) prevention of dermatophyte inhibition by C. albicans through incoporation of soda lime into the incubation atmosphere. The ability of carbon dioxide to inhibit dermatophyte growth was shared with other gases (methane and helium), but arthrospore formation was observed only with carbon dioxide. The possible significance of carbon dioxide's induction of arthrospores, a form occasionally observed in active dermatophyte lesions, is discussed.

Studies on the biological effects of deuteriated organic compounds. I. Antifungal activity of perdeuteriated fatty acids on dermatophytes in vitro.

The antifugal activity of some perdeuteriated fatty acids, with normal chain 11 to 18 carbon atoms, was investigated on common dermatophytes Epidermophyton floccosum, Microsporum canis, Trichophyton mentagrophytes and T. rubrum under in vitro conditions. These studies were performed by dilution technique and with respiratory measurements, Perdeuteriation of some fatty acids increases their inhibitory effect on the dermatophyte growth. Perdeuteriated n-hendecanoic acid proved to be the most active of the substances tested. Possible mechanisms behind the enhanced antifungal activity due to the perdeuteriation of fatty acids are discussed.