Efficacy of griseofulvin and itraconazole in the treatment of experimentally induced dermatophytosis in cats

To evaluate the efficacy of itraconazole and griseofulvin in the treatment of Microsporum canis infection, 15 juvenile cats were infected by topical application of 10(5) live M canis macroconidia to the skin of the lateral part of the trunk, and an occlusive bandage was applied. After 3 weeks, cats were randomly assigned to 1 of 3 treatment groups (n = 5 each): cats in the first group received griseofulvin (50 mg/kg of body weight, PO, q 24 h); the second group received itraconazole (10 mg/kg, PO, q 24 h); and the third group (control) received an equivalent volume of vehicle (without drug, PO, q 24 h). Treatment continued for 100 days, or until mycologic cure (lack of dermatophyte isolation on 3 consecutive weekly fungal cultures) was achieved. Infection in all cats peaked in severity at week 6 after inoculation, then gradually resolved over the next 11 weeks. The itraconazole-treated group was the first to achieve a cure, after receiving 56 days of treatment, followed by the griseofulvin-treated group at 70 days. None of the cats in the control group reached mycologic cure after 100 days of treatment. As early as day 14 of treatment, the griseofulvin- and itraconazole-treated groups had significantly (P < 0.05) lower mean infection scores, compared with those in the control group. Significant differences in the mean infection scores between the itraconazole- and griseofulvin-treated groups were not found.(ABSTRACT TRUNCATED AT 250 WORDS)

Inability of two topical treatments to influence the course of experimentally induced dermatophytosis in cats

An experimental model of dermatophytosis was used to compare the efficacy of 2 topical antifungal treatments against Microsporum canis infection in cats. Infection was established in 24 cats by topical application of 10(5) M canis macroconidia to the skin of the lateral part of the abdomen under an occlusive bandage. Three groups of 6 cats each then were treated twice weekly for 18 weeks with chlorhexidine shampoo and dip, detergent shampoo vehicle only, or glyceryl monolaurate shampoo. Six cats were left untreated as controls. The experimentally induced infections strongly resembled naturally developing infections of moderate to severe nature. Signs of infection peaked in severity at 5 weeks after inoculation, then gradually resolved over 7 to 16 additional weeks. Dermatophytes were consistently isolated on culture for at least 8 weeks of treatment. Mycologic cure (defined as lack of dermatophyte isolation on 3 successive weekly cultures) was attained in 8 cats at the end of 18 weeks of treatment. Infections appeared to resolve at equivalent rates in all groups of cats, including controls. Consistent or meaningful significant differences in variables such as lesion size, clinical sign score, or total infection score were not found between treated and control groups. Our study revealed that this topical treatment regimen with chlorhexidine or glyceryl monolaurate is ineffective against M canis infection in cats.

Calcium induced alterations in structural and functional role of phospholipids in Microsporum gypseum

The effect of calcium on the structural and functional aspects of phospholipids in Microsporum gypseum was examined. Cells grown in presence of calcium exhibited increased content of phospholipids and enhanced synthesis of phospholipids as monitored by the incorporation of [32P] orthophosphoric acid. The rise in the levels of phospholipids was found to be due to increased synthesis of fatty acids as observed from [14C] acetate incorporation studies. The rise in the levels of phospholipids were reflected in the subcellular fractions also. Change in the phospholipid composition increased the fluidity of the membrane as is evident from fluorescence polarization studies using 1-anilinonaphthalene-8-sulfonate (ANS) and 1,6-diphenyl-1,3,5-hexatriene (DPH). The increased membrane fluidity was consistent with the enhanced uptake of [3H] proline in calcium grown cells.

Evaluation of topical therapies for the treatment of dermatophyte-infected hairs from dogs and cats

Seven commonly used, topical antifungal products (i.e., lime sulfur, chlorhexidine, captan, povidone-iodine, sodium hypochlorite, and enilconazole solutions, and ketoconazole shampoo) were evaluated for their antifungal activity on Microsporum canis-infected hairs from dogs and cats in an in vitro study. Hairs were soaked or shampooed in each product for five minutes twice a week for four weeks. Of the seven products used in this study, lime sulfur and enilconazole solutions were superior in inhibiting fungal growth; no growth occurred on fungal cultures after two treatments with either product. Chlorhexidine and povidone iodine solutions were effective after four treatments, and sodium hypochlorite solution and ketoconazole shampoo inhibited fungal growth after eight treatments. Captan did not inhibit fungal growth during the test period.

Screening of hundred Rwandese medicinal plants for antimicrobial and antiviral properties

A series of 100 Rwandese medicinal plants (267 plant extracts), used by traditional healers to treat infections, were screened for antibacterial, antifungal and antiviral properties. The results of the testing showed that 45% were active against Staphylococcus aureus, 2% against Escherichia coli, 16% against Pseudomonas aeruginosa, 7% against Candida albicans, 80% against Microsporum canis and 60% against Trichophyton mentagrophytes. Not less than 27% of the plant species exhibited prominent antiviral properties against one or more test viruses, more specifically 12% against poliomyelitis, 16% against coxsackie, 3% against Semliki forest, 2% against measles and 8% against herpes simplex virus.

Antidermatophytic activity of garlic (Allium sativum) in vitro

BACKGROUND

Interest in herbal medicine is enjoying a renaissance at present. Garlic (Allium sativum) is an intriguing herb with a long history of medicinal use for a variety of diseases including ringworm infections.

METHODS

Antidermatophytic activity of the aqueous extract of garlic (A. sativum) was investigated against 88 clinical isolates of dermatophytes by an agar dilution technique. The isolates included Microsporum canis (50), M. audouinii (5), Trichophyton rubrum (6), T. mentagrophytes (5), T. violaceum (12), T. simii (5), T. verrucosum (1), T. erinacei (1), and Epidermophyton floccosum (2). The results were compared with the minimal inhibitory concentrations of ketoconazole.

RESULTS

The aqueous extract of garlic, diluted 1:150 and 1:100, had inhibited 50 and 90% of the isolates tested, whereas the respective values for ketoconazole were 1 and 2.5 micrograms/mL.

CONCLUSIONS

Garlic (A. sativum) could be used as an effective antidermatophytic agent. Further purification and extraction of the active principle of garlic would give a true antidermatophytic activity comparable to standard antifungal drugs.

Antimicrobial activity of Cassia alata from Malaysia

Ethanolic extract of Cassia alata leaves was investigated for its antimicrobial activities on several microorganisms including bacteria, yeast, dermatophytic fungi and non-dermatophytic fungi. In vitro, the extract exhibited high activity against various species of dermatophytic fungi but low activity against non-dermatophytic fungi. However, bacterial and yeast species showed resistance against in vitro treatment with the extract. The minimum inhibitory concentration (MIC) values of the extract revealed that Trichophyton mentagorphytes var. interdigitale, Trichophyton mentagrophytes var. mentagorophytes, Trichophyton rubrum and Microsporum gypseum had the MIC of 125 mg/ml, whereas Microsporum canis had the MIC of 62.5 mg/ml. The inhibition can be observed on the macroconidia of Microsporum gypseum which resulted in structural degeneration beyond repair. The mechanism of inhibition can be related to the cell leakage as observed by irregular, wrinkle shape and loss in rigidity of the macroconidia.

Antifungal effects of the 3-methyl-5-aminoisoxazole-4-thiocyanate on some dermatophytes

This preliminary research demonstrates the dose dependent antimycotic effect of 3-methyl-5-aminoisoxazole-4-thiocyanate against a number of animal and human dermatophytes. The in vitro results suggest potential medical applications.

Disk diffusion susceptibility testing of dermatophytes with allylamines

BACKGROUND

Allylamines are a newly developed group of drugs possessing a broad spectrum of activity against a wide range of fungi. With the advent of new antifungal drugs, susceptibility testing of fungi is receiving increased attention as important laboratory procedures for aiding in the selection of appropriate drug therapy.

METHODS

In vitro susceptibility testing of 43 clinical isolates of dermatophytes which included Microsporum sp., (18) Trichophyton sp., (23) and Epidermophyton floccosum (2) were carried out against the two allylamine derivatives, naftifine and terbinafine, by agar dilution and disk diffusion methods.

RESULTS

Terbinafine was found to be more active minimal inhibitory concentration (MIC range < or = 0.0001-0.1 micrograms/mL), inhibiting 50% (MIC 50) and 90% (MIC 90) of the isolates at 0.01 and 0.1 micrograms/mL, respectively. The MIC 50s and MIC 90s of naftifine were 0.1 micrograms/mL (MIC range 0.001-0.5 micrograms/mL). Both the drugs showed good correlation between the MIC and sizes of zones of inhibition around the disks. Regression analysis was used to measure the degree of correlation between the MIC values and matched averaged zones of inhibition; the correlation coefficients for both terbinafine and naftifine were -0.6841 (P < 0.001) and -0.5455 (P < 0.001), respectively.

CONCLUSIONS

The allylamines, naftifine and terbinafine, could be used successfully for susceptibility testing of dermatophytes by the disk diffusion method. With proper standardization of the test conditions, in vitro susceptibility testing of filamentous fungi by disk diffusion would become a useful laboratory procedure in the near future for determining the best drug therapy.

Itraconazole versus griseofulvin in the treatment of tinea capitis: a double-blind randomized study in children

BACKGROUND

Tinea capitis is a fungal infection in which topical therapy is often unsuccessful. Griseofulvin has been considered to be a first-line therapy. Other antifungal agents are the azole derivatives. Among these, itraconazole was compared with griseofulvin in children in a double-blind study.

PATIENTS AND METHODS

Thirty-four children and one adult with clinical signs and symptoms of tinea capitis and with positive culture and microscopy for dermatophytes have been included in a double-blind comparison between itraconazole, 100 mg daily, and ultramicronized griseofulvin, 500 mg daily. Both drugs were given for 6 consecutive weeks. The final evaluation was made 8 weeks after the end of treatment to allow the hairs to regrow. Seventeen itraconazole- and 15 griseofulvin-treated patients received the complete 6-week treatment course. Fifteen of these 17 itraconazole patients and 14 of the 15 griseofulvin patients had infections caused by Microsporum canis. Fifteen of 17 patients were cured by itraconazole (88%) and 15 of 17 patients by griseofulvin (88%). One of the patients who discontinued griseofulvin therapy after 4 weeks was clinically and mycologically cured. Two of the original 17 griseofulvin patients discontinued therapy because of vomiting. None of the itraconazole-treated children experienced side effects.

CONCLUSIONS

Itraconazole is the first azole derivate that matches griseofulvin for the treatment of tinea capitis in children. The drug also appears to be better tolerated than griseofulvin.

Antifungal activity of some 2,2':5',2"-terthiophene derivatives

The dermatophyte Microsporum cookei Ajello was treated with nine new natural and synthetic 2,2':5',2"-terthiophenes to determine their possible antifungal activity. In the dark the thiophenes were inactive, while when photoactivated with UV-A they induced a remarkable reduction in the growth rate of the fungus. The only exception was (E)-N-(2-methylpropyl)-3-(2,2':5',2"-terthien-5-yl)-propenamide , which was not fungistatic even at the highest dose tested (24 microM). The more active compounds were 3'-methoxy-2,2':5',2"-terthiophene and 3'-methylthio-2,2':5',2"-terthiophene, whose activity seems to be related to the presence of a substituent in the 3' position of the central ring of thiophenes. Transmission electron microscopic observations demonstrated the photoactive nature of the synthetic molecules to be similar to that of alpha-terthienyl, a natural thiophene present in some Asteraceae. The dark treatment caused only the accumulation of the compound in vacuoles, without other evident alterations. After UV-A irradiation the activated thiophene causes severe modifications to the endomembrane system, probably via oxygen-dependent mechanism.

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.

Synthesis and structure-activity relationships of the novel homopropargylamine antimycotics

Analogues of the antimycotic allylamine terbinafine were prepared in which the naphthalene and the tert-butyl-acetylene moieties were preserved, but the spacer between these two groups was varied, and the antifungal activity of the new compounds was evaluated. All modifications of the original spacer such as reduction of the double bond, switching the position of the nitrogen atom, shortening, and elongation resulted in decreased potencies with one exception: Compounds with the CH2NMeCH2CH2 group between the 1-naphthalene and the optionally substituted tert-butyl-acetylene function demonstrated high antifungal activity in vitro. The new homopropargylamine derivatives are more potent than terbinafine against Aspergillus fumigatus. The results support the hypothesis that two lipophilic domains linked by a spacer of appropriate length and a polar center at a defined position in the spacer are the general requirements for high activity of allylamine antimycotics.

Plants used in Guatemala for the treatment of dermatophytic infections. 2. Evaluation of antifungal activity of seven American plants

From 52 plants screened for antifungal activity, 26 (50%) were active against dermatophytes. This paper reports further evaluation of seven American plants against four pathogenic fungi (Aspergillus flavus, Epidermophyton floccosum, Microsporum gypseum and Trichophyton rubrum), the part showing most activity, the best solvent and, in three cases, the minimal inhibitory concentration (MIC) against the fungus in pure culture. Antifungal activity was confirmed in all of the plants, but not all parts; the most active parts were the bark and leaves. The most active species were Byrsonima crassifolia, Cassia grandis, Gliricidia sepium and Malpighia glabra. Diphysa robinioides, Rhizophora mangle and Cassia occidentalis were less active. The most susceptible fungi were E. floccosum and T. rubrum; A. flavus was not susceptible. Ethanol was usually the best solvent and the MIC of C. grandis, C. occidentalis and D. robinioides was 50 micrograms/ml.

Influence of cyclic AMP on the biosynthesis of phosphatidylcholine in Microsporum gypseum

The influence of intracellular cAMP on phosphatidylcholine biosynthesis in Microsporum gypseum has been examined using radiolabelled precursors. The incorporation of labelled choline, methionine and ethanolamine into total lipids, phospholipids and choline containing phospholipids increased in aminophylline and decreased in atropine grown cells as a result of rise and fall in cAMP levels in these cells. The enhanced uptake of labelled methionine and ethanolamine in comparison to labelled choline in choline containing phospholipids in aminophylline grown cells suggests that methylation pathway is more influenced by cAMP than CDP-choline pathway.

In vitro susceptibility of dermatophytes to antifungal drugs: a comparison of two methods

BACKGROUND

There is an evidence that some fungal strains are resistant to certain antimycotic drugs with resulting therapeutic failures. Unlike testing of antibacterial agents, the activity of these drugs against the given fungal strains is not tested routinely. The paper presented is an approach to such a procedure.

METHODS

The minimum inhibitory concentration (MIC) values obtained using the dilution method were compared with the diameters of growth inhibition zones using the disk-diffusion method. Seven antifungal drugs (griseofulvin, natamycin, naftifine, clotrimazole, bifonazole, miconazole, ketoconazole) were tested with 80 fungal strains, including Trichophyton rubrum, T. mentagrophytes, Microsporum canis, and Epidermophyton floccosum.

RESULTS

The majority of fungal strains were inhibited by griseofulvin at concentrations not exceeding 10 mg/L. The least susceptible was T. mentagrophytes. The most effective drug was naftifine, and the least effective was natamycin. Naftifine inhibited 98.75% of the strains tested at a concentration not exceeding 1.0 mg/L. An increase of the MIC value was accompanied by a decrease in the growth inhibition diameter. The relation was statistically significant.

CONCLUSIONS

T. rubrum strains are more susceptible to antifungal drugs than T. mentagrophytes. Naftifine proved to be the most effective drug in dermatophytoses. Natamycin is a useful drug against yeast-like fungi but not against dermatophytes. The disk-diffusion method of fungal susceptibility assessment yields data consistent with results obtained from the dilution method and is recommended for routine use because of its simplicity.

Fungitoxicity of essential oils against dermatophytes

Sixteen essential oils were screened in vitro for their fungitoxicity against the two dermatophytes Trichophyton rubrum and Microsporum gypseum. Five oils (from Artemisia nelagrica, Caesulia axillaris, Chenopodium ambrosioides, Cymbopogon citratus and Mentha arvensis) showed strong activity and were assessed for their fungitoxicity against eight other dermatophytes as well as against Aspergillus fumigatus and Cladosporium trichoides. These five essential oils by formulation of ointments were able to cure experimental ringworm in guinea pigs within 7 to 12 days. Artemisia oil was found to be the most effective essential oil.

Oral itraconazole versus topical bifonazole treatment in experimental dermatophytosis

Guinea pigs, infected with either Trichophyton mentagrophytes or Microsporum canis, were treated orally or topically with azole antifungals daily for two weeks. Fungi located in the stratum corneum were affected similarly by both treatment schedules, showing typical cell wall changes after azole exposure and necrosis of internal organelles. Fungi located in the hair sheaths were affected only by the oral treatment, which not only prevented invasion of the inner hair structures and inflammatory responses but also led to a complete clearance of the infection within 7 days. Topically applied azole treatment was not able to injure fungi in the hair sheaths and did not suppress invasion into the hair shafts. These observations are in favour of oral antifungal medication with azoles for the treatment of dermatophyte infections involving hairy skin.

Further studies on the influence of aminophylline on lipids of Microsporum gypseum

Aminophylline added to the growth medium of Microsporum gypseum for varying periods exhibited varied effects on lipid synthesis. A decreased incorporation of [14C]acetate into both lipids and phospholipids was initially observed which showed increase after 24 hr of incubation. Short-time exposure of aminophylline also resulted in decreased activity of glycerol-3-phosphate acyltransferase, the key enzyme of lipid synthesis, which, however, got stimulated on longer incubation, supporting the decreased/increased synthesis of lipids during short/long time exposure. Changes in the intracellular levels of cAMP at different time points account for the induced alterations in lipid synthesis, possibly due to formation of metabolites of aminophylline during growth of the organism.

In vitro susceptibility to antimycotics of Microsporum canis isolates from cats

One hundred thirty-four isolates of Microsporum canis, obtained from cats, were tested for in vitro susceptibility to various antifungal agents. The fungi were classified as susceptible, resistant, and intermediate by measuring the size of the zone of inhibited growth on yeast nitrogen base agar medium. Clotrimazole had the highest activity (99.2%), followed by tioconazole (89.6%), griseofulvin (88.8%), econazole (73.1%), ketoconazole (50.7%), miconazole (15.7%), and isoconazole (12.7%). We found 14.9% of the isolates to be susceptible to all the assayed drugs, whereas the highest resistance frequency (41.8%) was against 2 antimycotics. A simultaneous resistance to all the tested antimycotics was not found. The differences among the antifungal drugs activity were examined, and administration of drugs for which a simultaneous resistance was minimal is suggested.

Effect of reducing agents on proteolytic and keratinolytic activity of enzymes of Microsporum gypseum

The effect of sodium sulphite, cysteine, glutathione, mercaptoethanol and dithioerythritol (0.1-10 mmol l-1) on the activity of proteases of Microsporum gypseum was studied using azocasein, cross-linked bovine serum albumin and keratin as substrates. With the substrate without disulphide bonds (casein) no stimulation was found, and reducing agents inhibited proteolysis in most cases. With the remaining two substrates, all substances enhanced the activity of proteases probably through the cleavage of the substrate disulphide bonds. Sulphite was more effective than the four used thiols and enhanced the activity against serum albumin up to 3.2 times and against keratin up to 2.9 times. Using sulphitolysed sheep wool, keratinolytic activity increased after sulphitolysis of more than 20% of disulphide bonds. With the fully sulphitolysed wool the activity increased 43 times. The obtained results support the author's hypothesis on keratin degradation by sulphite excretion prior to attack by fungal proteases. Stimulation of proteolysis and keratinolysis by cleavage of disulphide bonds is not specific for dermatophytic proteases because trypsin and pronase behaved similarly in the experiments.

Low voltage scanning electron microscopy study of naftifine activity on Microsporum canis

Scanning electron microscopy (SEM) is at present considered a good way to observe the morphological alterations induced by an antifungal on pathogenic fungi. Owing to its high precision, low voltage scanning electron microscopy (LVSEM) improves the quality of observations. The Microsporum canis morphology alterations induced by naftifine at a concentration of 0.9 microgram ml-1 (10 times the minimum inhibitory concentration (MIC) for 7 days were studied in LVSEM. The young lateral ramifications and the aborted buds take on a granulous aspect. These granulations can be localized as brassard shapes around hyphae. The mycelial filaments often appear irregularly swollen with bulbous tips. Macroconidia are selectively covered with a microfibrillar network. In addition, LVSEM on control samples reveals pavimentous angular structures on the macroconidial surface and fine granulations on the filament surface of M. canis unknown until now. A cytological study with transmission electron microscopy (TEM) of filaments altered by naftifine permitted us to observe the disorganization of cell wall fibrillar structure, an excessive plasma membrane undulation and an intracytoplasmic accumulation of large vesicles with probably lipidic contents.

Control of zoopathogenic fungi in vitro by polyamine biosynthesis inhibitors

Effect of inhibitors of polyamine (PA) biosynthesis, alpha-difluoromethylornithine (DFMO), methylglyoxal bis (guanylhydrazone)--MGBG and bis (cyclohexylammonium) sulphate (BCHA) on mycelial growth of three clinically important fungi-Trichophyton mentagrophytes, Microsporum gypseum and Aspergillus flavus was examined in vitro. All inhibitors at concentrations 1 to 50 mM produced greater inhibition of mycelial growth in all fungi tested in a dose-dependent manner. MGBG was the most effective inhibitor, and T. mentagrophytes was the most sensitive fungus to all inhibitors followed by M. gypseum and A. flavus. The results suggested that control of fungal diseases in animals and human beings with specific inhibitors of PA biosynthesis is possible.

Correlation between intracellular cAMP levels and phospholipids of Microsporum gypseum

Atropine, a modulator of cAMP has been used to examine the relationship between phospholipids and intracellular levels of cAMP in Microsporum gypseum. A decreased phospholipid content was observed in atropine grown cells as a result of reduced levels of intracellular cAMP. This decline was caused by the inhibitory effect of atropine on adenylate cyclase. Lowered phospholipid content was supported by decreased [14C]acetate incorporation as well as reduced activities of key enzymes of phospholipid biosynthesis. In vitro supplementation of atropine in control cells also caused inhibition in lipid synthesis indicating similar effects of atropine and its metabolites. These results in conjunction with our previous report, in which enhanced levels of cAMP resulted in increased phospholipid synthesis, suggest a direct correlation between phospholipid biosynthesis and intracellular levels of cAMP in M. gypseum.

Antifungal activity of two benzofuran-imidazoles in different experimental conditions

A number of experiments was performed in order to analyze the in vitro activity of two new benzofuran-imidazoles, IM/B/4-62 and IM/B/4-66. Studies included the determination of minimum inhibitory concentrations (MICs) on three culture media, at different pH values and at different inoculum sizes. Furthermore, the killing activity and induced resistance were determined. In all the experiments econazole, clotrimazole and bifonazole were the reference compounds. The best MIC values of the two new imidazoles were observed on modified Sabouraud's medium, at neutral pH and an inoculum size of 10(4) cells/ml. The two substances showed killing activity and no resistance was observed. On the whole, the more favorable results were obtained with the compound IM/B/4-66.

Disinfectants in the control of small animal ringworm due to Microsporum canis

Twelve disinfectant products or compounds were evaluated for their ability to kill Microsporum canis harvested from naturally infected material. The disinfectants were diluted to the concentration recommended for the disinfection of clean surfaces and the potency of each substance was determined by the degree to which it could be further diluted before losing its fungicidal action. Hypochlorite, benzalkonium chloride and glutaraldehyde based compounds were the most effective agents and phenolics, alcohol and anionic detergents were inadequate. Urea (10 mM) did not adversely affect the potency of any of the compounds.

A clinical and laboratory study of ciclopirox olamine (8% Batrafen) in the treatment of onychomycosis

Ciclopirox olamine, a new synthetic substituted pyridone derivative, is an antimycotic agent with activity against a broad spectrum of pathogenic and nonpathogenic fungi. The clinical efficacy and safety of 8% ciclopirox olamine nail liquor were evaluated in 100 cases with finger (or great toe) onychomycosis. After 16 weeks and 24 weeks of treatment for finger and great toe onychomycosis, respectively, the overall therapeutic results were excellent in 36 cases, good in 17, fair in 24, and poor in 23. The period of treatment was extended in 31 cases; among them, 10 cases showed further improvement. As for in vitro inhibitory activity, the MIC of ciclopirox olamine against T. rubrum and C. albicans was 1 to 4 mg/L and 1 to 16 mg/L, respectively. This study indicates that 8% ciclopirox olamine nail liquor, with its satisfactory efficacy and lack of side effects, is a good remedy for onychomycosis.

Influence of aminophylline on the lipids in Microsporum gypseum

The effect of aminophylline on the lipid synthesis of Microsporum gypseum has been examined. A decreased incorporation of [14C]acetate into lipids was observed when the cells were incubated for 1 h with aminophylline which was reflected in all the individual lipid fractions. However, cells grown with aminophylline in the growth medium exhibited increased levels of total phospholipids, which was probably due to a rise in intracellular cAMP as these cells exhibited 4-fold increased levels of cAMP. Decreased activity of phosphodiesterase by aminophylline accounts for the increased cAMP levels. Increased phospholipid content in aminophylline grown cells was further supported by the increased incorporation of [14C]acetate into phospholipids as well as increased activities of phospholipid biosynthetic enzymes in comparison to non-supplemented cells.

Studies on the mode of action of tolnaftate in Microsporum gypseum

Studies were performed on the mode of action of tolnaftate and resistance to this drug in Microsporum gypseum. Cells grown in the presence of tolnaftate (at the IC 50) showed a reduced content of total phospholipids and sterols whereas there was an increase in total RNA content. Incubation of cells with tolnaftate (at 10 x MIC), followed by addition of different macromolecule precursors revealed inhibition of the biosynthesis of all macromolecules except for RNA. The activity of membrane-bound enzymes did not change on treatment with tolnaftate (10 x MIC) whereas an increase in the leakage of intracellular 32P was observed. The content of total phospholipids was higher in tolnaftate-resistant cells, whereas the content of total sterols, DNA, RNA and protein was comparable to that of susceptible cultures. Activity of phosphodiesterase decreased and 5'-nucleotidase increased in tolnaftate-resistant cells. Our results suggest that the antifungal activity of tolnaftate is due to differential action on various targets site(s) which are modified in strains resistant to the drug.

Cycloheximide enhances factor binding to the native 40S ribosomal subunit of Microsporum canis

Native and derived ribosomal particles from the mycelial cells of Microsporum canis grown in the presence and absence of cycloheximide were compared by CsCl equilibrium density gradient centrifugation. Since the buoyant densities of ribonucleoprotein complexes are dependent on the protein-RNA ratio, they reflect the composition of these particles. The native monosomes from cells grown in the presence and absence of cycloheximide had a buoyant density of 1.585 g/cc. The native 60S subunits showed a density of 1.540 g/cc from cells grown in both presence and absence of cycloheximide, while the derived subunits showed a density of 1.610 g/cc. The derived 40S subunits had a density of 1.550 g/cc while the native 40S showed a major species of density 1.535 g/cc with three other minor species ranging in densities from 1.450-1.390 g/cc. The mycelia grown in the presence of cycloheximide showed an increased proportion of native 40S subunits in the density range of 1.450-1.390 g/cc, indicating that the drug enhances factor binding to native ribosomal subunits in M. canis.

Effects of butenafine hydrochloride, a new benzylamine derivative, on experimental dermatophytosis in guinea pigs

Butenafine hydrochloride, N-4-tert-butylbenzyl-N-methyl-1-naphthalenemethylamine hydrochloride (butenafine), is a novel antifungal agent of the class of benzylamine derivatives. Butenafine was investigated for its activity against guinea pig dermatophytosis caused by Trichophyton mentagrophytes or Microsporum canis in comparison with those of naftifine, tolnaftate, clotrimazole, and bifonazole. Topical butenafine showed excellent efficacy against dermatophytosis when it was applied once daily, and the effect was superior to those of all four reference drugs. When applied once at 24 or 48 h before infection, the drug exhibited excellent prophylactic efficacy against experimental T. mentagrophytes infection. The concentrations of butenafine in animal skin at 24 and 48 h after application of 0.2 ml of a 1% solution were several hundred times higher than those required to kill T. mentagrophytes and M. canis. The good efficacy of butenafine against dermatophytosis may be attributable to its fungicidal activity and long retention in the skin after topical application.

The sensitivity of dermatophytes to griseofulvin

13 isolates of Trichophyton violaceum and 7 Microsporum langeroni from Zambia and Cameroon were tested in vitro for their sensitivity to griseofulvin. No strain was found resistant. All the 13 T. violaceum were inhibited by 4-8 micrograms/ml while 4 M. langeroni were inhibited by 0.5-1 microgram/ml.

Further studies on the influence of dibutyryl cAMP, theophylline and prostaglandin E1 on composition and biosynthesis of phospholipids in Microsporum gypseum

Exogenous supplementation of dibutyryl cAMP and cAMP modulators like theophylline and prostaglandin E1 in the growth medium of Microsporum gypseum lead to increase in the levels of phosphatidylcholine and lysophosphatidylcholine and thereby in total phospholipid content. These observations were further confirmed by the increased incorporation of [32P]orthophosphoric acid into total phospholipid and [14C]choline into phosphatidylcholine and lysophosphatidylcholine. The activity of sn-glycerol-3-phosphate acyltransferase, the enzyme involved in phospholipid synthesis, was stimulated in the presence of dibutyryl cAMP, theophylline and PGE1 supporting the increased synthesis of phospholipids.

Electron microscopy of Microsporum cookei after 'in vitro' treatment with protoanemonin: a combined SEM and TEM study

The ranunculaceous derivative protoanemonin (PrA) was studied as an antifungal agent on the dermatophyte Microsporum cookei. The ultrastructural changes that PrA brought about in this fungus were observed with both the transmission and scanning electron microscopes. The main anomalies noted were abnormally shaped hyphae and within the cytoplasm, multimembranous bodies which were irregular in shape and size, and tubules of 25 and 60 nm in diameters. Mitochondria, nuclei and vacuoles were also variously affected by PrA. Although multifarious, the observed cellular alterations in M. cookei can be considered the result of a PrA interaction with cytoplasmic microtubules. Since these cell structures contain a great number of ASH groups, our previous hypothesis, that sulphydryl groups are the primary targets of this molecule, appears to be supported.

Additive effect of the combination of griseofulvin and ketoconazole against Microsporum canis in vitro

The susceptibility of 28 strains of Microsporum canis to griseofulvin, to ketoconazole and to a combination of both antifungal drugs was determined. Griseofulvin proved to be more active than ketoconazole. The combination of both antifungal agents was found to exert an additive effect.

Influence of supplementation of saturated alkanes on the membrane properties of Microsporum gypseum

Microsporum gypseum cells grown on saturated alkanes of different chain lengths (C10, C12, C14, C16 and C18) exhibited increased levels of total phospholipids and sterols. A significant increase in the content of phosphatidylcholine was observed in alkane-grown cells. Increased saturation of phospholipid fatty acid was observed with all the alkanes studied, which was mainly due to the decreased amount of C18:1 and C18:2 with concomitant increase in the levels of palmitic acid. The affinity for glycine changed in alkane-supplemented cells as compared to glucose-grown cells. 1-Anilino-naphthalene-8-sulphonate (ANS) binding to the spheroplast membrane demonstrated increased binding sites in supplemented cells. These results are discussed in terms of the effect of altered lipid composition on the membrane structure and function of this fungus.

Fungitoxic studies on bark extract of Lawsonia inermis against ringworm fungi

During screening of barks of 30 plants species against Microsporum gypseum and Trichophyton mentagrophytes, only Lawsonia inermis exhibited absolute toxicity. The Lawsonia bark extract was found to possess fungistatic nature at its maximum inhibitory dilution of 1:30 (W/V) against both the test pathogens but, become fungicidal at 1:10 (W/V). The extract showed broad fungitoxic spectrum when tested against 13 ring worm fungi. Further the fungitoxicity of the extract remained unaltered at high temperature, on autoclaving and after long storage.

Dermatophyte-hormone relationships: characterization of progesterone-binding specificity and growth inhibition in the genera Trichophyton and Microsporum

We reported previously that Trichophyton mentagrophytes contains a cytoplasmic macromolecule which specifically binds progesterone. Progesterone is also an effective inhibitor of growth of the fungus. We report here studies which characterize more fully the specific binding properties and the functional responses of T. mentagrophytes and taxonomically related fungi to a series of mammalian steroid hormones. Scatchard analysis of [3H]progesterone binding in both the + and - mating types of Arthroderma benhamiae and in Microsporum canis revealed a single class of binding sites with approximately the same affinity as that in T. mentagrophytes (Kd, 1 X 10(-7) to 2 X 10(-7) M). Trichophyton rubrum had a protein with a higher binding affinity (Kd, 1.6 X 10(-8) M). Characterization of the [3H]progesterone-binding sites in T. mentagrophytes showed the binder to be a protein which was destroyed by trypsin and heating to 56 degrees C. Previous examination of the steroid-binding specificity in T. mentagrophytes had demonstrated that deoxycorticosterone (DOC) and dihydrotestosterone (DHT) were effective competitors for [3H]progesterone binding. Expansion of this study to include other competitors revealed that R5020 (a synthetic progestin), androstenedione, and dehydroepiandosterone possessed relative binding affinities which were 20, 11, and 9% of that of progesterone, respectively. Other ligands tested were less effective. Competition studies for the binder in M. canis resulted in similar findings: DOC and DHT were effective competitors for [3H]progesterone binding. The growth of A. benhamiae + and -, M. canis, and T. rubrum were all inhibited by progesterone in a dose-responsive manner, with 50% inhibition achieved at concentrations of 9.8 x 10(-6), 1.2 x 10(-5), 1.5 x 10(-5), and 2.7 x 10(-6) M. respectively,.

Activities of compound G2 isolated from alfalfa roots against dermatophytes

An antimycotic agent, compound G2, isolated from alfalfa roots exhibited considerable activity against the six most common dermatophytes. MICs in agar and broth dilutions ranged from 10 to 30 micrograms/ml and from 2 to 10 micrograms/ml, respectively. G2 was fungicidal at 5 to 22 micrograms/ml. Structure and toxicity relations are discussed.

[Experimental study of the effect of raw materials of the neem tree and neem extracts on dermatophytes, yeasts and molds]

In traditional Indian medicine, various parts of the neem tree have been used for centuries, especially with skin diseases. These products are often applied in human mycoses. We tested some dried neem materials, neem oils as well as simple neem preparations and extracts with regard to their effect on 14 of the most common pathogenic fungi. Neither the dried neem materials nor the medical preparations and oils had any effect on fungal growth; most of them were even contaminated with molds. Some of the extracts, however, showed antimycotic properties, which decreased with rising solvent polarity. Petrolether leaf extract proved most effective. One of the possible explanations might be the fact that it contains quercetin, a flavonoid.

3-Carbonylacrylic derivatives as potential antimicrobial agents. Correlations between activity and reactivity toward cysteine

A number of 3-carbonylacrylic acid derivatives were prepared, with a view to varying systematically the stereoelectronic environment of the conjugated double bond. The rates of reaction with cysteine were measured spectrophotometrically when possible or by stopped flow when very fast. Some of the final reaction products were isolated. Other properties examined were partition substituent constants and antimicrobial activity. On the basis of published data and these studies, the activity appears to be the combined effect of at least two mechanisms, one probably related to the effect of these structures on surface tension, the other to the electrophilic properties of the unsaturated system.

Synthesis and structure-activity relationships of naftifine-related allylamine antimycotics

Naftifine (1) is the first representative of the new antifungal allylamine derivatives. Its biological activity is strictly bound to specific structural requirements that are unrelated to those of known antifungals. A tertiary allylamine function seems to be a prerequisite for activity against fungi. By systematic variation of the individual structural elements in 1, detailed structure-activity relationships are defined in which the phenyl ring is the structural feature permitting the widest variations. Versatile synthetic routes to allylamine derivatives and comparative biological data are presented.