In Vitro Antifungal Activity of Novel Triazole Efinaconazole and Five Comparators against Dermatophyte Isolates

Asymptomatic colonization of stray dogs and domestic cats with Trichophyton mentagrophytes II in Northern Iran

BACKGROUND

Despite changes in the epidemiology of dermatophyte infections, the incidence of fungal infections associated with Trichophyton species still remains high among dogs and cats. The objective of the present study was to isolate and characterize dermatophytes from dogs and cats in Iran.

METHOD

From December 2022 to May 2023, skin and hair samples were collected from symptomatic and asymptomatic cats and dogs in Mazandaran, a northern province of Iran. The samples were then inoculated into Mycosel™ Agar. Dermatophyte isolates were identified by sequencing the internal transcribed spacer region. Antifungal susceptibility tests were conducted using the Clinical and Laboratory Standards Institute (CLSI-M38-A3).

RESULT

Of the 250 samples collected (from 200 dogs and 50 cats), 20 (from 19 dogs and one cat) (8.0 %) were positive for dermatophyte growth. Based on sequence and phylogenetic analysis, all isolates belonged to T. mentagrophytes II*. Of these positive samples, 14 (70.0 %), 3 (15.0 %), 2 (10.0 %), and 1 (2.0 %) were isolated from asymptomatic stray dogs, symptomatic stray dogs, symptomatic domestic dogs, and symptomatic cats, respectively. Luliconazole and terbinafine displayed potent activity against all T. mentagrophytes isolates, with Minimum inhibitory concentration (MIC) values of 0.016 µg/ml. Miconazole and griseofulvin demonstrated higher MIC (1 and 8 µg/ml).

CONCLUSION

The present study indicated that T. mentagrophytes II* asymptomatic carriage is frequent in stray dogs in Iran. The potential risk to public health needs to be evaluated However, T. mentagrophytes genotype VIII, considered as an endemic and emerging human pathogenic clone in several countries, was not detected during the present survey.

Design, synthesis, docking studies and bioactivity evaluation of 1,2,3-triazole eugenol derivatives

Aim: The design, synthesis, docking studies and evaluation of the in vitro antifungal and cytotoxic properties of eugenol (EUG) containing 1,2,3-triazole derivatives are reported. Most of the derivatives have not been reported.Materials & methods: The EUG derivatives were synthesized, molecular docked and tested for their antifungal activity.Results: The compounds showed potent antifungal activity against Trichophyton rubrum, associated with dermatophytosis. Compounds 2a and 2i exhibited promising results, with 2a being four-times more potent than EUG. The binding mode prediction was similar to itraconazole in the lanosterol-14-α-demethylase wild-type and G73E mutant binding sites. Additionally, the pharmacokinetic profile prediction suggests good gastrointestinal absorption and potential oral administration.Conclusion: Compound 2a is a promising antifungal agent against dermatophytosis caused by T. rubrum.

Treatment of onychomycosis in an era of antifungal resistance: Role for antifungal stewardship and topical antifungal agents

A growing body of literature has marked the emergence and spread of antifungal resistance among species of Trichophyton, the most prevalent cause of toenail and fingernail onychomycosis in the United States and Europe. We review published data on rates of oral antifungal resistance among Trichophyton species; causes of antifungal resistance and methods to counteract it; and in vitro data on the role of topical antifungals in the treatment of onychomycosis. Antifungal resistance among species of Trichophyton against terbinafine and itraconazole-the two most common oral treatments for onychomycosis and other superficial fungal infections caused by dermatophytes-has been detected around the globe. Fungal adaptations, patient characteristics (e.g., immunocompromised status; drug-drug interactions), and empirical diagnostic and treatment patterns may contribute to reduced antifungal efficacy and the development of antifungal resistance. Antifungal stewardship efforts aim to ensure proper antifungal use to limit antifungal resistance and improve clinical outcomes. In the treatment of onychomycosis, critical aspects of antifungal stewardship include proper identification of the fungal infection prior to initiation of treatment and improvements in physician and patient education. Topical ciclopirox, efinaconazole and tavaborole, delivered either alone or in combination with oral antifungals, have demonstrated efficacy in vitro against susceptible and/or resistant isolates of Trichophyton species, with low potential for development of antifungal resistance. Additional real-world long-term data are needed to monitor global rates of antifungal resistance and assess the efficacy of oral and topical antifungals, alone or in combination, in counteracting antifungal resistance in the treatment of onychomycosis.

In Vitro and In Vivo Effect of the Imidazole Luliconazole against Lomentospora prolificans and Scedosporium spp

Infections with Scedosporium spp. and Lomentospora prolificans have become a serious threat in clinical settings. The high mortality rates associated with these infections can be correlated with their multidrug resistance. The development of alternative treatment strategies has become crucial. Here, we investigate the in vitro and in vivo activity of luliconazole (LLCZ) against Scedosporium apiospermum (including its teleomorph Pseudallescheria boydii) and Lomentospora prolificans. The LLCZ MICs were determined for a total of 37 isolates (31 L. prolificans isolates, 6 Scedosporium apiospermum/P. boydii strains) according to EUCAST. Furthermore, the LLCZ antifungal activity was tested in vitro, using an XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt] growth kinetics assay and biofilm assays (crystal violet and XTT assay). In addition, a Galleria mellonella infection model was used for in vivo treatment assays. The MIC90 of LLCZ was determined to be 0.25 mg/L for all tested pathogens. Growth was inhibited within 6 to 48 h of the start of incubation. LLCZ inhibited biofilm formation in both preadhesion stages and late-stage adhesion. In vivo, a single dose of LLCZ increased the survival rate of the larvae by 40% and 20% for L. prolificans and Scedosporium spp., respectively. This is the first study demonstrating LLCZ activity against Lomentospora prolificans in vitro and in vivo and the first study showing the antibiofilm effect of LLCZ in Scedosporium spp. IMPORTANCE Lomentospora prolificans and S. apiospermum/P. boydii are opportunistic, multidrug-resistant pathogens causing invasive infections in immunosuppressed patients and sometimes in healthy persons. Lomentospora prolificans is panresistant against the currently available antifungals, and both species are associated with high mortality rates. Thus, the discovery of novel antifungal drugs exhibiting an effect against these resistant fungi is crucial. Our study shows the effect of luliconazole (LLCZ) against L. prolificans and Scedosporium spp. in vitro, as well as in an in vivo infection model. These data reveal the previously unknown inhibitory effect of LLCZ against L. prolificans and its antibiofilm effect in Scedosporium spp. It represents an extension of the literature regarding azole-resistant fungi and could potentially lead to the development of future treatment strategies against these opportunistic fungal pathogens.

In vitro antifungal susceptibility profile of Iranian Fusarium isolates: Emphasising on the potent inhibitory effect of efinaconazole compared to other drugs

BACKGROUND

Fusarium species are opportunistic human pathogens that remarkably cause fungal infections ranging from superficial to fatal invasive disseminated infections. Fusarium species are notoriously resistant to the majority of antifungal agents.

OBJECTIVES

Therefore, detailed studies regarding in vitro susceptibility are required and may lead to a better prognosis of severe infections.

METHODS

We evaluated 25 antifungal drugs in vitro against 282 clinical and environmental Fusarium isolates.

RESULTS

Fusarium species demonstrated high MICs/MECs values to the most commonly used antifungal drugs in clinical practice. The geometric mean (GM) MICs for luliconazole (0.004 μg/ml) and lanoconazole (0.012 μg/ml) were the lowest, followed by efinaconazole (0.98 μg/ml) and amphotericin B (1.04 μg/ml).

CONCLUSIONS

Efinaconazole, a novel triazole, may be a promising candidate for the treatment of superficial Fusarium infections. Furthermore, the development of systemic formulations of these drugs as well as further in vitro and in vivo investigations could aid in the treatment of systemic fusariosis.

Eumycetoma Causative Agents are Inhibited in vitro by Luliconazole, Lanoconazole and Ravuconazole

Introduction

Eumycetoma is a subcutaneous mutilating disease that can be caused by many different fungi. Current treatment consists of prolonged itraconazole administration in combination with surgery. In many centres, due to their slow growth rate, the treatment for eumycetoma is often started before the causative agent is identified. This harbours the risk that the causative fungus is not susceptible to the given empirical therapy. In the open‐source drug program MycetOS, ravuconazole and luliconazole were promising antifungal agents that were able to inhibit the growth of Madurella mycetomatis, the most common causative agent of mycetoma. However, it is currently not known whether these drugs inhibit the growth of other eumycetoma causative agents.

Materials and methods

Here, we determined the in vitro activity of luliconazole, lanoconazole and ravuconazole against commonly encountered eumycetoma causative agents. MICs were determined for lanoconazole, luliconazole and ravuconazole against 37 fungal isolates which included Madurella species, Falciformispora senegalensis, Medicopsis romeroi and Trematosphaeria grisea and compared to those of itraconazole.

Results

Ravuconazole, luliconazole and lanoconazole showed high activity against all eumycetoma causative agents tested with median minimal inhibitory concentrations (MICs) ranging from 0.008–2 µg/ml, 0.001–0.064 µg/ml and 0.001–0.064 µg/ml, respectively. Even Ma. fahalii and Me. romeroi, which are not inhibited in growth by itraconazole at a concentration of 4 µg/ml, were inhibited by these azoles.

Conclusion

The commonly encountered eumycetoma causative agents are inhibited by lanoconazole, luliconazole and ravuconazole. These drugs are promising candidates for further evaluation as potential treatment for eumycetoma.

OUP accepted manuscript

The increasing incidence and changing epidemiology of invasive fungal infections continue to present many challenges to their effective management. The repertoire of antifungal drugs available for treatment is still limited although there are new antifungals on the horizon. Successful treatment of invasive mycoses is dependent on a mix of pathogen-, host- and antifungal drug-related factors. Laboratories need to be adept at detection of fungal pathogens in clinical samples in order to effectively guide treatment by identifying isolates with acquired drug resistance. While there are international guidelines on how to conduct in vitro antifungal susceptibility testing, these are not performed as widely as for bacterial pathogens. Furthermore, fungi generally are recovered in cultures more slowly than bacteria, and often cannot be cultured in the laboratory. Therefore, non-culture-based methods, including molecular tests, to detect fungi in clinical specimens are increasingly important in patient management and are becoming more reliable as technology improves. Molecular methods can also be used for detection of target gene mutations or other mechanisms that predict antifungal drug resistance. This review addresses acquired antifungal drug resistance in the principal human fungal pathogens and describes known resistance mechanisms and what in-house and commercial tools are available for their detection. It is emphasized that this approach should be complementary to culture-based susceptibility testing, given the range of mutations, resistance mechanisms and target genes that may be present in clinical isolates, but may not be included in current molecular assays.

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.

Application of triazoles in the structural modification of natural products

Nature products have been extensively used in the discovery and development of new drugs, as the most important source of drugs. The triazole ring is one of main pharmacophore of the nitrogen-containing heterocycles. Thus, a new class of triazole-containing natural product conjugates has been synthesised. These compounds reportedly exert anticancer, anti-inflammatory, antimicrobial, antiparasitic, antiviral, antioxidant, anti-Alzheimer, and enzyme inhibitory effects. This review summarises the research progress of triazole-containing natural product derivatives involved in medicinal chemistry in the past six years. This review provides insights and perspectives that will help scientists in the fields of organic synthesis, medicinal chemistry, phytochemistry, and pharmacology.

Molecular identification and antifungal susceptibility of 75 clinical isolates of Trichophyton spp. from southern Brazil

BACKGROUND

Dermatophytoses affect more than 20% of the world's population and is caused by filamentous fungi, mainly of the genus Trichophyton. The species identification through microscopic direct examination and culture methods is challenging, with molecular presenting high sensitivity and specificity. Although there are several therapy options for dermatophyte infections, treatment failures and antifungal resistance are growing concerns.

OBJECTIVE

This study aimed to identify clinical isolates of Trichophyton spp. from southern Brazil using molecular methods and determine their in-vitro antifungal susceptibility.

MATERIAL AND METHODS

Seventy-five isolates were identified through sequencing of the ITS region. The exposure to seven antifungals drugs was performed according to protocol M28-A2 of the Clinical and Laboratory Standards Institute (CLSI).

RESULTS

Sixty-one isolates (81%) were identified as T. interdigitale, which differs from the epidemiological data present in the literature. Thirteen isolates were identified as T. rubrum and one as T. tonsurans. Terbinafine was the most effective antifungal, followed by itraconazole and voriconazole, which is in accordance with the results reported in previous studies.

CONCLUSIONS

The use of molecular methods to identify Trichophyton spp. clinical isolates and the performance of susceptibility tests are relevant to epidemiological data, identification of the emergence of antifungal resistance, and to help to translate the in-vitro antifungal susceptibility results into clinical practice.

In Vitro Antifungal Activity of Luliconazole, Efinaconazole, and Nine Comparators Against Aspergillus and Candida Strains Isolated from Otomycosis

Background: Aspergillus and Candida species are the most commonly identified fungal pathogens in otomycosis. However, we usually encounter some difficulties in its treatment because many patients show resistance to antifungal agents and present a high recurrence rate. Objectives: The current research was conducted to compare the in vitro activities of luliconazole (LUL), and efinaconazole (EFN) and the nine comparators on Aspergillus and Candida strains isolated from otomycosis. Methods: The in vitro activities of nine common antifungal drugs (amphotericin B (AMB), voriconazole (VRC), fluconazole (FLU), itraconazole (ITC), ketoconazole (KTO), clotrimazole (CLO), nystatin (NYS), terbinafine (TRB), and caspofungin (CAS)) and two novel new azoles (LUL and EFN) against 108 clinical isolates of Aspergillus and Candida species obtained from otomycosis were assessed according to the CLSI broth microdilution document. Results: The LUL and EFN had the geometric mean minimum inhibitory concentrations (GM MICs) of 0.098 and 0.109 μg/mL against all Aspergillus strains, respectively. Furthermore, the GM MICs of all Candida isolates for LUL, EFN, CAS, CLO, VRC, AMB, ITC, KTO, FLU, NYS, and TRB were calculated to be 0.133, 0.144, 0.194, 0.219, 0.475, 0.537, 0.655, 1.277, 4.905, 9.372, and 13.592 μg/mL, respectively. Additionally, 6 (35.29%), 2 (11.7%), and 1 (5.88%) Candida isolates were resistant to FLU, CAS, and VRC, respectively. Conclusions: As the findings indicated, LUL and EFN showed the lowest GM MIC values against the examined species. Accordingly, these novel imidazole and triazole antifungal agents can be regarded as proper candidates for the treatment of otomycosis caused by Aspergillus and Candida strains.

Multicentre validation of a EUCAST method for the antifungal susceptibility testing of microconidia-forming dermatophytes

OBJECTIVES

Terbinafine resistance is increasingly reported in Trichophyton, rendering susceptibility testing particularly important in non-responding cases. We performed a multicentre evaluation of six EUCAST-based methods.

METHODS

Ten laboratories susceptibility tested terbinafine, itraconazole, voriconazole and amorolfine against a blinded panel of 38 terbinafine WT and target gene mutant isolates. E.Def 9.3.1 modifications included: medium with/without addition of chloramphenicol and cycloheximide (CC), incubation at 25°C to 28°C for 5-7 days and three MIC endpoints [visually and spectrophotometrically (90%/50% inhibition)], generating 7829 MICs. Quality control (QC) strains were Aspergillus flavus ATCC 204304 and CNM-CM1813. Eyeball, ECOFFinder (where ECOFF stands for epidemiological cut-off) and derivatization WT upper limits (WT-ULs), very major errors (VMEs; mutants with MICs ≤WT-ULs) and major errors (MEs; WT isolates with MICs >WT-ULs) were determined.

RESULTS

MICs fell within the QC ranges for ATCC 204304/CNM-CM1813 for 100%/96% (voriconazole) and 84%/84% (itraconazole), respectively. Terbinafine MICs fell within 0.25-1 mg/L for 96%/92%, suggesting high reproducibility. Across the six methods, the number of terbinafine MEs varied from 2 to 4 (2.6%-5.2%) for Trichophyton rubrum and from 0 to 2 (0%-2.0%) for Trichophyton interdigitale. Modes for WT and mutant populations were at least seven 2-fold dilutions apart in all cases. Excluding one I121M/V237I T. rubrum mutant and two mixed WT/mutant T. interdigitale specimens, the numbers of VMEs were as follows: T. rubrum: CC visual, 1/67 (1.5%); CC spectrophotometric 90% inhibition, 3/59 (5.1%); and CC spectrophotometric 50% inhibition, 1/67 (1.5%); and T. interdigitale: none. Voriconazole and amorolfine MICs were quite uniform, but trailing growth complicated determination of itraconazole visual and spectrophotometric 90% inhibition MIC.

CONCLUSIONS

Although none of the laboratories was experienced in dermatophyte testing, error rates were low. We recommend the CC spectrophotometric 50% inhibition method and provide QC ranges and WT-ULs for WT/non-WT classification.

Antifungal resistance in Superficial mycoses

BACKGROUND AND OBJECTIVE

With the widespread use of antifungals to treat superficial mycoses, reports of antifungal resistance are increasing. Antifungal resistance is becoming a public health challenge and needs to be addressed in parallel with antibacterial and antiviral resistance.

METHODS

We review the growing resistance of fungal pathogens such as Trichophyton species and the emergence of novel pathogens, including multidrug-resistant strains in superficial mycoses. We also discuss the importance of laboratory diagnosis and antifungal susceptibility testing (AFST) in the management of recalcitrant infections.

RESULTS AND CONCLUSION

Antifungal resistance can occur naturally or develop over time when fungi are exposed to antifungals. The frequency of terbinafine-resistant Trichophyton isolates is increasing. Opportunistic pathogens such as Aspergillus and Candida species have developed resistance to classic azoles such as itraconazole and fluconazole, and the newer azoles such as posaconazole and voriconazole. Although uncommon, topical antifungals such as efinaconazole and tavaborole have shown to induce resistance in Trichophyton rubrum. The emergence of multidrug-resistant Trichophyton mentagrophytes/interdigitale, Candida auris, and Aspergillus species causing severe infections is highly concerning. Routine AFST should be considered to determine the most effective treatment, especially if there is failure to therapy. Combination treatment of oral and topical antifungals may be a consideration for managing recalcitrant infections.

Molecular Epidemiology and Antifungal Susceptibility of Trichophyton Isolates in Greece: Emergence of Terbinafine-Resistant Trichophytonmentagrophytes Type VIII Locally and Globally

Trichophyton isolates with reduced susceptibility to antifungals are now increasingly reported worldwide. We therefore studied the molecular epidemiology and the in vitro antifungal susceptibility patterns of Greek Trichophyton isolates over the last 10 years with the newly released EUCAST reference method for dermatophytes. Literature was reviewed to assess the global burden of antifungal resistance in Trichophyton spp. The in vitro susceptibility of 112 Trichophyton spp. molecularly identified clinical isolates (70 T. rubrum, 24 T. mentagrophytes, 12 T. interdigitale and 6 T. tonsurans) was tested against terbinafine, itraconazole, voriconazole and amorolfine (EUCAST E.DEF 11.0). Isolates were genotyped based on the internal transcribed spacer (ITS) sequences and the target gene squalene epoxidase (SQLE) was sequenced for isolates with reduced susceptibility to terbinafine. All T. rubrum, T. interdigitale and T. tonsurans isolates were classified as wild-type (WT) to all antifungals, whereas 9/24 (37.5%) T. mentagrophytes strains displayed elevated terbinafine MICs (0.25–8 mg/L) but not to azoles and amorolfine. All T. interdigitale isolates belonged to ITS Type II, while T. mentagrophytes isolates belonged to ITS Type III* (n = 11), VIII (n = 9) and VII (n = 4). All non-WT T. mentagrophytes isolates belonged to Indian Genotype VIII and harbored Leu393Ser (n = 5) and Phe397Leu (n = 4) SQLE mutations. Terbinafine resistance rates ranged globally from 0–44% for T. rubrum and 0–76% for T. interdigitale/T. mentagrophytes with strong endemicity. High incidence (37.5%) of terbinafine non-WT T. mentagrophytes isolates (all belonging to ITS Type VIII) without cross-resistance to other antifungals was found for the first time in Greece. This finding must alarm for susceptibility testing of dermatophytes at a local scale particularly in non-responding dermatophytoses.

Molecular identification and antifungal susceptibility profiles of Candida dubliniensis and Candida africana isolated from vulvovaginal candidiasis: A single-centre experience in Iran

Background

Vulvovaginal candidiasis (VVC) is a common and debilitating long‐term illness affecting million women worldwide. This disease is caused mainly by Candida albicans and a lesser extent by other species, including the two phylogenetically closely related pathogens Candida africana and Candida dubliniensis.

Objectives

In this study, we report detailed molecular epidemiological data about the occurrence of these two pathogenic yeasts in Iranian patients affected by VVC, or its chronic recurrent form (RVVC), and provide, for the first time, data on the antifungal activity of two new drugs, efinaconazole (EFN) and luliconazole (LUL).

Methods

A total of 133 vaginal yeast isolates, presumptively identified as Calbicans by phenotypic and restriction analysis of rDNA, were further analysed by using a specific molecular method targeting the HWP1 gene. All Cafricana and Cdubliniensis isolates were also tested for their in vitro susceptibility to a panel of modern and classical antifungal drugs.

Results and Conclusions

Based on the molecular results, among 133 germ‐tube positive isolates, we identify 119 Calbicans (89.47%), 11 Cafricana (8.27%) and 3 Cdubliniensis (2.26%) isolates. Cafricana and Cdubliniensis showed low MIC values for most of the antifungal drugs tested, especially for EFN and LUL, which exhibited a remarkable antifungal activity. High MIC values were observed only for nystatin and terbinafine. Although Calbicans remains the most common Candida species recovered from Iranian VVC/RVVC patients, our data show that its prevalence may be slightly overestimated due to the presence of difficult‐to‐identify closely related yeast, especially Cafricana.

In vitro antifungal susceptibility patterns of Trichophyton benhamiae complex isolates from diverse origin

BACKGROUND

Species from the Trichophyton benhamiae complex are mostly zoophilic dermatophytes which cause inflammatory dermatophytosis in animals and humans worldwide.

OBJECTIVES

This study was purposed to (a) to identify 169 reference and clinical dermatophyte strains from the T benhamiae complex species by molecular method and adhering to the newest taxonomy in the complex (b) to evaluate the in vitro antifungal susceptibility profile of these strains against eight common and new antifungal agents that may be used for the treatment of dermatophytosis.

METHODS

All isolates, mainly originated from Europe but also from Iran, Japan and USA, were subjected to ITS-rDNA sequencing. The in vitro antifungal susceptibility profiles of eight common and new antifungal drugs against the isolates were determined by CLSI M38-A2 protocol and according to microdilution method.

RESULTS

Based on the ITS-rDNA sequencing, T benhamiae was the dominant species (n = 102), followed by T europaeum (n = 29), T erinacei (n = 23), T japonicum (n = 10), Trichophyton sp (n = 4) and T eriotrephon (n = 1). MIC ranges across all isolates were as follows: 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: 0.06-2 µg/ml, griseofulvin: 0.25-4 µg/ml, amorolfine hydrochloride: 0.125-4 µg/ml and tavaborole: 1-16 µg/ml.

CONCLUSION

Luliconazole, efinaconazole and terbinafine were the most potent antifungals against T benhamiae complex isolates, regardless of the geographic locations where strains were isolated. These data might help dermatologists to develop effective therapies for successful treatment of infections due to T benhamiae complex species.

Molecular Identification and Antifungal Susceptibility of Yeasts and Molds Isolated from Patients with Otomycosis

Fungal otitis externa, an infection of the external auditory canal caused by molds and yeasts, accounts for approximately 10-20% of ear canal infections accompanying high recurrence. The purpose of the current study was to assess the pattern of etiological agents of otomycosis and resistance profile as well as the rate of tympanic membrane perforation. A total of 1040 patients with symptoms of fungal otitis externa, in a period of two years, were investigated. The mycological tests revealed the presence of different fungi in 237 ears (22.8%). Fungal otitis was more related to filamentous fungi of the species Aspergillus flavus (54.43%), A. tubingensis (10.97%), and A. niger (8.86%), followed by yeasts, Candida orthopsilosis (7.59%), C. albicans (6.75%), and C. parapsilosis (5.06%). Tympanic membrane perforation rate was found to be 6.75% and was more common with otomycosis caused by A. flavus, A. tubingensis and C. albicans. In antifungal susceptibility tests, all tested drugs showed generally good activity against most isolates of molds and yeasts, while tolnaftate, clotrimazole, nystatin, and terbinafine had lowest effects. We found that among Aspergillus isolates, one A. niger isolate was resistant to voriconazole, and one A. flavus isolate was resistant to amphotericin B. Furthermore, among Candida species, three isolates of C. orthopsilosis showed high MIC values to fluconazole, two C. albicans isolates were considered fluconazole resistant and one isolate of C. parapsilosis was resistant to caspofungin and 3 isolates were resistant to fluconazole. Regarding the existence of the cases with perforated tympanic membrane and emerging species causing fungal otitis in the current report, the importance of the early physical examination, precise molecular identification, and the antifungal susceptibility evaluation is highlighted.

Familial Cases of Trichophyton benhamiae Infection Transmitted from a Guinea Pig in Iran

Trichophyton benhamiae is a zoophilic dermatophyte mainly transmitted to humans from guinea pigs. This zoophilic species can also cause dermatophytosis as reported by human contact with other animals, such as rabbit, cat, and fox. Here, we report the tinea faciei and tinea corporis cases: a 12-year-old girl and her 53-year-old father, with no history of immunodeficiency and underlying disease, caused by T. benhamiae transmitted from a guinea pig in Iran. Dermatological examination revealed several erythematous, round, scaly, and approximately 1-4-cm-diameter lesions in both patients. The girl had seven skin lesions, and her father presented two skin lesions on the front side of his neck. The girl's lesions had started 3 weeks before and her father's lesions appeared 7 days after the first clinical appearance of the lesions in the daughter. The girl had daily close contact with a guinea pig, while her father did not have any direct exposure to the pet. Examination of the lesions scraping with 10% potassium hydroxide (KOH 10%) revealed hyaline septate hyphae and arthroconidia. The dermatophyte isolated in culture was identified as T. benhamiae using molecular analysis. The patients were successfully treated using topical sertaconazole nitrate 2% cream twice a day for 4 weeks.

Molecular identification and antifungal susceptibility among clinical isolates of dermatophytes in Shiraz, Iran (2017-2019)

Dermatophytosis is a common superficial mycotic infection affecting individual's quality of life worldwide. The present study aimed to perform species-level identification and evaluate the antifungal susceptibility patterns of dermatophytes isolated in Shiraz, Iran. This cross-sectional study was conducted on clinical samples collected during 2017-2019 from 307 patients suspected of having dermatophytosis. The isolates were identified by direct microscopy, culture and internal transcribed spacer ribosomal DNA sequencing, and their antifungal susceptibility patterns were determined by the microdilution method. Among 307 patients, dermatophytosis was diagnosed by microscopy in 190 (61.8%) subjects and confirmed in 130 (42.3%) cases by both microscopy and culture. It was found out tinea pedis was the most common clinical manifestation, and Trichophyton mentagrophytes was the most prevalent species (28.4%), followed by T tonsurans (23.8%), Microsporum canis (11.5%), T interdigitale (10%), T verrucosum (6.9%), T rubrum (6.9%), T benhamiae (4.6%), T violaceum (3%), T simii (3%), Epidermophyton floccosum (0.7%) and M ferrugineum (0.7%). Moreover, it was revealed that luliconazole with a geometric mean (GM) minimum inhibitory concentration (MIC) of 0.03 μg ml^-1 was the most effective agent against all tested isolates. Regardless of species, 30% of isolates responded to high MICs of griseofulvin (MIC₉₀  > 2 μg ml^-1 ). The increasing prevalence of nonindigenous species of T simii, T benhamiae and M ferrugineum in Shiraz, Iran, was a notable finding. In addition, infections due to zoophilic species showed an increasing trend. These epidemiological data, along with antifungal susceptibility patterns, may have implications for clinical decision-making and successful treatment.

Regional Differences in Antifungal Susceptibility of the Prevalent Dermatophyte Trichophyton rubrum

In vitro susceptibility testing for Trichophyton rubrum has shown resistance to terbinafine, azoles and amorolfine, locally, but epidemiological cutoffs are not available. In order to assess the appropriateness of current first-line antifungal treatment for T. rubrum in China, we characterized antifungal susceptibility patterns of Chinese T. rubrum strains to nine antifungals and also described the upper limits of wild-type (WT) minimal inhibitory concentrations (MIC) (UL-WT) based on our study and another six studies published during the last decades. Sixty-two clinical isolates originating from seven provinces in China were identified as T. rubrum sensu stricto; all Chinese strains showed low MICs to eight out of nine antifungal drugs. Terbinafine (TBF) showed the lowest MICs of all antifungal classes tested in both the Chinese and global groups, with a 97.5% UL-WT MIC-value of 0.03 mg/L. No non-WT isolates were observed for TBF in China, but were reported in 18.5% of the global group. Our study indicated that TBF was still the most active drug for Chinese T. rubrum isolates, and all strains were within the WT-population. TBF therefore remains recommended for primary therapy to dermatophytosis caused by T. rubrum in China now, but regular surveillance of dermatophytes and antifungal susceptibility is recommended.

Investigation of in vitro antifungal susceptibility testing and genetic diversity of clinical isolates of Trichophyton benhamiae and Trichophyton eriotrephon in Iran

BACKGROUND

Trichophyton benhamiae is a zoophilic dermatophyte, known as one of the causative agents of dermatophytosis.

OBJECTIVES

The purpose of this study was to explore the genotypes of T. benhamiae strains isolated from geographically different areas of Iran and also to evaluate in vitro antifungal susceptibility profile of these strains against seven antifungal drugs.

METHODS

Twenty-two strains of T. benhamiae and two strains of T. eriotrephon were isolated from patients with distinct types of dermatophytosis. DNA extraction and amplification of rDNA regions using ITS1 and ITS4 primers were conducted on the isolates. The in vitro antifungal susceptibility of posaconazole (PSC), voriconazole (VRC), itraconazole (ITC), ketoconazole (KET), caspofungin (CAS), terbinafine (TRB) and griseofulvin (GRZ) was evaluated according to CLSI M38-A2 protocol.

RESULTS

The multiple alignment of the ITS-rDNA sequences of T. benhamiae indicated a mean similarity of 99.5%, with 0-3 interspecies nucleotide difference. The geometric mean (GM) values of minimum inhibitory concentrations (MICs) and minimum effective concentrations (MECs) across the all isolates were respectively: TRB: 0.025 mg/L, PSC: 0.032 mg/L, ITC: 0.050 mg/L and VRC: 0.059 mg/L with lower values and CAS: 0.31 mg/L, KTZ: 0.56 mg/L and GRZ: 0.76 mg/L with higher values.

CONCLUSION

Diverse ITS sequence types of T. benhamiae were shown in different geographical regions of Iran. The TRB, PSC and ITC were the most effective drugs against T. benhamiae strains, respectively. Furthermore, in our study, two strains of T. eriotrephon as a scarce dermatophyte species were described.

In-Vitro Activity of Nano Fluconazole and Conventional Fluconazole against Clinically Important Dermatophytes

Background:

Dermatophytosis is one of the most common fungal infections in humans. Antifungals such as fluconazole are effectively used for treating dermatophytosis; however, drug resistance was observed in many cases. Therefore, a newer treatment strategy is essential.

Methods:

This study (Conducted in the Laboratory of the School of Public Health, Tehran University of Medical Sciences, Tehran, Iran in 2018) evaluated the antifungal susceptibility of nano fluconazole compared to conventional fluconazole on dermatophyte isolates using CLSI M38-A2guidelines. Dermatophyte species isolated from clinical cases of dermatophytosis were identified using PCR sequencing techniques. Zeta potential and size of the nano particles containing fluconazole were measured; scanning electron microscope (SEM) was used to determine nano particle structure.

Results:

The size of liposomal fluconazole obtained was 88.9 ± 12.14 nm with –20.12 ± 3.8 mV for zeta potential. The encapsulation rate for fluconazole was 75.1± 4.2%. MIC₅₀ for the three tested species was 32, 16, and 8 μg/ml for Trichophyton interdigitale, T. rubrum, and Epidermophyton floccosum isolates, respectively. The corresponding values for nano fluconazole were 8 μg/ml for the three tested species.

Conclusion:

MIC value for nano-fluconazole was lower than conventional fluconazole in all dermatophytes species tested; therefore, nano-fluconazole could inhibit the growth of dermatophytes better than fluconazole at a lower concentration of the drug.

MIC and Upper Limit of Wild-Type Distribution for 13 Antifungal Agents against a Trichophyton mentagrophytes-Trichophyton interdigitale Complex of Indian Origin

Dermatophytosis due to the Trichophyton mentagrophytes-Trichophyton interdigitale complex is being increasingly reported across India. Reports of therapeutic failure have surfaced recently, but there are no clinical break points (CBP) or epidemiological cutoffs (ECVs) available to guide the treatment of dermatophytosis. In this study, a total of 498 isolates of the T. mentagrophytes -interdigitale complex were collected from six medical centers over a period of five years (2014 to 2018). Antifungal susceptibility testing of the isolates was carried out for itraconazole, fluconazole, ketoconazole, voriconazole, luliconazole, sertaconazole, miconazole, clotrimazole, terbinafine, amorolfine, naftifine, ciclopirox olamine, and griseofulvin. The MICs (in mg/liter) comprising >95% of the modeled populations were as follows: 0.06 for miconazole, luliconazole, and amorolfine; 0.25 for voriconazole; 0.5 for itraconazole, ketoconazole, and ciclopirox olamine; 1 for clotrimazole and sertaconazole; 8 for terbinafine; 16 for naftifine; 32 for fluconazole; and 64 for griseofulvin. A high percentage of isolates above the upper limit of the wild-type MIC (UL-WT) were observed for miconazole (29%), luliconazole (13.9%), terbinafine (11.4%), naftifine (5.2%), and voriconazole (4.8%), while they were low for itraconazole (0.2%). Since the MICs of itraconazole were low against the T. mentagrophytes -interdigitale complex, this could be considered the choice of first-line treatment. The F397L mutation in the squalene epoxidase (SE) gene was observed in 77.1% of isolates with a terbinafine MIC of ≥1 mg/liter, but no mutation was detected in isolates with a terbinafine MIC of <1 mg/liter. In the absence of CBPs, evaluation of the UL-WT may be beneficial for managing dermatophytosis and monitoring the emergence of isolates with reduced susceptibility.

Emergence of Terbinafine Resistant Trichophyton mentagrophytes in Iran, Harboring Mutations in the Squalene Epoxidase (SQLE) Gene

Introduction

Trichophyton mentagrophytes and T. interdigitale are important causative agents of superficial mycoses, demonstrating emergent antifungal drug resistance. We studied the antifungal susceptibility profiles in Iranian isolates of these two species.

Methods

A total of 96 T. interdigitale and 45 T. mentagrophytes isolates were subjected to molecular typing by ribosomal ITS region. Antifungal susceptibility profiles for terbinafine, griseofulvin, clotrimazole, efinaconazole, luliconazole, amorolfine and ciclopirox were obtained by CLSI broth microdilution method. The squalene epoxidase (SQLE) gene was subjected to sequencing for mutations, if any, in isolates exhibiting elevated MICs for terbinafine.

Results

Luliconazole and efinaconazole showed the lowest MIC values against T. mentagrophytes and T. interdigitale isolates. There were five isolates with terbinafine MICs ≥32 µg/mL in our sample. They belonged to T. mentagrophytes type VIII and harbored two alternative SQLE gene sequence variants, leading to Phe397Leu and Ala448Thr or Leu393Ser and Ala448Thr substitutions in the enzyme. All terbinafine resistant strains could be inhibited by luliconazole and efinaconazole.

Conclusion

This study documented a step in the global spread of resistance mechanisms in T. mentagrophytes. However, treatment alternatives for resistant isolates were available.

Antifungal Activity of a Novel Triazole, Efinaconazole and Nine Comparators against 354 Molecularly Identified Aspergillus Isolates

Management of superficial aspergillosis is a major challenge owing to the frequent relapses and treatment failure, which may pose a potential risk, thereby gradually developing resistant species. Therefore, necessitating the development of new antifungals with higher potency should be considered as alternative strategies for efficient management of infections. We aimed to investigate the susceptibility of Aspergillus isolates toward a novel triazole, efinaconazole, in comparison with various classes of antifungal drugs. Antifungal susceptibility testing was performed according to the Clinical and Laboratory Standards Institute M38-A2 guidelines. Efinaconazole exhibited poor activity against mutant A. fumigatus strains, A. niger sensu stricto, and A. tubingensis with GM MIC values of 3.62, 1.62, and 2 μg/ml, respectively; however, surprisingly, it efficiently inhibited the growth of A. terreus sensu stricto, followed by wild-type A. fumigatus and A. flavus with GM MIC values of 0.29, 0.42, and 0.52 μg/ml, respectively. Presumably, efinaconazole is inefficient in aspergillosis treatment due to the low susceptibility of A. niger sensu stricto, A. tubingensis, and mutant A. fumigatus; however, it may be effective in treating superficial aspergillosis caused by wild-type A. fumigatus, A. terreus sensu stricto, and A. flavus. Further studies are needed to determine how these findings may translate into in vivo efficacy.

Comparison of in vitro antifungal activity of novel triazoles with available antifungal agents against dermatophyte species caused tinea pedis

OBJECTIVE

Dermatophytes are a group of keratinophilic fungi that invade and infect the keratinized tissues and cause dermatophytosis. We investigated effectiveness of novel triazole (luliconazole and lanaconazole) in comparison with available antifungal agents against dermatophyte species isolated from patients with tinea pedis.

MATERIAL AND METHODS

A total of 60 dermatophytes species were isolated from the patients with tinea pedis. Identification of species was done by DNA sequencing of the ITS1-5.8S rDNA-ITS2 rDNA region. In vitro antifungal susceptibility testing with luliconazole and lanaconazole and available antifungal agent was done in accordance with the Clinical and Laboratory Standards Institute, M38-A2 document.

RESULTS

In all investigated isolates, luliconazole had the lowest minimum inhibitory concentration (MIC) (MIC range=0.0005-0.004μg/mL), while fluconazole (MIC range=0.4-64μg/mL) had the highest MICs. Geometric mean MIC was the lowest for luliconazole (0.0008μg/mL), followed by lanoconazole (0.003μg/mL), terbinafine (0.019μg/mL), itraconazole (0.085 μg/mL), ketoconazole (0.089μg/mL), econazole (0.097μg/mL), griseofulvin (0.351 μg/mL), voriconazole (0.583μg/mL) and fluconazole (11.58μg/mL).

CONCLUSION

The novel triazoles showed potent activity against dermatophytes and promising candidates for the treatment of tinea pedis caused by Trichophyton and Epidermophyton species. However, further studies are warranted to determine the clinical implications of these investigations.

Proteome-Wide Identification of Lysine Propionylation in the Conidial and Mycelial Stages of Trichophyton rubrum

Posttranslational modifications (PTMs) exist in a wide variety of organisms and play key roles in regulating various essential biological processes. Lysine propionylation is a newly discovered PTM that has rarely been identified in fungi. Trichophyton rubrum (T. rubrum) is one of the most common fungal pathogens in the world and has been studied as an important model organism of anthropic pathogenic filamentous fungi. In this study, we performed a proteome-wide propionylation analysis in the conidial and mycelial stages of T. rubrum. A total of 157 propionylated sites on 115 proteins were identified, and the high confidence of propionylation identification was validated by parallel reaction monitoring (PRM) assay. The results show that the propionylated proteins were mostly involved in various metabolic pathways. Histones and 15 pathogenicity-related proteins were also targets for propionylation modification, suggesting their roles in epigenetic regulation and pathogenicity. A comparison of the conidial and mycelial stages revealed that most propionylated proteins and sites were growth-stage specific and independent of protein abundance. Based on the function classifications, the propionylated proteins had a similar distribution in both stages; however, some differences were also identified. Furthermore, our results show that the concentration of propionyl-CoA had a significant influence on the propionylation level. In addition to the acetylation, succinylation and propionylation identified in T. rubrum, 26 other PTMs were also found to exist in this fungus. Overall, our study provides the first global propionylation profile of a pathogenic fungus. These results would be a foundation for further research on the regulation mechanism of propionylation in T. rubrum, which will enhance our understanding of the physiological features of T. rubrum and provide some clues for the exploration of improved therapies to treat this medically important fungus.

Anti-inflammatory effect of lanoconazole on 12-O-tetradecanoylphorbol-13-acetate- and 2,4,6-trinitrophenyl chloride-induced skin inflammation in mice

Background

Lanoconazole (LCZ) is a topical antifungal agent clinically used to treat fungal infections such as tinea pedis. LCZ has not only antifungal effects but also anti‐inflammatory effects, which have the potential to provide additional clinical benefits. However, the characteristic features of the inhibitory effects of LCZ on skin inflammation remain unclear.

Objective

We evaluated the inhibitory effects of topical application of LCZ, and compared the effects of LCZ with those of other antifungal agents including liranaftate, terbinafine and amorolfine.

Methods

Each antifungal agent was topically applied on 12‐O‐tetradecanoylphorbol‐13‐acetate‐induced irritant dermatitis and 2,4,6‐trinitrophenyl chloride‐induced contact dermatitis in mice (BALB/c). The ear thickness, myeloperoxidase activity and inflammatory mediator contents were evaluated.

Results

LCZ dose‐dependently suppressed 12‐O‐tetradecanoylphorbol‐13‐acetate‐induced irritant dermatitis, suppressed the production of neutrophil chemotactic factors such as keratinocyte‐derived chemokine and macrophage inflammatory protein‐2, and inhibited neutrophil infiltration to the inflammation site. Moreover, 1% LCZ reduced the ear swelling in mice with 2,4,6‐trinitrophenyl chloride‐induced contact dermatitis in accordance with the inhibition of interferon‐γ production. The inhibitory potency of LCZ on these types of dermatitis in mice was stronger than that of other types of antifungal agents.

Conclusion

The anti‐inflammatory effects of LCZ were exerted through the inhibition of inflammatory mediator production. These effects may contribute to the relief of dermatitis symptoms in patients with tinea pedis.

1,2,3-Triazole-containing hybrids as leads in medicinal chemistry: A recent overview

The 1,2,3-triazole ring is a major pharmacophore system among nitrogen-containing heterocycles. These five-membered heterocyclic motifs with three nitrogen heteroatoms can be prepared easily using 'click' chemistry with copper- or ruthenium-catalysed azide-alkyne cycloaddition reactions. Recently, the 'linker' property of 1,2,3-triazoles was demonstrated, and a novel class of 1,2,3-triazole-containing hybrids and conjugates was synthesised and evaluated as lead compounds for diverse biological targets. These lead compounds have been demonstrated as anticancer, antimicrobial, anti-tubercular, antiviral, antidiabetic, antimalarial, anti-leishmanial, and neuroprotective agents. The present review summarises advances in lead compounds of 1,2,3-triazole-containing hybrids, conjugates, and their related heterocycles in medicinal chemistry published in 2018. This review will be useful to scientists in research fields of organic synthesis, medicinal chemistry, phytochemistry, and pharmacology.

Multiple abscesses in the lower extremities caused by Trichophyton rubrum

Background

Dermatophytes are keratinophilic fungi, that usually infect the hair, stratum corneum, and nails. However, dermatophytes occasionally invade the dermis, subcutaneous tissues, and internal organs, resulting in a condition called deep dermatophytosis. We report a case of an unusual presentation of Trichophyton rubrum infection causing multiple fungal abscesses in the lower extremities of an immunocompromised patient.

Case presentation

A 66-year-old male who had been receiving immunosuppressive drugs for 7 years developed numerous subcutaneous nodules in the lower extremities. The yellow purulent fluid obtained from the cyst was positive for T. rubrum. Topical bifonazole cream was effective for tinea pedis, but oral Sporanox 400 mg/day was discontinued after 2 months because the patient died from pneumonia after hospitalization for a lumbar fracture.

Conclusions

Although deep dermatophytosis is very rare, dermatomycosis should be considered in any examination of patients who are receiving immunosuppressive drugs. Fungi can enter the bloodstream and disseminate to distant major organs, including the lymph nodes, liver, brain, and bone, which often causes systemic infections that can be fatal.

Efficacy of Luliconazole Against Broad-Range Filamentous Fungi Including Fusarium solani Species Complex Causing Fungal Keratitis

PURPOSE

Fungal keratitis can be difficult to medically treat. Topical antifungals are usually applied empirically as the initial option in treating fungal keratitis. Natamycin (NAT) and/or voriconazole (VRCZ) have been widely used in the treatment of fungal keratitis. However, Fusarium solani species complex (FSSC), which are the dominant species of fungal keratitis, are resistant to VRCZ. This study investigated in vitro efficacy of luliconazole (LLCZ), a new imidazole antifungal, against FSSC and other filamentous fungi.

METHODS

A total of 18 Fusarium isolates and 7 others were grown on potato dextrose agar at 30 and 37°C. For Fusarium, species identification and phylogenetic tree analysis were performed based on elongation factor-1α (EF-1α) DNA sequencing. The broth microdilution method was used for antifungal susceptibility testing of 11 antifungal drugs including LLCZ.

RESULTS

The 18 identified Fusarium isolates belonged to FSSC (n = 13), Fusarium oxysporum species complex (FOSC; n = 2), Fusarium chlamydosporum species complex (FCSC; n = 1), Fusarium incarnatum-equiseti species complex (FIESC; n = 1), and Fusarium fujikuroi species complex (FFSC; n = 1). We further divided 13 FSSC isolates into 3 clades, FSSC5 (n = 8), FSSC3 + 4 (n = 4), and FSSC9-a (n = 1), with 8 FSSC strains growing at 37°C. LLCZ showed lowest minimum inhibitory concentrations (MICs) against all tested filamentous fungi, with a MIC90 against the Fusarium species of 0.06 μg/mL, whereas MIC90 for NAT and VRCZ were 4 and 8 μg/mL, respectively.

CONCLUSIONS

LLCZ has the strongest in vitro antifungal activity among all drugs used against broad-range filamentous fungi including FSSC. LLCZ may potentially be a new medical treatment option for fungal keratitis.

Evaluation of drug susceptibility test for Efinaconazole compared with conventional antifungal agents

BACKGROUND

Superficial fungal infections are one of the most common and burdensome skin problems affecting quality of life in patients. Various conventional antifungal agents have been used to treat fungal infections; however, various problems have been reported including drug interaction, drug resistance and low effectiveness. Efinaconazole is a novel antifungal agent, which has proven to be particularly effective against onychomycosis compared with conventional antifungal agents. However, the antifungal efficacy of Efinaconazole for specific strains has not been analysed.

OBJECTIVE

We conducted an in-vitro study to measure the antifungal activity of Efinaconazole against strains of Trichophyton rubrum, Trichophyton mentagrophytes and Candida albicans compared with widely-used antifungal drugs.

METHODS

We obtained strains of T. rubrum, T. mentagrophytes and C. albicans isolated from patients with onychomycosis and tinea pedis. The minimal inhibitory concentration (MIC) for various strains of fungal species was evaluated for the antifungal susceptibility test.

RESULTS

Efinaconazole showed a low MIC against almost strains of dermatophytes and C albicans and also presented low resistance, indicating high potency of efinaconazole for treatment of superficial fungal infections.

CONCLUSION

Efinaconazole could be a comparable alternative to replace existing conventional agents.

Correlation of In Vitro Susceptibility Based on MICs and Squalene Epoxidase Mutations with Clinical Response to Terbinafine in Patients with Tinea Corporis/Cruris

Recalcitrant dermatophytoses are on the rise in India. High MICs of terbinafine (TRB) and squalene epoxidase (SQLE) gene mutations conferring resistance in Trichophyton spp. have been recently documented. However, studies correlating laboratory data with clinical response to TRB in tinea corporis/cruris are lacking. For this study, we investigated the clinicomycological profile of 85 tinea corporis/cruris patients and performed antifungal susceptibility testing by CLSI microbroth dilution and SQLE mutation analysis of the isolates obtained and correlated these with the responses to TRB. Patients confirmed by potassium hydroxide (KOH) mounting of skin scrapings were started on TRB at 250 mg once a day (OD). If >50% clinical clearance was achieved by 3 weeks, the same dose was continued (group 1). If response was <50%, the dose was increased to 250 mg twice a day (BD) (group 2). If the response still remained below 50% after 3 weeks of BD, the patients were treated with itraconazole (ITR; group 3). Overall, skin scrapings from 64 (75.3%) patients yielded growth on culture. Strikingly, all isolates were confirmed to be Trichophyton interdigitale isolates by internal transcribed spacer (ITS) sequencing. Thirty-nine (61%) of the isolates had TRB MICs of ≥1 µg/ml. Complete follow-up data were available for 30 culture-positive patients. A highly significant difference in modal MICs to TRB among the three treatment response groups was noted (P = 0.009). Interestingly, 8 of the 9 patients in group 3 harbored isolates exhibiting elevated TRB MICs (8 to 32 µg/ml) and SQLE mutations. The odds of achieving cure with TRB MIC < 1 µg/ml strains were 2.5 times the odds of achieving cure with the strain exhibiting MIC ≥1 µg/ml.