Mapping the Global Spread of T. indotineae: An Update on Antifungal Resistance, Mutations, and Strategies for Effective Management.

INTRODUCTION: The global spread of Trichophyton indotineae presents a pressing challenge in dermatophytosis management. This systematic review explores the current landscape of T. indotineae infections, emphasizing resistance patterns, susceptibility testing, mutational analysis, and management strategies. METHODS: A literature search was conducted in November 2023 using Embase, PubMed, Scopus, and Web of Science databases. Inclusion criteria covered clinical trials, observational studies, case series, or case reports with T. indotineae diagnosis through molecular methods. Reports on resistance mechanisms, antifungal susceptibility testing, and management were used for data extraction. RESULTS AND DISCUSSION: A total of 1148 articles were identified through the systematic search process, with 45 meeting the inclusion criteria. The global spread of T. indotineae is evident, with cases reported in numerous new countries in 2023. Tentative epidemiological cut-off values (ECOFFs) suggested by several groups provide insights into the likelihood of clinical resistance. The presence of specific mutations, particularly Phe397Leu, correlate with higher minimum inhibitory concentrations (MICs), indicating potential clinical resistance. Azole resistance has also been reported and investigated in T. indotineae, and is a growing concern. Nevertheless, itraconazole continues to be an alternative therapy. Recommendations for management include oral or combination therapies and individualized approaches based on mutational analysis and susceptibility testing. CONCLUSION: Trichophyton indotineae poses a complex clinical scenario, necessitating enhanced surveillance, improved diagnostics, and cautious antifungal use. The absence of established clinical breakpoints for dermatophytes underscores the need for further research in this challenging field.

Impact of sphingolipid synthesis inhibition on the drug susceptibility patterns of Trichophyton species.

The well known dermatophyte infections caused by Trichophyton species are an ambiguous problem to treat using the present arsenal of antifungals. This study expounds on the effect of inhibition of sphingolipid pathway on Trichophyton growth. Findings from the drug susceptibility assays suggest sphingolipid inhibition severely restricts the growth of T. interdigitale and T. tonsurans. The observed synergistic effects of combinations of sphingolipid inhibitor and conventional drugs provide a promising treatment strategy against Trichophyton infection.

Expert Panel Review of Skin and Hair Dermatophytoses in an Era of Antifungal Resistance.

Dermatophytoses are fungal infections of the skin, hair, and nails that affect approximately 25% of the global population. Occlusive clothing, living in a hot humid environment, poor hygiene, proximity to animals, and crowded living conditions are important risk factors. Dermatophyte infections are named for the anatomic area they infect, and include tinea corporis, cruris, capitis, barbae, faciei, pedis, and manuum. Tinea incognito describes steroid-modified tinea. In some patients, especially those who are immunosuppressed or who have a history of corticosteroid use, dermatophyte infections may spread to involve extensive skin areas, and, in rare cases, may extend to the dermis and hair follicle. Over the past decade, dermatophytoses cases not responding to standard of care therapy have been increasingly reported. These cases are especially prevalent in the Indian subcontinent, and Trichophyton indotineae has been identified as the causative species, generating concern regarding resistance to available antifungal therapies. Antifungal-resistant dermatophyte infections have been recently recognized in the United States. Antifungal resistance is now a global health concern. When feasible, mycological confirmation before starting treatment is considered best practice. To curb antifungal-resistant infections, it is necessary for physicians to maintain a high index of suspicion for resistant dermatophyte infections coupled with antifungal stewardship efforts. Furthermore, by forging partnerships with federal agencies, state and local public health agencies, professional societies, and academic institutions, dermatologists can lead efforts to prevent the spread of antifungal-resistant dermatophytes.

In vitro Azole Susceptibility Testing of Japanese Isolates of Itraconazole-Resistant Dermatophytes.

We conducted antifungal susceptibility testing on itraconazole (ITCZ)-resistant isolates of Trichophyton interdigitale and Trichophyton rubrum collected from Japanese patients in 2021 and 2022. The aim of the present study was to determine the most effective drug against ITCZ-resistant strains of dermatophytes. In all isolates, the minimum inhibitory concentrations (MICs) were > 32 mg/l for ITCZ, < 0.03 to 0.5 mg/l for ravuconazole (RVCZ), and < 0.03 mg/l for efinaconazole (EFCZ), luliconazole (LUCZ), and terbinafine (TRBF). Thus, in tinea unguium cases with ITCZ-resistant strains, treatment should be switched to TRBF or other azoles with a stronger antifungal efficacy, such as EFCZ, LUCZ, or RVCZ, and treatment must continue until the infectious organisms are completely eliminated.

The Domestic Isolation of Terbinafine- and Itraconazole-Resistant Trichophyton indotineae in Chinese Mainland.

BACKGROUND: Trichophyton indotineae, a new species of dermatophytes, has become a significant concern in treating dermatophytosis due to the high level of terbinafine resistance reported in India and even worldwide. OBJECTIVES: This study aimed to report the terbinafine- and itraconazole-resistant T. indotineae in Chinese mainland, by identifying the phylogenetic classification of the isolate strain, and detecting the drug resistance, gene mutation and expression. PATIENTS/METHODS: The skin scales of the patient were cultured on SDA and the isolate was authenticated by DNA sequencing and MALDI-TOF MS. Antifungal susceptibility testing was performed following the M38-A2 CLSI protocol to examine the MICs values of terbinafine, itraconazole, fluconazole, etc. The strain was screened for mutations in the squalene epoxidase (SQLE) gene by Sanger sequencing and detected the expression of CYP51A and CYP51B by qRT-PCR. RESULTS: A multi-resistant ITS genotype VIII sibling of the T. mentagrophytes complex (T. indotineae) was isolated in Chinese mainland. The strain harbored high terbinafine MIC of > 32 µg/mL and itraconazole MIC of 1.0 µg/mL, which was identified a mutation in the squalene epoxidase gene with amino acid substitution (Phe397Leu, mutation 1191C > A). In addition, overexpression of CYP51A and CYP51B was observed. With multiple relapses, the patient finally achieved clinical cure by itraconazole pulse therapy and topical clotrimazole cream for 5 weeks. CONCLUSIONS: The first domestic strain of terbinafine- and itraconazole-resistant T. indotineae from a patient in Chinese mainland was isolated. Itraconazole pulse therapy can be an effective method for the treatment of T. indotineae.

In vitro Azole Susceptibility Testing of Japanese Isolates of Terbinafine-Resistant Trichophyton indotineae and Trichophyton rubrum.

Multi-antifungal-resistant strains of Trichophyton indotineae and Trichophyton rubrum have been isolated in Japan. In the present study, we examined the in vitro susceptibility of terbinafine (TRBF) -resistant isolates of T. indotineae and T. rubrum to efinaconazole (EFCZ) and luliconazole (LUCZ). In all isolates, the minimum inhibitory concentrations were ≥ 32 mg/l for TRBF, < 0.03 to 16 mg/l for itraconazole, < 0.03 to 16 mg/l for ravuconazole, < 0.03 to 0.5 mg/l for LUCZ, and < 0.03 to 4 mg/l for EFCZ. Of note, T. rubrum NUBS21012 and T. indotineae NUBS 19006T showed resistance to LUCZ and/or EFCZ unlike the other isolates.

Epidemiological study of antifungal-resistant dermatophytes isolated from Japanese patients.

An epidemiological study of antifungal drug-resistant dermatophytes was conducted as a follow-up to our 2020 survey. Dermatophytes were isolated in 2022 from the same dermatology clinics as in the previous study. In total, 288 Trichophyton interdigitale and Trichophyton rubrum clinical isolates were obtained from 288 human cases of dermatophytosis in Tokyo, Saitama, Shizuoka, and Kumamoto, Japan. Four strains were found to be resistant to terbinafine (TRF) and susceptible to itraconazole (ITZ), luliconazole (LCZ), and ravuconazole (RVZ), and three other strains were found to be resistant to ITZ and susceptible to TRF, LCZ, and RVZ. We determined the sequences of the squalene epoxidase (SQLE)-encoding gene in the three TRF-resistant T. rubrum strains, and found that two strains harbored L393F missense mutations, and one strain harbored a F397L missense mutation. The results of the present study indicated that the prevalence of TRF-resistant dermatophytes has not increased since 2020. However, TRF-resistant T. interdigitale (L393F mutation) was isolated for the first time, indicating that attention should be paid to the presence of TRF-resistant T. interdigitale in the future. We also examined for the first time the epidemiology of ITZ-resistant T. rubrum in Japanese patients. Although the number of ITZ-resistant strains was not large, the results confirmed that ITZ-resistant T. rubrum strains do exist in Japanese patients.

First Terbinafine-Resistant Trichophyton indotineae Isolates with Phe397Leu and/or Thr414His Mutations in Turkey.

Fungal infections of the skin, nails, and hair caused by dermatophyte species continue to be a worldwide concern. The increase in terbinafine-resistant superficial dermatophytosis has become a major concern over the last decade. In this report, we presented two cases of infection with terbinafine-resistant Trichophyton indotineae, the first diagnosis of this species in Turkey. One patient exhibited erythematous pruritic patches and plaques in the inguinal and gluteal regions, while the other patient showed annular erythematous scaly plaques in the bilateral posterior thigh and gluteal regions. One patient harbored a CD36 mutation. Both strains harbored the same amino acid substitution in the squalene epoxidase gene, whereas one isolate had another unknown mutation. Clinical improvement was observed with resveratrol treatment in the patient with the CD36 mutation but not in the other patient.

Efficacy of antifungal agents against fungal spores: An in vitro study using microplate laser nephelometry and an artificially infected 3D skin model.

Dermal fungal infections seem to have increased over recent years. There is further a shift from anthropophilic dermatophytes to a growing prevalence of zoophilic species and the emergence of resistant strains. New antifungals are needed to combat these fungi and their resting spores. This study aimed to investigate the sporicidal effects of sertaconazole nitrate using microplate laser nephelometry against the microconidia of Trichophyton, chlamydospores of Epidermophyton, blastospores of Candida, and conidia of the mold Scopulariopsis brevicaulis. The results obtained were compared with those from ciclopirox olamine and terbinafine. The sporicidal activity was further determined using infected three-dimensional full skin models to determine the antifungal effects in the presence of human cells. Sertaconazole nitrate inhibited the growth of dermatophytes, molds, and yeasts. Ciclopirox olamine also had good antifungal activity, although higher concentrations were needed compared to sertaconazole nitrate. Terbinafine was highly effective against most dermatophytes, but higher concentrations were required to kill the resistant strain Trichophyton indotineae. Sertaconazole nitrate, ciclopirox olamine, and terbinafine had no negative effects on full skin models. Sertaconazole nitrate reduced the growth of fungal and yeast spores over 72 h. Ciclopirox olamine and terbinafine also inhibited the growth of dermatophytes and molds but had significantly lower effects on the yeast. Sertaconazole nitrate might have advantages over the commonly used antifungals ciclopirox olamine and terbinafine in combating resting spores, which persist in the tissues, and thus in the therapy of recurring dermatomycoses.

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.

Modulation of ERG gene expression in fluconazole-resistant human and animal isolates of Trichophyton verrucosum.

Dermatophytes are a group of eukaryotic microorganisms characterized by high capacity to colonize keratinized structures such as the skin, hair, and nails. Over the past years, the incidence of infections caused by zoophilic species, e.g., Trichophyton verrucosum, has been increasing in some parts of the world, especially in Europe. Moreover, the emergence of recalcitrant dermatophytoses and in vitro resistant dermatophytes has become a cause of concern worldwide. Here, we analyzed the mechanisms underlying resistance to fluconazole among clinical isolates of T. verrucosum. Quantitative RT-PCR was carried out to determine the relative expression levels of mRNA transcripts of ERG3, ERG6, and ERG11 genes in the fungal samples using the housekeeping gene GAPDH as a reference. Our results showed that the upregulation of the ERG gene expression is a possible mechanism of resistance to fluconazole in this species. Furthermore, ERG11 is the most statistically significantly overexpressed gene in the pool of fluconazole-resistant T. verrucosum isolates. Additionally, we have demonstrated that exposure to fluconazole increases the levels of expression of ERG genes in fluconazole-resistant isolates of T. verrucosum. In conclusion, this study has shown one of the possible mechanisms of resistance to fluconazole among zoophilic dermatophytes, which involves the maintenance of high levels of expression of ERG genes after drug exposure.

Evaluation of DermaGenius® resistance real-time polymerase chain reaction for rapid detection of terbinafine-resistant Trichophyton species.

BACKGROUND: Treatment-resistant dermatophytosis caused by Trichophyton mentagrophytes/interdigitale complex has emerged as a global public health threat, particularly in endemic countries like India and has spread to many other countries. This veritable spread is alarming due to increase in resistance to terbinafine, which targets the ergosterol biosynthetic pathway by inhibiting the enzyme squalene epoxidase (SQLE). About two third of studies worldwide have reported amino acid substitutions Phe397Leu and Leu393Phe in the SQLE protein to be responsible for high terbinafine MICs. OBJECTIVES: We evaluated the efficacy of the newly developed DermaGenius® Resistance real-time PCR assay to rapidly identify Trichophyton isolates harbouring most common SQLE mutant (Phe397Leu and Leu393Phe) conferring high terbinafine resistance from wild-type susceptible isolates. METHODS: A total of 97 Trichophyton isolates confirmed by ITS sequencing as T. mentagrophytes/interdigitale (recently named T. indotineae n = 90), T. rubrum/T. soudanense (n = 3), T mentagrophytes (n = 2) and T tonsurans (n = 2) were analysed to evaluate DermaGenius® Resistance real-time PCR assay. All 40 T. indotineae isolates exhibiting amino acid substitutions Phe397Leu or Leu393Phe identified by SQLE gene sequencing were evaluated for detection of non-wild-type strains by real-time PCR. Antifungal susceptibility testing for terbinafine was done by CLSI microbroth dilution method. RESULTS: All terbinafine-resistant isolates harbouring amino acid substitutions Phe397Leu or Leu393Phe in SQLE gene were correctly recorded as SQLE mutants by the DermaGenius® Resistance real-time PCR assay. CONCLUSIONS: The DermaGenius® Resistance real-time PCR assay effectively identified Trichophyton species and distinguished wild-type from SQLE mutant genotype that harbour Phe397Leu and Leu393Phe amino acid substitutions.

Lactobacillus plantarum strain HT-W104-B1: potential bacterium isolated from Malaysian fermented foods for control of the dermatophyte Trichophyton rubrum.

The objective was to screen and evaluate the anti-fungal activity of lactic acid bacteria (LABs) isolated from Malaysian fermented foods against two Trichophyton species. A total of 66 LAB strains were screened using dual culture assays. This showed that four LAB strains were very effective in inhibiting growth of T. rubrum but not T. interdigitale. More detailed studies with Lactobacillus plantarum strain HT-W104-B1 showed that the supernatant was mainly responsible for inhibiting the growth of T. rubrum. The minimum inhibitory concentration (MIC), inhibitory concentration, the 50% growth inhibition (IC50) and minimum fungicide concentration (MFC) were 20 mg/mL, 14 mg/mL and 30 mg/mL, respectively. A total of six metabolites were found in the supernatant, with the two major metabolites being L-lactic acid (19.1 mg/g cell dry weight (CDW)) and acetic acid (2.2 mg/g CDW). A comparative study on keratin agar media showed that the natural mixture in the supernatants predominantly contained L-lactic and acetic acid, and this significantly controlled the growth of T. rubrum. The pure two individual compounds were less effective. Potential exists for application of the natural mixture of compounds for the treatment of skin infection by T. rubrum.

A comparative study between two antifungal agents, Luliconazole and Efinaconazole, of their preventive effects in a Trichophyton-infected guinea pig onychomycosis model.

An efficacious period of two topical antifungal drugs was compared in a Trichophyton mentagrophytes-infected onychomycosis model in guinea pigs treated with antifungal drugs prior to infection. Luliconazole 5% (LLCZ) and efinaconazole 10% (EFCZ) test solutions were applied to the animals' nails once daily for 2 weeks followed by a nontreatment period of 2, 4, and 8 weeks. After each nontreatment period, the nails were artificially infected by the fungus. Drug efficacy was quantitatively evaluated by qPCR and histopathological examination of the nails collected following a 4-week post-infection period. The fungal infection was confirmed in the untreated group. Both LLCZ and EFCZ prevented fungal infection in the treated groups with the nontreatment period of 2 weeks. After the nontreatment period of 4 weeks, no infection was observed in the LLCZ-treated group; however, infection into the nail surface and fungal invasion into the nail bed were observed in the EFCZ-treated group. After the nontreatment period of 8 weeks, fungi were found in the nail surface and nail bed in some nails treated with EFCZ; however, no infection was observed in the nail bed of the LLCZ-treated group. The results suggest that LLCZ possesses longer-lasting antifungal effect in nails of the guinea pigs than EFCZ, and that this animal model could be useful for translational research between preclinical and clinical studies to evaluate the pharmacological efficacy of antifungal drugs to treat onychomycosis. This experimentally shown longer-lasting preventive effects of LLCZ could also decrease the likelihoods of onychomycosis recurrence clinically.

Evaluation of susceptibility and response in the surface of agents of surface mycoses (Trichophyton mentagrophytes; T. tonsurans) to antifungal drugs of interest in a medical clinic / Avaliação da susceptibilidade e resposta in vitro de agentes de micoses superficiais (Trichophyton mentagrophytes; T. tonsurans) à drogas antifúngicas de interesse em clínica médica

INTRODUCTION: The resistance of fungal species to drugs usually used in clinics is of great interest in the medical field. OBJECTIVE: To evaluate susceptibility and in vitro response of species of Trichophyton spp. to antifungal drugs of interest in clinical medicine. METHODS: 12 samples of clinical isolates from humans were used, nine of T. mentagrophytes and three of T. tonsurans. Susceptibility tests were performed according to the agar diffusion (AD) and broth microdilution (BM) methods. RESULTS: In the AD method, the species T. tonsurans presented a percentage of sensitivity of 33% in relation to amphotericin B and 66% to itraconazole, with 100% resistance to ketoconazole and fluconazole. T. mentagrophytes also showed 100% resistance to ketoconazole in this technique, with 11% sensitivity to ketoconazole, 22% to itraconazole and 22% of samples classified as sensitive dose dependent. In the MC method, the species T. tonsurans presented a sensitivity percentage of 66%, 55% and 33% in relation to ketoconazole, fluconazole and itraconazole, respectively. The T. mentagrophytes species presented sensitivity percentages of 11%, 11%, 33% and 55% for amphotericin B, itraconazole, ketoconazole and fluconazole, respectively. CONCLUSION: There was resistance in vitro of the species of T. mentagrophytes and T. tonsurans against the antifungal fluconazole and relative resistance against ketoconazole in the AD method. In BM, however, important percentages of sensitivity were observed for the two species analyzed in relation to the antifungals fluconazole and ketoconazole when compared to itraconazole and amphotericin B.

INTRODUÇÃO: A resistência de espécies fúngicas às drogas usualmente empregadas no meio clínico é motivo de grande interesse na área médica. OBJETIVO: Avaliar susceptibilidade e resposta in vitro de espécies de Trichophyton spp. a drogas antifúngicas de interesse em clínica médica. MÉTODOS: Foram utilizadas 12 amostras de isolados clínicos de humanos, sendo nove de T. mentagrophytes e três de T. tonsurans. Foram realizados testes de susceptibilidade segundo os métodos de difusão em ágar (DA) e microdiluição em caldo (MC). RESULTADOS: No método de DA, a espécie T. tonsurans apresentou percentual de sensibilidade de 33% em relação à anfotericina B e de 66% ao itraconazol, com 100% de resistência frente ao cetoconazol e ao fluconazol. A espécie T. mentagrophytes também apresentou 100% de resistência frente ao cetoconazol nesta técnica, com 11% de sensibilidade ao cetoconazol, 22% ao itraconazol e 22% das amostras classificadas como sensível dose dependente. No método de MC, a espécie T. tonsurans apresentou percentual de sensibilidade de 66%, 55% e 33% em relação ao cetoconazol, fluconazol e itraconazol, respectivamente. A espécie T. mentagrophytes apresentou percentuais de sensibilidade de 11%, 11%, 33% e 55% para anfotericina B, itraconazol, cetoconazol e fluconazol, respectivamente. CONCLUSÃO: Houve resistência in vitro das espécies do T. mentagrophytes e T. tonsurans frente ao antifúngico fluconazol e resistência relativa frente ao cetoconazol no método de DA. Na MC, no entanto, foram observados importantes percentuais de sensibilidade das duas espécies analisadas frente aos antifúngicos fluconazol e cetoconazol quando comparadas ao itraconazol e à anfotericina B.

Complementary effect of mechanism of multidrug resistance in Trichophyton mentagrophytes isolated from human dermatophytoses of animal origin.

BACKGROUND: Dermatophytoses have gained interest worldwide due to the increased resistance to terbinafine and azoles and difficulty in management of these refractory diseases. OBJECTIVES: In this study, we identified and analysed Trichophyton mentagrophytes clinical isolates obtained from humans with infections of animal origin. METHODS: We used quantitative real-time PCR (qRT-PCR) to examine the transcriptional modulation of three MDR genes (PDR1, MDR2 and MDR4) and analysed squalene epoxidase (SQLE) gene sequences from multidrug-resistant Trichophyton mentagrophytes isolates. RESULTS: The expression profile revealed a 2- to 12-fold increase in mRNA accumulation in the presence of any of the antifungals, compared to cells incubated without drugs. A statistically significant relationship between the isolates exposed to itraconazole and increased expression of the tested genes was revealed. Substantially lower transcription levels were noted for cells exposed to luliconazole, that is, a third-generation azole. Additionally, in the case of 50% of terbinafine-resistant strains, Leu397Phe substitution in the SQLE gene was detected. Furthermore, the reduced susceptibility to itraconazole and voriconazole was overcome by milbemycin oxime. CONCLUSIONS: In conclusion, our study shed more light on the role of the ABC transporter family in T. mentagrophytes, which, if overexpressed, can confer resistance to single azole drugs and even cross-resistance. Finally, milbemycin oxime could be an interesting compound supporting treatment with azole drugs in the case of refractory dermatomycoses.

Antifungal activity of extracts and purified saponins from the rhizomes of Chamaecostus cuspidatus against Candida and Trichophyton species.

AIM: To evaluate the antifungal activity of extracts of Chamaecostus cuspidatus against Candida and Trichophyton species. METHODS AND RESULTS: Crude ethanol extracts of leaves, stems and rhizomes were prepared and evaluated for antimicrobial activity. Only the rhizomes extract (RE) showed antifungal activity but had no inhibitory effect against bacteria (Staphylococcus aureus and Escherichia coli). The RE was then submitted to liquid-liquid partition with hexane (Hex), dichloromethane, chloroform, ethyl acetate and water. The Hex fraction (Hex Fr) from the RE was found to have the best antifungal effect. Three known saponins were isolated from the Hex Fr, of which two (dioscin and aferoside A) showed good antifungal activity. In addition, Hex Fr and the two bioactive compounds had no antibacterial effect, but exhibited fungicidal activity, caused significant changes in the morphology of the fungal cells and showed anti-Candida albicans biofilm activity. Finally, the bioactive plant products presented greater selectivity for fungal cells over normal human cells. CONCLUSIONS: The rhizomes of C. cuspidatus have bioactive saponins that function as effective antifungals against Candida and Trichophyton species, and have antibiofilm activity against C. albicans. SIGNIFICANCE AND IMPACT OF THE STUDY: Chamaecostus cuspidatus REs may have potential clinical application towards the management of superficial mycoses caused by Candida and Trichophyton species.

8-Hydroxyquinoline 1,2,3-triazole derivatives with promising and selective antifungal activity.

Fungal infections that affect humans and plants have increased significantly in recent decades. However, these pathogens are still neglected when compared to other infectious agents. Due to the high prevalence of these infections, the need for new molecules with antifungal potential is recognized, as pathogenic species are developing resistance to the main drugs available. This work reports the design and synthesis of 1,2,3-triazole derivatives of 8-hydroxyquinoline, as well as the determination of their activities against a panel of fungal species: Candida spp., Trichosporon asahii, Magnusiomyces capitatus, Microsporum spp., Trichophyton spp. and Fusarium spp. The triazoles 5-(4-phenyl-1H-1,2,3-triazol-1-yl)quinolin-8-ol (12) and 5-(4-(cyclohex-1-en-1-yl)-1H-1,2,3-triazol-1-yl)quinolin-8-ol (16) were more promising, presenting minimum inhibitory concentration (MIC) values between 1-16 µg/ml for yeast and 2-4 µg/ml for dermatophytes. However, no relevant anti-Fusarium spp. activity was observed. In the time-kill assays with Microsporum canis, 12 and 16 presented time-dependent fungicide profile at 96 h and 120 h in all evaluated concentrations, respectively. For Candida guilliermondii, 12 was fungicidal at all concentrations at 6 h and 16 exhibited a predominantly fungistatic profile. Both 12 and 16 presented low leukocyte toxicity at 4 µg/ml and the cell viability was close to 100% after the treatment with 12 at all tested concentrations. The sorbitol assay combined with SEM suggest that damages on the fungal cell wall could be involved in the activity of these derivatives. Given the good results obtained with this series, scaffold 4-(cycloalkenyl or phenyl)-5-triazol-8-hydroxyquinoline appears to be a potential pharmacophore for exploration in the development of new antifungal agents.

Different susceptibility of spores and hyphae of Trichophyton rubrum to methylene blue mediated photodynamic treatment in vitro.

BACKGROUND: In recent years, methylene blue mediated-photodynamic therapy (MB-PDT) has proved to be an effective inhibitor to a variety of microorganisms, including Trichophyton rubrum, the most common dermatophyte worldwide. However, previous studies mainly focused on the spore form of T rubrum, but rarely on its hyphal form, although the latter is the main pathogenic form of T rubrum in vivo. OBJECTIVE: To investigate the inhibitory effect of MB-PDT on T rubrum in different growth phases in vitro. METHODS: The suspensions of spores and hyphae obtained from T rubrum (ATCC28188) were prepared, respectively, incubated with MB solution (0.15-40 µg/mL) and irradiated with 635 nm red light. Varied light energy and MB concentration were used. The specimen in the absence of light exposure or/and MB served as controls. MIC determination, colony counts and MTT assay were employed to evaluate the antifungal effect of MB-PDT. RESULTS: The MICs of MB-PDT for hyphae and spores of T. rubrum were 6.300 ± 1.072 µg/mL and 1.984 ± 1.072 µg/mL, respectively, at a fixed light dose of 60 J/cm2 . CFU counts gave the minimum critical combinations of MB concentration and light dose to achieve 100% inhibitory rate. For hyphae, they were 5 µg/mL + 100 J/cm2 or 10 µg/mL + 60 J/cm2 . For spores, they were 1.25 µg/mL + 40 J/cm2 or 5 µg/mL + 20 J/cm2 . The outcomes of MTT assay were consistent with those of CFU counts, but less accurate. CONCLUSION: MB-PDT is a potent inhibitor to both spores and hyphae of T. rubrum in vitro, and the spores are more sensitive to it. Its antifungal efficacy is positively correlated with the concentration of MB and light dose.