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Experimental inoculation of dermatophytes on psoriatic skin.

Two dermatophytic agents, Trichophyton rubrum and Trichophyton mentagrophytes were used in the experimental inoculation of psoriatic lesions in 27 volunteer patients (13 males and 14 females with an age range from 17 to 72 yr). T. rubrum was inoculated in 14 patients and T. mentagrophytes (varietas granulare) in 13. For purposes of control in each patient the same agent was also inoculated on healthy skin. Results were noted once a week for a period of 1 mo. A positive response was found in 12 of the 14 patients inoculated with T. rubrum but only in 4 of the 13 inoculated with T. mentagrophytes. Healthy skin was found to have a positive response in only 5 cases, in 4 with T. rubrum, and in 1 with T. mentagrophytes. These results confirm the possibility of invasion of psoriatic lesions by dermatophytes and suggest that the coexistance of psoriasis and dermatophytic infection may be not always purely coincidental. The importance of the awareness of the presence of mycotic lesions and their possible spread with the application of steroid ointments under occlusive dressings in a psoriatic patient is stressed.

Adolescent↗

An ATP bioluminescence assay applicable to rapid fluconazole susceptibility testing of dermatophytes.

An ATP bioluminescence assay as a rapid reference method for fluconazole (FLCZ) susceptibility testing of dermatophytes, as well as yeasts, was developed and evaluated by comparing it with viability, turbidity and fungal protein content-based conventional methods. FLCZ susceptibility results obtained with strains of Candida albicans and dermatophytes by the bioluminescence method in high-resolution medium were well correlated with those obtained by conventional methods currently used in clinical microbiology laboratories or reported previously, including a broth dilution method by the National Committee for Clinical Laboratory Standards (NCCLS). Thus, ATP bioluminescence assay can be used to monitor fungal growth in liquid culture media. The procedure has considerable potential for the rapid testing of FLCZ susceptibility of dermatophytes and other fungi.

Adenosine Triphosphate↗

Short-duration therapy with terbinafine for dermatophyte onychomycosis: a multicentre trial.

Terbinafine, an orally active antifungal agent, is effective in the treatment of dermatophyte onychomycosis when given for 12 months in the case of toenail infection (TN) and 6 months for fingernail infection (FN). The rapid response and short mycological cure time indicate a potential for a reduced treatment duration. In this multicentre double-blind placebo-controlled trial, 112 patients with mycologically proven dermatophyte onychomycosis were given 250 mg/day of terbinafine for 3 months. Twenty-seven patients were excluded, leaving 85 fully evaluable [average age 44 (range 19-78) years; 55 men; 75 TN, 10 FN]. Forty-nine of the TN patients and seven of the FN patients received terbinafine. At the end of the follow-up period, the TN mycological cure rate with active treatment was 82% (37/45), but no patient taking placebo maintained mycological cure (P less than 0.001). Of the FN patients treated with active drug, 71% (5/7) achieved mycological cure at the end of follow-up. Minor side-effects occurred in 41% of the placebo-treated group compared with 33% of those taking terbinafine. These adverse events were mainly gastrointestinal. Two patients taking terbinafine discontinued treatment--one with tonsillitis and another with diarrhoea. In conclusion, 3-month treatment with terbinafine is effective, well tolerated and safe in dermatophyte onychomycosis. Short-duration therapy for this indication represents a major therapeutic advance.

Adult↗

Antifungal activity of Juniperus essential oils against dermatophyte, Aspergillus and Candida strains.

AIMS: The increasing resistance to antifungal compounds and the reduced number of available drugs led us to search therapeutic alternatives among aromatic plants and their essential oils, empirically used by antifungal proprieties. In this work the authors report on the antifungal activity of Juniperus essential oils (Juniperus communis ssp. alpina, J. oxycedrus ssp. oxycedrus and J. turbinata). METHODS AND RESULTS: Antifungal activity was evaluated by determination of MIC and MLC values, using a macrodilution method (NCCLS protocols), on clinical and type strains of Candida, Aspergillus and dermatophytes. The composition of the oils was ascertained by GC and GC/MS analysis. All essential oils inhibited test dermatophyte strains. The oil from leaves of J. oxycedrus ssp. oxycedrus is the most active, with MIC and MLC values ranging from 0.08-0.16 microl ml(-1) to 0.08-0.32 microl ml(-1), respectively. This oil is mainly composed of alpha-pinene (65.5%) and delta-3-carene (5.7%). CONCLUSIONS: J. oxycedrus ssp. oxycedrus leaf oil proved to be an emergent alternative as antifungal agent against dermatophyte strains. delta-3-Carene, was shown to be a fundamental compound for this activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Results support that essential oils or some of their constituents may be useful in the clinical management of fungal infections, justifying future clinical trials to validate their use as therapeutic alternatives for dermatophytosis.

Aspergillosis↗

Antifungal susceptibility testing with dermatophytes.

The determination of the in vitro activity of antimycotics against dermatophytes has for long been considered as irrelevant from a practical point of view. Recently, however, this approach has been questioned. Various different tests such as agar diffusion test, agar dilution test and broth dilution test can be used for the determination of minimum inhibitory concentrations with dermatophytes. A close correlation between in vitro data and clinical outcome could especially be demonstrated for the micro dilution test. In future, the antimycogram of a dermatophyte isolated from an individual patient should gain more and more importance for the selection of the drug to be used and its dosage.

Antifungal Agents↗

Outdoor airborne dermatophytes and related fungi: a survey in Turin (Italy).

Aerial dispersal of propagules, an important mechanism of fungal spread, has not been sufficiently studied for skin-infecting fungi. Over a period of one year, we have monitored the distribution of dermatophytes in the air of Turin. We have also examined the related aleurioconidic and arthroconidic fungi, which share physiological and morphological characters with dermatophytes and are sometimes considered to cause similar infections. A viable volumetric collector was used. Samples were taken each month; each sample collected 9.6 m3 of air. The medium was Dermasel agar supplemented with cycloheximide and chloramphenicol. Thirty-two species were isolated, within the genera Aphanoascus, Arthrographis, Chrysosporium, Geomyces, Gymnoascus, Malbranchea, Myceliophthora, Myxotrichum, Ovadendron, Trichophyton. The total mycoflora load obtained was rather low throughout the year and particularly in the hottest months. Apart from T. rubrum and T. mentagrophytes, which are dermatophytes very frequently encountered in Turin, many of the species detected have known pathogenic potential and/or keratinolytic activity.

Air Microbiology↗

Dermatophytes on the feet of HIV-infected patients: frequency, species distribution, localization and antimicrobial susceptibility.

Skin scrapings from the toe clefts, soles and nail plates of 138 HIV-infected patients at various stages were examined for the presence of dermatophytes using both microscopy and culture. Dermatophytes, in particular Trichophyton rubrum, could be grown in 58 cases (42%). Although cultures were more often positive in late stages of disease, there was no close correlation with the clinical stage or the T4/T8 ratio. Susceptibility to itraconazole, but not to other antimycotics, was correlated with the immune status (P < 0.05). Pedal dermatophyte infection does not seem to be a major problem in HIV infection.

Adult↗

UV susceptibility and negative phototropism of dermatophytes.

High doses of ultraviolet radiation (UVR) have well-known inhibitory effects upon dermatophytes. In the present study, the effect of repetitive low doses of UVR on mycelial growth of dermatophytes was tested. Pellets of Trichophyton rubrum, T. mentagrophytes and Microsporum canis were placed between two thin layers of Sabouraud glucose agar. Obverse, reverse or both sides of these 'sandwich' agars were irradiated for 10 days twice daily with 0.13 or 0.17 J cm-2 UVB. To simulate microaerophilic conditions, one or both agar sides were covered by transparent airtight plastic lids. In addition, T. rubrum was also grown as usual on plates of Sabouraud glucose agar without any covering, and irradiated on its obverse side twice daily with UVA (13.5 J cm-2), UVB (0.17, 0.34 or 0.69 J cm-2) or infrared light, or once only with 3.8-15.1 J cm-2 UVB. As a result, thallus diameters of all strains were found to be reduced by repetitive UVB irradiation under both aerobic and microaerophilic growth conditions. T. rubrum was unaffected by infrared irradiation, responded with an increased pigmentation to UVA (13.5 J cm-2 twice daily) and was inhibited by a single dose of 15.1 J cm-2 UVB. Negative phototropism of dermatophytes is a new observation. It may be biologically relevant as a mechanism to evade harmful doses of UVR.

Aerobiosis↗

In vitro antifungal activity of Polyporaceae against yeasts and dermatophytes.

The antifungal activity of 38 Polyporaceae sensu lato against yeasts and dermatophytes was tested in vitro by the agar dilution method. Strains were typed organisms and clinical isolates. In this first report, Pycnoporellus fulgens (Fr.) Donk was found to be the most active species against pathological fungi and showed broad-spectrum antifungal activity against yeasts (Candida albicans, Candida glabrata) and dermatophytes (Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum). Other Polyporaceae species also showed antifungal activity, but only against dermatophytes.

Antifungal Agents↗

Extracellular enzyme activities of dermatophytes and yeast isolates on solid media.

A total of 123 isolates of 14 species of dermatophytes and yeasts were screened for the activity of five extracellular enzymes including elastase, keratinase, protease (gelatinase), lipase and phospholipase, by using solid media. The optimal production and activity of each enzyme was determined with regard to different pH and temperatures. Keratinase activity was high with all the tested fungi with exception of Malassezia furfur. Protease (gelatinase) was produced only by dermatophytes. Elastase was secreted by three dermatophytes viz. Microsporum gypseum, Trichophyton mentagrophytes var. mentagrophytes and T. verrucosum, whereas lipase and phospholipase were detected in all the species except T. violaceum.

Arthrodermataceae↗

[Dermatophytes do not produce sialidase in vitro].

Sialidase (EC 3.2.1.18) is a pathogenicity factor of many microorganisms, and may also play a role in adhesion of dermatophytes to the epithelia of their hosts by the hydrolytical cleavage of terminal, negatively charged sialic acids of glycoconjugates on the cell surfaces, thus allowing fungal lectins to bind to the subterminal sugars. Therefore, 116 strains of seven species of dermatophytes were investigated for sialidase production. Two highly sensitive, quantitative sialidase assays were applied to cell homogenates and culture supernatants from seven different media of the fungi, but were always negative for sialidase activity. However, sialidase activity was always detected in Ophiostoma stenoceras used as a positive control cultivated in parallel; the enzyme was inducible by sialylated mucins. A sialidase-dependent pathomechanism for dermatophytes appears unlikely based on the results presented.

Animals↗

In vitro evaluation of voriconazole against clinical isolates of yeasts, moulds and dermatophytes in comparison with itraconazole, ketoconazole, amphotericin B and griseofulvin.

The in vitro activity of voriconazole (UK-109, 496), a new antifungal triazole derivative, against 650 clinical isolates of yeasts, moulds and dermatophytes was compared with that of itraconazole, ketoconazole, amphotericin B and griseofulvin. The geometric means of the minimum inhibitory concentrations (MICs) of voriconazole were 0.05 microgram ml-1 against yeasts (n = 187), 0.58 microgram ml-1 against moulds (n = 260) and 0.08 microgram ml-1 against dermatophytes (n = 203). The overall activity of voriconazole against yeasts and moulds was good, being similar to that of itraconazole, ketoconazole and amphotericin B. Voriconazole was highly effective against Aspergillus fumigatus (mean MIC 0.23 microgram ml-1) and other Aspergillus species and showed noteworthy activity (mean MICs 0.08-0.78 microgram ml-1) against emerging and less common clinical isolates of opportunistic moulds, such as Alternaria spp., Cladosporium spp., Acremonium spp., Chrysosporium spp. and Fusarium spp. On the other hand, voriconazole was less active in vitro than the comparative agents studied against various species of zygomycetes, such as Mucor spp., Rhizopus spp. and Absidia spp. Voriconazole and the other two azoles, itraconazole and ketoconazole, were more active than griseofulvin in vitro against most dermatophytes tested.

Amphotericin B↗

Pulse itraconazole vs. continuous terbinafine for the treatment of dermatophyte toenail onychomycosis in patients with diabetes mellitus.

BACKGROUND: Oral terbinafine and oral itraconazole are two of the most common agents used for the treatment of toenail dermatophyte onychomycosis. Despite the fact that diabetic patients are more likely to have onychomycosis than normal individuals are, there is little research into the efficacy of standard oral regimens of terbinafine and itraconazole for onychomycosis in the diabetic population. STUDY DESIGN: We present a prospective, randomized, single-blind, parallel group, comparator-controlled, multi-centre study designed to assess the efficacy of the pulse itraconazole (200 mg twice daily, 1 week on, 3 weeks off, for 12 weeks) vs. continuous terbinafine (250 mg once daily for 12 weeks) oral therapies in the treatment of dermatophyte toenail distal and lateral subungual onychomycosis (DLSO) in the diabetic population. EFFICACY PARAMETERS: Primary efficacy measures included mycological cure rate (negative KOH and culture) and effective cure (mycological cure plus nail plate involvement of 10% or less) at Week 48. RESULTS: At Week 48, mycological cure was attained by 88.2% (30 of 34) and 79.3% (23 of 29) of patients in the itraconazole and terbinafine groups, respectively (P not significant). Effective cure (mycological cure with <or=10% of nail plate involvement) was attained by 52.9% (18 of 34) of the itraconazole group and 51.7% (15 of 29) of the terbinafine group (P not significant). Three itraconazole patients experienced side effects in the form of gastrointestinal problems. There were no serious adverse events and no interactions with concomitant medications recorded. DISCUSSION: Both continuous terbinafine and itraconazole pulse therapy are effective and safe in the management of dermatophyte toenail onychomycosis in people with diabetes.

Antifungal Agents↗

Use of arbitrarily primed polymerase chain reaction to differentiate Trichophyton dermatophytes.

Dermatophytes such as Trichophyton species are common human pathogens, the infection of which results in dermatophytosis (also known as ringworm). Several laboratory tests are used routinely for the diagnosis of dermatophytosis, but they are either slow or lacking specificity. Through examination of genomic DNA from Trichophyton dermatophytes and other fungi in arbitrarily primed PCR, it was shown that a random primer 5'-ACCCGACCTG-3' produced bands of 4.3 kb, 1.9 kb, 1.7 kb and 0.7 kb in T. rubrum DNA, bands of 2.5 kb, 1.9 kb and 0.8 kb in T. mentagrophytes var. interdigitale and T. mentagrophytes var. mentagrophytes DNA, and bands of 2.5 kb, 1.9 kb, 1.5 kb and 0.9 kb in T. tonsurans DNA. This primer amplified bands of different sizes in other fungal DNA. Therefore, based on the distinct band patterns observed in arbitrarily primed PCR using this primer, T. rubrum, T. mentagrophytes and T. tonsurans dermatophytes could be rapidly differentiated.

DNA Primers↗

Dermatophytes in healthy Chilians.

To study the presence of dermatophytes in healthy persons, 1060 skin samples from the scalp, complexion, inguinal region and sole were taken from 265 healthy individuals who live in Valdivia, Chile. The carpet technique of Mariat and Tapia was used. The isolated dermatophytes were identified according to Rebell and Taplin. Zoophilic dermatophytes were isolated in only 4.9% of the healthy individuals. Microsporum canis was found in the scalp and inguinal area of children (1.5%). Trichophyton mentagrophytes was isolated from the feet and inguinal skin of adults (3.4%). Measures to avoid a mycosis or/and to reduce the risk of infections are suggested.

Adolescent↗

Antimycotic susceptibility testing of dermatophytes in microcultures with a standardized fragmented mycelial inoculum.

Standardization of a fragmented dermatophyte mycelial inoculum free of conidia for use in a broth microculture antimycotic susceptibility testing system is described. Ten clinical dermatophyte isolates were grown in submerged broth cultures at 35 degrees C. The mycelia were harvested before conidia appeared and were fragmented to 10 to 50-micron segments with a Broeck ground-glass tissue grinder. The density of the fragmented mycelium preparation was found to be adjustable on the basis of its spectrophotometric density expressed as absorbance measured at 450 nm. The minimal absorbance density that produced a 100% inoculation efficiency was determined for each isolate, and from these data an absorbance density of 0.600 was selected for inoculation of microcultures used in antimycotic susceptibility testing. The 0.600-absorbance inoculum of each dermatophyte isolate was tested for its capacity to successfully inoculate antimycotic agent-containing microcultures and generate minimal inhibitory concentrations of griseofulvin, clotrimazole, miconazole, and ketoconazole. The effect of the length of incubation on the minimal inhibitory concentrations was determined. It was concluded that the 0.600-absorbance density fragmented mycelial inoculum assured the rapid and uniform inoculation of the broth microculture antimycotic susceptibility system.

Antifungal Agents↗

Isolation of glycopeptides with skin test activity from dermatophytes.

By using ethylene glycol extraction of whole submerged cultures followed by Sephadex G-200 and diethylaminoethyl-Sephadex chromatography, we isolated four distinct glycopeptides from Trichophyton mentagrophytes, T. rubrum, and Microsporum canis. Chemical analyses revealed that these glycopeptides contained mostly carbohydrate (42.5 to 81.6%) and protein (4.3 to 11.3%), with lesser amounts of phosphorus (0.4 to 6.0%) and hexosamines (0.3 to 0.6%). Based upon total carbohydrate and monosaccharide content, these dermatophyte glycopeptides could be divided into two chemical groups: glucopeptides (DSI1) and mannopeptides (DSI2, DSII1, and DSII2). The mannopeptides and glucopeptides of each species of dermatophyte were not significantly different chemically from those derived from the other two dermatophyte species studied. Skin testing of DSI1-glycopeptides or DSI2-mannopeptides in immunized guinea pigs indicated that only the DSI2-mannopeptides elicited a delayed hypersensitivity reaction. Skin testing T. mentagrophytes 62-infected guinea pigs with the four purified DS-glycopeptides, as well as earlier fractions from the purification scheme, derived from T. mentagrophytes, T. rubrum, and M. canis, again indicated that only the DSI2-mannopeptides of the two Trichophyton species elicited a delayed hypersensitivity reaction. The number of infections or duration of infection had no effect on the size of the skin test response. DSI2-mannopeptides were non-cross-reactive between genera when tested in Trichophyton-immunized or -infected guinea pigs and Microsporum-immunized guinea pigs.

Animals↗

Suppression of in vitro lymphocyte transformation during an experimental dermatophyte infection.

During primary Trichophyton mentagrophytes infection of strain 2 guinea pigs, the colony-forming units (CFU) of fungi present within the lesion peaked between days 7 and 14, whereas the severity of the lesion itself peaked between days 11 and 16. Concomitant with the latter peak, a pronounced depression in the in vitro mitogenic activity of spleen cells (SPC) and lymph node cells (LNC) was observed. Only after resolution of the primary infection (day 21) did LNC show increased deoxyribonucleic acid (DNA) synthesis in the presence of fungal antigens. During cutaneous reinfection, there was no distinct peak fungal load and CFU appeared to decrease steadily during the accelerated course of a reinfection disease. LNC from guinea pigs with severe, ulcerated reinfection lesions generally exhibited a heightened response to fungal antigen in vitro. LNC from guinea pigs with mild reinfection dermatophytosis had depressed in vitro reactivity to mitogens and dermatophyte antigen. The suppression of blastogenic activity during dermatophyte infection appeared to be associated with autologous serum components, since increased DNA synthesis resulted when SPC or LNC were cultured with fetal calf serum. The depressed in vitro DNA synthesis of lymphocytes (cultured with dermatophyte antigens) that were harvested during reinfection was not accompanied by an impaired ability of infected guinea pigs to respond with a delayed-type hypersensitivity skin test in vivo. These results support the hypothesis that experimental T. mentagrophytes dermatophytosis is a cell-mediated hypersensitivity disease that can be modified by immunosuppressive control mechanisms elaborated or induced by the fungus.

Animals↗