Antifungal Resistance in Dermatology

Superficial Fungal Infections and Artificial Intelligence: A Review on Current Advances and Opportunities: REVISION

BACKGROUND

Superficial fungal infections are among the most common infections in world, they mainly affect skin, nails and scalp without further invasion. Superficial fungal diseases are conventionally diagnosed with direct microscopy, fungal culture or histopathology, treated with topical or systemic antifungal agents and prevented in immunocompetent patients by improving personal hygiene. However, conventional diagnostic tests can be time-consuming, also treatment can be insufficient or ineffective and prevention can prove to be demanding. Artificial Intelligence (AI) refers to a digital system having an intelligence akin to a human being. The concept of AI has existed since 1956, but hasn't been practicalised until recently. AI has revolutionised medical research in the recent years, promising to influence almost all specialties of medicine.

OBJECTIVE

An increasing number of articles have been published about the usage of AI in cutaneous mycoses.

METHODS

In this review, the key findings of articles about utilisation of AI in diagnosis, treatment and prevention of superficial fungal infections are summarised. Moreover, the need for more research and development is highlighted.

RESULTS

Fifty-four studies were reviewed. Onychomycosis was the most researched superficial fungal infection. AI can be used diagnosing fungi in macroscopic and microscopic images and classify them to some extent. AI can be a tool and be used as a part of something bigger to diagnose superficial mycoses.

CONCLUSION

AI can be used in all three steps of diagnosing, treating and preventing. AI can be a tool complementary to the clinician's skills and laboratory results.

Efinaconazole 10% solution: a comprehensive review of its use in the treatment of onychomycosis

INTRODUCTION

Onychomycosis is an infection of the nail bed and the nail plate. While oral antifungals are first-line for moderate-to-severe onychomycosis, topical efinaconazole 10% solution (JUBLIA®; Clenafin®) is effective and safe for mild-to-moderate severity onychomycosis. It is FDA-approved for patients aged 6 years and above.

AREAS COVERED

This literature review includes pharmacokinetics, microbiology, efficacy, safety, and post-marketing surveillance. It demonstrates consistent safety and efficacy across diverse patient demographics and comorbidities, including pediatric, diabetic and the elderly populations, without systemic side effects or drug interactions.

EXPERT OPINION

Efinaconazole 10% solution is an important addition to the armamentarium of therapies available to treat onychomycosis. Certain subgroups respond particularly well: females versus males, children versus adults, early onset onychomycosis (<1-year disease), those with mild onychomycosis (≤25% nail involvement), absence of tinea pedis, and thin nail plates at baseline (<1 mm thickness). Efinaconazole 10% solution is effective in diabetics and has demonstrated efficacy against dermatophytomas. Efinaconazole may be a consideration when terbinafine resistance is a concern, due to its different target of action.

Synergistic Inhibition of Synbiotic Cultures among Lactobacilli and Plant Extracts against Vaginal Discharge Causing Candida albicans

Vulvovaginal candidiasis (VVC) is the most common cause of vaginal discharge among women. The present study aimed to investigate the synergistic anticandidal effect of lactobacillus cultures supplemented with plant extracts. Among 600 isolates of lactic acid bacteria, 41 isolates exhibited inhibitory activity against Candida albicans ATCC10231. Six out of 41 cell-free supernatants demonstrated the most potent antibacterial and anticandidal activities. They also inhibited the clinical isolates of C. albicans, causing VVC and non-C. albicans. The synergistic effect between Lactobacillus crispatus 84/7 and Limosilactobacillus reuteri 89/4 was demonstrated by the lowest fractional inhibitory concentration index (FICI = 0.5). The synbiotic culture of bacterial combination, cultured with Jerusalem artichoke (H. tuberosus) extract, also exhibited the strongest inhibition against the tested C. albicans. Biofilm formation decreased after 12 h of incubation in the selected cell-free supernatants of this synbiotic culture. The anticandidal activity of crude extracts was lost after treatment with proteinase K and trypsin but not with heating conditions, suggesting that it may be a heat-stable substance. In conclusion, the combination of L. crispatus 84/7 and L. reuteri 89/4 with H. tuberosus may be a promising candidate for inhibiting Candida infection and biofilm formation, with the potential use as ingredients in vaginal biotherapeutic products.

Safety, Efficacy and Attributes of 2.5% Selenium Sulfide Shampoo in the Treatment of Dandruff: A Single-Center Study

BACKGROUND

Selenium sulfide, available as a shampoo or topical lotion at 1%, or 2.5% concentrations in India, is used as a topical antiseborrheic and antifungal for the treatment of dandruff, seborrheic dermatitis, psoriasis, and tinea versicolor. In the present study, the safety, efficacy, and attributes of 2.5% selenium sulfide shampoo were evaluated in Indian participants with dandruff.

METHODS

A single-center, single-arm, prospective, investigator-initiated, open-label, post-marketing interventional study was conducted on Indian subjects aged 18-70 years diagnosed with moderate dandruff who were prescribed 2.5% selenium sulfide shampoo every three days for four weeks. The primary endpoints were 1) reduction in total dandruff score assessed using a clinical grading scale for adherent and loose dandruff from baseline to weeks 1, 2, and 4, and 2) incidence of adverse events up to the end of the study. The key secondary endpoints were 1) participants' perception of shampoo attributes (dandruff reduction, scalp itch, scalp oiliness/greasiness, or fragrance) as assessed by a subjective self-assessment questionnaire post-first wash and at weeks 1, 2, and/or 4; 2) satisfaction with treatment as assessed by investigators and participants using a subjective self-assessment questionnaire at week 4; and 3) reduction in scalp sebum as assessed with a meibometer at weeks 2 and 4. Statistical analysis was performed using the Wilcoxon signed-rank test for continuous variables and the Chi-square test for categorical variables. A p-value of 0.05 was considered to be statistically significant.

RESULTS

Of 34 enrolled subjects, 30 completed the four-week study. The mean (standard deviation, SD) age of the study participants was 29.8 (7.87) years, with the majority being females (n=18; 60.0%). Mean (SD) total dandruff score significantly (p=0.001) reduced from a baseline score of 11.5 (2.15) to 7.17 (2.12) at week 1, 4.93 (1.72) at week 2, and 2.5 (1.17) at week 4. All the participants reported dandruff reduction and acceptable fragrance of the shampoo at four weeks. Absence of itching and reduction in oiliness was reported by 73.3% (n=22) of participants at week 4 and by 50.0% (n=15) of participants at week 2, respectively. All participants reported good, very good, or excellent satisfaction with the test shampoo at week 4, whereas the investigators rated the shampoo as very good or excellent in managing dandruff in all participants. At week 4, erythema was reported to be absent in all participants. No adverse events were reported during the study.

CONCLUSIONS

The 2.5% selenium sulfide shampoo was found to be effective in the management of dandruff and related symptoms like itching, oiliness, and greasiness and had a good safety profile in Indian participants with dandruff.

Development and Characterization of Terbinafine-Loaded Nanoemulgel for Effective Management of Dermatophytosis

Dermatophytosis, the most prevalent fungal infection, is witnessing a rising incidence annually. To address this challenge, we developed a terbinafine-loaded oil-in-water nanoemulsion (TH-NE) through the aqueous microtitration method. The formulation comprised olive oil (oil phase), Span 80 (surfactant), and propylene glycol (co-surfactant). Pseudo-phase ternary diagrams and thermodynamic studies underscored the stability of TH-NE. Employing the Box-Behnken design (BBD), we optimized TH-NE, which resulted in a remarkable particle size of 28.07 nm ± 0.5, a low polydispersity index (PDI) of 0.1922 ± 0.1, and a substantial negative zeta potential of -41.87 mV ± 1. Subsequently, TH-NE was integrated into a 1.5% carbopol matrix, yielding a nanoemulgel (TH-NEG). Texture analysis of TH-NEG demonstrated a firmness of 168.00 g, a consistency of 229.81 g/s, negative cohesiveness (-83.36 g), and a work of cohesion at -107.02 g/s. In vitro drug release studies revealed an initial burst effect followed by sustained release, with TH-NEG achieving an impressive 88% release over 48 h, outperforming TH-NE (74%) and the marketed formulation (66%). Ex vivo release studies mirrored these results, with TH-NEG (86%) and TH-NE (71%) showcasing sustained drug release in comparison to the marketed formulation (67%). Confocal microscopy illustrated that TH-NEG and TH-NE penetrated to depths of 30 µm and 25 µm, respectively, into the epidermal layer. Furthermore, dermatokinetic studies highlighted the enhanced drug penetration of TH-NEG compared to TH-NE through mouse skin. In summary, our study establishes TH-NEG as a promising carrier for terbinafine in treating dermatophytosis, offering improved drug delivery and sustained release potential.

Curcumin nanoparticles: the topical antimycotic suspension treating oral candidiasis

Phytotherapeutics is widely used nowadays as an alternative to the current antifungal drugs to reduce their side effects. Curcumin, with its wide therapeutic array as antioxidant and anti-inflammatory agent, is one of the natural compounds that ha..s an antifungal effect, especially when being used at nanoscale to increase its bioavailability. Our research aimed to evaluate clinically and microbiologically the effect of using topical nanocurcumin suspension to treat oral candidiasis. After 4 days from induction of oral candidiasis (baseline), we randomly divided 39 female BALB/c mice into three groups of 13 animals; nanocurcumin, nystatin, and sham groups. All animals in nanocurcumin and nystatin groups received topical treatment twice daily for 10 days. Then, we performed clinical and microbiological evaluations at baseline, day 5, and day 10. By the end of treatment, our results revealed that nanocurcumin promoted a significant reduction in the number of candida colonies. There was no statistically significant difference neither clinically nor microbiologically between nanocurcumin and nystatin groups. In conclusion, nanocurcumin has a good antifungal effect as nystatin, however, its therapeutic efficacy takes a longer time to appear than nystatin. The enhanced bioavailability of curcumin at the nanoscale qualifies this nano-herb as a promising alternative therapy for oral candidiasis, evading nystatin-associated morbidity.

Antifungal stewardship: What we need to know

Antimicrobial stewardship refers to a well-coordinated program which promotes the scientific and rational use of antimicrobials, reduces the chances of drug resistance and improves patient outcomes. A comprehensive English language literature search was done across multiple databases (PubMed, EMBASE, MEDLINE and Cochrane) for the period 1990-2022, revealing a large volume of reports of growing resistance to established antifungal therapies, against a backdrop of irrational and unscientific prescriptions. As a result of this, antifungal stewardship, a new kid on the block, has recently garnered attention. This review article is an attempt to summarise the basic concept of stewardship programs, highlighting the dire need to implement the same in the present situation of antifungal resistance and treatment failure.

Species Distribution and Antifungal Susceptibility Profile of Dermatophytes from a Tertiary Care Centre in North India

Objective Dermatophytoses, one of the most ancient diseases, is becoming a menace in recent times. This has made the knowledge of antifungal susceptibility a priority in today's times.

Material and Methods This is a prospective study conducted over 18 months including all dermatophytes isolated during the period. Dermatophytes were identified by routine phenotypic methods. Antifungal susceptibility testing was performed for griseofulvin, terbinafine, and itraconazole as per the Clinical Laboratory Standard Institute M38 A2, and minimum inhibitory concentrations (MICs) were read after 5 days.

Results Patient details and associated risk factors were recorded. Fixed dose combinations with steroids were associated with 79.3% (46 out of 58) of patients with dermatophytosis of skin. Among the 72 dermatophytes isolated during the study period, 58 (80.5%) were isolated from skin scrapings and 14 (19.4%) from nail samples. Tinea corporis with cruris was the most common presentation. The most common dermatophyte isolated from skin scrapings was Trichophyton mentagrophytes complex (70.6%, 41 out of 58), while from nail samples it was Trichophyton rubrum complex (78.57%, 11 out of 14). Based on the MIC50 and MIC90 results, itraconazole showed the lowest MICs, followed by terbinafine and then griseofulvin.

Conclusion With the changing epidemiology of species distribution and antifungal resistance, there is a need for continuous surveillance of these parameters of dermatophytes.

Discovery of spirooxindole-pyrrolidine heterocyclic hybrids with potent antifungal activity against fungal pathogens

Fungal pathogens mainly Candida and Cryptococcus species causes serious life-threating infections to humans, especially in individuals who are immunocompromised. Increasing frequency of antifungal drug resistance along with paucity of FDA-approved drugs suggest a dire need for new antifungal drugs. Our screening of newly synthesized spirooxindole heterocyclic hybrid compounds revealed that the novel small molecule, DPA-3, has potent antifungal activity without inducing mammalian cell cytotoxicity. Furthermore, DPA-3 significantly reduced hyphal and biofilm formation of Candida albicans ATCC 10231 strain, out-competing two FDA approved antifungal drugs. The results of our study conclude that DPA-3 is a compelling candidate for further development as an antifungal drug.

Review of the alternative therapies for onychomycosis and superficial fungal infections: posaconazole, fosravuconazole, voriconazole, oteseconazole

Terbinafine and itraconazole are the most commonly used oral antifungals to treat onychomycosis and superficial dermatomycoses. Recently, poor response to oral terbinafine has been reported. We have summarized the most appropriate dosing regimens of posaconazole, fosravuconazole, voriconazole, and oteseconazole (VT-1161) to treat onychomycosis and superficial fungal infections. A structured search on PubMed and Google Scholar was conducted. Additionally, the bibliographies of selected articles were searched to identify relevant records. The number of records identified from the searches was 463, with 50 articles meeting the inclusion criteria for review. None of the new azoles are US FDA approved for onychomycosis treatment; however, an increasing number of studies have evaluated these agents. The efficacies (complete cure and mycologic cure) of the antifungal agents for dermatophyte great toenail onychomycosis treatment are terbinafine 250 mg/day × 12 weeks (Phase III trial) (38%, 70%), itraconazole 200 mg/day × 12 weeks (Phase III trial) (14%, 54%), posaconazole 200 mg/day × 24 weeks (Phase IIB) (54.1%, 70.3%), fosravuconazole 100 mg/day ravuconazole equivalent × 12 weeks (Phase III) (59.4%, 82.0%), and oteseconazole 300 mg/day loading dose × 2 weeks (Phase II), followed by 300 mg/week × 10 weeks (maintenance dose) (45%, 70%). Guidelines for monitoring are also presented.

Molecular characterization and antifungal activity against non-dermatophyte molds causing onychomycosis

Onychomycosis is a fungal disease that caused by different types of fungi. Non-dermatophyte molds are a large saprophytic fungi group that live in nature and could affect traumatic nails. The aim of this study was to identify non-dermatophyte molds causing onychomycosis and evaluation of several antifungal activities against the isolates. The samples consisted of 50 non-dermatophyte molds isolated from patients with onychomycosis confirmed by direct and culture examination fungal. DNA was extracted, amplified, and sequenced. Disk diffusion method was used to evaluate itraconazole, fluconazole, ketoconazole, terbinafine, posaconazole, and econazole activity against the isolates. The species identified as: Aspergillus flavus 22 (44%), A. niger 12 (24%), A. fumigates, 3 (6%), A. sydowii 3 (6%), A. terreus 1 (2%), Penicillium commune 2 (4%), P. glabrum 2 (4%), P. chrysogenum, 1 (2%), Fusarium solani 3 (6%) and F. thapsinum 1 (2%). Most of the samples were sensitive to terbinafine, itraconazole, and econazole and 94% of the isolates were resistant to fluconazole. This study showed that Aspergillus species were the most common cause of non-dermatophyte mold onychomycosis and fluconazole was the most resistant antifungals. Care must be taken to choose the appropriate antifungal drug for a better cure.

In vitro evaluation of photodynamic activity of methylene blue against Trichophyton verrucosum azole-susceptible and -resistant strains

The intense search for the "Holy Grail" of antifungal therapy can be observed today. The searches are not limited only to discovery of potential antifungal drugs, but also new therapeutic strategies involving the use of chemosensitizers to achieve synergistic effect or physicochemical factors inducing stress conditions in fungal cells. In this study was examined in vitro effectiveness of photodynamic antifungal strategy with methylene blue using a light beam with a wavelength equal to 635 nm toward the Trichophyton verrucosum susceptible and itraconazole- and/or fluconazole-resistant strains. Methylene blue used at concentration equal to 5 μg/mL and in the presence of 40 J/cm² of light energy showed fungicidal effect toward the susceptible strains. However, for azole-resistant isolates, only the energy dose equal to 60 J/cm² at 5 μg/mL of methylene blue allowed to kill the pathogen. This study confirms that methylene blue induced by red light has a definite inhibitory effect on zoophilic dermatophytes.

Epidemiological Characterization of Clinical Fungal Isolates from Pauls Stradinš Clinical University Hospital, Latvia: A 4-Year Surveillance Report

Nosocomial fungal infections are an emerging global public health threat that requires urgent attention and proper management. With the limited availability of treatment options, it has become necessary to understand the emerging epidemiological trends, mechanisms, and risk factors. However, very limited surveillance reports are available in the Latvian and broader European context. We therefore conducted a retrospective analysis of laboratory data (2017-2020) from Pauls Stradinš Clinical University Hospital (PSCUH), Riga, Latvia, which is one of the largest public multispecialty hospitals in Latvia. A total of 2278 fungal isolates were analyzed during the study period, with Candida spp. comprising 95% of the isolates, followed by Aspergillus spp. and Geotrichum spp. Amongst the Candida spp., C. albicans and C. glabrata made up about 75% of the isolates. The Department of Lung Diseases and Thoracic Surgery had the highest caseload followed by Intensive Care Department. Majority of the fungal isolates were collected from the bronchoalveolar lavage (37%), followed by urine (19%) and sputum (18%) samples. A total of 34 cases of candidemia were noted during the study period with C. albicans being the most common candidemia pathogen. Proper surveillance of emerging epidemiological trends serve as the most reliable and powerful cornerstone towards tackling this emerging threat.

Genipin in an Ex Vivo Corneal Model of Bacterial and Fungal Keratitis

Purpose

To determine whether genipin (a natural crosslinker) could reduce the colonization and proliferation of bacteria and fungi in an ex vivo model of corneal infection.

Methods

This study, using an ex vivo model of bacterial and fungal keratitis, investigated the antimicrobial efficacy of genipin crosslinking. Excised corneoscleral buttons were wounded by scalpel incision and subsequently infected with Staphylococcus aureus, Pseudomonas aeruginosa, or Candida albicans. After inoculation, corneas were treated with genipin for 24 hours at 37°C. Histologic examinations were carried out, and the number of viable colony-forming units (CFU)/cornea was determined.

Results

Genipin exerts bactericidal action against S. aureus and P. aeruginosa, as well as fungicidal action against C. albicans and significantly reduced the CFU compared to contralateral eyes that received saline treatment (P < 0.05).

Conclusions

These data identify genipin as a novel ocular antimicrobial agent that has the potential to be incorporated into the therapeutic armamentarium against microbial keratitis.

Translational Relevance

This study provided evidence for the antimicrobial and antifungal properties of genipin as an alternative crosslinker that could be used in the management of infectious keratitis.

A Paradigm Shift in the Treatment and Management of Onychomycosis

There is an increase in the incidence of onychomycosis, especially in at-risk populations. Onychomycosis is difficult to treat, as the efficacy of most antifungal agents is relatively low. Nondermatophyte molds (NDMs) and mixed infection (dermatophyte plus NDM) onychomycosis are contributing to growing antifungal resistance, as they are often underestimated and ignored due to incorrect diagnosis. There is a need for a paradigm shift in the management of onychomycosis to a patient-centered, holistic approach with an emphasis on laboratory diagnosis prior to initiating treatment, which enables the rational choice of the antifungal agent. Additionally, in the case of resistant infections, antifungal susceptibility testing is recommended. Strategies for effective management of onychomycosis include disinfection of fungal reservoirs in shoes and socks and prophylaxis posttreatment using topical antifungal agents. These measures may reduce the recurrence of onychomycosis and improve long-term clinical success.

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.

A Review on Antifungal Efficiency of Plant Extracts Entrenched Polysaccharide-Based Nanohydrogels

Human skin acts as a physical barrier; however, sometimes the skin gets infected by fungi, which becomes more severe if the infection occurs on the third layer of the skin. Azole derivative-based antifungal creams, liquids, or sprays are available to treat fungal infections; however, these formulations show various side effects on the application site. Over the past few years, herbal extracts and various essential oils have shown effective antifungal activity. Additionally, autoxidation and epimerization are significant problems with the direct use of herbal extracts. Hence, to overcome these obstacles, polysaccharide-based nanohydrogels embedded with natural plant extracts and oils have become the primary choice of pharmaceutical scientists. These gels protect plant-based bioactive compounds and are effective delivery agents because they release multiple bioactive compounds in the targeted area. Nanohydrogels can be applied to infected areas, and due to their contagious nature and penetration power, they get directly absorbed through the skin, quickly reaching the skin's third layer and effectively reducing the fungal infection. In this review, we explain various skin fungal infections, possible treatments, and the effective utilization of plant extract and oil-embedded polysaccharide-based nanohydrogels.

Etiological prevalence and antifungal sensitivity patterns of dermatophytosis in India - A multicentric study

BACKGROUND

The prevalence of dermatophytes varies with season, geographical area, socio-economic factors and effective management strategies.

AIMS

The aim of the study was to assess the prevalence of pathogenic dermatophytes, clinical types of dermatophyte fungal infection, and in vitro antifungal drug susceptibility testing against dermatophytes.

METHODS

Three hundred and ninety five patients with dermatophytosis were enrolled from five cities (Mumbai, Delhi, Lucknow, Kolkata and Hyderabad) across India. All patients were subjected to clinical examination and investigations, including potassium hydroxide microscopy, fungal culture and antifungal drug susceptibility testing.

RESULTS

Trichophyton rubrum was the most common species identified (68.4%), followed by T. mentagrophytes (29.3%). Within species, T. mentagrophytes was prevalent in humid environmental conditions (Mumbai and Kolkata), whereas T. rubrum was prevalent in noncoastal areas (Delhi, Lucknow and Hyderabad). Tinea corporis (71.4%) and tinea cruris (62.0%) were the common clinical types observed. antifungal drug susceptibility testing data indicated that minimum inhibitory concentration required to inhibit the growth of 90% of organisms (MIC-90) was lowest for griseofulvin (0.25-3.0 μg/mL). Among oral antifungals, the mean MIC of itraconazole was within the range (0.84 [0.252] μg/ mL), whereas high mean MIC values were reported for terbinafine (0.05 [0.043] μg/mL). Among topical agents, lowest mean MIC values were reported for luliconazole (0.29 [0.286] μg/mL), eberconazole (0.32 [0.251]) μg/mL and amorolfine (0.60 [0.306]) μg/mL.

LIMITATIONS

Lack of correlation between in vitro antifungal susceptibility and clinical outcome and absence of defined MIC breakpoints.

CONCLUSION

T. rubrum was the most common, followed by T. mentagrophytes as an emerging/codominant fungal isolate in India. Tinea corporis was the most common clinical type of dermatophytosis. Mean MIC of terbinafine was above the reference range, while it was within the range for itraconazole; griseofulvin had the lowest mean MIC. Luliconazole presented the lowest mean MIC values across cities.

Nondermatophyte mould onychomycosis

Nondermatophyte moulds (NDMs) onychomycosis is often difficult to diagnose as NDMs have been considered contaminants of nails. There are several diagnostic methods used to identify NDMs, however, repeated laboratory isolation is recommended to validate pathogenicity. With NDM and mixed infection (dermatophytes plus NDM) onychomycosis on the rise, accurate clinical diagnosis along with mycological tests is recommended. Systemic antifungal agents such as itraconazole and terbinafine (e.g. pulse regimen: 1 pulse = every day for one week, followed by no treatment for three weeks) have shown efficacy in treating onychomycosis caused by various NDMs such as Aspergillus spp., Fusarium spp., Scopulariopsis brevicaulis, and Onychocola canadensis. Studies investigating topical therapy and devices for NDM onychomycosis are limited. The emergence of antifungal resistance necessitates the incorporation of antifungal susceptibility testing into diagnosis when possible, for the management of recalcitrant infections. Case studies documented in the literature show newer azoles such as posaconazole and voriconazole as sometimes effective in treating resistant NDM onychomycosis. Treatment with broad-spectrum antifungal agents (e.g. itraconazole and efinaconazole) and other combination therapy (oral + oral and/or oral + topical) may be considerations in the management of NDM onychomycosis.

The increasing problem of treatment-resistant fungal infections: a call for antifungal stewardship programs

Antimicrobial stewardship (AMS) programs have been widely recognized among the public health community. These programs focus majorly on bacterial infections, efficient antibiotic use, and measures to curb increasing antibacterial resistance. AMS programs are successfully established around the globe; however, very few include antifungal stewardship (AFS). The increasing incidence of superficial and invasive fungal infections, combined with delayed or inaccurate diagnosis, has contributed to the overprescribing and overuse of antifungal agents. Such increased exposure to antifungal agents may be a reason for the emergence of increasing antifungal resistance among fungal pathogens. With mounting reports of treatment failures and resistant infections, the evidence to support the need for AFS programs is increasing. AFS is an emerging branch of AMS programs that requires global attention and recognition.

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 Melaleuca alternifolia Essential Oil (TTO) and Its Synergy with Itraconazole or Ketoconazole against Trichophyton rubrum

Over the past 20–30 years, Trichophyton rubrum represented the most widespread dermatophyte with a prevalence accounting for 70% of dermatophytosis. The treatment for cutaneous infections caused by Trichophyton spp. are imidazoles (ketoconazole (KTZ)) and triazoles (itraconazole (ITZ)). T. rubrum can develop resistance to azoles after prolonged exposure to subinhibitory concentrations resulting in therapeutic failures and chronic infections. These problems have stimulated the search for therapeutic alternatives, including essential oils, and their potential use in combination with conventional antifungals. The purpose of this study was to evaluate the antifungal activity of tea tree oil (TTO) (Melaleuca alternifolia essential oil) and the main components against T. rubrum and to assess whether TTO in association with KTZ/ITZ as reference drugs improves the antifungal activity of these drugs. We used a terpinen-4-ol chemotype (35.88%) TTO, and its antifungal properties were evaluated by minimum inhibitory and minimum fungicidal concentrations in accordance with the CLSI guidelines. The interaction between TTO and azoles was evaluated through the checkerboard and isobologram methods. The results demonstrated both the fungicide activity of TTO on T. rubrum and the synergism when it was used in combination with azoles. Therefore, this mixture may reduce the minimum effective dose of azole required and minimize the side effects of the therapy. Synergy activity offered a promise for combination topical treatment for superficial mycoses.

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.

Synthetic peptides against Trichophyton mentagrophytes and T. rubrum: Mechanisms of action and efficiency compared to griseofulvin and itraconazole

AIMS

According to the WHO, 20-25% of people worldwide are affected by skin infections caused by dermatophytes, such as those of the Trichophyton genus. Additionally, several dermatophytes have developed resistance to drugs such as griseofulvin and itraconazole. This study tested 2S albumins-derived antimicrobial peptides (AMPs) as alternative antidermatophytic molecules.

MAIN METHODS

Membrane pore formation assays, tests to detect overproduction of ROS, scanning electron microscopy (SEM) and fluorescence microscopy (FM) were carried out to provide insight into the mechanisms of antidermatophytic action.

KEY FINDINGS

All AMPs (at 50 μg mL^-1) tested reduced the mycelial growth of T. mentagrophytes and T. rubrum by up to 95%. In contrast, using a concentration 20-fold higher, griseofulvin only inhibited T. mentagrophytes by 35%, while itraconazole was not active against both dermatophytes. Scanning electron and fluorescence microscopies revealed that the six AMPs caused severe damage to hyphal morphology by inducing cell wall rupture, hyphal content leakage, and death. Peptides also induced membrane pore formation and oxidative stress by overproduction of ROS. Based on the stronger activity of peptides than the commercial drugs and the mechanism of action, all six peptides have the potential to be either employed as models to develop new antidermatophytic drugs or as adjuvants to existing ones.

SIGNIFICANCE

The synthetic peptides are more efficient than conventional drug to treat infection caused by dermatophytes being potential molecules to develop new drugs.

Drug-Induced Neutropenia During Treatment of Non-Neoplastic Dermatologic Diseases: A Review

Idiosyncratic drug-induced neutropenia (DIN) is a rare, potentially fatal adverse reaction. A literature search was performed on Pubmed and Embase, targeting articles indicating neutropenia as a complication during the treatment of non-neoplastic dermatological disorders. In 66 identified articles, the common incriminated drugs included conventional oral immunomodulators, topical cytotoxic agents, antibacterials, antifungals, biologics and targeted synthetic disease-modifying antirheumatic drugs, non-steroidal anti-inflammatory drugs, and retinoids, with dapsone being reported most often. The duration of drug exposure before the diagnosis of neutropenia varied, but mostly ranged from days to weeks. The majority of patients recovered after drug discontinuation and supportive management including antibiotics and granulocyte colony-stimulating factor, but fatal cases were reported. The proposed pathogenesis of DIN consists of direct drug toxicity and immune-mediated reaction. Certain genetic variants, individual variability in enzyme efficiency, and concomitant use of other drugs may increase the risk of DIN. Being familiar with the most commonly implicated agents and risk factors helps early identification and prompt management of this potentially fatal complication.

Mo-CBP4, a purified chitin-binding protein from Moringa oleifera seeds, is a potent antidermatophytic protein: In vitro mechanisms of action, in vivo effect against infection, and clinical application as a hydrogel for skin infection

Dermatophytes belonging to Trichophyton ssp. are important anthropophilic and zoophilic pathogens, which developed resistance to griseofulvin, the common antifungal drug used to treat dermatophytosis. In this context, Moringa oleifera seed proteins have been described as antifungal agents with potential applications. Thus, this work aimed to evaluate the antidermatophytic in vitro, focusing on mechanisms, and in vivo potential of Mo-CBP₄, purified from M. oleifera seeds. Mo-CBP₄was purified after protein extraction with 50 mM Tris-HCl buffer, pH 8.0, and chromatography on chitin and CM Sepharose™ columns and antidermatophytic potential of Mo-CBP₄ evaluated in vitro and in vivo. In vitro, Mo-CBP₄ reduced in 50% the germination of microconidia of Trichophyton mentagrophytes at 45 μM; but did not show inhibition of mycelial growth. Mo-CBP₄ (45 μM) presents the inhibitory activity even when incubated with N-acetyl-d-glucosamine (NAG). Analysis of the mechanisms of Mo-CBP₄ revealed an increase in membrane permeability, ROS overproduction and damage to cell wall leading to microconidia death. Furthermore, using in vivo models, Mo-CBP₄ (5, 10 and 20 mg g^-1) reduced the severity and time of dermatophytosis. Altogether, these findings indicate that Mo-CBP₄ has great potential for the development of novel antifungal drugs for the clinical treatment of dermatophytosis.

Fluconazole conjugated-gold nanorods as an antifungal nanomedicine with low cytotoxicity against human dermal fibroblasts

Herein, a nanotechnology-based approach was adopted to develop a facile and effective nanoplatform for the treatment of superficial fungal infections. Gold nanorods (GNR) functionalized with thiolated poly ethylene glycol (PEG-SH) or thiolated PEGylated cholesterol (Chol-PEG-SH) moieties were conjugated with Fluconazole and loaded into poloxamer 407 hydrogel. The obtained nanocomplexes; PEG-Fluc-GNR and Chol-Fluc-GNR were characterized by optical spectroscopy, hydrodynamic size and effective surface charge. The anti-fungal activity of the nanocomplexes was investigated by estimating the minimum inhibitory concentration (MIC) and the percentage reduction of fungal viable count against Candida (C.) albicans. PEG-Fluc-GNR and Chol-Fluc-GNR resulted in 5-fold and 14-fold reduction in MIC of GNR, and in 9-fold and 12-fold reduction in MIC of Fluconazole, respectively. The average log-reduction of the viable fungal cells upon treatment with the nanocomplexes was 5 log cycles, and it ranged from 1.3–3.7 log cycles when loaded into poloxamer 407 hydrogel. Transmission electron microscope imaging of the treated C. albicans revealed an enhanced uptake of the nanoparticles into the fungus's cell wall within the first 120 min of exposure. The nanocomplexes demonstrated low cytotoxicity towards human dermal fibroblasts which represent the human skin dermal cells. Conjugating Fluconazole with GNR is a promising approach for the effective treatment of superficial fungal infections.

A nanotechnology-based approach was adopted to develop a facile and effective nanoplatform for the treatment of superficial fungal infections.

Emerging Terbinafine Resistance in Trichophyton: Clinical Characteristics, Squalene Epoxidase Gene Mutations, and a Reliable EUCAST Method for Detection

In recent years, cases involving terbinafine-resistant Trichophyton isolates have been reported increasingly, particularly in India. We present 14 cases of terbinafine treatment failure in Trichophyton-infected Danish patients due to acquired resistance. Patients infected with Trichophyton rubrum (n = 12) or Trichophyton interdigitale (n = 2) with elevated terbinafine MICs during 2013-2018 were included. Antifungal susceptibility testing (AFST) was performed following a modified EUCAST E.Def 9.3.1 method (5 days of incubation) with or without cycloheximide and chloramphenicol (CC) supplementation of the growth medium. The squalene epoxidase (SE) target gene was sequenced, and 3-dimensional enzyme homology modeling was performed. Most patients (12/14 [86%]) were male. The mean age was 53.5 years (range, 11 to 77 years). The mean duration of infections was 4.8 years at the time of resistance detection. Prior systemic terbinafine treatment was documented for all patients, and topical therapy for 62% (information was missing in one case). Overall, nine isolates (64%) displayed high terbinafine resistance (MICs, 4 to >8 mg/liter), while two (14%) displayed moderate (MICs, 1 to 2 mg/liter) and three (21%) displayed low (MICs, 0.125 to 0.25 mg/liter) terbinafine resistance compared with control isolates. MICs generated with or without CC supplementation were similar, but CC prevented contamination. Known and novel SE amino acid substitutions (F397L, L393F, L393S, F415S, H440Y F484Y, and I121M V237I) were detected in resistant but not control isolates. Three-dimensional homology modeling suggested a role of the novel I121M and V237I alterations. Terbinafine resistance has been detected in Denmark using a modified EUCAST method, which facilitated susceptibility testing of dermatophytes. Action is needed for this emerging public health problem.

Cutaneous candidiasis in Tehran-Iran: from epidemiology to multilocus sequence types, virulence factors and antifungal susceptibility of etiologic Candida species

BACKGROUND AND OBJECTIVES

Cutaneous candidiasis is a multipicture fungal infection caused by members of the genus Candida which is considered as a public health problem all over the world with urgency of effective treatment and control. This study was performed to analyze the clinical epidemiology and molecular aspects of cutaneous candidiasis in Tehran-Iran in relation to antifungal susceptibility and virulence factors of etiologic Candida species.

MATERIALS AND METHODS

Candida species were isolated from skin (27.3%) and nail scrapings (72.7%) of suspected patients and identified by ITS sequencing. Phylogeny of the isolates was evaluated using multilocus sequence typing (MLST) and antifungal susceptibility and virulence factors of the isolates were determined in relation to clinical presentation.

RESULTS

Candida albicans was the most prevalent species (39.8%), followed by C. parapsilosis (32.9%), C. orthopsilosis (10.4%), C. tropicalis (7.9%), C. glabrata and C. guilliermondii, each (4.5%). Molecular typing of 35 C. albicans isolates by MLST revealed 28 novel sequence types with 11 singletons with 80.0% new diploid sequence types (DSTs). Majority of the isolates were susceptible to amphotericin B (91.5%), followed by posaconazole (90.3%), fluconazole (84.3%), itraconazole (74.1%), caspofungin (53.6%), and voriconazole (26.8%). Biofilm formation, yeast-to-hyphae transformation and phospholipase activity were reported species-dependent.

CONCLUSION

Our results demonstrated clinical epidemiology of various Candida species from cutaneous candidiasis distributed in new molecular types with increasing importance of drug resistant of non-albicans Candida species. Our results showed that drug susceptibility and genetic variability of Candida species may be attributed to their clinical features and source of isolation.

Antifungal resistance in dermatophytes: Recent trends and therapeutic implications

Dermatophytoses or tinea refers to superficial fungal infection of keratinized tissues. Although generally considered easy to treat, recalcitrant infections, presenting as extensive and difficult to treat tinea corporis and cruris, are on the rise in some parts of the world. The situation demands an understanding of the pharmacokinetic and pharmacodynamic properties of the available antifungals against dermatophytes and the possible contribution of drug resistance and other factors to the present scenario. In this review, we provide the readers a comprehensive account of the available literature on in-vitro and in-vivo resistance to clinically used antifungals among dermatophytes. We have also added, in brief, the relevant skin pharmacokinetics of important systemic drugs. The established and postulated mechanisms of drug resistance are discussed and aspects on lack of in vivo correlation of in vitro resistance are presented. Finally, the lacunae in our existing knowledge on the topic and the arenas for future research are highlighted.

Development of a Method for the Quantification of Clotrimazole and Itraconazole and Study of Their Stability in a New Microemulsion for the Treatment of Sporotrichosis

Sporotrichosis occurs worldwide and is caused by the fungus Sporothrix brasiliensis. This agent has a high zoonotic potential and is transmitted mainly by bites and scratches from infected felines. A new association between the drugs clotrimazole and itraconazole is shown to be effective against S. brasiliensis yeasts. This association was formulated as a microemulsion containing benzyl alcohol as oil, Tween^® 60 and propylene glycol as surfactant and cosurfactant, respectively, and water. Initially, the compatibility between clotrimazole and itraconazole was studied using differential scanning calorimetry (DSC), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), and X-ray powder diffraction (PXRD). Additionally, a simple and efficient analytical HPLC method was developed to simultaneously determine the concentration of clotrimazole and itraconazole in the novel microemulsion. The developed method proved to be efficient, robust, and reproducible for both components of the microemulsion. We also performed an accelerated stability study of this formulation, and the developed analytical method was applied to monitor the content of active ingredients. Interestingly, these investigations led to the detection of a known clotrimazole degradation product whose structure was confirmed using NMR and HRMS, as well as a possible interaction between itraconazole and benzyl alcohol.

Antifungal Efficacy of Spice Extracts against Candida albicans: An in vitro study

Background

Candida species are normal commensals and are isolated intra-orally in 17%-75% of healthy individuals and all debilitated people. Eradication of candidiasis is complicated by the emergence of Candida strains that are resistant to the currently used antifungal agents. Plants as remedies are gaining popularity in developed countries. Although many plants have already been investigated against Candida albicans, the search is still to find a long-term prevention or cure for oral candidiasis.

Objectives

The objective of this study was (1) to evaluate the antifungal activity of black pepper, bay leaf, cinnamon, and cumin against C. albicans and (2) to determine the minimum inhibitory concentration (MIC) of spice extracts against C. albicans.

Materials and Methods

Spices obtained from the local market were dried and powdered. Solvent extracts were obtained by maceration with methanol followed by filtration and evaporation. The antifungal efficacy was assessed using cup-plate diffusion method followed by the determination of MIC by serial tube dilution technique. Statistical analysis was done using one-way analysis of variance followed by Tukey's post hoc test. P < 0.05 was considered as statistically significant.

Results

All the extracts evaluated showed variable degree of inhibition zones against C. albicans with cinnamon showing the highest inhibition (49.3 ± 0.52) mm and also with least MIC against C. albicans (<0.05 mg/ml).

Conclusion

These results exhibit the antifungal activity of the spice extracts against C. albicans, which may be useful in the treatment of oral candidiasis.