Tinea capitis dermatophytes: susceptibility to antifungal drugs tested in vitro and in vivo

Tinea capitis among schoolchildren in Ethiopia: A systematic review and meta analysis

BACKGROUND

Tinea capitis accounts for25 to 30% of all fungal infections, but it is often ignored because it is not life threatening in nature. It is more common among schoolchildren particularly in developing countries. Due to the presence of significant variability among the previous studies, this study was conducted to provide a pooled prevalence and associated factors of tinea capitis in Ethiopian schoolchildren.

METHOD

We conducted a systematic search in five major databases for articles similar to our topic. This review included school-based cross-sectional studies that were reported in English and conducted from 2006 through 2022. The data were extracted using Microsoft Excel and further analysis was done using StataTM Version 17.0 statistical software. Forest plots were used to assess the presence of heterogeneity with 95% confidence intervals. A random effects meta- analysis model was used to pool primary estimates. To declare the presence or absence of association, 95% confidence interval with odds ratio was used.

RESULTS

Fourteen studies with a total of 9465 schoolchildren were included. The pooled prevalence was 29.03% (95%CI: 15.37-42.71). There was observed heterogeneity, which could be explained by publication bias (P = 0.04). Family history of tinea capitis (OR: 9.18, 95%CI: 3.5-24.02), under the age of 10 years (OR: 1.65, 95%CI: 1.17-2.33) were factors increasing the development of tinea capitis among schoolchildren and schoolchildren who had hair wash at least once a week (OR: 0.31, 95%CI: 0.24-0.42) was significantly associated with reduced risk for tinea capitis.

CONCLUSION

One of the most prevalent childhood health condition in Ethiopia is tinea capitis, which affects over one in every four schoolchildren. Schoolchildren who had family history of tinea capitis and under the age of 10 years were the identified risk factors but they had hair wash at least once a week was the protective factor of tinea capitis among schoolchildren. Clinical and public engagement activities are needed to overcome the burden of the disease.

Antimicrobial Compounds from Microorganisms

Antimicrobial resistance is an exigent public health concern owing to the emergence of novel strains of human resistant pathogens and the concurrent rise in multi-drug resistance. An influx of new antimicrobials is urgently required to improve the treatment outcomes of infectious diseases and save lives. Plant metabolites and bioactive compounds from chemical synthesis have found their efficacy to be dwindling, despite some of them being developed as drugs and used to treat human infections for several decades. Microorganisms are considered untapped reservoirs for promising biomolecules with varying structural and functional antimicrobial activity. The advent of cost-effective and convenient model organisms, state-of-the-art molecular biology, omics technology, and machine learning has enhanced the bioprospecting of novel antimicrobial drugs and the identification of new drug targets. This review summarizes antimicrobial compounds isolated from microorganisms and reports on the modern tools and strategies for exploiting promising antimicrobial drug candidates. The investigation identified a plethora of novel compounds from microbial sources with excellent antimicrobial activity against disease-causing human pathogens. Researchers could maximize the use of novel model systems and advanced biomolecular and computational tools in exploiting lead antimicrobials, consequently ameliorating antimicrobial resistance.

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

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

A Household Microsporum canis Dermatophytosis Suggested by Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry Analysis

Case series

Patients: Female, 4-year-old • her family (father, mother, sister)

Final Diagnosis: Microsporum canis dermatophytosis

Symptoms: Itiching

Medication: —

Clinical Procedure: Time-of-flight mass spectrometry (TOF-MS)

Specialty: Infectious Diseases

Mechanism of streptomyces albidoflavus STV1572a derived 1-heneicosanol as an inhibitor against squalene epoxidase of Trichophyton mentagrophytes

An increase in incidences of tinea infections paves the way to discover the novel antifungal drugs from unexplored natural resources. The quality of life in patients with tinea infection may be affected by different factors, including morbidity, length of illness, social and demographic factors. The present investigation explores the functional principle of a bioactive compound isolated from actinomycetes, S. albidoflavus STV1572a by in-silico and in-vitro studies. In continuation of our previous reports on the antidermatophytic potential of S. albidoflavus STV1572a, this study progresses with the in-silico molecular docking study of the seven GC-MS discovered ligands, and six dermatophytic modelled targets. Through virtual screening, it was revealed that a docking score -8.8 between 1-heneicosanol and squalene epoxidase favored partially in understanding the mode of action. Further validation of in-silico study was performed by a sterol quantification assay which confirmed the antidermatophytic mechanism of 1-heneicosanol. Taken together, the evidence from this study suggests that 1-heneicosanol has a potential antidermatophytic compound and can be considered for dermatophytic treatment.

Spread of Terbinafine-Resistant Trichophyton mentagrophytes Type VIII (India) in Germany-"The Tip of the Iceberg?"

Chronic recalcitrant dermatophytoses, due to Trichophyton (T.) mentagrophytes Type VIII are on the rise in India and are noteworthy for their predominance. It would not be wrong to assume that travel and migration would be responsible for the spread of T. mentagrophytes Type VIII from India, with many strains resistant to terbinafine, to other parts of the world. From September 2016 until March 2020, a total of 29 strains of T. mentagrophytes Type VIII (India) were isolated. All patients were residents of Germany: 12 females, 15 males and the gender of the remaining two was not assignable. Patients originated from India (11), Pakistan (two), Bangladesh (one), Iraq (two), Bahrain (one), Libya (one) and other unspecified countries (10). At least two patients were German-born residents. Most samples (21) were collected in 2019 and 2020. All 29 T. mentagrophytes isolates were sequenced (internal transcribed spacer (ITS) and translation elongation factor 1-α gene (TEF1-α)). All were identified as genotype VIII (India) of T. mentagrophytes. In vitro resistance testing revealed 13/29 strains (45%) to be terbinafine-resistant with minimum inhibitory concentration (MIC) breakpoints ≥0.2 µg/mL. The remaining 16 strains (55%) were terbinafine-sensitive. Point mutation analysis revealed that 10/13 resistant strains exhibited Phe³⁹⁷Leu amino acid substitution of squalene epoxidase (SQLE), indicative for in vitro resistance to terbinafine. Two resistant strains showed combined Phe³⁹⁷Leu and Ala⁴⁴⁸Thr amino acid substitutions, and one strain a single Leu³⁹³Phe amino acid substitution. Out of 16 terbinafine-sensitive strains, in eight Ala⁴⁴⁸Thr, and in one Ala⁴⁴⁸Thr +, new Val⁴⁴⁴ Ile amino acid substitutions were detected. Resistance to both itraconazole and voriconazole was observed in three out of 13 analyzed strains. Treatment included topical ciclopirox olamine plus topical miconazole or sertaconazole. Oral itraconazole 200 mg twice daily for four to eight weeks was found to be adequate. Terbinafine-resistant T. mentagrophytes Type VIII are being increasingly isolated. In Germany, transmission of T. mentagrophytes Type VIII from the Indian subcontinent to Europe should be viewed as a significant public health issue.

Outbreak of Trichophyton soudanense causing tinea capitis in an orphanage in Myanmar

We report an outbreak of Trichophyton soudanense causing tinea capitis and corporis in an orphanage in Myanmar. The thirty orphan children were suspected to have anthropophilic tinea but zoonotic tinea could not be excluded as all children were playing with stray dogs. Direct mycological examinations of hair and scalp samples showed filaments but culture assays remained sterile. We revealed T. soudanense as the infectious agent by PCR amplification of extracted fungal DNA and further sequencing of the PCR products. Children were successfully treated by terbinafine and reinfection was prevented by hygiene measures. This case report shed the light on T. soudanense infection on another continent than Africa and on the significant help of PCR identification.

Epidemiology of Dermatophytoses in Switzerland According to a Survey of Dermatophytes Isolated in Lausanne between 2001 and 2018

Dermatophytes are the most common pathogenic agents of superficial mycoses in humans and animals. Knowledge of their epidemiology can facilitate the prevention of dermatophytosis and improve prophylactic measures. We sought to determine the incidence of the different dermatophyte species diagnosed in Lausanne (Switzerland) from 2001 to 2018. In total, 10,958 dermatophytes were isolated from patients and 459 from pets. Overall, 99% of tinea unguium and tinea pedis were caused by Trichophyton rubrum and Trichophyton interdigitale with a prevalence ratio of 3:1. Trichophyton violaceum and Trichophyton soudanense were mainly found in tinea capitis in patients of African and Mediterranean origin. Interestingly, while Epidermophyton floccosum and Trichophyton verrucosum were prevalent 50 years ago in an epidemiological analysis carried out in the same laboratory from 1967 to 1970, these two species were rarely detected from 2001 to 2018. Trichophyton mentagrophytes, Trichophyton benhamiae and Microsporum canis were the prevalent zoophilic pathogenic species in children and young adults. Our investigation of animal samples revealed the main reservoirs of these zoophilic species to be cats and dogs for T. mentagrophytes and M. canis, and Guinea pigs for T. benhamiae. This study provides an epidemiological overview of dermatophytoses in Switzerland to improve their surveillance.

Terbinafine Resistance of Trichophyton Clinical Isolates Caused by Specific Point Mutations in the Squalene Epoxidase Gene

Terbinafine is one of the allylamine antifungal agents whose target is squalene epoxidase (SQLE). This agent has been extensively used in the therapy of dermatophyte infections. The incidence of patients with tinea pedis or unguium tolerant to terbinafine treatment prompted us to screen the terbinafine resistance of all Trichophyton clinical isolates from the laboratory of the Centre Hospitalier Universitaire Vaudois collected over a 3-year period and to identify their mechanism of resistance. Among 2,056 tested isolates, 17 (≈1%) showed reduced terbinafine susceptibility, and all of these were found to harbor SQLE gene alleles with different single point mutations, leading to single amino acid substitutions at one of four positions (Leu³⁹³, Phe³⁹⁷, Phe⁴¹⁵, and His⁴⁴⁰) of the SQLE protein. Point mutations leading to the corresponding amino acid substitutions were introduced into the endogenous SQLE gene of a terbinafine-sensitive Arthroderma vanbreuseghemii (formerly Trichophyton mentagrophytes) strain. All of the generated A. vanbreuseghemii transformants expressing mutated SQLE proteins exhibited obvious terbinafine-resistant phenotypes compared to the phenotypes of the parent strain and of transformants expressing wild-type SQLE proteins. Nearly identical phenotypes were also observed in A. vanbreuseghemii transformants expressing mutant forms of Trichophyton rubrum SQLE proteins. Considering that the genome size of dermatophytes is about 22 Mb, the frequency of terbinafine-resistant clinical isolates was strikingly high. Increased exposure to antifungal drugs could favor the generation of resistant strains.

Antimicrobial, cytotoxic, and anti-inflammatory activities of Pleopeltis polylepis

AIM OF THE STUDY

Pleopeltis polylepis (Polypodaceae) is a fern used in the traditional Mexican medicine to treat fever, bleeding, typhoid, cough, pertussis, chest pain, and renal and hepatic diseases. The aim of this study was to analyze the bioactivities of different extracts, fractions and isolated compounds from this species to scientifically validate its medicinal applications.

MATERIALS AND METHODS

Aerial parts of P. polylepis were macerated and extracted consecutively with hexane, chloroform, and methanol. These extracts were subsequently fractionated and compounds from hexane and methanol extracts were purified. The antimicrobial activity was assessed using a panel of eight Gram-positive and -negative bacterial and four fungal strains. The cytotoxicity of the compounds was assessed by flow cytometry using propidium iodide and the human-derived monocytic cell line THP-1. The anti-inflammatory activity was investigated by measuring the secretion of interleukin-6 and IL-10 using also the cell line THP-1.

RESULTS

Various extracts, fractions and compounds obtained from this plant showed antibacterial activity against both Gram-positive and -negative strains. Antifungal activity was confirmed only in Candida albicans and Tricophyton mentagrophytes. Two fractions and two isolated compounds (butyl myristate and β-sitosterol) showed no significant cytotoxicity and were further evaluated for their anti-inflammatory activity. All four samples tested showed an anti-inflammatory activity similar to prednisone used as a control.

CONCLUSIONS

The benefit of P. polylepis as a traditional plant related to its antimicrobial and anti-inflammatory activities was confirmed by in vitro assays. To the best of our knowledge, this is the first study reporting the isolation and bioactivities of extracts, fractions or isolated compounds from P. polylepis.

Diagnosis of Dermatophytosis Using Molecular Biology

Identification of fungi in dermatological samples using PCR is reliable and provides significantly improved results in comparison with cultures. It is possible to identify the infectious agent when negative results are obtained from cultures. In addition, identification of the infectious agent can be obtained in 1 day. Conventional and real-time PCR methods used for direct fungus identification in collected samples vary by DNA extraction methods, targeted DNA and primers, and the way of analysing the PCR products. The choice of a unique method in a laboratory is complicated because the results expected from skin and hair sample analysis are different from those expected in cases of onychomycosis. In skin and hair samples, one dermatophyte among about a dozen possible species has to be identified. In onychomycosis, the infectious agents are mainly Trichophyton rubrum and, to a lesser extent, Trichophyton interdigitale, but also moulds insensitive to oral treatments used for dermatophytes, which renders fungal identification mandatory. The benefits obtained with the use of PCR methods for routine analysis of dermatological samples have to be put in balance with the relative importance of getting a result in a short time, the price of molecular biology reagents and equipment, and especially the time spent conducting laboratory manipulations.

Are the classic diagnostic methods in mycology still state of the art?

The diagnostic workup of cutaneous fungal infections is traditionally based on microscopic KOH preparations as well as culturing of the causative organism from sample material. Another possible option is the detection of fungal elements by dermatohistology. If performed correctly, these methods are generally suitable for the diagnosis of mycoses. However, the advent of personalized medicine and the tasks arising therefrom require new procedures marked by simplicity, specificity, and swiftness. The additional use of DNA-based molecular techniques further enhances sensitivity and diagnostic specificity, and reduces the diagnostic interval to 24-48 hours, compared to weeks required for conventional mycological methods. Given the steady evolution in the field of personalized medicine, simple analytical PCR-based systems are conceivable, which allow for instant diagnosis of dermatophytes in the dermatology office (point-of-care tests).

Methods for in vitro evaluating antimicrobial activity: A review

In recent years, there has been a growing interest in researching and developing new antimicrobial agents from various sources to combat microbial resistance. Therefore, a greater attention has been paid to antimicrobial activity screening and evaluating methods. Several bioassays such as disk-diffusion, well diffusion and broth or agar dilution are well known and commonly used, but others such as flow cytofluorometric and bioluminescent methods are not widely used because they require specified equipment and further evaluation for reproducibility and standardization, even if they can provide rapid results of the antimicrobial agent's effects and a better understanding of their impact on the viability and cell damage inflicted to the tested microorganism. In this review article, an exhaustive list of in vitro antimicrobial susceptibility testing methods and detailed information on their advantages and limitations are reported.

Dermatophyte identification in skin and hair samples using a simple and reliable nested polymerase chain reaction assay

BACKGROUND

Dermatophyte identification in tinea capitis is essential for choosing the appropriate treatment and in tinea infections to identify the possible source. The failure of fungi to grow in cultures frequently occurs, especially in cases of previous antifungal therapy.

OBJECTIVES

To develop a rapid polymerase chain reaction (PCR) sequencing assay for dermatophyte identification in tinea capitis and tinea corporis.

MATERIAL AND METHODS

Fungal DNA was extracted from hair and skin samples that were confirmed to be positive by direct mycological examination. Dermatophytes were identified by the sequence of a 28S ribosomal DNA subunit amplicon generated by nested PCR.

RESULTS

Nested PCR was found to be necessary to obtain amplicons in substantial amounts for dermatophyte identification by sequencing. The results agreed with those of classical mycological identification in 14 of 23, 6 of 10, and 20 of 23 cases of tinea capitis, tinea corporis and tinea pedis, respectively, from which a dermatophyte was obtained in culture. In seven of the 56 cases, another dermatophyte was identified, revealing previous misidentification. A dermatophyte was identified in 12 of 18, three of five, and four of nine cases of tinea capitis, tinea corporis and tinea pedis, respectively, in cases in which no dermatophyte grew in culture.

CONCLUSIONS

Although the gold standard dermatophyte identification from clinical samples remains fungal cultures, the assay developed in the present study is especially suitable for tinea capitis. Improved sensitivity for the identification of dermatophyte species was obtained as it is possible to identify the dermatophyte when the fungus fails to grow in cultures.

A random comparative study of terbinafine versus griseofulvin in patients with tinea capitis in Western China

OBJECTIVE

To compare the efficacy and safety of terbinafine with griseofulvin in the treatment of tinea capitis in Western China.

METHODS

Children (2-14 years of age) with clinically diagnosed and potassium hydroxide microscopy-confirmed tinea capitis were randomized into three groups: group GRI4 received 4 weeks of griseofulvin; group TBF2 received 2 weeks of terbinafine; and Group TBF4 received 4 weeks of terbinafine. Clinical and mycological evaluations were done in 0, 2, 4, and 8 weeks and 1 year after therapy started. The isolated pathogenic fungi were evaluated for in vitro susceptibility by detecting the minimal inhibitory concentration (MIC) against terbinafine, griseofulvin, itraconazole, and ketoconazole.

RESULTS

The clinical effectiveness rate of GRI4, TBF2, and TBF4 were 100% (95% CI-confidence interval: 82-100%), 96.3% (95% CI: 81-100%), and 100%(95% CI: 85-100%), respectively, at week 8 and 100% after 1 year for the 3 groups; clinical cure rates were 84.2%(95% CI: 77-99%), 85.2%(95% CI: 71-98%), and 78.3%(95% CI: 61-95%), respectively, at week 8 and 100% after 1 year for all agents; mycological cure rates were 100%(95% CI: 74-100%), 95.0%(95% CI: 74-100%), and 94.1%(95% CI: 50-93%) at week 8 and 100% after 1 year for the 3 groups. In vitro, all patient-derived cultures were sensitive to the four antifungal agents.

CONCLUSION

Data from the clinical trial and in vitro antifungal activity indicated that terbinafine is efficacious and well tolerated in the treatment for Trichophyton infections (T. violaceum; Arthroderma vanbreuseghemii; and T. tonsurans) of the scalp, i.e., a 2- to 4-week course of terbinafine is as effective as a 4-week course of griseofulvin; in fact, a 2-week course of terbinafine is sufficient. Terbinafine is an effective alternative to griseofulvin against tinea capitis of Trichophyton infections.

The spectrum of fungal infections with a special reference to dermatophytoses in the capital area of Kuwait during 2000-2005: a retrospective analysis

BACKGROUND

Fungal infections constitute a major health problem all over the world. Signs and symptoms induced by various dermatophytic infections are difficult to distinguish clinically from each other. So, characterization by in vitro culture is required for appropriate diagnosis and treatment as well as to study the epidemiological characteristics in a region.

OBJECTIVES

The present retrospective work was aimed to study the spectrum of fungal infections of the skin, nails and hairs in the Capital area of Kuwait over a span of 5 years and to compare the results with those reported earlier from this region and other parts of the world. PATIENTS/MATERIALS: The study was conducted on 2,730 patients referred from dermatology outpatients to mycology laboratory suspected to have fungal infection over a 5-year period. Identification of dermatophyte isolates obtained was done by conventional microscopic examination in all patients, whereas culture techniques were performed for 1,593 of them.

RESULTS

Among 2,730 patients, 1,437 were men and 1,293 were women with a men to women ratio of 1.1:1. The age ranged from 3 months to 70 years (mean age 28.5 years). The clinical diagnosis of these patients was as follows: onychomycosis; tinea corporis; tinea capitis; tinea pedis; tinea cruris; tinea manum and tinea versicolor. Potassium hydroxide (KOH) examination showed positive results in 39% of all cases, whereas positive cultures were obtained in 29% of cultured specimens. Among dermatophytes, six species were isolated: Trichophyton mentagrophytes (39%), Microsporum canis (16%), Trichophyton rubrum (10%), Epidermophyton floccosum (6.2%), Trichophyton violaceum (2.4%) and Trichophyton verrucosum (0.4%). Trichophyton mentagrophytes was isolated from all body sites. Candida and Aspergillus niger were isolated on cycloheximide-free cultures in cases with onychomycosis.

CONCLUSIONS

Cutaneous fungal infections including dermatophytes remain prevalent in this part of the world. The most common isolate was T. mentagrophytes followed by Candida species. The least isolate was T. verrucosum. Species identification in relation to factors such as time, place and population is warranted in order to implement treatment regimens and to propose potential control measures.

Effects of a thiosemicarbazide camphene derivative on Trichophyton mentagrophytes

Thiosemicarbazides are compounds known for their biological activity, particularly their antimicrobial properties, which include activity against fungi. The difficulty of treating fungal diseases induced us to assess the antifungal properties of some novel thiosemicarbazide compounds. We selected the natural products limonene and camphene as sources for the preparation of these new thiosemicarbazide derivatives. The compound N(4)-[2,2-dimethyl-3-methylnorbornane]-thiosemicarbazide (TIO C) showed an antifungal effect on Trichophyton mentagrophytes, with values of MIC = 55 μmol L^-1 and MFC = 110 μmol L^-1. Scanning-electron microscopy showed a decrease in mycelium development and morphological alterations of T. mentagrophytes cultured on nail fragments and treated with TIO C. In an attempt to discover its mode of action, we noted that ergosterol is apparently not a target of TIO C activity. An effect of TIO C on T. mentagrophytes cell walls and dividing cross-walls was shown by observed impairment of the fluorescence of tissues stained with calcofluor white, a specific marker for fungal chitin, suggesting that the compound can affect and damage the cell-wall structure or may interfere with its formation, during cell division, growth, and morphogenesis. This approach to the synthesis of new derivatives might provide interesting compounds with greater biological activity in pharmacological research.

Current status of antifungal susceptibility testing methods

Antifungal susceptibility testing is a very dynamic field of medical mycology. Standardization of in vitro susceptibility tests by the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST), and current availability of reference methods constituted the major remarkable steps in the field. Based on the established minimum inhibitory concentration (MIC) breakpoints, it is now possible to determine the susceptibilities of Candida strains to fluconazole, itraconazole, voriconazole, and flucytosine. Moreover, utility of fluconazole antifungal susceptibility tests as an adjunct in optimizing treatment of candidiasis has now been validated. While the MIC breakpoints and clinical significance of susceptibility testing for the remaining fungi and antifungal drugs remain yet unclear, modifications of the available methods as well as other methodologies are being intensively studied to overcome the present drawbacks and limitations. Among the other methods under investigation are Etest, colorimetric microdilution, agar dilution, determination of fungicidal activity, flow cytometry, and ergosterol quantitation. Etest offers the advantage of practical application and favorable agreement rates with the reference methods that are frequently above acceptable limits. However, MIC breakpoints for Etest remain to be evaluated and established. Development of commercially available, standardized colorimetric panels that are based on CLSI method parameters has added more to the antifungal susceptibility testing armamentarium. Flow cytometry, on the other hand, appears to offer rapid susceptibility testing but requires specified equipment and further evaluation for reproducibility and standardization. Ergosterol quantitation is another novel approach, which appears potentially beneficial particularly in discrimination of azole-resistant isolates from heavy trailers. The method is yet investigational and requires to be further studied. Developments in methodology and applications of antifungal susceptibility testing will hopefully provide enhanced utility in clinical guidance of antifungal therapy. However, and particularly in immunosuppressed host, in vitro susceptibility is and will remain only one of several factors that influence clinical outcome.

Phylogenetic analysis of Trichophyton mentagrophytes human and animal isolates based on MnSOD and ITS sequence comparison

Dermatophytes are keratinophilic fungi able to infect keratinized tissues of human or animal origin. Among them, Trichophyton mentagrophytes is known to be a species complex composed of several species or variants, which occur in both human and animals. Since the T. mentagrophytes complex includes both anthropophilic and zoophilic pathogens, accurate molecular identification is a critical issue for comprehensive understanding of the clinical and epidemiological implications of the genetic heterogeneity of this complex. Here, 41 T. mentagrophytes isolates from either human patients (14 isolates) or animals (27 isolates) with dermatophytosis were prospectively isolated by culture and identified on morphological bases at the University Hospital Centres of Lille and Poitiers, and the Veterinary School of Alfort, respectively. The isolates were differentiated by DNA sequencing of the variable internal transcribed spacer (ITS) regions flanking the 5.8S rDNA, and of the housekeeping gene encoding the manganese-containing superoxide dismutase (MnSOD), an enzyme which is involved in defence against oxidative stress and has previously provided interesting insight into both fungal taxonomy and phylogeny. ITS1-ITS2 regions and MnSOD sequences successfully differentiate between members of the T. mentagrophytes complex and the related species Trichophyton rubrum. Whatever the phylogenetic marker used, members of this complex were classified into two major clades exhibiting a similar topology, with a higher variability when the ITS marker was used. Relationships between ITS/MnSOD sequences and host origin, clinical pattern and phenotypic characteristics (macroscopic and microscopic morphologies) were analysed.

In vitro methods for antifungal susceptibility testing of Trichophyton spp

In general, methods to test the susceptibility of fungi to antifungal drugs require standardized techniques, but so far there is no methodology that is widely applicable to dermatophytes. Here we introduced modifications to the protocols from documents of the National Committee for Clinical Laboratory Standards (CLSI) M38-A and the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) that are usually applied to moulds and fermentative yeasts, in order to adjust the conditions for the growth of dermatophytes. The modifications included: growth on potato dextrose agar supplemented with 2% in-house rice flour to encourage sporulation, the addition of 2% glucose to the culture media (RPMI-1640), and an incubation temperature of 28 degrees C. In addition, the incubation period was 7d, the minimum inhibitory concentration (MIC) was defined as 80% growth inhibition endpoints for azole agents, and the inocula only contained microconidia. Results obtained by both tested methodologies were very similar to the ones reported by other researchers. MIC90 (MIC at which 90% of isolates tested were inhibited) values were identical for four out of five antifungal drugs tested and there was only a difference of one or two dilutions when MIC50 values were compared. Although the modifications introduced did not interfere with the results, more studies are necessary to establish a standard technique to test susceptibility of dermatophytes to antifungal drugs.

Fast and reliable PCR/sequencing/RFLP assay for identification of fungi in onychomycoses

Fusarium spp. and other non-dermatophyte fungi are repeatedly isolated from abnormal nails. To investigate whether these fungi are the aetiological agents of infection or simply transient contaminants, a PCR/sequencing/RFLP assay was developed for direct and routine identification of the infecting fungi in onychomycosis. Fungal DNA was readily extracted using a commercial kit after dissolving nail fragments in a Na2S solution. Amplification of part of the 28S rDNA by PCR was performed with universal primers and the fungal species were identified by sequencing. The PCR/sequencing results were comparable with microbiological identification from the same nail sample. In addition to dermatophytes, Fusarium spp. and other less frequently isolated non-dermatophyte fungi were identified as single fungal agents in onychomycosis. Moreover, mixed infections were clearly demonstrated in 10 % of cases by RFLP analysis of PCR products. Identification of infectious agents could be obtained in 2 days, whilst results from fungal cultures take 1–3 weeks. Rapid and reliable molecular identification of the infectious fungus expedites the choice of appropriate antifungal therapy, thereby improving the cure rate of onychomycosis.

Comparative study of in vitro methods to analyse the antifungal activity of propolis against yeasts isolated from patients with superficial mycoses

AIM

To test a total of 15 strains belonging to four species of yeasts by different in vitro methods against propolis and itraconazole (ITC).

METHODS AND RESULTS

Three methods were compared for susceptibility testing of yeast isolates to propolis: disc diffusion method, agar dilution method and National Committee for Clinical Laboratory Standards (NCCLS, M27A) broth microdilution method. ITC was selected as the antifungal agent for comparison study. Using the broth microdilution method, the geometric mean for MIC (microg ml(-1)) with regard to all isolates was < or =0.06 for propolis and < or =0.35 for ITC. The broth microdilution and the agar dilution methods were in good agreement (75%) for propolis against yeasts isolated from patients with superficial mycoses. Using the diffusion method, all strains showed a broad zone of inhibition at the first available reading time (24 or 48 h). An increase of MIC values was accompanied by a decrease of growth inhibition zone diameter. A favourable correlation was found between MIC and inhibition zone around the disc for propolis sample and the correlation coefficient was: r = -0.626 (P < 0.01).

CONCLUSIONS

This study suggests the potential value of the agar dilution and disc diffusion method as a convenient alternative method for testing of yeasts to propolis.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrated that propolis and ITC were very active against yeasts from patients with superficial mycoses. The other prominent finding in this study is that RPMI 1640 with L-glutamine was the available broth for the in vitro susceptibility testing of yeasts.

Effect of culture medium on the disk diffusion method for determining antifungal susceptibilities of dermatophytes

We have evaluated a disk diffusion method to determine the activities of five drugs against 50 strains of dermatophytes and to assess the influence of the culture medium (antibiotic medium 3, high-resolution medium, and RPMI) on the inhibition zone diameters (IZD). There were no differences among the medium/drug combinations, except for itraconazole-RPMI, which showed the narrowest IZD.

Inhibition of the growth in vitro of Trichophyton mentagrophytes, Trichophyton erinacei and Microsporum persicolor by miconazole and chlorhexidine

An agar dilution technique was used to assess the minimum inhibitory concentrations (MICs) of miconazole, chlorhexidine and a 1:1 combination of both agents for 9 isolates of Trichophyton mentagrophytes, 9 isolates of Trichophyton erinacei and 5 isolates of Microsporum persicolor. MICs of chlorhexidine did not vary significantly between the three dermatophyte species tested, but the MICs of miconazole alone and in combination with chlorhexidine for T. erinacei were significantly greater that those for T. mentagrophytes and M. persicolor. A synergistic drug interaction was noted with one isolate of T. erinacei and one isolate of M. persicolor. An additive effect was demonstrated for 13 isolates (5 T. mentagrophytes, 6 T. erinacei, 2 M. persicolor), and indifference was noted in 8 isolates (4 T. mentagrophytes, 2 T. erinacei, 2 M. persicolor). Although synergy was less often seen when compared with a previous study of Microsporum canis, the synergistic or additive effects seen with the majority (15 out of 23) of isolates studied in vitro provides a rationale for the combined use of miconazole and chlorhexidine in the adjunctive topical therapy of dermatophytosis caused by T. mentagrophytes, T. erinacei and M. persicolor.

In vitro Antifungal Activity of Sertaconazole Compared with Nine Other Drugs against 250 Clinical Isolates of Dermatophytes and Scopulariopsis brevicaulis

We have tested 250 strains belonging to 15 species of clinically important dermatophytes and Scopulariopsis against ten antifungal drugs using an agar diffusion method (NeoSensitabstrade mark, Rosco, Taastrup, Denmark). Some of the experimental factors were adapted to dermatophyte development, such as temperature (28 vs. 35 degrees C) and time of incubation (2-5 days vs. 21-74 h). The antifungals used are itraconazole, ketoconazole, miconazole, clotrimazole, sertaconazole, terbinafine, tioconazole, fluconazole, isoconazole and econazole. Except for fluconazole, all the drugs tested have shown to be highly effective, especially sertaconazole and terbinafine. Percentages of susceptibility ranged between 94% for terbinafine, 87.6% for sertaconazole and 86.4% clotrimazole; 81.6% econazole; 42.8% fluconazole; 57.2% isoconazole; 78.4% itraconazole; 74.4% ketoconazole; 73.3% miconazole, and 85.2% for tioconazole. Percentages of resistance were similar between sertaconazole and terbinafine (4%) but in contrast to the 48% obtained for fluconazole.

A prospective study of cutaneous adverse events induced by low-dose alpha-interferon treatment for malignant melanoma

INTRODUCTION

alpha-Interferon is associated with numerous cutaneous side effects, but the accurate incidence of these complications is not clearly known.

OBJECTIVES

A prospective study was designed to evaluate the incidence and clinical pattern of cutaneous side effects in a cohort of patients receiving adjuvant therapy with low-dose interferon for malignant melanoma.

MATERIAL AND METHODS

A cohort of 33 patients with stage IIA and IIB melanoma treated with low-dose alpha-interferon (3 MIU 3 times a week for 18 months) were prospectively enrolled in a single-center study. The patients responded to a questionnaire on their medical history and were systematically examined for any cutaneous lesions before treatment and every 3 months afterwards.

RESULTS

29/33 patients (87%) experienced 1 or more cutaneous side effects. The most frequent was hair loss and occurred in 16 cases (48.4%). Hair discoloration was noted in 6 cases (18%). Eczematous reactions at injection sites or at remote sites were observed in 13 patients (39%). Pruritus occurred in 10 cases (30%). Xerostomia, Raynaud's phenomenon or livedo reticularis were observed in 10 patients, associated with an increase in circulating autoantibody titer in 2 cases. Some rare side effects were observed: urticaria (1 case) or angioedema (1 case), worsening of preexisting seborrheic dermatitis (3 cases), herpetic recurrence (2 cases), pityriasis versicolor (1 case), worsening of recurrent buccal aphthous ulcer (1 case) and vitiligo (1 case).

CONCLUSION

Cutaneous adverse events during adjuvant immunotherapy of melanoma with low-dose alpha-interferon seem to be frequent but do not result in treatment discontinuation. A good awareness of these side effects may be useful for a more accurate survey and clinical management of patients receiving this treatment.

In vitro susceptibility testing of dermatophytes: comparison of disk diffusion and reference broth dilution methods

A total of 56 strains belonging to 4 species of dermatophytes were tested against 10 antifungal drugs by using a modification of the NCCLS (M38-P) standard for filamentous fungi. The minimum inhibitory concentration (MIC) values obtained using the dilution method were compared with the diameters of growth inhibition zones using the disk diffusion method. The antifungals used were itraconazole, fluconazole, ketoconazole, miconazole, sulconazole, oxiconazole, bifonazole, griseofulvin, ciclopiroxolamine, and terbinafine. Relative to the other agents tested, terbinafine possessed the highest antifungal activity against all of the dermatophytes. In contrast, fluconazole was the least active drug. An increase of MIC values was accompanied by a decrease of growth inhibition zone diameter. The disk diffusion method of fungal susceptibility assessment yields data consistent with results obtained from the dilution method. The study suggests the potential value of the disk diffusion method as a convenient alternative method for testing the susceptibilities of dermatophytes.

Tinea capitis in Brussels: epidemiology and new management strategy

BACKGROUND

We found pre-established directives inadequate to cope with the current increase in anthropophilic tinea capitis in Brussels.

OBJECTIVES

To study new epidemiological profiles and to define new strategies for management and prevention.

PATIENTS AND METHODS

A total of 122 children affected by tinea capitis were followed in our department from October 1, 2001, until September 30, 2002. The results were assessed retrospectively.

RESULTS

Anthropophilic tinea capitis represented 89.34% of the cases. The implicated anthropophilic dermatophytes were by decreasing frequency: Microsporum langeronii (39.34%), Trichophyton soudanense (28.69%), Trichophyton violaceum (18.03%) and Trichophyton tonsurans (3.28%).

CONCLUSION

The responsible pathogens reflect immigration flows originating mostly from Black and North Africa. Precise recommendations for each visit are detailed.

In vitro Activity of Sertaconazole against Dermatophyte Isolates with Reduced Fluconazole Susceptibility

We have studied the in vitro antifungal activity of sertaconazole against 114 dermatophytes with low susceptibility to fluconazole following the National Committee for Clinical Laboratory Standards for filamentous fungi (M38-P). However, several important factors such as the temperature (28 vs. 35 degrees C) and time of incubation (4-10 days vs. 21-74 h), have been found to affect dermatophytes. Isolates were recently recovered from human samples. Sertaconazole was active against 114 isolates of 12 fungal dermatophyte species, showing an overall geometric mean of 0.41 microg/ml with a minimum inhibitory concentration (MIC) range of 0.01-2 microg/ml against these isolates with reduced fluconazole susceptibility. Differences between both antifungals were significant (p < 0.05). MIC(50) and MIC(90) of sertaconazole were of 0.5 and 1 microg/ml, respectively, while the MIC of fluconazole was >/=16 microg/ml. None of the isolates was resistant to sertaconazole during the study while for four isolates the MIC of fluconazole was >/=64 microg/ml. No evidence of cross-resistance between both antifungals was found.

Interlaboratory evaluation of the Etest for antifungal susceptibility testing of dermatophytes

A three-site interlaboratory reproducibility evaluation of the Etest concentration gradient strip method for testing antifungal susceptibilities was conducted using 30 strains of dermatophytes exposed to strips loaded with ketoconazole (KTZ), itraconazole (ITZ), amphotericin B (AMB) and fluconazole (FCZ). Etest minimal inhibitory concentrations were compared with those obtained using a broth microdilution method. All isolates produced clearly detectable growth at 28 degrees C within 72-96 h for reading with the Etest method. The highest interlaboratory agreement between Etest and the microdilution method was shown with FCZ (94%), and the lowest was seen with KTZ (60%). Overall, agreement between the Etest and microdilution method was variable. It was excellent for AMB (97%), good for ITZ (80%) and KTZ (77%), and low for fluconazole (27%).

Identification of dermatophyte species by 28S ribosomal DNA sequencing with a commercial kit

We have shown that dermatophyte species can be easily identified on the basis of a DNA sequence encoding a part of the large-subunit (LSU) rRNA (28S rRNA) by using the MicroSeq D2 LSU rRNA Fungal Sequencing Kit. Two taxa causing distinct dermatophytoses were clearly distinguished among isolates of the Trichophyton mentagrophytes species complex.

Survey of dermatophyte infections in the Lausanne area Switzerland

BACKGROUND

The dermatophytes are important in the Swiss medical environment since 5-10% of consultations in dermatology concern mycotic infections.

OBJECTIVE

To obtain information about the prevailing species of dermatophytes in the south-west of Switzerland and their pattern of infection.

METHODS

An analysis was made of the dermatophytes isolated in the Department of Dermatology at the University Hospital of Lausanne and from samples collected in private practices of Switzerland during an 8-year period (1993-2000). The total number of samples sent for mycological analysis was 33,725.

RESULTS

4,193 cultures revealed a dermatophyte. Trichophyton rubrum was the most frequently isolated species accounting for 62.5% of the strains followed by T. mentagrophytes (24.5%) and Microsporum canis (5.0%). Less frequent isolates included Epidermophyton floccosum, M. langeroni, M. gypseum, T. soudanense, T. violaceum, T. verrucosum, T. gourvili and T. tonsurans. Analysis of the localisation of the isolated fungi confirms that the dermatophyte species have a predilection for certain body areas.

CONCLUSIONS

The relative frequencies of isolation of the dermatophyte species partially depending of the record of the different tinea vary from one country to another. Our study reveals the importance of T. rubrum and the appreciable frequency of M. canis in the Swiss autochthonous population and the apparition of new species with immigrants.

Collaborative evaluation of optimal antifungal susceptibility testing conditions for dermatophytes

A multicenter study was conducted to define the most suitable testing conditions for antifungal susceptibility of dermatophytes. Broth microdilution MICs of clotrimazole, itraconazole, and terbinafine were determined in three centers against 60 strains of dermatophytes. The effects of inoculum density (ca. 10(3) and 10(4) CFU/ml), incubation time (3, 7, and 14 days), endpoint criteria for MIC determination (complete [MIC-0] and prominent [MIC-2] growth inhibition), and incubation temperature (28 and 37 degrees C) on intra- and interlaboratory agreement were analyzed. The optimal testing conditions identified were an inoculum of 10(4) CFU/ml, a temperature of incubation of 28 degrees C, an incubation period of 7 days, and MIC-0.

Immune-mediated complications during interferon therapy in hematological patients

Interferon (IFN), a leukocyte-derived cytokine, has been used to treat several hematological malignancies. The most common adverse effects of IFN are flu-like symptoms. Autoimmune side effects are infrequent but may be hazardous and irreversible. These may occur in several ways: autoantibodies may either appear during the treatment or existing titers may rise, subclinical autoimmune phenomena may become clinically manifest or autoimmune diseases may appear de novo. The main categories of IFN immune-mediated side effects are: thyroid, hematological, connective tissue, renal and miscellaneous disorders. The most common ones are thyroid disorders, which manifest either as hypo- or hyperthyroidism. Patients with pre-existing autoantibodies are more susceptible to the exacerbation of thyroid autoimmunity, probably since IFN enhances the levels of autoimmunity. Hematological disorders include autoimmune anemia and thrombocytopenia and thrombotic thrombocytopenic purpura. The immunological derangement of autoimmune hemolytic anemia manifests as enhanced destruction of antibody-coated red blood cells and induction of autoreactive B cells secreting these antibodies. Although autoimmune thrombocytopenia is rare, a sharp reduction in the platelet counts, beyond that expected from the antiproliferative effects of IFN, should raise this possibility. Thrombotic thrombocytopenic purpura has recently been included among the autoimmune disorders. Sporadic cases have been reported in association with IFN treatment. The clinical spectrum of IFN-induced connective tissue disorders ranges from typical systemic lupus erythematosus to seropositive or seronegative rheumatoid arthritis. Some authors also reported on the development of Behçet's disease in chronic myeloid leukemia patients treated with IFN. The underlying reason for the skin hyperreactivity in Behçet's disease and the effect of IFN treatment in these patients may be altered neutrophil activity in both disorders. Several series evaluated the incidence of Raynaud's phenomenon in patients treated with IFN for hematological disorders. Some of them reported on a rather high incidence of nailfold capillary microscopy abnormalities with or without Raynaud's phenomenon. Whether IFN-induced Raynaud's phenomenon is immune-mediated or directly caused vasospasm, is still unknown although the occurrence of several autoantibodies suggests an immune mechanism. Adverse effects of IFN therapy on the kidney include proteinuria and rarely nephrotic syndrome or acute and chronic renal failure. The mechanism of renal injury is unclear although an immune mechanism is suggested. Sporadic cases of other immune-mediated side effects have been published. These include dermatological adverse effects manifesting as psoriasis, pemphigus and vitiligo, and also rare cases of sarcoidosis, hepatitis, colitis or cryoglobulinemia. In conclusion, patients treated with IFN should be monitored for symptoms of autoimmunity. Patients with previous autoimmune phenomena should be treated, if possible, with alternative drugs since there is risk of exacerbation of these manifestations in these patients.

In vitro susceptibility of Microsporum canis and other dermatophyte isolates from veterinary infections during therapy with terbinafine or griseofulvin

We investigated the in vitro activity of terbinafine against fresh veterinary isolates of Microsporum canis and the potential of this organism to develop resistance in vivo during oral therapy. Dermatophyte cultures (n = 300) were obtained from naturally infected cats and dogs undergoing oral therapy with terbinafine or griseofulvin. M. canis comprised 92% of isolates; other species included Microsporum gypseum and Trichophyton mentagrophytes. Minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of terbinafine and griseofulvin were determined by broth macrodilution assay. Terbinafine was highly active against all three species with MIC90< or =0.03 microg ml(-1), in agreement with published data. However, terbinafine exhibited primary cidal activity against 66% of Microsporum isolates (n = 275) in contrast to the almost complete cidal effect in Trichophyton (n = 18). Griseofulvin was significantly less active than terbinafine (MIC90 = 4 microg ml(-1)) but had a primary cidal action on about 40% of the isolates. The data were analysed for changes in MIC and MFC during the course of therapy, which could be indicative for development of acquired resistance. Oral treatment of 37 animals with terbinafine for up to 39 weeks caused no increase in MIC or MFC of terbinafine, either in individual patients or in the whole group.

Pseudomycetoma caused by Microsporum canis in a Persian cat: lack of response to oral terbinafine

An eight-year-old neutered female Persian cat with a four-year history of relapsing skin disease, characterised by ulcerated nodules with a yellow granular discharge, was examined. A diagnosis of granulomatous dermatitis and panniculitis (pseudomycetoma) caused by Microsporum canis was made on the basis of history, clinical signs, histopathological examination of skin biopsy specimens and culture of macerated tissue. Because previous therapy, comprising repeated surgical excision and the administration of griseofulvin and itraconazole, had not been successful, terbinafine was administered for an eight-month period. However, lesions progressed despite this treatment and the cat was euthanased.

Antifungal susceptibility testing: practical aspects and current challenges

Development of standardized antifungal susceptibility testing methods has been the focus of intensive research for the last 15 years. Reference methods for yeasts (NCCLS M27-A) and molds (M38-P) are now available. The development of these methods provides researchers not only with standardized methods for testing but also with an understanding of the variables that affect interlaboratory reproducibility. With this knowledge, we have now moved into the phase of (i) demonstrating the clinical value (or lack thereof) of standardized methods, (ii) developing modifications to these reference methods that address specific problems, and (iii) developing reliable commercial test kits. Clinically relevant testing is now available for selected fungi and drugs: Candida spp. against fluconazole, itraconazole, flucytosine, and (perhaps) amphotericin B; Cryptococcus neoformans against (perhaps) fluconazole and amphotericin B; and Aspergillus spp. against (perhaps) itraconazole. Expanding the range of useful testing procedures is the current focus of research in this area.

In vitro activities of 10 antifungal drugs against 508 dermatophyte strains

We have tested 508 strains belonging to 24 species of dermatophytes against 10 antifungal drugs following mainly the NCCLS (M38-P) standard for filamentous fungi. However, several important factors, such as the temperature (28 versus 35 degrees C) and time of incubation (4 to 10 days versus 21 to 74 h), have been modified. The antifungals used were itraconazole, ketoconazole, miconazole, clotrimazole, voriconazole, terbinafine, amphotericin B, fluconazole, UR-9825, and G-1. In general, with the exception of fluconazole and G-1, all antifungals were shown to be highly effective.

Guidelines for the management of tinea capitis. British Association of Dermatologists

These guidelines for the management of tinea capitis have been prepared for dermatologists on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of epidemiological aspects, diagnosis and investigation.

Tinea capitis: current concepts

Tinea capitis is an important fungal infection that may at times be a clinical, diagnostic and therapeutic challenge. It is common in childhood around the world, becoming almost epidemic in some communities. The central European and American experience with it is somewhat variable, due to different etiologic fungi. The use of topical antifungal agents and other approaches is stressed as of value alongside the use of systemic antifungal medication.