Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine

Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies.     

Determination of susceptibility/resistance to antifungal drugs of Trichophyton mentagrophytes isolates by a macrodilution method

Onychomycosis is a common adult human mycosis, and dermatophytes of the Trichophyton genera are the most frequently isolated microorganism. Globally, from 3% to 10% of the human population is attacked by ony cho mycosis, and many cases involve toenails. The aim of this work was to determine the minimal inhibitory concentrations (MICs) of antifungal drugs (fluconazole, ketoconazole, itraconazole, terbinafine, and griseofulvin) often used for the treatment of ungueal dermatophytosis caused by Trichophyton mentagrophytes. The MICs were determined by the broth medium macrodilution method. The results showed that activities of terbinafine and itraconazole were significantly higher (MIC <0.007-0.015 microg.mL -1 and MIC = 0.062-1.000 microg.mL -1, respectively). All isolates had reduced susceptibility to fluconazole (MIC = 16 to >64 microg.mL -1). The MICs of ketoconazole and griseofulvin varied among strains, ranging from 0.125 to 2.000 microg.mL -1 for ketoconazole and from 0.25 to 2.00 microg.mL -1 for griseofulvin. These MICs were higher than those of other studies cited, possibly because of differences in culture medium used in the other studies.     

Standardization of hyphal growth inhibition rate as a means of evaluating Microsporum spp. in vitro susceptibility to terbinafine, griseofulvin, and ciclopiroxolamine

Reference methods for antifungal susceptibility tests recommend the use of conidia as inoculum. However, some isolates produce few conidia, while the invasive form of filamentous fungi in general is hyphae making susceptibility tests infeaseble. These facts suggest that other than conidia broth dilution method is required for susceptibility tests. The aim of this study was to clarify if the hyphal growth inhibition rate could be used as a method of determining the antifungal susceptibility of genus Microsporum. For this reason, a method which traces hyphal tips automatically and measures their growth rate was standardized for Microsporum spp. Control growth curves and test growth curves obtained by real-time observation of the hyphae groups responses to different concentrations of terbinafine, griseofulvin, and ciclopiroxolamine were used to compare with minimum inhibitory concentrations (MICs) obtained by conidia broth microdilution method. A visible reduction in the growth inhibition rate was observed when hyphal activity was evaluated using the third or fourth serial two-fold dilution below the MIC determined by broth microdilution for terbinafine and ciclopiroxolamine. For griseofulvin, this reduction occurred after the fifth dilution below the MIC. This study highlights the importance of the inoculum type used to determine the in vitro susceptibility of Microsporum strains. We conclude that measurement of hyphal growth inhibition, despite being time consuming, could be a suitable method for evaluating antifungal susceptibility, particularly for fungi as Microsporum spp. that produce a small (or not at all) number of conidia.     

In vitro susceptibility of dematiaceous fungi to ten antifungal drugs using an agar diffusion test

We assessed the usefulness of an agar diffusion method, NeoSensitabs, to determine in vitro sensitivity of 52 isolates of dematiaceous filamentous fungi against ten antifungal agents: amphotericin B, 5-fluorocytosine, ketoconazole, fluconazole, itraconazole, terbinafine, bifonazole, miconazole, clotrimazole, and griseofulvin. For the preparation of the inoculum, a spectrophotometric method including both Shadomy and Casitone agar (CAS) culture media was used. Dematiaceous filamentous fungi were sensitive to itraconazole, terbinafine and bifonazole. Ketoconazole (90.4%), miconazole (71%), and clotrimazole (46%) showed a variable susceptibility pattern. Most species were resistant to griseofulvin and fluconazole (96%). All isolates were resistant to 5-fluorocytosine. Sixty-three percent of strains were susceptible to amphotericin B and 28.8% resistant. Inhibition zones in the antifungal susceptibility testing did not vary according to culture medium, although fungal growth was better in CAS. Variations in antifungal sensitivity in Exophiala spinifera and Fonsecaea pedrosoi spp. would justify an in vitro susceptibility study when indicating antifungal therapy. These results show that NeoSensitabs agar diffusion method is simple, rapid, and low-cost and can be available to many clinical laboratories for the study of in vitro sensitivity of dematiceous moulds.     

4种抗真菌药物对糖尿病大鼠血糖的影响

目的观察酮康唑、氟康唑、伊曲康唑和特比萘芬与胰岛素组合使用以及单独使用时对糖尿病大鼠血糖水平的影响。方法建立糖尿病大鼠模型,随机分为10组,每组5只。前4组皮下注射胰岛素的同时分别喂食4种抗真菌药物;第5组单独皮下注射胰岛素;第6—9组分别喂食4种抗真菌药物;第10组既不注射胰岛素也不喂食抗真菌药物。定时对糖尿病大鼠尾静脉采血,使用CX5PRO生化检测仪对其血糖进行检测。结果酮康唑、氟康唑和伊曲康唑分别与胰岛素合用时,可使糖尿病大鼠血糖降低（P〈0．05）;不与胰岛素合用时,氟康唑和伊曲康唑均可使糖尿病大鼠血糖升高（P〈0．05）;特比萘芬无论是否与胰岛素合用,对糖尿病大鼠的血糖水平均无影响（P〉0．05）。结论唑类抗真菌药物无论是否与胰岛素合用均会影响糖尿病大鼠的血糖水平,特比萘芬无论是否与胰岛素合用,都不会影响糖尿病大鼠的血糖水平。     

Antifungal Activity of Antifungal Drugs,as Well as Drug Combinations Against <Emphasis Type="Italic">Exophiala dermatitidis</Emphasis>

To evaluate the in vitro efficacy of common antifungal drugs, as well as the interactions of caspofungin with voriconazole, amphotericin B, or itraconazole against the pathogenic black yeast Exophiala dermatitidis from China, the minimal inhibitory concentrations (MICs) of terbinafine, voriconazole, itraconazole, amphotericin B, fluconazole, and caspofungin against 16 strains of E. dermatitidis were determined by using CLSI broth microdilution method (M38-A2). The minimal fungicidal concentrations (MFCs) were also determined. Additionally, the interactions of caspofungin with voriconazole, amphotericin B, itraconazole or fluconazole, that of terbinafine with itraconazole, or that of fluconazole with amphotericin B were assessed by using the checkerboard technique. The fractional inhibitory concentration index (FICI) was used to categorize drug interactions as following, synergy, FICI ≤ 0.5; indifference, FICI > 0.5 and ≤4.0; or antagonism, FICI > 4.0. The MIC ranges of terbinafine, voriconazole, itraconazole, amphotericin B, fluconazole, and caspofungin against E. dermatitidis were 0.06–0.125 mg/l, 0.25–1.0 mg/l, 1.0–2.0 mg/l, 1.0–2.0 mg/l, 16–64 mg/l, and 32–64 mg/l, respectively. The in vitro interactions of caspofungin with voriconazole, amphotericin B, and itraconazole showed synergic effect against 10/16(62.5%), 15/16(93.75%), and 16/16(100%) isolates, while that of caspofungin with fluconazole showed indifference. Besides, the interaction of terbinafine with itraconazole as well as that of fluconazole with amphotericin B showed indifference. Terbinafine, voriconazole, itraconazole, and amphotericin B have good activity against E. dermatitidis. The combinations of caspofungin with voriconazole, amphotericin B or itraconazole present synergic activity against E. dermatitidis. These results provide the basis for novel options in treating various E. dermatitidis infections.     

Evaluation of some fungicides for seed treatment and foliar application in management of damping-off of seedlings and blight of rapeseed caused by Alternaria brassicae

Eighteen fungicides were first evaluated for their effects on growth of Alternaria brassicae and for ascertaining their fungicidal and fungistatic natures in artificial cultures. The chemicals emerging fungicidal in action, were later evaluated for their efficacy as seed treatment and foliar application in the management of damping-off of seedlings and blight of rapeseed separately. Of 18 fungicides tested, six fungicides, viz., Dithane M-45, Dithane Z-78, Ziram, Difolatan-80, Blitox-50 and Benlate completely inhibited the growth of the pathogen and were fungicidal in action. Thiram and Brestan-60, which also caused total growth inhibition, were, however, fungistatic. Benlate (0.1 %) followed by Dithane M-45 was best seed-dressing fungicide for controlling damping-off of seedlings. Dithane M-45 (0.2%) followed by Dithane Z-78 as foliar spray was most effective for controlling the blight and increasing the yield in field trials.     

Antimicrobial activity of [2-(methacryloyloxy)ethyl]trimethylammonium chloride against Candida spp

BackgroundCandida-associated denture stomatitis is the most common manifestation of oral candidal infection, caused mainly by Candida albicans. Several authors have attempted to add antifungal agents or antiseptics to denture temporary soft lining materials or to denture acrylic resins, without relevant results. Therefore, the investigation of a quaternary ammonium functionalized compound [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT), which copolymerizes with methacrylates and which could act as a fungal inhibitor, is of paramount importance.AimsTo evaluate the in vitro activity of MADQUAT against Candida species.MethodsThirty-one Candida strains were used to determine the in vitro antifungal activity of this compound. The minimum inhibitory concentrations and minimum fungicidal concentrations of MADQUAT and nystatin were determined.ResultsMADQUAT showed antifungal properties at concentrations of 6.25 to > 100 mg/ml, and fungicidal activity between 25 and > 100 mg/ml. The quantitative determinations of the fungistatic and fungicidal activity of MADQUAT showed fungistatic activity against all Candida albicans, Candida krusei and Candida parapsilosis strains, revealing fungicidal activity against some strains of the other species.ConclusionsMADQUAT has antifungal activity against Candida spp. Moreover, the sensitivity to this substance varies across the different species in terms of MIC values and fungicidal or fungistatic activity.     

In vitro fungitoxicity of the essential oil of Syzygium aromaticum

The in vitro antifungal activity of clove oil was studied against four test fungi namely Alternaria alternata, Fusarium chlamydosporum, Helminthosporum oryzae and Rhizoctonia bataticola by the agar well diffusion method. These test fungi were found to be highly sensitive to clove oil at a concentration of 100 μl/well. The inhibition zone diameter was found to be in the range of 55–65 mm. The toxicity of clove oil on the germination and growth of A. alternata was further examined in liquid medium. Concentration- and time-dependent toxicity was recorded from 0.05 to 20% (v/v) concentration. The minimum fungistatic concentration was found to be 0.05%. Above this concentration, lysis of conidia and inhibition of mycelial growth were detected. Microscopic analysis showed 20–40% lysis of conidia after 72 h of incubation at 5% concentration. However at higher clove oil concentration (10%), up to 20% of conidia were lysed within 24 h of incubation. Similar concentration- and time-dependent toxicity was observed at different concentrations and time intervals. The findings indicated that clove oil possesses fungicidal activity against phytopathogenic fungi. Further study is required to determine whether it could have value in the management of plant infectious diseases. This revised version was published online in July 2006 with corrections to the Cover Date.     

Antifungal effects of the volatile oils from Allium plants against Trichophyton species and synergism of the oils with ketoconazole

In an attempt to develop stable and safe antifungal agents from natural products (daily foodstuffs in particular), the activities of essential oils from Allium sativum for. pekinense, A. cepa, and A. fistulosum against three Trichophyton species responsible for severe mycoses in humans were investigated and compared with activity of allicin in this study. The fungistatic activities of Allium oils were evaluated by the broth dilution method and disk diffusion assay. The combined effects of Allium oils with ketoconazole were tested by the checkerboard titer test. Among the tested oils, A. sativum for. pekinense oil exhibited the strongest inhibition of growth of T. rubrum, T. erinacei, and T. soudanense with MICs (minimum inhibiting concentrations) of 64microg/ml, while the activities of A. cepa and A. fistulosum were relatively mild. The inhibiting activities of the oils on Sabouraud agar plates were dose dependent against Trichophyton species. Additionally, these oils showed significant synergistic antifungal activity when combined with ketoconazole in the checkerboard titer test and disk diffusion test.     

In-vitro studies with SF 86-327, a new orally active allylamine derivative

SF 86-327 (Sandoz Forschungsinstitut) is an orally active allylamine derivative related to naftifine. The antifungal activity of SF 86-327 was compared in vitro with those of naftifine, ketoconazole, and itraconazole (R 51,211, Janssen Pharmaceutica) by agar dilution. 120 fungal isolates were tested. Also, the antifungal activities of SF 86-327 and naftifine against 18 dimorphic pathogens were assayed in vitro by broth dilution. Results of these studies support claims that SF 86-327 is a broad spectrum antifungal agent. Results of the broth dilution studies also revealed that SF 86-327 was both fungistatic and fungicidal in vitro for isolates of Blastomyces dermatitidis, Histoplasma capsulatum and Sporothrix schenckii at concentrations as low as 0.05 micrograms ml-1 (18 isolates tested, MIC90 = 0.39 micrograms ml-1, MFC90 = 12.5 micrograms ml-1).     

Study of the role of iron in the anticryptococcal activity of human serum and fluconazole

Anticryptococcal activity of human serum and apotransferrin in RPMI 1640 was studied in vitro. The effects of varying concentrations of FeCl₃ on this activity was investigated. Possible synergy of serum and apotransferrin with fluconazole was also measured. The fungistatic activity of human serum, whether lyophilized, stored at 4 °C, fresh frozen or purchased from commercial sources vs. Cryptococcus neoformans was comparable. There was no significant loss of fungistatic activity after freezing and thawing the serum up to 10 times. The fungistatic activity of human serum was similar when tested in different tissue culture media with the exception of Medium 199. The addition of apotransferrin (2.0 or 0.2 mg/ml) to RPMI 1640 had an inhibitory effect on cryptococcal growth. This effect was reversed by 20 M of FeCl₃ at both apotransferrin concentrations. By contrast, addition of FeCl₃ to human serum and RPMI 1640 did not reverse inhibition of growth. Fluconazole synergized with the human serum preparations described, but not with pooled commercial serum, for fungicidal activity. Synergistic activity of fluconazole and human serum was not affected by the addition of FeCl₃. Apotransferrin did not show any synergistic fungicidal activity with fluconazole.     

In vitro activity of <Emphasis Type="Italic">Penicillium chrysogenum</Emphasis> antifungal protein (PAF) and its combination with fluconazole against different dermatophytes

Strains of five dermatophyte species (Microsporum canis, Microsporum gypseum, Trichophyton mentagrophytes, Trichophyton rubrum and Trichophyton tonsurans) were selected for testing against Penicillium chrysogenum antifungal protein (PAF) and its combination with fluconazole (FCZ). Inhibition of microconidia germination and growth was detected with MICs of PAF ranging from 1.56 to 200 mug ml(-1) when it was used alone, or at constant concentration (100 mug ml(-1)) in combination with FCZ at from 0.25 to 32 mug ml(-1). The MICs for FCZ were found to be between 0.25 and 128 mug ml(-1). PAF caused a fungicidal effect at 200 mug ml(-1) and reduced growth at between 50 and 200 mug ml(-1). Total growth inhibition with fungistatic activity was detected at 64 mug ml(-1) of FCZ for M. gypseum, T. mentagrophytes, and T. tonsurans, and at 32 mug ml(-1) FCZ for M. canis and T. rubrum. PAF and FCZ acted synergistically and/or additively on all of the tested fungi except M. gypseum, where no interactions were detected.     

Efficacy of Euphorbia splendens and Leonotis nepetaefolia on aflatoxin producing fungi Aspergillus flavus and Aspergillus parasiticus

Efficacy of three different concentrations (5, 10 and 15 mg/ml) of dry flower powder of E. splendens and L. nepetaefolia was tested on the growth of aflatoxin-producing toxigenic strains of fungi A. flavus (NCBT 101) and A. parasiticus (NCBT 128) in Sabouraud dextrose agar medium (SDA). Maximum (75%) inhibition of growth of A. flavus was seen at 15 mg/ml concentration of E. splendens flower dry powder, while A. parasiticus showed 50% inhibition of growth at 10 and 15 mg/ml concentrations. Total inhibition (100%) of growth of A. flavus was seen at 10 and 15 mg/ml for L. nepetaefolia and maximum (75%) inhibition of growth was seen for A. parasiticus at 15 mg/ml concentration. Bioassay with groundnut seeds soaked with different concentrations of flower extract proved that both fungi were incapable of infecting the seeds at 10 and 15 mg/ml of L. nepetaefolia flower extracts.     

In vitro antifungal efficacy of ciclopirox olamine alone and associated with zinc pyrithione compared to ketoconazole against Malassezia globosa and Malassezia restricta reference strains

The aim of this study was to determine the in vitro fungicidal and growth inhibitory activity of ciclopirox olamine alone (1% and 1.5%) or in association with 1% zinc pyrithione compared to 2% ketoconazole, against Malassezia species particularly involved in the pathogenesis of seborrheic dermatitis. Experiments were performed on Malassezia globosa IP 2387.96 and M. restricta IP 2392.96 strains. Growth inhibitory activity of the active compounds in solution was evaluated by measuring minimal inhibitory concentrations using a broth micro-method and their fungicidal activity by a filtration method after contact times between solutions and yeasts ranging from 3–5 to 30 min. Concerning the determination of minimal inhibitory concentration of ciclopirox olamine/zinc pyrithione, it revealed the marked synergistic inhibitory effect of the association, leading to a higher efficacy compared to ketoconazole. As to the fungicidal activity of ciclopirox olamine, it significantly increased with the contact time. After 15–30 min of contact between 1.5% ciclopirox olamine and Malassezia strains, a 2-log reduction of Malassezia counts was observed. The 1.5% ciclopirox olamine/1% zinc pyrithione association was characterized by a steady fungicidal efficacy whereas the 2% ketoconazole solution did not express any fungicidal effect. In conclusion, this study demonstrates the in vitro inhibitory and fungicidal efficacy of the ciclopirox olamine/zinc pyrithione association against Malassezia species and underscores its potential interest in the treatment of seborrheic dermatitis.     

New Antifungal Agents and New Formulations Against Dermatophytes

A variety of oral and topical antifungal agents are available for the treatment of superficial fungal infections caused by dermatophytes. This review builds on the antifungal therapy update published in this journal for the first special issue on Dermatophytosis (Gupta and Cooper 2008;166:353–67). Since 2008, there have not been additions to the oral antifungal armamentarium, with terbinafine, itraconazole, and fluconazole still in widespread use, albeit for generally more severe or recalcitrant infections. Griseofulvin is used in the treatment of tinea capitis. Oral ketoconazole has fallen out of favor in many jurisdictions due to risks of hepatotoxicity. Topical antifungals, applied once or twice daily, are the primary treatment for tinea pedis, tinea corporis/tinea cruris, and mild cases of tinea unguium. Newer topical antifungal agents introduced include the azoles, efinaconazole, luliconazole, and sertaconazole, and the oxaborole, tavaborole. Research is focused on developing formulations of existing topical antifungals that utilize novel delivery systems in order to enhance treatment efficacy and compliance.     

Synergy of fluconazole with macrophages for antifungal activity againstCandida albicans

The possible synergy between macrophages and fluconazole for antifungal activity against different isolates ofC. albicans was studied. The susceptibility ofC. albicans isolates to fluconazole (FCZ), when incubated in RPMI-1640 with 10% fetal bovine serum (FBS) and 10% fresh mouse serum (test medium, TM) was determined by using a quantative culture methodology. Multiplication of isolate Sh27 was strongly inhibited by FCZ, even at 1.0 µg/ml. However, FCZ even at 100 µg/ml was not fungicidal. Resident murine peritoneal macrophages (MP) incubated for 48 h in RPMI-1640+10% FBS (tissue culture medium, TCM), then challenged with Sh27 in TM for 24 h, were fungistatic (20±9%,n=4). Cultured macrophages synergized with FCZ (10 µg/ml) for fungicidal activity when co-cultured with Sh27 in TM for 24 h (46±8%) and for 48 h (74±5%),n=3. Macrophages and FCZ (10 µg/ml) could not synergize for significant killing of a less FCZ-sensitiveC. albicans isolate 94-164. Multiplication of a FCZ-resistant isolate (94–20) was not inhibited by FCZ at 10 µg/ml TM; however, macrophages and FCZ (10 µg/ml) could synergize for fungistatic (64%), but not fungicidal, activity.     

R 51211 (itraconazole) therapy of murine cryptococcosis

A new antifungal triazole, itraconazole (R51211), was compared with ketoconazole in treatment of murine cryptococcosis. Itraconazole is sparingly soluble in water, and must be administered orally in solvents such as polyethylene glycol. Serum concentrations are lower than those achieved with ketoconazole, but sustained for longer periods. Itraconazole was more effective than ketoconazole by MIC, but was similar to ketoconazole by minimum fungicidal concentration. Both drugs prolonged equally survival after intraperitoneal or intracerebral challenge with Cryptococcus neoformans. Tissue counts of C. neoformans were similar in mice treated with either drug. Neither drug sterilized brains of mice challenged intracerebrally. Itraconazole appears equally potent as ketoconazole, but in this model does not appear to offer any therapeutic advantage over ketoconazole.     

特比萘芬对24株黑酵母样真菌的体外药敏试验研究

目的 评价特比萘芬对7个属24株刺盾霉目（Chaetothyriales）黑酵母样真菌体外敏感性.方法 应用美国国家临床和实验室标准研究所（CLSI）的M38-A2方案.菌悬液终浓度为（0.4 ～5）＆#215;104 CFU/mL,30℃孵育5～7d,测定最低有效浓度（MEC）和最低抑菌浓度（MIC）.结果 特比萘芬对24株黑酵母样真菌MEC范围：0.125 ～4μg/mL,MEC90∶2μg/mL,MEC50∶0.25 μg/mL,GM∶0.392 9 μg/mL,特比萘芬对5株暗色真菌100％生长抑制,MIC范围：1～4 μg/mL,MIC50∶2μg/mL,MIC90∶4μg/mL.结论 特比萘芬对刺盾霉目（Chaetothyriales）中的黑酵母样真菌有较强的抑制作用,50％抑菌作用明显.     

Antifungal activities of the essential oils in Syzygium aromaticum (L.) Merr. Et Perry and Leptospermum petersonii Bailey and their constituents against various dermatophytes

This study was carried out in order to investigate the potential of using plant oils derived from Leptospermum petersonii Bailey and Syzygium aromaticum L. Merr. Et Perry as natural antifungal agents. The antifungal effects of essential oils at concentrations of 0.05, 0.1, 0.15, and 0.2 mg/ml on the dermatophytes Microsporum canis (KCTC 6591), Trichophyton mentagrophytes (KCTC 6077), Trichophyton rubrum (KCCM 60443), Epidermophyton floccosum (KCCM 11667), and Microsporum gypseum were evaluated using the agar diffusion method. The major constituents of the active fraction against the dermatophytes were identified by gas chromatography-mass spectrometry and high-performance liquid chromatography analysis. The antifungal activities of S. aromaticum oil (clove oil) against the dermatophytes tested were highest at a concentration of 0.2 mg/ml, with an effectiveness of more than 60%. Hyphal growth was completely inhibited in T. mentagrophytes, T. rubrum, and M. gypseum by treatment with clove oil at a concentration of 0.2 mg/ml. Eugenol was the most effective antifungal constituent of clove oil against the dermatophytes T. mentagrophytes and M. canis. Morphological changes in the hyphae of T. mentagrophytes, such as damage to the cell wall and cell membrane and the expansion of the endoplasmic reticulum, after treatment with 0.11 mg/ml eugenol were observed by transmission electron microscopy (TEM). At a concentration of 0.2 mg/ml, L. petersonii oil (LPO) was more than 90% effective against all of the dermatophytes tested, with the exception of T. rubrum. Geranial was determined to be the most active antifungal constituent of L. petersonii oil. Taken together, the results of this study demonstrate that clove and tea tree oils exhibited significant antifungal activities against the dermatophytes tested in this study.