Species distribution and antifungal susceptibilities of dermatophytes during a one year period at a university hospital in Turkey

Dermatophyte infections have been considered to be a major public health problem in many parts of the world. The aim of this study was to determine the causative agents of dermatophytoses and their antifungal susceptibilities in a Turkish University Hospital, west of Turkey. A total of 926 patients suspected to have dermatophytic lesions were examined over a period of 1 year (2001-2002). Samples collected from skin, hair and nails were submitted to direct microscopical examination using KOH and Calcofluor white stain, cultured on Sabouraud dextrose agar and Mycosel agar. The prevalence of dermatophytoses was 7.34% (68/926). Trichophyton rubrum was the most frequent dermatophyte isolated (56%) followed by T. mentagrophytes (38%), T. violaceum (1.5%), T. verrucosum (1.5%), Microsporum canis (1.5%) and Epidermophyton floccosum (1.5%). Tinea pedis (47%) was the most common type of infection, followed by tinea unguium (29%), tinea inguinalis (15%), tinea corporis (7.4%) and tinea capitis (1.6%). Secondary, we have tested 68 strains of dermatophytes against four antifungal agents following mainly the National Committee for Clinical Laboratory Standards M38-P standard for filamentous fungi. In general, all antifungals were shown to be highly effective and itraconazole and naftifine appeared more active than ketoconazole and oxiconazole.

Pycnanthuquinone C: a new terpenoid-quinone from Pycnanthus angolensis

A new compound containing a unique terpenoid-quinone skeleton, pycnanthuquinone C (1) along with the known sargachromenol (2), prunetin (3), biochanin A (4), calopiptin (5), (12 S,13 S)-12,13-dihydroxylabda-8(17),14-dien-18-oic acid (6), (12 R,13 S)-12,13-dihydroxylabda-8(17),14-dien-18-oic acid (7), and sitosterol 3- O-beta- D-glucopyranoside (8), were isolated from the stem bark of Pycnanthus angolensis. Their structures were elucidated by spectroscopic means and comparison with published data. The antifungal activity of compounds 1, 2 and 3 was evaluated. Compound 1 was active against Trichophyton soudanense. Compound 2 was active against Trichophyton mentagrophytes while compound 3 was active against Microsporum audouinii and Trichophyton mentagrophytes.

Use of isolated infected spores to determine the sporocidal efficacy of two commercial antifungal rinses against Microsporum canis

In this study, isolated infective Microsporum canis spores were used in an in vitro test model to compare the sporocidal activity of two commercial topical antifungal rinses. The two commercial test solutions used in the study were a lime sulphur solution 97.8% (LymDyp) and miconazole base 5.2%/chlorhexidine gluconate 5.9% mixture (Malaseb Concentrate Rinse). Water and household bleach were used as controls. Isolated infective spores were harvested from infected hairs and 500 microL of the spore suspension was incubated with an equal volume of dilutions of lime sulphur or the miconazole/chlorhexidine gluconate combination for 5 min and 4 h followed by fungal culture. There were too many to count colonies on the water control plates. Lime sulphur was 100% sporocidal at all test dilutions at both times. Miconazole/chlorhexidine gluconate was 100% sporocidal at all but the 1 : 128 dilution after 5 min of incubation and 100% sporocidal when incubated with spores for 4 h. It is not known if the two products have similar antifungal activity against infective spores on or within hairs; however, based on the findings of this study there is good evidence to recommend either rinse as an adjuvant topical therapy in a dermatophyte treatment and control program.

A New Pyrone Derivative from the Endophytic Fungus Penicillium paxilli PSU-A71

One new pyrone derivative, named penicillone (1), together with paxilline, pyrenocines A (2) and B (3) were isolated from the endophytic fungus Penicillium paxilli PSU-A71. The structures were elucidated by spectroscopic methods. Pyrenocine B (3) mildly inhibited the growth of Microsporum gypseum SH-MU-4 with a MIC value of 32 microg/ml.

In vitro activity of panomycocin, a novel exo-?-1,3-glucanase isolated from Pichia anomala NCYC 434, against dermatophytes

Killer proteins that are produced and secreted into the environment by certain yeast strains are considered as promising antifungal agents. In this study, in vitro activity of Pichia anomala NCYC 434 (K5) killer protein, panomycocin, which is a 49 kDa glycoprotein with an exo-beta-1,3-glucanase activity was tested against 41 isolates of dermatophytes. Minimum inhibitory concentrations (MICs) were determined by a broth microdilution method based on the reference document M38-A of Clinical and Laboratory Standards Institute (CLSI; formerly NCCLS). For panomycocin MIC determinations two end point criteria MIC-2 (prominent growth inhibition) and MIC-0 (complete growth inhibition) were recorded. All the tested isolates (Microsporum spp. and Trichophyton spp.) were found susceptible to panomycocin. The MIC-2 values ranged from 0.25 to 2 microg ml(-1) and MIC-0 values ranged from 1 to 8 microg ml(-1). These results showed that panomycocin is active in vitro against fungal strains that cause superficial infections and highlighted its probable use as a topical antifungal agent.

Antidermatophytic triterpenoids fromSyzygium jambos (L.) Alston (Myrtaceae)

Chemical investigation of the EtOAc extract of the stem bark of Syzygium jambos (L.) Alston (Myrtaceae) afforded a number of known triterpenes such as friedelin, beta-amyrin acetate, betulinic acid and lupeol. Friedelin was submitted to a Baeyer-Villiger oxidation, and was also reduced with LiAlH(4) to give the known friedelolactone and friedelanol, respectively. These compounds were identified by comparison of NMR spectral data with those from the literature. The EtOAc extract and the isolated compounds were tested for their antidermatophytic activity against three dermatophyte species: Microsporum audouinii, Trichophyton mentagrophytes and Trichophyton soudanense, commonly found in Cameroon. Betulinic acid and friedelolactone were the most active compounds, and the most sensitive fungi were Trichophyton soudanense and Trichophyton mentagrophytes.

Antifungal Effect of Eugenol and Nerolidol against Microsporum gypseum in a Guinea Pig Model

Essential oils have been widely used in anti-infectious application. In the present study, we elucidated the antifungal activities of eugenol and nerolidol isolated from Japanese cypress oil in a guinea pig model infected by Microsporum gypseum (M. gypseum). A minimal inhibitory concentration (MIC), skin lesion scoring, hair culture and histopathologic examination of skin tissues were performed to evaluate the antifungal effect of these oils. The MICs of eugenol, nerolidol and econazole (positive control) were 0.01-0.03% and 0.5-2% and 4-16 microg/ml, respectively. Based on these MICs, eugenol and nerolidol were adjusted to 10% concentration with a base of Vaseline petroleum jelly and were applied topically to the skin lesion infected with M. gypseum daily for 3 weeks. Both eugenol and nerolidol were clinically effective at improving the lesion during the first week of application, as determined by skin lesion scoring. Nerolidol improved the skin lesions infected by M. gypseum, but eugenol did not, as determined in the hair culture test. Histopathologic examination revealed that the eugenol- and nerolidol-treated groups had a lower degree of hyperkeratosis and inflammatory cell infiltration than the positive control. Taken together, these results suggest that eugenol and nerolidol could apply supplementary antifungal agents.

In vitro antifungal and anti-elastase activity of some aliphatic aldehydes from Olea europaea L. fruit

Olea europaea preparations are traditionally employed in a variety of troubles, including skin infections. Olive extracts and some of their pure compounds have shown antimicrobial activity in vitro. The present study deals with the antifungal activity of some aliphatic aldehydes from olive fruit [hexanal, nonanal, (E)-2-hexenal, (E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal] against Tricophyton mentagrophytes (6 strains), Microsporum canis (1 strains) and Candida spp. (7 strains). The capability of these substances to inhibit elastase, a virulence factor essential for the dermatophytes colonization, and their cytotoxicity on cultures of reconstructed human epidermis, are also described. Aldehydes tested, inhibited the growth of T. mentagrophytes and M. canis in the range of concentration between <1.9 and 125 microg/ml; the unsaturated aldehydes showed the most broad spectrum of activity in that inhibited all strains tested. None of the aldehydes exhibited activity against Candida spp. strains. (E)-2-octenal and (E)-2-nonenal inhibited the elastase activity in a concentration-dependent manner; the anti-elastase activity suggests an additional target of the antimicrobial activity of these compounds. Aldehydes were devoid of cytotoxicity on cultures of human reconstructed epidermis. The antifungal activity of the aldehydes from olive fruit here reported, substantiates the use of olive and olive oil in skin diseases and suggests that these natural compounds could be useful agents in the topical treatment of fungal cutaneous infections.

Pimarane diterpene and cytochalasin derivatives from the endophytic fungus Eutypella scoparia PSU-D44

Two pimarane diterpenes, named scopararanes A (1) and B (2), and two cytochalasins, named scoparasins A (3) and B (4), along with 4,8-dihydroxy-6-methoxy-4,5-dimethyl-3-methyleneisochroman-1-one (5) and diaportheins A (6) and B (7) were isolated from a culture broth of the endophytic fungus Eutypella scoparia PSU-D44. Their antimicrobial activities against Staphylococcus aureus ATCC 25923 and Microsporum gypseum SH-MU-4 were examined.

Steroidal glycosides from the underground parts of Allium ursinum L. and their cytostatic and antimicrobial activity

The aim of this study was the isolation and structural elucidation of steroidal glycosides from the underground parts of ramson Allium ursinum L. The structures of the isolated compounds were established based upon chromatographic methods and 1D- and 2D-NMR, MS and IR analyses. The mixture of two steroidal saponins: (25R)-spirost-5-en-3b-ol tetrasaccharide and (25R)-spirost-5, 25(27)-dien-3b-ol tetrasaccharide, along with a 3-hydroxypregna-5,16-dien-20-one glycoside were identified. The results of in vitro cytotoxic activity of the mixture of spirostanol saponins against cell lines melanoma B16 and sarcoma XC and human fibroblasts HSF are also reported. The spirostanol saponins mixture was investigated to determine its in vitro antimicrobal activity against Trichophyton mentagrophytes and Microsporum canis.

In vitro sensitivity of dermatophytes to urea

OBJECTIVE

Urea is commonly used as a keratolytic substance in the treatment of onychomycoses to improve the penetration of antifungal drugs in the lesion sites. The aim of the present study was to investigate the inhibitory action of urea on samples of dermatophytes in vitro.

METHOD

Minimum inhibitory concentration of urea was determined for 31 samples of dermatophytes cultured in Sabouraud-dextrose broth containing different concentrations (7.5% up to 40%) of urea. Absence of growth was the criterion adopted to determine the minimum inhibitory concentration.

RESULTS

The majority of samples (87%) were sensitive to urea at 12.5%, or less. 2 isolates of Trichophyton tonsurans and 2 of Trichophyton rubrum required 30%, and 40% urea, respectively, to be completely inhibited.

CONCLUSION

In vitro results demonstrate inhibitory activity of urea on dermatophytes, suggesting that it could be used as an adjuvant in topical treatments.

Antimicrobial activity of flavonoids from Pelargonium radula (Cav.) L'Hérit

Flavonoids from Pelargonium radula (Cav.) L'Hérit were purified by column chromatography. Two fractions were obtained: F1 (main flavonoid isoquercitrin) and F2 (main flavonoid rutin). In vitro antimicrobial activity of F1 and F2 were tested against eleven species of bacteria and eleven species of fungi. Both fractions demonstrated strong inhibitory activity against Staphylococcus aureus, Proteus rettgeri, Candida tropicalis and Microsporum gypseum. Staphylococcus sp. (coagulase-negative) and Candida lusitaniae were strongly inhibited only by fraction F1 and Fusarium graminearum only by fraction F2.

Dermatophytes growth curve and in vitro susceptibility test: a broth micro-titration method

The introduction of systemic antifungal drugs which act upon different targets is the main issue of the in vivo antifungal resistance control. Different factors, such as growth curve phase, quality of the specimen, quantity of the inoculum, temperature, pH, culture medium composition, incubation duration and solvent, are believed important factors affecting minimum inhibitory concentration (MIC) value to most of the antifungal agents. We assayed an in vitro susceptibility test with 40 isolates of dermatophytes: Microsporum canis, Trichophyton rubrum, Trichophyton mentagrophytes and Epidermophyton floccosum against griseofulvin, fluconazole, itraconazole and terbinafine, using the guidelines of the M38-P document approved by the NCCLS. We determined the growth curves, to estimate the specific growth rate (mu max) and the generation time (G) of each dermatophyte, using dry weight and spectrophotometry methods. We demonstrate that, at 192 h, all fungi tested had a constant growth curve and we considered this as the optimal time for MIC determination. Terbinafine, griseofulvin and itraconazole possessed the highest antifungal activity against the four groups of dermatophytes studied. Fluconazole demonstrated no efficacy. Our MIC results differ from other authors and this difference is due to the timing of the MIC determination based on the growth curve of each fungi tested.

Inhibition of the growth in vitro of Trichophyton mentagrophytes, Trichophyton erinacei and Microsporum persicolor by miconazole and chlorhexidine

An agar dilution technique was used to assess the minimum inhibitory concentrations (MICs) of miconazole, chlorhexidine and a 1:1 combination of both agents for 9 isolates of Trichophyton mentagrophytes, 9 isolates of Trichophyton erinacei and 5 isolates of Microsporum persicolor. MICs of chlorhexidine did not vary significantly between the three dermatophyte species tested, but the MICs of miconazole alone and in combination with chlorhexidine for T. erinacei were significantly greater that those for T. mentagrophytes and M. persicolor. A synergistic drug interaction was noted with one isolate of T. erinacei and one isolate of M. persicolor. An additive effect was demonstrated for 13 isolates (5 T. mentagrophytes, 6 T. erinacei, 2 M. persicolor), and indifference was noted in 8 isolates (4 T. mentagrophytes, 2 T. erinacei, 2 M. persicolor). Although synergy was less often seen when compared with a previous study of Microsporum canis, the synergistic or additive effects seen with the majority (15 out of 23) of isolates studied in vitro provides a rationale for the combined use of miconazole and chlorhexidine in the adjunctive topical therapy of dermatophytosis caused by T. mentagrophytes, T. erinacei and M. persicolor.

Fluconazole upregulates sconC expression and inhibits sulphur metabolism in Microsporum canis

Azole derivatives such as fluconazole are the mainstay of therapeutic agents for the treatment of fungal infections. Their mode of action involving alteration in the conversion of lanosterol to ergosterol is well established. Here we report the effect of fluconazole on the sulphur metabolism negative regulator gene (sconC) in Microsporum canis. Characterization of the M. canis sconC gene revealed that its ORF is comprised of 495bp interrupted by four introns of 47-70bp. Exposure of M. canis in suspension to fluconazole upregulates sconC mRNA level and protein expression as determined by Northern and Western blot analysis, respectively. Upregulation of sconC was accompanied by inhibition of sulphur metabolism of the fungus resulting in a greatly reduced incorporation of radioactive labelled sulphuric acid into fungal proteins. These data establish that in addition to its action on ergosterol synthesis, fluconazole acts on other biological pathways in fungal cells.

Antifungal activity of Ocimum gratissimum towards dermatophytes

The development of more effective and less toxic antifungal agents is required for the treatment of dermatophytosis. Plants and their preparations have been used as medicines against infectious diseases. Extracts of Ocimum gratissimum leaves were investigated for in vitro antifungal activity, using agar dilution technique against dermatophytes. The extracts (hexane, chloroform fractions, the essential oil and eugenol) produced antifungal activities against Microsporum canis, M. gypseum, Trichophyton rubrum and T. mentagrophytes. Trichophyton rubrum, the most common aetiological agent of dermatophytosis in Goiânia, state of Goiás, Brazil, was also the most susceptible dermatophyte. The hexane fraction and eugenol were the most active. Hexane fraction inhibited the growth of 100% of dermatophytes at a concentration of 125 microg ml(-1), while eugenol inhibited the growth of 80% of dermatophytes at this same concentration. These results show that extracts of O. gratissimum are active in vitro against human pathogenic dermatophytes.

Antifungal susceptibility and genotypical pattern ofMicrosporum canisstrains

Dermatophytes are a group of fungi that are capable of invading keratinized tissues of humans and other animals. Antifungal susceptibility analysis and genetic studies by random amplification of polymorphic DNA (RAPD), have been used to detect polymorphism as well as determining the possible resistance of dermatophytes to antifungals. The aim of this study was to evaluate the possible correlation between the antifungal susceptibility and genotypical pattern of Microsporum canis strains isolated in dogs and cats with dermatophytosis in Northeast Brazil. The antifungal susceptibility study was conducted using the broth microdilution test with griseofulvine, ketoconazole, itraconazole, and fluconazole. The genotypical analysis was performed using the RAPD method. The antifungal susceptibility analysis showed that all the strains of M. canis analyzed (n = 22) were sensitive to griseofulvine (0.25 µg/mL ≤ minimum inhibitory concentration (MIC) ≤ 1 µg/mL), ketoconazole (0.25 µg/mL ≤ MIC ≤ 2 µg/mL), itraconazole (0.25 µg/mL ≤ MIC ≤ 1 µg/mL), and fluconazole (1 µg/mL ≤ MIC ≤ 16 µg/mL). The RAPD results showed that all analyzed strains are genetically similar. Thus, based on antifungal susceptibility analysis and RAPD data, a possible correlation can be shown between the antifungal susceptibility and the genotypical pattern of the strains of M. canis from Northeast Brazil.Key words: Microsporum canis, antifungal susceptibility testing, RAPD.

In vitro susceptibility testing of Microsporum gypseum isolated from healthy cattle and soil samples against itraconazole, terbinafine, fluconazole and topical veterinarian drugs

The present study evaluated in vitro susceptibility testing of dermatophytes isolates from healthy cattle and soil samples against three antifungal agents and three topical veterinarian drugs. Itraconazole and terbinafine showed a higher in vitro fungicidal activity than fluconazole. The veterinarian drugs LEPECID and iodine 5% were more active in vitro than the UNGUENTO spray. All drugs showed fungicidal activity against Microsporum gypseum, and they may be considered as efficient agents for the topical treatment of dermatophytoses in cattle.

Production of heptaene antifungal antibiotic by Streptomyces purpeofuscus CM 1261

A strain of Streptomyces purpeofuscus CM 1261 isolated from a sample of compost collected locally was found to possess strong antagonistic activity against 4 human pathogenic fungi i.e., Candida albicans, Aspergillus niger, Microsporum gypseum and Trichophyton sp. The active antifungal compound produced by it was found to be a heptaene group of polyene antifungal antibiotic.

Comparison of disk diffusion method and broth microdilution method for antifungal susceptibility testing of dermatophytes

The use of the agar diffusion Neo-Sensitabs method to determine antifungal susceptibility of 59 isolates of dermatophytes, namely Epidermophyton floccosum, Microsporum canis, M. gypseum, Trichophyton mentagrophytes, T. rubrum and T. tonsurans to Clotrimazole (CLZ), Itraconazole (ITZ) and Terbinafine (TBF) is described. Results obtained are compared to the minimum inhibitory concentrations (MIC) determined by an adaptation of the NCCLS-M38-A procedure. Using the diffusion method, all strains showed a broad zone of inhibition at the first available reading time (3 or 7 days). Using the broth microdilution method, the geometric mean MIC (microg/ml) with regard to all isolates was < or = 0.03 for TBF, < or = 0.069 for CLZ and < or = 0.919 for ITZ. In both methods, TBF was the most active antifungal agent against all isolates tested. The two methods evaluated were able to detect the resistance of the quality control strains of Aspergillus fumigatus to ITZ. Even though a reference method for testing dermatophytes still has not been developed, our data suggest that the Neo-Sensitabs diffusion method could provide a simple procedure for the antifungal susceptibility testing of dermatophytes in the routine clinical laboratory.

[Evaluation the antimycotic activity of itraconazole in human stratum corneum with vitro fungi cultivation]

OBJECTIVE

To establish a new model to evaluate the antifungal activity of antimycotics.

METHODS

Twenty-one healthy adult volunteers without clinically significant differences in demographic characteristics, hydration status of the skin, and sebum excretion were randomly divided into two groups: group 1 receiving 200 mg itraconazole bid for 1 week, and group 2 receiving itraconazole 200 mg qd for 1 weeks. Stratum corneum stripping was taken from the forearm skin at days 0, 1, 4, 7, 10, 14, 21, 28, and 35. Spores of selected fungi (Trichophyton rubrum, Trichophyton mentagrophytes, and Microsporum canis) were deposited and cultured on the center of the stratum corneum stripping. After 1-week culture the stratum corneum stripping was staining by PAS, and the area covered by dermatophyte was measured by corneofungimetry and computerized-assisted image analysis so as to calculate the inhibitory effect of the oral antifungal agents administered.

RESULTS

All three dermatophytes grew on the stratum corneum stripping, the area covered by the dermatophyte was dense before administration of antifungal agent, and decreased gradually after the administration of drug, and to the least on the seventh day (P < 0.01), however, the area covered by the dermatophyte began to increase since the tenth day, and reach the biggest on the thirty-fifth day. Itraconazole at two different dosages showed significant activity against these 3 dermatophytes without significant difference between the two groups (all P > 0.05).

CONCLUSION

The ex vivo growth environment of dermatophyte on human stratum corneum is very similar to that of human milieu interne. Itraconazole displays a high antidermatophyte activity in human stratum corneum. Corneofungimetric bioassay is a new method between in vitro trial and in vivo effect.

Efficacy of pre-treatment with lufenuron for the prevention of Microsporum canis infection in a feline direct topical challenge model

Oral lufenuron is reportedly an effective treatment for some cats with dermatophytosis. The purpose of this study was to determine if lufenuron, when used as a pre-treatment prior to challenge exposure, would be protective against the development of infection after the direct topical application of fungal macrocondia (Microsporum canis spores). Three groups (n = 6/group) of juvenile cats were treated with either monthly oral lufenuron (30 or 133 mg/kg) or placebo. After 2 months of treatment, kittens were challenged using 10(5)Microsporum canis spores applied to the skin under occlusion. Cats were examined weekly and the following data collected: Wood's lamp examination; scoring for scale/crust, erythema and induration; lesion size; and the development of satellite lesions. Fungal cultures were performed bi-weekly. All cats became infected; the infections progressed, and then regressed, in a similar fashion in all groups. There were no consistent statistically significant differences in weekly infection scores between treated and untreated cats throughout the study. Treated cats did not recover faster than untreated cats. We conclude that oral lufenuron at the dosing schedule and conditions used in this study did not prevent dermatophytosis or alter the course of infection by direct topical challenge.

Tinea capitis caused by Microsporum canis treated with terbinafine

Tinea capitis is a disease found throughout the world. It frequently affects children and only rarely adults, usually post-menopausal women. Numerous dermatophytes of the genus Microsporum and Tricophyton can cause tinea capitis and griseofulvin is still today the treatment of choice. To study the effectiveness and tolerability of terbinafine treatment in tinea capitis caused by Microsporum canis we treated 26 patients - 22 children and four women - for a period of 12 weeks. Dosage adopted was 62.5 mg day(-1) in patients weighing less than 20 kg, 125 mg day(-1) in those weighing between 20 and 40 kg, and 250 mg day(-1) in patients weighing more than 40 kg. Clinical and mycological healing was achieved in 22 patients (84.6%), tolerability was excellent and in no cases were side effects or abnormal results in blood chemistry tests observed.

Antimicrobial and free radical scavenging activity of Gentianella nitida

The antimicrobial and free radical scavenging activity of the ethanol extract and fractions of Gentianella nitida have been assessed. The most susceptible microorganisms were Candida albicans, Trichophyton mentagrophytes and Microsporum gypseum. The antifungal activity was concentrated in the 90% methanol and nonsoluble fractions, while the radical scavenging activity was stronger in the ethyl acetate and nonsoluble fractions.

In vitro evaluation of griseofulvin against clinical isolates of dermatophytes from Isfahan. In-vitro-Empfindlichkeit klinischer Dermatophyten-Isolate aus Isfahan, Iran, gegenuber Griseofulvin

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.

The novel azole R126638 is a selective inhibitor of ergosterol synthesis in Candida albicans, Trichophyton spp., and Microsporum canis

R126638 is a novel triazole with in vitro activity similar to that of itraconazole against dermatophytes, Candida spp., and Malassezia spp. In animal models of dermatophyte infections, R126638 showed superior antifungal activity. R126638 inhibits ergosterol synthesis in Candida albicans, Trichophyton mentagrophytes, Trichophyton rubrum, and Microsporum canis at nanomolar concentrations, with 50% inhibitory concentrations (IC(50)s) similar to those of itraconazole. The decreased synthesis of ergosterol and the concomitant accumulation of 14 alpha-methylsterols provide indirect evidence that R126638 inhibits the activity of CYP51 that catalyzes the oxidative removal of the 14 alpha-methyl group of lanosterol or eburicol. The IC(50)s for cholesterol synthesis from acetate in human hepatoma cells were 1.4 microM for itraconazole and 3.1 microM for R126638. Compared to itraconazole (IC(50) = 3.5 microM), R126638 is a poor inhibitor of the 1 alpha-hydroxylation of 25-hydroxyvitamin D(3) (IC(50) > 10 microM). Micromolar concentrations of R126638 and itraconazole inhibited the 24-hydroxylation of 25-hydroxyvitamin D(3) and the conversion of 1,25-dihydroxyvitamin D(3) into polar metabolites. At concentrations up to 10 microM, R126638 had almost no effect on cholesterol side chain cleavage (CYP11A1), 11 beta-hydroxylase (CYP11B1), 17-hydroxylase and 17,20-lyase (CYP17), aromatase (CYP19), or 4-hydroxylation of all-trans retinoic acid (CYP26). At 10 microM, R126638 did not show clear inhibition of CYP1A2, CYP2A6, CYP2D6, CYP2C8, CYP2C9, CYP2C10, CYP2C19, or CYP2E1. Compared to itraconazole, R126638 had a lower interaction potential with testosterone 6 beta hydroxylation and cyclosporine hydroxylation, both of which are catalyzed by CYP3A4, whereas both antifungals inhibited the CYP3A4-catalyzed hydroxylation of midazolam similarly. The results suggest that R126638 has promising properties and merits further in vivo investigations for the treatment of dermatophyte and yeast infections.

Evaluation of inhibitory effect of the plant Phyllanthus amarus against dermatophytic fungi Microsporum gypseum

OBJECTIVE

The antifungal activity of various solvent extracts (such as ether, chloroform, ethyl acetate and ethyl alcohol) of the plant Phyllanthus amarus against dermatophytic fungi Microsporum gypseum was observed.

METHOD

Antifungal bioassay in terms of reduction in weight, colony diameter and sporulation of the target fungal colony was carried out using Broth Dilution method. Results Root part of the plant, extracted in various organic solvents did not show any noticeable antifungal activity. The percentage inhibition observed in different solvent extracts of aerial part was found as reduction in weight: chloroform [50.3%], ethyl acetate [27.7%] and ethyl alcohol [12.1%], reduction in colony diameter: chloroform [53.4%], ethyl acetate [31.4%] and ethyl alcohol [15.0%] and reduction in sporulation: maximum inhibition in chloroform extract, at test concentration of 4000 ppm at incubation period of 8 days.

CONCLUSION

Chloroform fraction of the aerial part of the plant P. amarus shows significant inhibitory effect against dermatophytic fungi M. gypseum and requires chemical characterization for its bioactive principle.

(E)- and (Z)-1,2,4-Triazolylchromanone oxime ethers as conformationally constrained antifungals

A series of 1,2,4-triazolylchromanone oxime ethers were synthesized and tested for in vitro antifungal activity. Many of these derivatives exhibit high activity against Candida albicans, Saccharomyces cerevisiae, Aspergillus niger and Microsporum gypseum.

Inhibitory effect of the plant Boerhavia diffusa l. against the dermatophytic fungus Microsporum fulvum

Antifungal activity (reduction in colony diameter) of various extracts (pt. ether, chloroform, ethyl acetate, ethyl alcohol and aqueous) of aerial and root parts of Boerhavia diffusa (Nictaginaceae) was screened against dermatophytic fungi Microsporum fulvum. Statistically significant increase has been recorded in the % inhibition of the target fungal species with increasing test concentrations (1000-5000 ppm) of chloroform, ethyl acetate and ethyl alcohol extracts of the root. The maximum % inhibition observed in various solvent extracts of root was about 26% (chloroform), 46% (ethyl alcohol) and 57% (ethyl acetate) at 5000 ppm concentration with time exposure of 10 days. The colony diameter of the target mycelial colony decreased with increasing supplementation of the phytoextract, showing the presence of significant amount of some antifungal phytochemical moiety.

Development of an in vitro, isolated, infected spore testing model for disinfectant testing of Microsporum canis isolates

The isolated infected hair model is a commonly used technique to test the fungicidal efficacy of topical therapies against Microsporum canis. The most commonly used model uses mats of infective hairs, and results from various laboratories have differed. The objectives of this study were to develop a method to produce spores for testing when only mycelial forms were available and to develop a semiquantitative testing method that used only infective spores from hairs, and not pooled hair samples for testing. Ten isolates of M. canis were used in this study. Juvenile guinea pigs were easily infected using mycelial forms of M. canis and large numbers of spores were easily harvested for testing. Eight dilutions of disinfectants were tested. Fungal culture data were evaluated using an endpoint dilution at which there was 100% fungicidal activity, i.e. no growth on the plates. The 10 samples showed identical results. Chlorhexidine and Virkon(R) S were ineffective even when used at x4 the manufacturer's recommended dilution. Lime sulphur (1 : 33), enilconazole (20 microL mL(-1)), and bleach (1 : 10) were consistently effective when used at the recommended dilution. In addition, lime sulphur and enilconazole were 100% fungicidal even when the recommended concentration was diluted 1 : 4 or x4 as dilute as recommended.

[In vitro activity of voriconazole and three other antifungal agents against dermatophytes]

INTRODUCTION

The increase in infections due to dermatophytes in recent years led us to study the effectiveness of new antifungal formulations against these microorganisms.

METHODS

The in vitro activity of a new antifungal agent, voriconazole, was compared with three other antifungal agents, itraconazole, fluconazole and terbinafine, against 120 dermatophytes belonging to four species (61 Trichophyton mentagrophytes, 34 Microsporum canis, 13 M. gypseum and 12 T. rubrum). A broth microdilution method was used following the recommendations of the NCCLS document M38-P with some modifications.

RESULTS

Terbinafine was the most active agent against the dermatophytes studied (MIC90 < or = 0.03 mg/ml), followed by voriconazole (MIC90, 0.25 micro g/ml) and itraconazole (MIC90, 0.5 micro g/ml). Fluconazole was the least active antifungal agent. The most susceptible species was M. canis.

CONCLUSIONS

Voriconazole was found to have effective activity against dermatophytes.

Tinea capitis due to Microsporum audouinii in Malta

We describe a case of tinea capitis in a 4-year-old boy caused by Microsporum audouinii var. langeronii. This is the first recorded case of tinea capitis due to this dermatophyte in the Maltese Islands.

Action mechanisms of modern antifungal agents and resulting problems in the management of onychomycosis

Successful treatment of onychomycosis in the infection site depends not only on achieving the minimal inhibitory concentration (MIC) of the antifungal agent, usually determined on fresh, proliferating fungal strains, but also on the effectivity against fungal spores dormant in nail keratin. Ciclopiroxolamine and terbinafine were investigated for their fungicidal properties against proliferating and dormant dermatophyte strains. While ciclopiroxolamine was 100% effective against Trichophyton mentagrophytes (50 microg ml(-1)) and Microsporum canis (5 microg ml(-1)) both in the proliferative and dormant phase after 5 days of incubation, the same result was achieved under identical test conditions with 0.002 microg ml(-1) terbinafine using T. mentagrophytes as test organism in the proliferative and 2.0 microg ml-1 in the dormant phase. The terbinafine concentrations of 0.52 microg g(-1) measured in the nail are well below 2.0. This explains the high treatment failure and relapse rates observed under monotherapy of toenail onychomycosis even with modern antifungals. Consequently, combined therapy is recommended, beginning with atraumatic removal of the affected toenails and continuing with an antifungal nail lacquer combined with a systemic antifungal.

Flurbiprofen, a unique non-steroidal anti-inflammatory drug with antimicrobial activity against Trichophyton, Microsporum and Epidermophyton species

AIMS

The objective of this study was to determine the antifungal activity of flurbiprofen against dermatophytes like Trichophyton, Microsporum and Epidermophyton species.

METHODS AND RESULTS

Susceptibility tests were performed against dermatophytes like Trichophyton, Microsporum and Epidermophyton species by the microbroth dilution method. Among the dermatophytes tested, Trichophyton, Microsporum and Epidermophyton species are remarkably susceptible to this compound (MIC(50): 8-16 microg ml(-1)). A yeast pathogen, Candida albicans, and a bacterium, Staphylococcus aureus, are also susceptible to flurbiprofen.

CONCLUSIONS

Flurbiprofen is a non-steroidal anti-inflammatory compound with strong antifungal activity, which is not found in two well known and medically used antifungal organic acids like benzoic and salicylic acids.

SIGNIFICANCE AND IMPACT OF THE STUDY

The present action of flurbiprofen on microbes indicates its future prospects as an antimicrobial agent against dermatophytes and yeast pathogens. However, in view of the anti-inflammatory property of flurbiprofen, its antifungal action may provide an additional advantage for use as a skin ointment.

Synthesis and antimicrobial properties of 3-aryl-1-(1,1'-biphenyl-4-yl)-2-(1H-imidazol-1-yl)propanes as 'carba-analogues' of the N-arylmethyl-N-[(1,1'-biphenyl)-4-ylmethyl])-1H-imidazol-1-amines, a new class of antifungal agents

A new series of 3-phenyl-1-(1,1'-biphenyl-4-yl)-2-(1H-imidazol-1-yl)propane derivatives 2a-l (related to the antifungal bifonazole) was synthesized and tested for antimicrobial activity. A number of substituents on the phenyl ring were chosen to compare the relative biological properties with those of corresponding aza-analogues, previously described by us. The in vitro antifungal activities of the newly synthesized azoles were tested against several pathogenic fungi responsible for human disease. Test pathogens included representatives of yeasts (Candida albicans, Candida parapsilosis, Criptococcus neoformans), dermathophytes (Tricophyton verrucosum, Tricophyton rubrum, Microsporum gypseum) and moulds (Aspergillus fumigatus). Bifonazole and miconazole were used as reference drugs. Title compounds were prepared by alkylation of 1-biphenyl-4-yl-2-imidazol-1-yl-ethanone with the proper arylmethyl halide and subsequent reduction of corresponding ketones applying the Huang-Minlon modification of the Wolff-Kishner reaction.

Fluconazole in the treatment of pediatric tinea capitis caused by Microsporum canis

Fluconazole has been shown to be effective in the treatment of fungal scalp infections in children; however, there is limited experience of its use in Microsporum scalp infections. We studied 11 children with tinea capitis caused by Microsporum canis who received oral fluconazole at a dose of 5-7.5 mg/kg/day for 6 weeks. Mycological cure was observed in two of the 11 patients at week 4 from the start of therapy, in four patients at week 8 and in three patients at week 16. One of the remaining patients had positive mycology at week 8, but was unavailable for further evaluation. Fluconazole was effective in treating pediatric tinea capitis caused by Microsporum canis and was well tolerated. Clinical and mycological response was achieved in some patients weeks after the cessation of the administration of fluconazole.

Antifungal activity of sterols and triterpenes isolated from Ganoderma annulare

Three sterols, 5alpha-ergost-7-en-3beta-ol, 5alpha-ergosta-7,22-dien-3beta-ol and 5,8-epidioxy-5alpha,8alpha-ergosta-6,22-dien-3beta-ol and five triterpenes, applanoxidic acids A, C, F, G and H, have been isolated from Ganoderma annulare. The applanoxidic acids A, C and F were found to inhibit the growth of the fungi Microsporum cannis and Trichophyton mentagrophytes at concentrations of 500 to 1000 microg/ml.

Effects of lufenuron treatment in cats on the establishment and course of Microsporum canis infection following exposure to infected cats

OBJECTIVE

To determine effects of lufenuron treatment in cats on the establishment and course of Microsporum canis infection following exposure to infected cats.

DESIGN

Experimental trial.

ANIMALS

24 healthy juvenile domestic shorthair cats.

PROCEDURE

8 cats were given lufenuron PO (133 mg/cat/mo, equivalent to a dose of 100 to 130 mg/kg [45 to 59 mg/lb] at the beginning of the study and 25 to 35 mg/kg [11 to 16 mg/lb] at the end of the study), and 8 were given lufenuron SC (40 mg every 6 months). The remaining 8 were used as untreated control cats. After 4 months, cats were challenged by the introduction of cats with mild, experimentally induced M canis infection into the rooms where cats were housed. Extent of resulting infections in the naïve cats was monitored for 22 weeks by physical examination and fungal culture.

RESULTS

All lufenuron-treated and control cats became infected with M canis. Cats treated with lufenuron had significantly lower infection scores, compared with control cats, during the early weeks following exposure, and there was a more prolonged initial progression phase of the infection. Once infections reached peak intensity, they resolved over similar periods in lufenuron-treated and control cats.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that oral or SC administration of lufenuron to cats, at the dosages used and under the conditions of this study, did not prevent establishment of dermatophytosis following exposure to infected cats. Infection was established more slowly among cats treated with lufenuron, but once established, infection resolved in approximately the same amount of time in lufenuron-treated as in control cats.

[Study of the cerbiden spectrum of antifungal activity against fungi pathogenic to humans]

A comparatively wide spectrum of cerbiden antifungal activity against the fungi pathogenic for human has been determined. Cerbiden is active against clinical and museum strains of Candida spp. and other yeasts; Trichophyton spp., Microsporum spp. of Dermatophytaceae family, museum strains of some species from Mucor, Rhizopus, Rhizomucor genera of Mucoraceae family; and it is not active with respect to studied fungi of Aspergillus and Penicillium genera of Moniliaceae family.

Inhibition of dermatophytes by optical brighteners

The aim of this study was to investigate a possible effect of optical brighteners on the growth of dermatophytes. Typical strains of Trichophyton rubrum, T. mentagrophytes, Microsporum canis and Epidermophyton floccosum were grown on agar plates containing two different brighteners of stilbenedisulfonic acid type in concentrations between 5 x 10(-5) and 1 x 10(-2) mol l-1 and their thallus diameters were compared with controls. In addition, hyphae grown with brighteners were compared with controls by fluorescence microscopy and by transmission electron microscopy. Both brighteners had a significant dose-dependent growth-suppressive effect on all dermatophytes tested, that was complete at a concentration of 10(-2) and 10(-3) mol l-1, respectively. Fluorescence microscopy of hyphae showed a pronounced fluorescence of the septal areas and a less-intense staining of the outer cell walls. Electron microscopy revealed a marked thickening and blurred contours of the cell walls grown with brighteners. These new observations relate very well to an interference of optical brighteners with the formation of normal chitin fibrils as described previously. Optical brighteners of stilbenedisulfonic acid type may be rewarding objects for the development of new antifungal agents.

Synergistic inhibition of the growth in vitro of Microsporum canis by miconazole and chlorhexidine

An agar dilution technique was used to assess the minimum inhibitory concentrations (MIC) of miconazole, chlorhexidine and a 1:1 combination of both agents for 10 isolates of Microsporum canis. For nine of 10 of the isolates, a combination of miconazole and chlorhexidine was more effective than either agent alone; fractional inhibitory concentration indices indicated a synergistic effect for five isolates and an additive effect for four. These results illustrate the potent antimycotic effect of miconazole and chlorhexidine against M. canis and are in accordance with previous clinical studies that showed the value of using miconazole and chlorhexidine shampoo in association with oral griseofulvin in the treatment of feline dermatophytosis caused by M. canis.

In vitro antagonistic activity of monoterpenes and their mixtures against 'toe nail fungus' pathogens

The antibiotic effect of the active ingredients in Meijer medicated chest rub (eucalyptus oil, camphor and menthol) as well as the inactive ingredients (thymol, oil of turpentine, oil of nutmeg and oil of cedar leaf) were studied in vitro using the fungal pathogens responsible for onychomycosis, such as the dermatophytes Tricophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Epidermophyton fl occosum and Epidermophyton stockdale. The zones of inhibition data revealed that camphor (1). menthol (2). thymol (3). and oil of Eucalyptus citriodora were the most efficacious components against the test organisms. The MIC(100) for mixtures of these four components in various carrier solvents revealed that formulations consisting of 5 mg/mL concentrations of each have a potential to be efffective in controlling onychomycosis.

Parmelia cirrhatum: a potential source of broad spectrum natural antifungal

During antifungal screening of some plants, the water extract of lichen, Parmelia cirrhatum was found to be most effective against tested pathogenic fungi at the range of 60-80 microL/mL concentrations. The extract showed heavy doses of inoculum potential at 80 microL/mL and the antifungal activity of the extract did not expire up to 24 months of storage. The extract did not showed any irritation on mammalian skin up to 10% concentration. Thus, the water extract of Parmelia cirrhatum can be used a potential source of natural antifungal against fungal infections.

Incidence of dermatophytes and cyclohexamide resistant fungi on healthy children hairs and nails in nurseries

In order to estimate the prevalence of dermatophytes and other fungi on healthy children hairs and nails, 92 hair samples and 85 nail samples (groups of 10 finger nails from each child) were collected from 5 nurseries (children aged 9 months up to 4 years) in Assiut city. From hair samples 22 species were collected, Trichophyton (2 species) and Microsporum (2 species) were the only recovered dermatophytes in addition to well known keratinophilic genus Chrysosporium (4 species). From nail samples, 18 species were identified, Trichophyton was represented by 4 species, Microsporum, 2 species and Chrysosporium, 4 species. Also, several other saprophytes and cycloheximide resistant fungi were isolated.

Antifungal activity of Boerhavia diffusa against some dermatophytic species of Microsporum

Various extracts petroleum ether, chloroform, ethyl acetate and ethyl alcohol) of aerial and root parts of Boerhavia diffusa was sereened for Antitungal activity (Inhibition in sporulation) against dermatophytic fungi Microsporum gypseum, M. fulvum and M. canis by using broth dilution method. Extracts of aerial part not show any noticeable antifungal activity. Ethyl acetate extract of root part of the plant was found to be most effective of against target fungal species. The maximum inhibition of mycelial growth was observed for M. gypseum (78.83%) followed by M. fulvum (62.33%) and M. canis (42.30%) of ethyl acetate in the test concentration of 1000 microg/ml 24 hours of incubation. The sporulation of target fungal species decreases with increasing supplementation of phytoextract, confirms the presence of some antifungal phytochemical moiety in roots of the plant.

In vitro antimicrobial activity of ethanol and water extracts of Cassia alata

Crude ethanol and water extract of leaves and barks from Cassia alata were tested in vitro against fungi, (Aspergillus fumigatus and Microsporum canis), yeast (Candida albicans) and bacteria (Staphylococcus aereus and Escherichia coli). C. albicans showed concentration-dependent susceptibility towards both the ethanol and water extracts from the barks, but resistant towards the extracts of leaves. The degree of susceptibility varied, the water extract from barks showed bigger inhibition zone than the ethanol extracts (12-16 and 10-14 mm, diameter respectively). The growth of Aspergillus fumigatus and Microsporum canis were not affected by all types of the plant extracts. Results were comparable to standard antifungal drug Tioconazole (18 mm diameter) at equivalent concentration. The anti-bacterial activity of C. alata extracts on S. aureus was detected with only the leaves extracts using water and ethanol. The water extract exhibited higher antibacterial activity than the ethanol extract from leaves (inhibition zones of 11-14 and 9-11 mm, respectively). E. coli showed resistance to all types of extracts. Based on the current findings, it can be concluded that this plant has antimicrobial activity, which is as potent as standard antimicrobial drugs against certain microorganisms.

Fluconazole downregulates metallothionein expression and increases copper cytotoxicity in Microsporum canis

Azole antifungals are widely used to treat infections with dermatophyte fungi. Whereas it is well established that this class of drugs interferes with fungal ergosterol synthesis, little is known about its potential other biological effects. Here we report the isolation and structural organization of Microsporum canis metallothionein gene and demonstrate that fluconazole is able to downregulate the baseline as well as copper-induced expression of this gene. Since this effect occurred within 30 min after exposure of the fungus to fluconazole, it is unlikely that it is due to impaired ergosterol synthesis. Our additional demonstration that fluconazole enhances copper toxicity for M. canis suggests that inhibition of metallothionein expression by fluconazole is biologically relevant and may represent an important additional mode of the antifungal action of this drug. Therefore our data indicate that antifungal effects of azole derivatives might not only be due to interference with cell wall synthesis but may also affect other biological circuits within the fungal cells.

[Comparative molecular field analysis(CoMFA) of allylamine and benzylamine antimycotics]

"Active analog approach" has been employed to search the pharmacophoric conformation of the allylamine and benzylamine antimycotics. A local minimum energy conformation, which is very similar to the crystallographically determined coordinate of naftifine or terbinafine, has been applied to build all compounds. Comparative molecular field analysis (CoMFA) has been used to examine the correlations between the activities against 6 common human pathogenic fungi and the physicochemical properties of 62 allylamine and benzylamine compounds which had been aligned by rms fit rule. The predictive abilities of the resulting 3D-QSAR models have been tested by 8 new synthetic compounds and 5 reported compounds. Finally, we propose an interaction pattern between allylamine, benzylamine antimycotics and the active site of pseudoreceptor based on the results of 2D-QSAR and 3D-QSAR.

Antifungal activity of essential oils from leaves and flowers of Inula viscosa (Asteraceae) by Apulian region

Some essential oils from several plants (Artemisia verlotorum, Lavandula augustifolia, Ocimum gratissimum) have proved to have acaricidal, antifungal and antibacterial activity. Inula viscosa Ait. (Asteraceae), a plant growing spontaneously in the Mediterranean area, is currently used by popular medicine for its therapeutic effects. Flavonoids, azulenes, sesquiterpenes, and essential oils have been isolated and identified from its leaves. This paper reports the results of the composition and antifungal activity in vitro against dermatophytes and Candida spp. of the four essential oils obtained by steam distillation of the leaves, flowers, whole plant and whole plants without flower extracts of I. viscosa. All the extracts proved to have a significant antifungal activity against dermatophytes even at low concentrations (0.01 mg/ml). The leaf extracts exhibited the greatest antifungal efficacy. The high concentration of the sesquiterpene (carboxyeudesmadiene), occurring in the leaf extracts, may explain its greater antifungal activity.

[Anti-yeast activity of ethanol extracts of Lilium candidum L]

The paper deals with anti-yeast activity of ethanolic extracts from the flowers and bulbs of Lilium candidum L., Liliaceae, as well as some compounds isolated from these extracts. Several different methods were used for the determination of anti-yeast activity: Lowry method of protein determination, dilution and cultivation method. The extract from the bulbs was shown to be more active than the extract from the flowers, while isolated compounds were inactive against the tested yeasts.