In vitro activities of 10 antifungal drugs against 508 dermatophyte strains

Dermatophytosis caused by Nannizzia nana (Microsporum nanum): a comprehensive review on a novel pathogen

Keratinophilic fungi are mostly soil-inhabiting organisms with occasional infections in humans and animals. Even though most dermatophytes are host-adapted, cross-species infections are common by zoophilic and geophilic dermatophytes. N. nana is considered an etiological agent of ringworm in pigs but has also been isolated from other animals, including humans. However, it also possesses many characteristics of geophilic dermatophytes including the ability to grow in soil. N. nana produces characteristic pear-shaped macroconidia and usually exhibits an ectothrix pattern of hair infection. It has been isolated from dermatitis lesions as well as from soil. N. nana infections in pigs are not of much concern as far as economy or health is concerned. But it has been associated with onychomycosis and gonathritis in humans, which are significant in human medicine. The shift in the predominance of dermatophytes in humans and the ability to evolve into a potential tinea pathogen necessitates more understanding of the physiology and genetics of N. nana. In this review, we have attempted a detailed analysis of the studies about N. nana, emphasizing growth and cultural characters, physiology, isolation, infection in humans and animals, molecular characterization and antifungal susceptibility.

Comparison of in vitro activities of newer triazoles and classic antifungal agents against dermatophyte species isolated from Iranian University Hospitals: a multi-central study

BACKGROUND

Dermatophytes have the ability to invade the keratin layer of humans and cause infections. The aims of this study were the accurate identification of dermatophytes by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism method and sequencing and comparison between the in vitro activities of newer and established antifungal agents against them.

METHODS

Clinical specimens of patients from five Iranian university laboratories were entered in this study. Samples were cultured on sabouraud dextrose agar medium. For molecular identification, extracted DNAs were amplified by the universal fungal primers ITS1 and ITS4, and digested with MvaI enzymes. The antifungal susceptibility test for each isolate to terbinafine, griseofulvin, caspofungin, fluconazole, itraconazole, luliconazole, and isavuconazole was performed, according to the microdilution CLSI M38-A2 and CLSI M61 standard methods.

RESULTS

Two hundred and seven fungi species similar to dermatophytes were isolated of which 198 (95.6%) were dermatophytes by molecular assay. The most commonly isolated were Trichophyton mentagrophytes (76/198), followed by Trichophyton interdigitale (57/198), Trichophyton rubrum (34/198), Trichophyton tonsurans (12/198), Microsporum canis (10/198), Trichophyton simii (3/198), Epidermophyton floccosum (3/198), Trichophyton violaceum (2/198), and Trichophyton benhamiae (1/198). The GM MIC and MIC₉₀ values for all the isolates were as follows: terbinafine (0.091 and 1 μg/ml), griseofulvin (1.01 and 4 μg/ml), caspofungin (0.06 and 4 μg/ml), fluconazole (16.52 and 32 μg/ml), itraconazole (0.861 and 8 μg/ml), isavuconazole (0.074 and 2 μg/ml), and luliconazole (0.018 and 0.25 μg/ml).

CONCLUSION

Trichophyton mentagrophytes, Trichophyton interdigitale, and Trichophyton rubrum were the most common fungal species isolated from the patients. luliconazole, terbinafine, and isavuconazole in vitro were revealed to be the most effective antifungal agents against all dermatophyte isolates.

Anti-dermatophyte activity of the aqueous extracts of Thai medicinal plants

Medicinal plants have long been prescribed in Thailand for centuries. Different constituents of extracts have been used for treating of various infectious diseases. However, there is even less information available regarding the use in fungal skin infection. In order to assess traditional Thai claims about the therapeutic potential, this study is focused on exploring the anti-dermatophyte property of the plants that are currently used as traditional medicines. The potential of four different plant species were selected for investigate in vitro anti-dermatophyte activity. Ethanolic extracts of Chromolaena odorata (L.), Ageratina adenophora (Spreng.), Eclipta prostrate (Linn.), and Acorus calamus (L.). were analysed for their total phenolic content as well as total flavonoid content and were then subjected to test of their anti-dermatophyte properties using agar well diffusion method. Qualitative flavonoids and phenolics analysis of the extracts showed their biologically active constituents. Among the species examined, the result indicated that most of the extracts demonstrated anti-dermatophyte activity. In particular, A. calamus showed the highest efficacy against test organisms. The experiment confirmed the chemical constituents and efficacy of some selected plants and provides a scientific confirmation of the use of Thai plants in traditional medicine for fungal skin infections.

Dermatophytic infection and in vitro activities of antifungal drugs against dermatophytes in rural India

Background Increase in resistance to conventional antifungals renders the need for antifungal sensitivity testing in Dermatophytes.   The present study aimed at determining the prevalence of dermatophytic infections and their susceptibility pattern in a rural healthcare facility. Methods Patients with suspected dermatophytosis attending the dermatology outpatient department were enrolled in the study. Specimen collection for mycological examinations was done. In-vitro antifungal sensitivity testing was performed as per the Clinical and Laboratory Standard Institute (CLSI) M38-A2 (2008) standards with broth microdilution method. Results Onychomycosis was the commonest (41.9%) presentation. Dermatophytic prevalence based on culture was 110 (70.9%). The commonest species was Trichophyton rubrum (36.8%). Terbinafine was found to be the most effective drug, followed by ketoconazole and itraconazole. Conclusion Antifungal sensitivity in dermatophytic infections should be made a routine in tertiary healthcare facilities as we are already witnessing the rampage of emerging fungal infection– Mucormycosis in the nation and worldwide.

In vitro activities of 8 antifungal agents against geophilic dermatophyte isolates

BACKGROUND

Members of the Nannizzia gypsea complex are globally the most common geophilic dermatophytes which cause infection in animals and human. Although the susceptibility patterns of anthropophilic or zoophilic dermatophyte species to antifungal agents are well documented, the effectiveness of such drugs against geophilic species have rarely been explored.

OBJECTIVES

This study was aimed to evaluate the in vitro antifungal activity of common and new antifungals against a set of environmental and clinical geophilic dermatophyte isolates.

METHODS

108 soil and clinical geophilic isolates from two genera Nannizzia (N. fulva n = 59; N. gypsea n = 43) and Arthroderma (A. quadrifidum n = 4; A. gertleri n = 1; A. tuberculatum n = 1) were included in the study. The in vitro antifungal susceptibility patterns of eight common and new antifungals against the isolates were determined according to broth microdilution method and by CLSI M38-A3 (3rd edition) protocol.

RESULTS

MIC values across all isolates from five species ranged as: luliconazole: 0.0002-0.002 µg/ml, terbinafine: 0.008-0.125 µg/ml, efinaconazole: 0.008-0.125 µg/ml, ciclopirox olamine: 0.03-0.5 µg/ml, itraconazole: 0.125-1 µg/ml, amorolfine hydrochloride: 0.125-4 µg/ml, griseofulvin: 0.25-2 µg/ml and tavaborole: 1-8 µg/ml, respectively.

CONCLUSION

Luliconazole, terbinafine and efinaconazole exhibited the highest in vitro efficacy, regardless of the dermatophyte species. Further surveillance studies are recommended to confirm the implication of such in vitro data for the clinical recovery rate of dermatophytosis with geophilic species following antifungal therapy.

Chronic Dermatophytosis: Clinico-Mycological Determinants and Antifungal Susceptibility Pattern

Background:

Recent years have witnessed a dramatic increase in chronic unresponsive dermatophytosis. A study was conducted to quantify the proportion of patients with chronic dermatophytosis and to determine the clinico-mycological predictors of chronicity including antifungal susceptibility.

Methods:

Hospital-based cross-sectional study design was adopted. Four hundred and twenty-five patients were studied. The outcome variable was chronic dermatophytosis and the determinants were clinico-mycological characteristics. Chi-square and odds ratio (OR) with 95% confidence interval (CI) were calculated.

Results:

Chronic dermatophytosis was seen in 29.4%. Past history of dermatophytosis, OR 0.44 (95% CI 0.28–0.68); family history of dermatophytosis, OR 1.66 (95% CI 1.06–2.56); HIV infection, OR 9.88 (95% CI 1.09–89.33); treatment with topical antifungals, OR 2.4 (95% CI 1.5–3.9); systemic antifungals, OR 3.9 (95% CI 2.5–6.1); topical steroids, OR 2.02 (95% CI 1.25–3.25); multiple-site infection, OR 1.97 (95% CI 1.24–3.13); and tinea unguium, OR 6.52 (95% CI 2.89–14.7) were the significant determinants. Trichophyton mentagrophytes (73.6%) was the most common isolate followed by Trichophyton rubrum and Microsporum gypseum (13.2%) each. A percentage of 77.4 of the isolates were resistant—73.6% isolates to terbinafine and 3.8% isolates to fluconazole. None of the isolates were resistant to itraconazole.

Conclusion:

Significant determinants were host-related factors. Thorough history taking, patient examination, and education can improve the present scenario. Microbiological resistance was not a significant predictor. High proportion of resistant strains should be an eye opener. Developing and adopting a standard uniform treatment protocol throughout the country should be the need of the hour.

Antimicrobial and cytotoxic activity of green synthesis silver nanoparticles targeting skin and soft tissue infectious agents

Combining traditional medicine with nanotechnology therefore opens the door to innovative strategies for treating skin and soft tissue infections (SSTIs) and also contributes to the fight against the rise of antimicrobial resistance. Acanthospermum australe (Loefl.) Kuntze is a medicinal plant used by indigenous peoples in northeastern Argentina to treat SSTIs. Spherical and stable silver nanoparticles (AgNPs) of 14 ± 2 nm were synthesized from the aqueous extract of A. australe and silver nitrate. The antimicrobial activity against main species causing SSTIs and cytotoxicity on peripheral blood mononuclear cells of AgNP solution and its synthesis components were evaluated. Compared to its synthesis components, AgNP solution showed greater antimicrobial activity and lower cytotoxicity. The antimicrobial activity of AgNPs was due to the silver and not to the metabolites of the aqueous extract present on the surface of the nanoparticles. The plant extract played an important role in the formation of stable AgNPs and acted as a modulator of cytotoxic and immune responses.

The in vitro effect of nanoliposomal amphotericin B against two clinically important dermatophytes

AIMS

The present study aimed to investigate the antifungal activity of amphotericin B-loaded nanoliposomes against Trichophyton interdigitale and Trichophyton rubrum. Moreover, it was attempted to assess the obtained resistance in vitro.

METHODS

In total, 29 archived clinical strains, namely, T. interdigitale (n = 16) and T. rubrum (n = 13), were included in this study. These strains were determined using a previous ITS1-ITS2 region sequence. Moreover, a liposomal formulation of amphotericin B was formulated by a thin-film hydration method. Particle size, polydispersity index (PdI), and zeta potential (ZP) were measured by a Zetasizer. Furthermore, physicochemical properties, such as appearance, aggregation of particles, particle size, PdI, and ZP, were determined at 0-, 1-, and 3-month intervals. A scanning electron microscope (SEM) was also used to examine nanoparticles structure. The minimum inhibitory concentration (MIC) of amphotericin B-loaded nanoliposomes, itraconazole, efinaconazole, terbinafine, and ciclopirox was determined according to the protocol of the broth microdilution method of CLSI M38-A2. The morphological changes of T. interdigitale and T. rubrum strains exposed to the amphotericin B-loaded nanoliposomes were observed using SEM.

RESULTS

The amphotericin B-loaded nanoliposomes displayed a lower MIC compared to those of the amphotericin B and liposomes when used separately. Based on the results, amphotericin B-loaded nanoliposomes induced no drug resistance in any of the tested strains.

CONCLUSION

Accordingly, amphotericin B-loaded nanoliposomes can be a potent antifungal for the topical treatment of onychomycosis. There was no in vitro evidence regarding the resistance of the tested strains to amphotericin B-loaded nanoliposomes. This reflects that amphotericin B-loaded nanoliposomes have a low probability to induce drug resistance in dermatophyte species.

The Emerging Terbinafine-Resistant Trichophyton Epidemic: What Is the Role of Antifungal Susceptibility Testing?

BACKGROUND

Dermatophytosis is commonly encountered in the dermatological clinics. The main aetiological agents in dermatophytosis of skin and nails in humans are Trichophyton (T.) rubrum, T. mentagrophytes and T. interdigitale (former T. mentagrophytes-complex). Terbinafine therapy is usually effective in eradicating infections due to these species by inhibiting their squalene epoxidase (SQLE) enzyme, but increasing numbers of clinically resistant cases and mutations in the SQLE gene have been documented recently. Resistance to antimycotics is phenotypically determined by antifungal susceptibility testing (AFST). However, AFST is not routinely performed for dermatophytes and no breakpoints classifying isolates as susceptible or resistant are available, making it difficult to interpret the clinical impact of a minimal inhibitory concentration (MIC).

SUMMARY

PubMed was systematically searched for terbinafine susceptibility testing of dermatophytes on October 20, 2020, by two individual researchers. The inclusion criteria were in vitro terbinafine susceptibility testing of Trichophyton (T.) rubrum, T. mentagrophytes and T. interdigitale with the broth microdilution technique. The exclusion criteria were non-English written papers. Outcomes were reported as MIC range, geometric mean, modal MIC and MIC50 and MIC90 in which 50 or 90% of isolates were inhibited, respectively. The reported MICs ranged from <0.001 to >64 mg/L. The huge variation in MIC is partly explained by the heterogeneity of the Trichophyton isolates, where some originated from routine specimens (wild types) whereas others came from non-responding patients with a known SQLE gene mutation. Another reason for the great variation in MIC is the use of different AFST methods where MIC values are not directly comparable. High MICs were reported particularly in isolates with SQLE gene mutation. The following SQLE alterations were reported: F397L, L393F, L393S, H440Y, F393I, F393V, F415I, F415S, F415V, S443P, A448T, L335F/A448T, S395P/A448T, L393S/A448T, Q408L/A448T, F397L/A448T, I121M/V237I and H440Y/F484Y in terbinafine-resistant isolates.

Comparison of the Sensititre YeastOne® and CLSI M38-A2 microdilution methods in determining the activity of nine antifungal agents against dermatophytes

BACKGROUND

Dermatophytes are the most common fungal pathogens causing superficial infections in humans with a high prevalence worldwide. The treatment of these infections is based on the use of topical and systemic antifungal agents. A convenient method with a high predictive value for testing the susceptibilities of dermatophytes is necessary.

OBJECTIVE

To evaluate the ability of the Sensititre YeastOne^® in testing the activity of nine antifungal agents against dermatophytes.

METHODS

We compared Sensititre^® with reference procedure for anidulafungin (ANID), micafungin sodium (MCF), caspofungin acetate (CAS), 5-fluorocytosine (5FC), posaconazole (PCZ), voriconazole (VCZ), itraconazole (ITZ), fluconazole (FLZ) and amphotericin B (AMB) against 79 dermatophyte isolates, the essential agreement (EA) and categorical agreement (CA) between the two methods were obtained.

RESULTS

The MICs or MECs obtained by the Sensititre^® were usually lower than those obtained by the M38-A2. The overall EA between the two methods of nine antifungals was best for 5FC (100%), followed by MCF (94.9%), PCZ (84.8%), AMB (67.1%), FLZ (65.8%), VCZ (63.3%), ANID (29.1%), ITZ (20.3%) and CAS (2.5%). The overall CA between the two methods for all drugs was 100% except for ANID (97.4%), MCF (95%) and PCZ (92.5%). Substantial discrepancies were observed with all drugs except for VCZ and 5FC. The results of M38-A2 in terms of GMIC (or GMEC) and MIC90 (or MEC90) were, in increasing order, as follows: MCF, PCZ, VCZ, ANID, ITZ, CAS, AMB, FLZ and 5FC.

CONCLUSIONS

The Sensititre YeastOne^® shows poor EA with the reference method for dermatophytes; therefore, M38-A2 should remain the reference procedure for antifungal susceptibility testing against dermatophytes.

Virulence and Antifungal Susceptibility of Microsporum canis Strains from Animals and Humans

The enzymatic and antifungal profiles of dermatophytes play an important role in causing infections in humans and animals. This study aimed to assess the virulence factors produced by Microsporum canis strains, in vitro antifungal profile and the relationship between virulence, antifungal profile and occurrence of lesions in animals and humans. A total of 100 M. canis strains from humans with tinea corporis (n = 10) and from animals presenting (n = 64) or not (n = 26) skin lesions was employed to evaluate phospholipase (Pz), hemolytic (Hz), lipase (Lz), catalase (Ca), and thermotolerance (GI) activities. In addition, in vitro antifungal profile was conducted using the CLSI broth microdilution method. A statistically significant difference (p < 0.05) in Lz and Ca values was revealed among strains from hosts with and without lesions. Voriconazole, terbinafine, and posaconazole were the most active drugs followed by ketoconazole, griseofulvin, itraconazole, and fluconazole in decreasing activity order. The significant positive correlation between azole susceptibility profile of M. canis and virulence factors (i.e., hemolysin and catalase) suggest that both enzyme patterns and antifungal susceptibility play a role in the appearance of skin lesions in animals and humans.

Strategies to Better Target Fungal Squalene Monooxygenase

Fungal pathogens present a challenge in medicine and agriculture. They also harm ecosystems and threaten biodiversity. The allylamine class of antimycotics targets the enzyme squalene monooxygenase. This enzyme occupies a key position in the sterol biosynthesis pathway in eukaryotes, catalyzing the rate-limiting reaction by introducing an oxygen atom to the squalene substrate converting it to 2,3-oxidosqualene. Currently, terbinafine—the most widely used allylamine—is mostly used for treating superficial fungal infections. The ability to better target this enzyme will have significant implications for human health in the treatment of fungal infections. The human orthologue can also be targeted for cholesterol-lowering therapeutics and in cancer therapies. This review will focus on the structural basis for improving the current therapeutics for fungal squalene monooxygenase.

In vitro activities of antifungal drugs against a large collection of Trichophyton tonsurans isolated from wrestlers

BACKGROUND

Trichophyton tonsurans is the most common agent causing tinea gladiatorum in wrestlers, and limited data on susceptibility profiles of Trichophyton tonsurans are available.

OBJECTIVES

We aimed to assess the in vitro activity of the common antifungal drug against a large collection of T tonsurans.

MATERIALS/METHODS

The in vitro activities to eight common antifungal drugs (sertaconazole, itraconazole, clotrimazole, fluconazole, butenafine, tolnaftate, terbinafine and griseofulvin) against 128 clinical isolates of T tonsurans strains, obtained from wrestlers with dermatophytosis, were performed according to CLSI M38-A2 broth microdilution document.

RESULTS

The geometric mean minimum inhibitory concentration was the lowest for tolnaftate (0.022 µg/mL), followed by itraconazole (0.026 µg/mL), terbinafine (0.033 µg/mL), butenafine (0.088 µg/mL), griseofulvin (0.566 µg/mL), sertaconazole (2.875 µg/mL), clotrimazole (3.419 µg/mL) and fluconazole (12.540 µg/mL).

CONCLUSIONS

Evaluation of antifungal susceptibility of dermatophytes showed that tolnaftate and itraconazole were the most effective drugs against T tonsurans and fluconazole had the least effect.

Low in vitro activity of sertaconazole against clinical isolates of dermatophyte

Background and Purpose:

Dermatophytes are a group of fungi specialized in invading humans and other vertebrate keratinized tissues. These fungi cause a variety of skin, nail, and hair disorders, called dermatophytosis (tinea). In some cases, drug resistance to antifungals necessitates special treatment. Among the antifungal agents, sertaconazole (i.e., a third-generation imidazole) has a broad-spectrum against dermatophyte species. Regarding this, the present study was conducted to investigate the antifungal susceptibility of dermatophytes obtained from patients with dermatophytosis in Mashhad located in northeastern Iran.

Materials and Methods:

A total of 75 clinical dermatophyte isolates, including Trichophyton mentagrophytes (n=21), T. interdigital (n=18), T. tonsurans (n=16), Epidermophyton floccosum (n=11), Microsporum canis (n=5), Nannizzia fulvum (n=2), T. benhamiae (n=1), and T. verrucosum (n=1), were evaluated against five antifungal agents of sertaconazole, itraconazole, clotrimazole, terbinafine, and griseofulvin based on the CLSI M38-A2 guideline.

Results:

According to the results, the minimum inhibitory concentration (MIC) ranges ofsertaconazole, terbinafine, griseofulvin, itraconazole, and clotrimazole were estimated at 0.125-16, 0.002-1, 0.5-4, 0.031-4, and 0.016-4 µg/ml, respectively, for dermatophyte species. In addition, the geometric mean (GM) values of the MIC of sertaconazole, terbinafine, griseofulvin, itraconazole, and clotrimazole were obtained as 3.39, 1, 1.44, 1.52, and 1.93, respectively.

Conclusion:

Among the tested antifungals, terbinafine and griseofulvin were the most effective agents against dermatophyte isolates. However, sertaconazole, a third-generation imidazole, did not show any significant effect. Furthermore, M. canis and E. floccosum showed the best response to the antifungal agents.

Immediate and residual antifungal activity of compounds used for whole body and adjuvant topical therapy against Microsporum canis: an in vitro study

BACKGROUND

Topical antifungal therapy is recommended to disinfect hairs of dermatophyte-infected animals.

OBJECTIVE

To determine the immediate and residual (24, 48 and 72 h) antifungal activity of commonly used products for focal (n = 11) and whole body application (n = 3).

ANIMALS

Hair samples from naturally infected kittens.

METHODS AND MATERIALS

Immediate antifungal activity was assessed using isolated infected spores. In a more robust challenge, toothbrushes containing whole infected hairs were repeatedly treated with products until culture-negative. Residual activity was determined by treating 0.04 g of uninfected hair with test products, allowing hairs to dry and then plating hairs onto fungal culture plates inoculated with Microsporum canis. Residual activity was assessed at 24, 48 and 72 h post-treatment.

RESULTS

All products showed good efficacy against isolated infected spores. Two products required three treatments to disinfect whole infected hairs (miconazole 0.2% and ketoconazole 0.15%); all other products were efficacious after one treatment. For each product residual activity at 24, 48 and 72 h was similar. For the whole body products, lime sulfur and enilconazole showed residual activity, but as expected none was detected for 2% miconazole nitrate/ 2% chlorhexidine shampoo. For focal therapy products, residual activity was detected for clotrimazole 1%, terbinafine 1%, miconazole at 0.2, 1 or 2% (with or without chlorhexidine), climbazole 0.5% with chlorhexidine gluconate, and ketoconazole 1% with chlorhexidine gluconate. A ketoconazole 0.15% with 0.15% chlorhexidine gluconate showed no residual activity.

CONCLUSIONS AND CLINICAL IMPORTANCE

Findings support twice weekly application of enilconazole and lime sulfur, and application of adjuvant focal topical therapy daily or every other day.

Lipid Systems for the Delivery of Amphotericin B in Antifungal Therapy

Amphotericin B (AmB), a broad-spectrum polyene antibiotic in the clinic for more than fifty years, remains the gold standard in the treatment of life-threatening invasive fungal infections and visceral leishmaniasis. Due to its poor water solubility and membrane permeability, AmB is conventionally formulated with deoxycholate as a micellar suspension for intravenous administration, but severe infusion-related side effects and nephrotoxicity hamper its therapeutic potential. Lipid-based formulations, such as liposomal AmB, have been developed which significantly reduce the toxic side effects of the drug. However, their high cost and the need for parenteral administration limit their widespread use. Therefore, delivery systems that can retain or even enhance antimicrobial efficacy while simultaneously reducing AmB adverse events are an active area of research. Among those, lipid systems have been extensively investigated due to the high affinity of AmB for binding lipids. The development of a safe and cost-effective oral formulation able to improve drug accessibility would be a major breakthrough, and several lipid systems for the oral delivery of AmB are currently under development. This review summarizes recent advances in lipid-based systems for targeted delivery of AmB focusing on non-parenteral nanoparticulate formulations mainly investigated over the last five years and highlighting those that are currently in clinical trials.

Epidermophyton floccosum: nucleotide sequence analysis and antifungal susceptibility testing of 40 clinical isolates

Purpose. Epidermophyton floccosum is an anthropophilic dermatophyte species, which is one of the common causative agents of dermatophytosis in different parts of the world. The aim of the present investigation was to evaluate the genetic diversity of E. floccosum strains isolated from different parts of Iran and to define the in vitro susceptibility profiles of seven antifungal drugs against these clinical isolates.Methodology. Forty clinical strains of E. floccosum isolated from 40 patients with dermatophytosis were subjected to DNA extraction and PCR amplification of the ITS rDNA region using universal primers ITS1 and ITS4. The in vitro activities of griseofulvin, itraconazole, voriconazole, posaconazole, caspofungin, ketoconazole and terbinafine were determined using a broth microdilution method according to the CLSI-M-38A2 protocol.Results. A mean genetic similarity of 99.5 % was found between E. floccosum strains, with intraspecies differences ranging from 0 to 3 nt. The geometric mean (GM) MICs and minimum effective concentrations (MECs) across all isolates were, in increasing order, as follows: terbinafine (GM=0.018 mg l^-1), posaconazole (GM=0.022 mg l^-1), itraconazole (GM=0.034 mg l^-1) and voriconazole (GM=0.045 mg l^-1), which had low MICs against all tested strains, whereas caspofungin (GM=0.22 mg l^-1), ketoconazole (GM=0.41 mg l^-1) and griseofulvin (GM=0.62 mg l^-1) demonstrated higher MICs.Conclusion. Our study showed low intraspecies variation within strains of E. floccosum. Furthermore, terbinafine, posaconazole, itraconazole and voriconazole were shown to be the most potent antifungal drugs against E. floccosum strains.

Determination of antifungal minimum inhibitory concentration and its clinical correlation among treatment failure cases of dermatophytosis

Introduction:

Dermatophytes are most common infectious agents causing superficial mycosis worldwide. A number of topical as well as systemic antifungal drugs are available for treatment of dermatophytosis. Superficial mycosis caused by dermatophytes can be easily treated by topical or oral antifungal drugs, but in the course of time, an increased number of treatment failure cases are appearing. Possible cause for treatment failure could be poor patient compliance, poor drug penetration into affected lesion, and also drug resistance in dermatophytes. The aim of this study is to investigate minimum inhibitory concentration and clinical correlation in treatment failure cases of dermatophytosis.

Methods:

Skin, hair and nail samples were collected from treatment failure cases of dermatophytosis. A total 75 isolates were tested for MIC against four antifungal drugs in the study. Fluconazole, itraconazole, ketoconazole and terbinafine were the antifungal drugs tested using broth microdilution method. MIC₅₀ and MIC₉₀ values were recorded.

Results:

A total of 75 dermatophytic isolates were tested. Dermatophytic isolates in this study were Trichophyton mentagrophytes (n = 31), T. rubrum (n = 13), T. tonsurans (n = 12), T. verrucosum (n = 9), M. gypseum (n = 5), E. floccosum (n = 4) and T. violaceum (n = 1). MIC₉₀ value for fluconazole and terbinafine was significantly higher.

Conclusion:

MIC of 17.33% isolates for fluconazole and 33.33% isolates for terbinafine were lower than cut-off value, which indicates that not all treatment failure cases are due to drug resistance.

Molecular epidemiology and in vitro antifungal susceptibility of Trichophyton schoenleinii, agent of tinea capitis favosa

Trichophyton schoenleinii is an anthropophilic dermatophyte usually causing tinea favosa. Only few studies have provided data on molecular epidemiology and antifungal profiles of this fungus due to its limited prevalence after 1950s. Forty-nine strains from Asia (n = 27), Africa (n = 10), Europe (n = 10) and from unknown regions (n = 2) were analysed with amplified fragment length polymorphism fingerprinting (AFLP) to reveal intraspecific genetic diversity in this dataset. Amplified fragment length polymorphism fingerprinting genotyping revealed five clusters which did not correspond to geographic origins or clinical characteristics. Additionally, in vitro antifungal susceptibility to seven antifungals was provided for all strains. Terbinafine, ketoconazole, miconazole and itraconazole proved to be the most effective drugs, followed by griseofulvin. No correlation between genotypes and differences in antifungal susceptibility was observed. It is concluded that the AFLP groups are lineages within a single species.

Molecular characterization and antifungal susceptibility profile of dermatophytes isolated from scalp dermatophyte carriage in primary school children in Arak city, Center of Iran

OBJECTIVE

Asymptomatic carriage is a condition of positive dermatophyte scalp culture without signs and symptoms of tinea capitis. Carriers are the source of dermatophytes that are able to transfer fungal agents to other people. The aim of this study was evaluating asymptomatic dermatophyte scalp carriage among students of primary schools in Arak city.

MATERIALS AND METHODS

Sampling by a sterilized hairbrush from scalp was performed among 3174 students. Hairbrush was inoculated onto Mycosel agar plates. Dermatophyte isolates were identified by PCR-RFLP using MvaI enzyme. In vitro antifungal susceptibility test was done according to the Clinical and Laboratory Standards Institute (CLSI) M38-A2 protocol. The antifungal drugs used included griseofulvin (GRZ), terbinafine (TER), itraconazole (ITC) and fluconazole (FLU).

RESULTS

A total of 3174 schoolchildren were screened, 15 cases (0.48%) had a positive culture for dermatophytes. Asymptomatic carriers including 11 (73.3%) boys and 4 (26.7%) girls and their age range were between 7-12 years. Trichophyton tonsurans (80%), T. interdigitale (13.3%) and T. rubrum (6.7%) were the most common isolated dermatophyte. Based on the obtained antifungal susceptibility results, terbinafine had the lowest and fluconazole had the highest MIC values for all of the tested dermatophyte isolates.

CONCLUSION

In the study, T. tonsurans was the most common species isolated from asymptomatic carriers and of the four antifungals tested, terbinafine had the most active antifungal in vitro against all isolates. Identifying and treating scalp dermatophyte carriers can prevent the spread of tinea capitis in the community.

Therapy and Antifungal Susceptibility Profile of Microsporum canis

Microsporum canis is a worldwide diffused zoophilic dermatophyte which causes clinical conditions often characterised by multifocal alopecia, scaling, and circular lesions in many animal species, including humans. A large variety of oral and topical antifungal protocols is available for treating M. canis infection. However, the efficacy of these drugs and treatment protocols is variable, with treatment failure up to 40% of patients possibly due to resistance phenomena. The lack of standardised reference methods for evaluating the antifungal susceptibility of M. canis represents a major hindrance in assessing microbiological resistance in unresponsive clinical cases. Therefore, data about conventional therapy against M. canis and the protocols employed to test the antifungal activity of the most commonly employed drugs (i.e., azoles, polyenes, allylamines, and griseofulvin) have been summarised herein. This article focuses on technical parameters used for antifungal susceptibility tests, their effects on the minimum inhibitory concentration value, as well as their clinical implications.

Is Antifungal Resistance a Cause for Treatment Failure in Dermatophytosis: A Study Focused on Tinea Corporis and Cruris from a Tertiary Centre?

Background:

Dermatophytoses are one of the most common skin diseases that have been largely simple to treat. However, in recent years, these infections have become recalcitrant to treatment which can possibly be due to antifungal resistance.

Aim:

To analyze the resistance pattern of patients with recalcitrant dermatophytoses.

Materials and Methods:

A cross-sectional evaluation was undertaken of 40 consecutive patients with recalcitrant tinea corporis/cruris/both who had taken systemic antifungal treatment and did not respond completely to therapy or had recurrent lesion within 1 month of stopping the therapy. Terbinafine, fluconazole, itraconazole, ketoconazole, amphotericin B, and voriconazole were the antifungals tested using broth microdilution assay for antifungal susceptibility testing of dermatophytes, and MIC50, 90 values were recorded.

Results:

KOH mount was positive in 18 (45%) patients, culture was positive in 28 (70%) patients. Trichophyton mentagrophytes (35%) and T. rubrum (27.5%) were the predominant isolates. Overall, activity of terbinafine and itraconazole were significantly higher than the other drugs tested. For terbinafine, both T. mentagrophytes and T. rubrum were inhibited at MIC₉₀ of 0.125 μg/ml. Itraconazole-inhibited T. mentagrophytes and T. rubrum at MIC₉₀ of 0.0625 and 0.25 μg/ml, respectively. All isolates had reduced susceptibility to fluconazole.

Conclusion:

While MIC seen were higher than western data, in-vitro resistance (>1 μg/ml) to antifungals was not seen and probably may not be a cause of treatment failure. Possibly, treatment failure lies in the intricate host fungal interaction and virulence of species which help it to evade host immune response.

Voriconazole

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In Vitro Antifungal Susceptibility Profiles of 12 Antifungal Drugs against 55 Trichophyton schoenleinii Isolates from Tinea Capitis Favosa Patients in Iran, Turkey, and China

Trichophyton schoenleinii is an anthropophilic dermatophyte mainly causing tinea favosa of the scalp in certain regions of the world, especially Africa and Asia. We investigated the in vitro susceptibilities of 55 T. schoenleinii isolates collected over the last 30 years from Iran, Turkey, and China to 12 antifungals using the CLSI broth microdilution method. Our results revealed that terbinafine and ketoconazole were the most potent antifungal agents among those tested, independently of the geographic regions where strains were isolated.

Determination of minimum inhibitory concentrations of itraconazole, terbinafine and ketoconazole against dermatophyte species by broth microdilution method

PURPOSE

Various antifungal agents both topical and systemic have been introduced into clinical practice for effectively treating dermatophytic conditions. Dermatophytosis is the infection of keratinised tissues caused by fungal species of genera Trichophyton, Epidermophyton and Microsporum, commonly known as dermatophytes affecting 20-25% of the world's population. The present study aims at determining the susceptibility patterns of dermatophyte species recovered from superficial mycoses of human patients in Himachal Pradesh to antifungal agents; itraconazole, terbinafine and ketoconazole. The study also aims at determining the minimum inhibitory concentrations (MICs) of these agents following the recommended protocol of Clinical and Laboratory Standards Institute (CLSI) (M38-A2).

METHODOLOGY

A total of 53 isolates of dermatophytes (T. mentagrophyte-34 in no., T. rubrum-18 and M. gypseum-1) recovered from the superficial mycoses were examined. Broth microdilution method M38-A2 approved protocol of CLSI (2008) for filamentous fungi was followed for determining the susceptibility of dermatophyte species.

RESULTS

T. mentagrophyte isolates were found more susceptible to both itraconazole and ketoconazole as compared to terbinafine (MIC50: 0.125 µg/ml for itraconazole, 0.0625 µg/ml for ketoconazole and 0.5 µg/ml for terbinafine). Three isolates of T. mentagrophytes (VBS-5, VBSo-3 and VBSo-73) and one isolate of T. rubrum (VBPo-9) had higher MIC values of itraconazole (1 µg/ml). Similarly, the higher MIC values of ketoconazole were observed in case of only three isolates of T. mentagrophyte (VBSo-30 = 2 µg/ml; VBSo-44, VBM-2 = 1 µg/ml). The comparative analysis of the three antifungal drugs based on t-test revealed that 'itraconazole and terbinafine' and 'terbinafine and ketoconazole' were found independent based on the P < 0.005 in case of T. mentagrophyte isolates. In case of T. rubrum, the similarity existed between MIC values of 'itraconazole and ketoconazole' and 'terbinafine and ketoconazole'.

CONCLUSION

The MIC values observed in the present study based on standard protocol M38-A2 of CLSI 2008 might serve as reference for further studies covering large number of isolates from different geographic regions of the state. Such studies might reflect on the acquisition of drug resistance among isolates of dermatophyte species based on MIC values.

In vitro activity of new azoles luliconazole and lanoconazole compared with ten other antifungal drugs against clinical dermatophyte isolates

In vitro susceptibilities of 100 clinical dermatophyte isolates belonging to five species from Iran toward lanoconazole and luliconazole were compared with ten other antifungal agents including econazole, itraconazole, miconazole, fluconazole, griseofulvin, butenafine, terbinafine, caspofungin, anidulafungin and tolnaftate. MIC and MEC values were analyzed according to CLSI M38-A2 document. The isolates were previously identified to the species level using PCR-RFLP on ITS rDNA region. The range of luliconazole and lanoconazole minimum inhibitory concentrations (MICs) was 0.016-0.032 and 0.063-1 μg/ml, respectively for dermatophyte species. Luliconazole and lanoconazole revealed potent activity against all dermatophyte isolates. Anidulafungin, caspofungin, and luliconazole showed the best activity with the lowest geometric mean 0.01, 0.016, and 0.018 μg/ml, respectively, followed by tolnaftate (0.06 μg/ml), terbinafine (0.07 μg/ml), itraconazole (0.183 μg/ml), butenafine (0.188 μg/ml), econazole (0.20 μg/ml), lanoconazole (0.24 μg/ml), griseofulvin (1.28 μg/ml), miconazole (2.34 μg/ml) and fluconazole (15.34 μg/ml). The current study demonstrated luliconazole and lanoconazole displayed excellent activity against all dermatophyte isolates, although the majority of dermatophyte isolates showed low susceptibility to griseofulvin and very low to miconazole, and fluconazole.

Compensatory expression of multidrug-resistance genes encoding ABC transporters in dermatophytes

Genomic sequencing of several dermatophyte species has revealed that they show small differences in genetic content and genome organization, although each fungus has adapted to specific niches. Thus, it seemed relevant to compare gene expression between species. Here, we examined the transcription modulation of three ATP-binding cassette (ABC) transporter genes (pdr1, mdr2 and mdr4), which code for membrane transporter proteins in four species of Trichophyton ; T. interdigitale, T. rubrum, T. tonsurans and T. equinum . These fungal species were challenged with sub-lethal doses of griseofulvin, itraconazole, terbinafine and amphotericin B. A mutant strain of T. interdigitale, Δmdr2, was also analysed for the modulation of pdr1 and mdr4 genes to evaluate the possible functional interaction among these three genes. Disruption of the mdr2 gene resulted in the accumulation of high levels of mdr4 transcripts when challenged with griseofulvin, suggesting that the mdr4 gene is compensating for the inactivation of mdr2 by providing resistance to this antifungal. Although the three ABC transporter genes have high homology between the four dermatophytes analysed, it is likely that they have specific functions, suggesting that the action of each drug is dependent on other factors inherent to each species. Our data suggest that these ABC transporter genes act synergistically in dermatophytes, and they may compensate for one another when challenged with antifungal drugs. This may be an important cause of therapeutic failure when treating fungal infections.

Molecular Characterization and In Vitro Antifungal Susceptibility of 316 Clinical Isolates of Dermatophytes in Iran

Dermatophytosis is a common mycotic infection of the skin, nail, and hair, associated with major public health concern worldwide. Various species of dermatophytes show significant differences in susceptibility to antifungals. Here, we present the antifungal susceptibility of a large collection of molecularly identified dermatophyte isolates obtained from tropical region of south of Iran. A total of 9485 patients clinically suspected to have cutaneous fungal infections were examined. Dermatophytosis was confirmed in 1502 cases by direct microscopy and culture. Three hundred and sixteen isolates recovered in culture were identified to species level using PCR sequencing of ITS region and RFLP. Tinea corporis was the most prevalent type of clinical manifestation (35.2 %), followed by tinea cruris (17 %), tinea capitis (12.8 %), tinea pedis (11.3 %), tinea manuum (11 %), tinea unguium (6.9 %), and tinea barbae (5.8 %). Trichophyton interdigitale was the most common isolate (49.36 %), followed by Trichophyton rubrum (18.98 %), Epidermophyton floccosum (13.29 %), Microsporum canis (9.17 %), Arthroderma benhamiae (T. anamorph of A. benhamiae; 5.38 %), and Trichophyton tonsurans (3.79 %). Overall, irrespective of the geographical region, terbinafine was the most potent antifungal against all isolates, with an MIC range of 0.002-0.25 μg/mL, followed by itraconazole (0.004-0.5 μg/mL), griseofulvin (0.125-8 μg/mL), and fluconazole (4-128 μg/mL). Analysis of our data revealed a significant increase in the frequency of A.benhamiae, which definitely warrants further investigation to explore source of this infection in south of Iran. Moreover, terbinafine was the most effective antifungal against all isolates, in vitro.

Comparison of the in vitro activities of newer triazoles and established antifungal agents against Trichophyton rubrum

One hundred eleven clinical Trichophyton rubrum isolates were tested against 7 antifungal agents. The geometric mean MICs of all isolates were, in increasing order: terbinafine, 0.03 mg/liter; voriconazole, 0.05 mg/liter; posaconazole, 0.11 mg/liter; isavuconazole, 0.13 mg/liter; itraconazole, 0.26 mg/liter; griseofulvin, 1.65 mg/liter; and fluconazole, 2.12 mg/liter.

Investigation of In Vitro Activity of Five Antifungal Drugs against Dermatophytes Species Isolated from Clinical Samples Using the E-Test Method

OBJECTIVE

Dermatomycosis is an infection with fungi related to the skin: glabrous skin, hair and/or nails. Oral treatment of fungal infections in dermatology has become a preferred modality for the management of these very common conditions. Although there are increasing numbers of antifungals available for treatment of dermatophytes, some cases and relapses have been unresponsive to treatment. The determination of fungus in-vitro antifungal susceptibility has been reported to be important for the ability to eradicate dermatophytes. It is necessary to perform antifungal susceptibility testing of dermatophytes. E-test (AB Biodisk, Sweden) is a rapid, easy-to-perform in-vitro antifungal susceptibility test. The aim of this study was to investigate the susceptibility of the different species of dermatophyte strains isolated clinical specimens to five antifungal agents using the E-test method.

MATERIALS AND METHODS

A total of 66 specimens were collected from the nails, feet, inguinal region, trunk and hands. These strains tested MIC endpoints of E-test for amphotericin B, fluconazole, itraconazole, caspofungin, and ketoconazole were read after 72, and 96 hours incubation for each strain on RPMI 1640 agar.

RESULTS

The dermatophytes tested included Trichophyton rubrum 43 (65.1%), Trichophyton mentagrophytes 7 (10.7%), Microsporum canis 5 (7.6%), Trichophyton tonsurans 5 (7.6%), Epidermophyton floccosum 4 (6.0%) and Trichophyton violaceum 2 (3.0%). The most active agent against all dermatophytes species was caspofungin with a minimal inhibitory concentration (MIC) range (μg/mL(-1)) (0.02-3, 0.032-4, 0.125-0.50, 0.032-2, 0.25-0.50, 0.125-0.50) and it raconazole with an MIC range (μg/mL(-1)) (0.038-1.5, 0.094-1.5, 1-32, 0.016-0.50, 0.25-0.50, 0.125-0.50). The least active agent was fluconazole with an MIC range (μg/mL(-1)) (0, 19-48, 2-256, 2-8, 256, 256, 8-24).

CONCLUSION

E-test seems to be an alternative method to MIC-determination of antifungal drugs for dermatophytes species, since it is a less-laborious methodology and results could be obtained faster.

In vitro antifungal susceptibility of Trichophyton violaceum isolated from tinea capitis patients

OBJECTIVES

Trichophyton violaceum is an anthropophilic dermatophyte that is endemic to parts of Africa and Asia and is sporadic in Europe. T. violaceum mainly causes tinea capitis in both children and adolescents. Although the infections caused by T. violaceum are of considerable medical importance, its antifungal susceptibility profile remains poorly examined.

METHODS

In this study, we tested the in vitro antifungal susceptibility of a set of clinical T. violaceum isolates obtained from tinea capitis patients, using the CLSI broth microdilution method. We tested eight antifungals and used isolates collected from Western China (21), Eastern China (12), the Middle East (1), Europe (20), South Africa (7) and Canada (1).

RESULTS

The geometric means of the MICs of the antifungals for all isolates were as follows (in increasing order): posaconazole, 0.021 mg/L; terbinafine, 0.023 mg/L; voriconazole, 0.062 mg/L; amphotericin B, 0.20 mg/L; itraconazole, 0.34 mg/L; caspofungin, 0.56 mg/L; fluconazole, 4.23 mg/L; and flucytosine, 8.46 mg/L. No statistically significant differences in the susceptibility profiles of T. violaceum were detected within the geographical regions tested.

CONCLUSIONS

Posaconazole, terbinafine and voriconazole were shown to be the most potent antifungal agents against T. violaceum isolates obtained from tinea capitis patients worldwide. These results might help clinicians in developing appropriate therapies that have a high probability of successfully treating tinea capitis due to T. violaceum.

Anti dermatophytic therapy--prospects for the discovery of new drugs from natural products

Millions of people and animals suffer from superficial infections caused by a group of highly specialized filamentous fungi, the dermatophytes, which only infect keratinized structures. With the appearance of AIDS, the incidence of dermatophytosis has increased. Current drug therapy used for these infections is often toxic, long-term, and expensive and has limited effectiveness; therefore, the discovery of new anti dermatophytic compounds is a necessity. Natural products have been the most productive source for new drug development. This paper provides a brief review of the current literature regarding the presence of dermatophytes in immunocompromised patients, drug resistance to conventional treatments and new anti dermatophytic treatments.

Trichophyton tonsurans strains from Brazil: phenotypic heterogeneity, genetic homology, and detection of virulence genes

The objective of this study was to establish the phenotypical and molecular patterns of clinical isolates of Trichophyton tonsurans circulating in the state of Ceará, northeastern Brazil. For this purpose, 25 T. tonsurans strains isolated from independent cases of tinea capitis in children were phenotypically evaluated regarding their macro- and micro-morphological characteristics, vitamin requirements, urease production, and antifungal susceptibility. The molecular characterization was carried out with random amplified polymorphic DNA molecular markers and M13 fingerprinting. The presence of the genes CarbM14, Sub2, CER, URE, ASP, PBL, and LAC, which encode enzymes related to fungal virulence, was also evaluated. Finally, melanin production was assessed through specific staining. The data obtained demonstrated that these T. tonsurans strains have considerable phenotypical variation, although they showed a low degree of genetic polymorphism according to the markers used. The genes CarbM14, Sub2, CER, and URE were detected in all the analyzed strains. The gene LAC was also identified in all the strains, and melanin synthesis was phenotypically confirmed. The strains were susceptible to antifungals, especially itraconazole (GM = 0.06 μg/mL) and ketoconazole (GM = 0.24 μg/mL). Therefore, T. tonsurans strains can present great phenotypical heterogeneity, even in genetically similar isolates. Moreover, the presence of the LAC gene indicates the possible participation of melanin in the pathogenesis of these dermatophytes.

In vitro activities of antifungal drugs against dermatophytes isolated in Tokat, Turkey

BACKGROUND

In this study, we aimed to establish the in vitro antifungal susceptibilities of terbinafine, miconazole, itraconazole, ketoconazole, griseofulvin, and amphotericin B against dermatophyte isolates.

METHODS

One hundred and seventy-seven clinical isolates were tested: Trichophyton rubrum (n = 78), Trichophyton mentagrophytes (n = 49), Epidermophyton floccosum (n = 30), Trichophyton verrucosum (n = 16), and Trichophyton tonsurans (n = 4). The broth microdilution assay for antifungal susceptibility testing of dermatophytes was performed according to Clinical and Laboratory Standards Institute guidelines in the M38-A2 document.

RESULTS

Our minimum inhibitory concentration (MIC) results showed that the values for terbinafine for all dermatophyte isolates were significantly lower than the values for amphotericin B, miconazole, itraconazole, ketoconazole, and griseofulvin. For T. rubrum isolates, amphotericin B was more active than miconazole, itraconazole, and ketoconazole. Among the antifungal drugs tested, griseofulvin had the highest minimum inhibitory concentration values for T. mentagrophytes isolates.

CONCLUSION

Terbinafine was found to be the most effective antifungal drug against all tested dermatophyte isolates. Griseofulvin was the less active antifungal drug against T. mentagrophytes isolates. Performing antifungal susceptibility testing is especially important for screening the development of antifungal resistance.

Increase in resistance to fluconazole and itraconazole in Trichophyton rubrum clinical isolates by sequential passages in vitro under drug pressure

Trichophyton rubrum, an anthropophilic dermatophyte fungus, is the predominant causative agent of superficial skin infections in human population. There are only scanty reports on drug susceptibility profiling of T. rubrum. Neither mechanisms for drug resistance development nor correlation between in vitro drug susceptibility and in vivo response to treatment is known for that species. In this study, changes in the in vitro susceptibilities to fluconazole (FLZ) and itraconazole (ITZ) among thirty T. rubrum clinical strains subjected to sequential passages in the presence or absence of the azoles were investigated. Each strain was passaged 12 times at 4-week intervals as three parallel cultures, maintained on a drug-free medium (1), and a medium containing FLZ (2) or ITZ (3) at subinhibitory concentrations. Susceptibility to FLZ and ITZ of the original strain and its 3 subcultures was determined by microdilution method. The MIC values of the two azoles remained unaltered for all T. rubrum strains tested, after 12 passages on a drug-free medium. Among the strains grown with FLZ, an increase in the MICs of FLZ and ITZ was noted in 17 (56.7 %) and 19 (63.3 %) strains, respectively. Increased MICs of ITZ and FLZ were demonstrated for 24 (80 %) and 20 (66.7 %) strains that were propagated with ITZ. The results indicate the capacity of T. rubrum to develop resistance toward the azoles after prolonged exposure to these drugs. Resistance of T. rubrum to azoles plays an important role in therapy failures and consequently contributes to persistence and chronicity of the infections.

A Phase 1, randomized, open-label crossover study to evaluate the safety and pharmacokinetics of 400 mg albaconazole administered to healthy participants as a tablet formulation versus a capsule formulation

Background

Albaconazole is a novel triazole being developed for the oral treatment of fungal diseases. Once-weekly oral dosing with 400 mg albaconazole for 24 or 36 weeks resulted in high rates of clinical and mycological resolution for distal subungual onychomycosis, as well as a favorable safety and tolerability profile.

Purpose

To compare four 100-mg albaconazole capsules to one 400-mg albaconazole tablet for bioavailability, bioequivalence, tolerability, and safety.

Patients and methods

Forty participants were enrolled in this Phase I, open-label, two-sequence crossover study. Twenty participants were exposed to a single 400-mg tablet dose of albaconazole before being crossed over to a single dose of four 100-mg albaconazole capsules. The second group of 20 participants received the study products in reverse order. Blood samples were taken over 15 days post-dose to assess the plasma concentrations and pharmacokinetic parameters of albaconazole and its primary metabolite, 6-hydroxyalbaconazole. Safety was assessed throughout the study.

Results

The area under the curve (AUC) and maximum measured plasma concentration (C_max) of the albaconazole tablet were approximately 10% and 22% lower, respectively, than for the albaconazole capsules. Statistical significance was reached for the C_max but not for the AUC measurements (AUC_0-t and AUC_0-inf). Because the 90% confidence intervals based on the differences between the tablet and capsule were outside the 80%–125% range for both the C_max and AUC, we concluded that the formulations were not bioequivalent with respect to the rate or extent of absorption. Both formulations were safe and well-tolerated in this study. All adverse events (AEs) were generally mild and were mainly gastrointestinal- or nervous system-related (eg, dizziness, headache). No electrocardiogram findings were reported as an AE, and no serious AEs or deaths were reported.

Conclusion

The AUC and C_max of albaconazole after a single 400-mg oral dose administered as a tablet formulation were lower than those of a capsule formulation. Albaconazole tablets and capsules cannot, therefore, be considered bioequivalent.

[Influence of the ecological group on the in vitro antifungal susceptibility of dermatophytic fungi]

BACKGROUND

Dermatophytes can be divided into geophilic (soil), zoophilic (animals) and anthropophilic (humans) strains, depending on the source of the keratin that they use for nutritional purposes.

AIMS

The in vitro susceptibility of clinical isolates of dermatophyte fungi has been studied in the 3 ecological groups with several antifungal agents for the topical management of dermatophytoses in order to determine their relationship with the ecological group.

METHODS

A standardised dilution micromethod in a liquid medium was used for the determination of the in vitro antifungal activity of 9 topical antifungal drugs: amorolfine (AMR), bifonazole (BFZ), clotrimazole, econazole, ketoconazole, miconazole, oxiconazole, terbinafine (TRB) and tioconazole. The in vitro activity was obtained against 124 clinical isolates of dermatophyte moulds from the anthropophilic, zoophilic and geophilic ecological groups.

RESULTS

The in vitro antifungal activity was different depending on the ecological group, although a species-dependent profile was also observed.

CONCLUSIONS

Azole derivatives showed a similar antifungal profile, being more active against anthropophilic dermatophytes > zoophilic > geophilic. Activity of TRB and AMR was different from that of azole derivatives (zoophilic > anthropophilic > geophilic). A higher in vitro antifungal activity against the 3 ecological groups was observed with TRB and AMR, whilst BFZ was the less active drug.