Malassezia species in skin diseases

Facial Physiological Characteristics and Skin Microbiomes Changes are Associated with Body Mass Index (BMI)

Background

Overweight and obesity have become public health problems worldwide. An increasing number of research works are focusing on skin physiology and the manifestations of obesity-associated skin diseases, but little is known about the correlations between body mass index (BMI), facial skin physiological parameters, and the facial skin microbiome in healthy women.

Objective

To investigate the correlations between BMI, facial skin physiological parameters and facial bacteria and fungi in 198 women aged 18 to 35 years in Shanghai.

Methods

According to the international BMI standard and Chinese reference standard, subjects were divided into three groups, "lean" B1, "normal" B2 and "overweight" B3, and the physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiota was analyzed by 16S rRNA and ITS high-throughput sequencing.

Results

Compared with the skin physiological parameters of the normal group, those of the overweight group exhibited a significant increase in trans-epidermal water loss (TEWL), which indicated that the skin barrier was impaired. The skin haemoglobin content was significantly increased, and skin surface pH was significant decreased in those with a high BMI. Furthermore, α-diversity, analysed using the Shannon, Chao, Sobs, and Ace indexes, was increased in the overweight group, suggesting that the diversity and species abundance of facial bacterial and fungal microbiota were also increased. Moreover, the overweight group had higher abundances of Streptococcus, Corynebacterium, Malassezia, and Candida. Notably, skin surface pH was significantly and negatively correlated with the relative abundances of Malassezia, Candida, and Cladosporium. Besides, the abundance of Malassezia was positively associated with the abundances of Staphylococcus and Corynebacterium.

Conclusion

These results indicate that BMI is associated with differences in the biophysical properties and microbiome of the facial skin. A high BMI affects the integrity of skin barrier and changes the skin flora diversity and species composition.

Anti-Malassezia Drug Candidates Based on Virulence Factors of Malassezia-Associated Diseases

Malassezia is a lipophilic unicellular fungus that is able, under specific conditions, to cause severe cutaneous and systemic diseases in predisposed subjects. This review is divided into two complementary parts. The first one discusses how virulence factors contribute to Malassezia pathogenesis that triggers skin diseases. These virulence factors include Malassezia cell wall resistance, lipases, phospholipases, acid sphingomyelinases, melanin, reactive oxygen species (ROS), indoles, hyphae formation, hydrophobicity, and biofilm formation. The second section describes active compounds directed specifically against identified virulence factors. Among the strategies for controlling Malassezia spread, this review discusses the development of aryl hydrocarbon receptor (AhR) antagonists, inhibition of secreted lipase, and fighting biofilms. Overall, this review offers an updated compilation of Malassezia species, including their virulence factors, potential therapeutic targets, and strategies for controlling their spread. It also provides an update on the most active compounds used to control Malassezia species.

A Clinical and Epidemiological Study of Pityriasis Versicolor in Baghdad City

BACKGROUND: Pityriasis versicolor (PV) is a common and chronic superficial mycosis seen in all age groups and characterized by dyspigmented lesions caused by dimorphic lipophilic yeast. AIM: The aim of the study was to study the clinical aspects, prevalence, and demographic data of patients with PV in Baghdad City. MATERIALS AND METHODS: Total of 175 patients with PV attending the department of Dermatology at Al Imamein Al Kadhemein Medical City and Alkarama Teaching Hospital in Baghdad city from January 2019 to January 2020 were included in this study. Diagnosis was done clinically. Interviews with patients were done using a questionnaire designed by the researcher. RESULTS: From 175 patients with PV, there were 71 (40.6%) males and 104 (59.4%) females. The mean age was 23.97 ± 10.25 years. The majority of cases 71 (40.6%) were 21–30 years. Eighty-one (46.3%) patients were presented from April to June. Itching presented in 21.7% of patients. The majority of patients (48.6%) presented with hyperpigmented type. Neck was the most common site to be involved in 101 patients (57.7%). CONCLUSION: The most common age group affected was 21–30 years. Females were commonly affected. Peak incidence was observed in April–July months. Neck was the most common site affected. Hyperpigmented type is more commonly presented type.

Malassezia: Zoonotic Implications, Parallels and Differences in Colonization and Disease in Humans and Animals

Malassezia spp. are commensals of the skin, oral/sinonasal cavity, lower respiratory and gastrointestinal tract. Eighteen species have been recovered from humans, other mammals and birds. They can also be isolated from diverse environments, suggesting an evolutionary trajectory of adaption from an ecological niche in plants and soil to the mucocutaneous ecosystem of warm-blooded vertebrates. In humans, dogs and cats, Malassezia-associated dermatological conditions share some commonalities. Otomycosis is common in companion animals but is rare in humans. Systemic infections, which are increasingly reported in humans, have yet to be recognized in animals. Malassezia species have also been identified as pathogenetic contributors to some chronic human diseases. While Malassezia species are host-adapted, some species are zoophilic and can cause fungemia, with outbreaks in neonatal intensive care wards associated with temporary colonization of healthcare worker’s hands from contact with their pets. Although standardization is lacking, susceptibility testing is usually performed using a modified broth microdilution method. Antifungal susceptibility can vary depending on Malassezia species, body location, infection type, disease duration, presence of co-morbidities and immunosuppression. Antifungal resistance mechanisms include biofilm formation, mutations or overexpression of ERG11, overexpression of efflux pumps and gene rearrangements or overexpression in chromosome 4.

A case of anti- pityriasis versicolor therapy that preserves healthy mycobiome

Background

The impact of Malassezia yeasts on skin mycobiome and health has received considerable attention recently. Pityriasis versicolor (PV), a common dermatosis caused by Malassezia genus worldwide, is a manifestation of dysbiosis. PV can be associated with hyper- and/or hypopigmented skin lesions. This disease entity is characterized by high percentage of relapses, which demands a proper antifungal therapy that is based on unambiguous species identification and drug susceptibility testing.

Case presentation

Comprehensive analysis of PV case in man presenting simultaneously hyper- and hypopigmented skin lesions was performed. Conventional and molecular diagnostic procedures revealed Malassezia furfur and Malassezia sympodialis, respectively as etiological agents of skin lesions observed. Susceptibility tests showed significantly lowered sensitivity of M. furfur cells to fluconazole. Based on susceptibility profiles local antifungal therapy with drugs characterized by entirely different mechanism of action was included.

Conclusions

Our study indicates that cases of PV represented by two types of skin lesions in one patient may be associated with distinct Malassezia species. Moreover, as observed in this case, each of the isolated etiological agents of PV may differ significantly in susceptibility to antifungals. This can significantly complicate the treatment of dermatosis, which by definition is associated with a significant percentage of relapses. In the presented case localized topical treatment was sufficient and successful while allowing maintaining the physiological mycobiome.

Critical synthesis of available data in Malassezia folliculitis and a systematic review of treatments

Folliculitis is an inflammatory process involving the hair follicle, frequently attributed to infectious causes. Malassezia, an established symbiotic yeast that can evolve to a skin pathogen with opportunistic attributes, is a common source of folliculitis, especially when intrinsic (e.g. immunosuppression) or extrinsic (high ambient temperature and humidity, clothing) impact on the hair follicle and the overlying skin microenvironment. Our aim was to critically review the pathophysiology and clinical characteristics of Malassezia folliculitis, to describe laboratory methods that facilitate diagnosis and to systematically review treatment options. Malassezia folliculitis manifests as a pruritic, follicular papulopustular eruption distributed on the upper trunk. It commonly affects young to middle-aged adults and immunosuppressed individuals. Inclusion into the differential diagnosis of folliculitis is regularly oversighted, and the prerequisite-targeted diagnostic procedures are not always performed. Sampling by tape stripping or comedo extractor and microscopic examination of the sample usually identifies the monopolar budding yeast cells of Malassezia without the presence of hyphae. However, confirmation of the diagnosis with anatomical association with the hair follicle is performed by biopsy. For systematic review of therapies, PubMed was searched using the search string "(malassezia" [MeSH Terms] OR "malassezia" [All Fields] OR pityrosporum [All Fields]) AND "folliculitis" [MeSH Terms] and EMBASE was searched using the search string: 'malassezia folliculitis.mp OR pityrosporum folliculitis.mp'. In total, 28 full-length studies were assessed for eligibility and 21 were selected for inclusion in therapy evaluation. Conclusively Malassezia folliculitis should be considered in the assessment of truncal, follicular skin lesions. Patient's history, comorbidities and clinical presentation are usually indicative, but microscopically and histological examination is needed to confirm the diagnosis. Adequate samples obtained with comedo extractor and serial sections in the histological material are critical for proper diagnosis. Therapy should include systemic or topical measures for the control of the inflammation, as well as the prevention of recurrences.

Bacillomycin D effectively controls growth of Malassezia globosa by disrupting the cell membrane

Malassezia globosa is an opportunistic pathogen that causes various skin disorders, which disturbs people's life all the time, and conventional drugs are not completely satisfactory. Bacillomycin D (BD), an antifungal lipopeptide, could inhibit various fungi growth. However, the reports about its effect on M. globosa were not found yet. In this study, we showed that BD and BD-C16 (fatty acid chain had sixteen carbon atoms) completely inhibited growth of M. globosa at concentration of 64 μg/ml in 15 h, which was confirmed with the observation of irregular morphological change of M. globosa treated with BD. Significantly, the study on the working mechanism showed that BD induced cell death by changing cell membrane permeability and thus promoting the release of cellular contents, which may be mediated by the interaction between BD and ergosterol from membrane. Further study showed that BD reduced the overall content of cellular sterol, and interestingly, the expression of some genes involved in membrane and ergosterol synthesis were significantly upregulated, which was likely to be a feedback regulation. Besides, we found that BD had additive and synergistic effects with ketoconazole and amphotericin B, respectively, on inhibition of M. globosa, suggesting that combination use of BD with other commercial drugs could be a promising strategy to relieve skin disorders caused by M. globosa. KEY POINTS: • BD could efficiently inhibit the growth of M. globosa. • BD increases cell membrane permeability and thus promotes the release of cellular contents. • BD has additive or synergistic effect with other antifungal drugs.

Therapy of Skin, Hair and Nail Fungal Infections

Treatment of superficial fungal infections has come a long way. This has, in part, been through the development and evaluation of new drugs. However, utilising new strategies, such as identifying variation between different species in responsiveness, e.g., in tinea capitis, as well as seeking better ways of ensuring adequate concentrations of drug in the skin or nail, and combining different treatment methods, have played equally important roles in ensuring steady improvements in the results of treatment. Yet there are still areas where we look for improvement, such as better remission and cure rates in fungal nail disease, and the development of effective community treatment programmes to address endemic scalp ringworm.

In Vitro Anti-Malassezia Activity of Castanea crenata Shell and Oil-Soluble Glycyrrhiza Extracts

Background

A new shampoo with anti-Malassezia properties obtained from various plants is required to provide seborrheic dermatitis patients with a wider range of treatment options.

Objective

The aim of this study was to obtain in vitro susceptibility profiles of Malassezia restricta and M. globosa, the most important pathogenic organisms in the development of seborrheic dermatitis, to the plant extracts used in commercial anti-dandruff shampoos.

Methods

Minimal inhibitory concentrations (MICs) were determined for eight candidate plant extracts and two plant-derived natural products diluted with Leeming and Notman medium to final concentrations of 0.016 to 1 mg/ml.

Results

Castanea crenata shell, Camellia sinensis leaf, and oil-soluble Glycyrrhiza extracts presented relatively low MIC values (≤0.5 mg/ml) against both strains. The C. crenata shell and oil-soluble Glycyrrhiza extracts demonstrated especially high anti-Malassezia activity, suggesting their potential use in the treatment of seborrheic dermatitis. The extracts also showed fungistatic activity against other common facultative pathogenic yeasts, Cryptococcus and Candida.

Conclusion

C. crenata shell and oil-soluble Glycyrrhiza extracts could potentially be used as active ingredients in anti-seborrheic and anti-dandruff shampoo formulations. They could be helpful for repeated treatments and regular prophylaxis of scalp seborrheic dermatitis.

Oral Terbinafine in the Treatment of Multi-Site Seborrheic Dermatitis: A Multicenter, Double-Blind Placebo-Controlled Study

Seborrheic dermatitis (SD) is a common disorder for which no satisfactory curative treatment exists. Preliminary studies suggest that terbinafine may be effective. The efficacy and tolerability of oral terbinafine was evaluated in multi-site SD in a randomized, double-blind, placebo-controlled study. For this purpose, 174 adult patients with SD lesions involving ≥3 skin areas, each causing ≥2 moderate/severe symptoms according to a pre-defined clinical score, were classified according to the localization of lesions: patients with lesions predominantly involving non-exposed skin areas, such as scalp and hairline and sternum and/or interscapular area (Population A, n=83) or patients with lesions in exposed sites, mainly the face (Population B, n=91). Patients were randomized to oral terbinafine (250 mg/day) (n=86) or matching placebo (n=88), each given for 6 weeks. Primary efficacy variable was the response rate, defined as ≥50% decrease in baseline total clinical score without rescue medication intake after 6 weeks of treatment. The main secondary assessments were: subject's global assessment of relief and proportion of patients satisfied with treatment. Recurrence rate was assessed in responder patients during a 4-week treatment-free period. In Population A the response rate after 6 weeks of treatment was significantly higher with terbinafine (70% vs 45.4%; p=0.03) and so was the proportion of patients who reported relief (75% vs 41%; p=0.007) and who were satisfied (66% vs 40%; p=0.02). No significant differences were recorded in Population B. Adverse events occurred in 11.5% of terbinafine patients and 8% of placebo patients. One patient discontinued treatment with terbinafine because of adverse events (mild tachycardia and insomnia). In conclusion, our results show that terbinafine is significantly more effective than placebo in reducing the severity of SD lesions in non-exposed sites. Clinical trials comparing terbinafine to standard treatment regimens in different types of patients with SD are warranted.

The Prevalence and Species Composition of Malassezia yeasts in Patients with Clinically Suspected Onychomycosis

Introduction:

There are limited numbers of studies which focused on the identification of Malassezia yeasts to a species level in onychomycosis. Therefore, the aim of our study was to determine the prevalence and species composition of Malassezia yeasts in patients with clinically suspected onychomycosis and to examine if the range of species varies with patient gender, age, site of involvement and clinical pattern of onychomycosis.

Methods:

Specimens were taken from 785 patients presenting signs of onychomycosis and then incubated on Sabouraud dextrose agar and modified Dixon agar. The yeasts isolated were identified according to their macroscopic and microscopic features and physiological characteristics.

Results:

Malassezia species were diagnosed both by microscopy and culture in fourteen (1.8%) patients. M. globosa was the predominant, if not only, species identified from nail samples. Mixed cultures were observed in five cases: in 4 cases Malassezia was co-isolated with Candida albicans and in one case with dermatophyte. Fingernails were affected more frequently than toenails (85.7%) and distolateral subungual onychomycosis was the most common clinical type (78.6%).

Conclusion:

No significant differences were found in the distribution of Malassezia species isolated according to demographic parameters.

Mycoflora of the interdigital spaces among girl students in ahvaz, iran

BACKGROUND

Fungi have been extensively isolated and investigated from skin in various parts of the world. Determining the mycoflora of normal people is important when the role of skin is considered as a reservoir for microorganisms.

OBJECTIVES

The current study aimed to investigate the incidence of fungal flora on interdigital spaces of the human foot.

PATIENTS AND METHODS

Samples were collected from interdigital spaces of 865 girl students who lived in the dormitories of Ahvaz Jundishapur University of Medical Sciences. A part of the sample was digested with 20% KOH and screened by a light microscope for fungal elements. Another part of the sample was cultured on Sabouraud glucose agar (SGA) and SGA containing 0.05 mg/mL chloramphenicol and 0.5 mg/mL cycloheximide. The fungal colonies were identified based on morphological and microscopic characteristics and biochemical tests.

RESULTS

In the current study, out of the 865 samples, 616 (71. 2%) were positive in direct examination or culture. Of these, 267 samples (30. 9%) were positive in direct examination. The most common fungal isolates in direct test were yeast (29. 4%), followed by conidia (0. 92%), melanised hypha (0. 35%) and non-septated hyphae (0. 23%). Trichophyton mentagrophytes was isolated in one of the specimens.

CONCLUSIONS

The present study demonstrated the incidence of fungal flora on interdigital spaces of human foot. The current study results showed that fungi can survive on surfaces of skin without showing the sign of infection.

Molecular identification and prevalence of malassezia species in pityriasis versicolor patients from kashan, iran

Background:

Malassezia species are lipophilic yeasts found on the skin surface of humans and other warm-blooded vertebrates. It is associated with various human diseases, especially pityriasis versicolor, which is a chronic superficial skin disorder.

Objectives:

The aim of the present study was to identify Malassezia species isolated from patients’ samples affected by pityriasis versicolor, using molecular methods in Kashan, Iran.

Patients and Methods:

A total of 140 subjects, suspected of having pityriasis versicolor from Kashan, were clinically diagnosed and then confirmed by direct microscopic examination. The scraped skin specimens were inoculated in modified Dixon’s medium. DNA was extracted from the colonies and PCR amplification was carried out for the 26s rDNA region. PCR products were used to further restriction fragment length polymorphism by CfoI enzyme.

Results:

Direct examination was positive in 93.3% of suspected pityriasis versicolor lesions. No statistically significant difference was observed in the frequency of Malassezia species between women and men. The highest prevalence of tinea versicolor was seen in patients 21–30 years-of-age. No difference could be seen in the frequency of Malassezia species depending on the age of the patients. In total, 65% of patients with pityriasis versicolor had hyperhidrosis. The most commonly isolated Malassezia species in the pityriasis versicolor lesions were; Malassezia globosa (66%), M. furfur (26%), M. restricta (3%), M. sympodialis (3%), and M. slooffiae (2%). Malassezia species were mainly isolated from the neck and chest.

Conclusions:

This study showed M. globosa to be the most common Malassezia species isolated from Malassezia skin disorders in Kashan, Iran. The PCR-RFLP method was useful in the rapid identification of the Malassezia species. By using these methods, the detection and identification of individual Malassezia species from clinical samples was substantially easier.

Update on therapy for superficial mycoses: review article part I

Superficial fungal infections of the hair, skin and nails are a major cause of morbidity in the world. Choosing the right treatment is not always simple because of the possibility of drug interactions and side effects. The first part of the article discusses the main treatments for superficial mycoses - keratophytoses, dermatophytosis, candidiasis, with a practical approach to the most commonly-used topical and systemic drugs , referring also to their dosage and duration of use. Promising new, antifungal therapeutic alternatives are also highlighted, as well as available options on the Brazilian and world markets.

Identification of Malassezia species in patients with seborrheic dermatitis in China

BACKGROUND

The causes of seborrheic dermatitis (SD) are complex and incompletely understood. Among the factors, Malassezia yeasts have been reported to play a major etiological role in SD. Many previous studies adopted conventional culture methods that were disadvantaged to detect Malassezia microflora in SD patients, resulting in a low detection rate for each species and high variance in types of microflora observed.

OBJECTIVE

This study analyzed Malassezia microflora in SD patients by applying a transparent dressing to the lesional skin and using direct detection of fungal DNA using nested PCR.

METHODS

We collected samples from the lesional skin of 146 SD patients in China and extracted fungal DNA directly from the lesional samples without culture. Specific primers for each Malassezia species were designed to amplify existing yeasts in each sample. Some samples were randomly selected to culture and identified by morphological and physiologic criteria.

RESULTS

M. globosa and M. restricta were found in 87.0 and 81.5% of seborrheic dermatitis patients, respectively, which together accounted for more than 50% of Malassezia spp. recovered in these Chinese patients. The majority of SD patients (82.9%) showed co-colonization of two or more Malassezia species.

CONCLUSION

M. globosa and M. restricta predominated in Malassezia colonization in Chinese SD patients. Compared with conventional culture, non-culture-based methods may more accurately reflect Malassezia microflora constitution.

Characterization of the fungal microbiota (mycobiome) in healthy and dandruff-afflicted human scalps

The human scalp harbors a vast community of microbial mutualists, the composition of which is difficult to elucidate as many of the microorganisms are not culturable using current culture techniques. Dandruff, a common scalp disorder, is known as a causative factor of a mild seborrheic dermatitis as well as pityriasis versicolor, seborrheic dermatitis, and atopic dermatitis. Lipophilic yeast Malassezia is widely accepted to play a role in dandruff, but relatively few comprehensive studies have been reported. In order to investigate fungal biota and genetic resources of dandruff, we amplified the 26S rRNA gene from samples of healthy scalps and dandruff-afflicted scalps. The sequences were analyzed by a high throughput method using a GS-FLX 454 pyrosequencer. Of the 74,811 total sequence reads, Basidiomycota (Filobasidium spp.) was the most common phylum associated with dandruff. In contrast, Ascomycota (Acremonium spp.) was common in the healthy scalps. Our results elucidate the distribution of fungal communities associated with dandruff and provide new avenues for the potential prevention and treatment of dandruff.

Clinical aspects of patients with pityriasis versicolor seen at a referral center for tropical dermatology in Manaus, Amazonas, Brazil

BACKGROUND

Pityriasis versicolor (tinea versicolor) is a chronic superficial mycosis caused by yeasts of the Malassezia spp. genus commensal of the keratinized layers of the skin. Under conditions not yet understood, it becomes pathogenic determining the clinical manifestations of the disease. It is a recurrent skin condition and persistent hypopigmentation may remain after treatment, causing social problems to those affected.

OBJECTIVE

To describe the clinical and epidemiological features of patients diagnosed with tinea versicolor treated at a referral center for dermatology (Alfredo da Matta Foundation).

METHODS

Case-studies in which cutaneous manifestations and epidemiological characteristics of patients diagnosed with tinea versicolor treated at Alfredo da Matta Foundation were detailed.

RESULTS

One hundred and sixteen patients were included in the study from January to August 2008. Most subjects were male, of mixed ethnicity and young age. Most were students who were predisposed to the development of macules. The majority had extensive injuries and past history of the disease.

CONCLUSION

The results revealed a high proportion of individuals with extensive clinical manifestations and duration of the disease.

N-termini of fungal CSL transcription factors are disordered, enriched in regulatory motifs and inhibit DNA binding in fission yeast

BACKGROUND

CSL (CBF1/RBP-Jκ/Suppressor of Hairless/LAG-1) transcription factors are the effector components of the Notch receptor signalling pathway, which is critical for metazoan development. The metazoan CSL proteins (class M) can also function in a Notch-independent manner. Recently, two novel classes of CSL proteins, designated F1 and F2, have been identified in fungi. The role of the fungal CSL proteins is unclear, because the Notch pathway is not present in fungi. In fission yeast, the Cbf11 and Cbf12 CSL paralogs play antagonistic roles in cell adhesion and the coordination of cell and nuclear division. Unusually long N-terminal extensions are typical for fungal and invertebrate CSL family members. In this study, we investigate the functional significance of these extended N-termini of CSL proteins.

METHODOLOGY/PRINCIPAL FINDINGS

We identify 15 novel CSL family members from 7 fungal species and conduct bioinformatic analyses of a combined dataset containing 34 fungal and 11 metazoan CSL protein sequences. We show that the long, non-conserved N-terminal tails of fungal CSL proteins are likely disordered and enriched in phosphorylation sites and PEST motifs. In a case study of Cbf12 (class F2), we provide experimental evidence that the protein is proteolytically processed and that the N-terminus inhibits the Cbf12-dependent DNA binding activity in an electrophoretic mobility shift assay.

CONCLUSIONS/SIGNIFICANCE

This study provides insight into the characteristics of the long N-terminal tails of fungal CSL proteins that may be crucial for controlling DNA-binding and CSL function. We propose that the regulation of DNA binding by Cbf12 via its N-terminal region represents an important means by which fission yeast strikes a balance between the class F1 and class F2 paralog activities. This mode of regulation might be shared with other CSL-positive fungi, some of which are relevant to human disease and biotechnology.

Epidemiologic Study of Malassezia Yeasts in Patients with Malassezia Folliculitis by 26S rDNA PCR-RFLP Analysis

BACKGROUND

So far, studies on the inter-relationship between Malassezia and Malassezia folliculitis have been rather scarce.

OBJECTIVE

We sought to analyze the differences in body sites, gender and age groups, and to determine whether there is a relationship between certain types of Malassezia species and Malassezia folliculitis.

METHODS

Specimens were taken from the forehead, cheek and chest of 60 patients with Malassezia folliculitis and from the normal skin of 60 age- and gender-matched healthy controls by 26S rDNA PCR-RFLP.

RESULTS

M. restricta was dominant in the patients with Malassezia folliculitis (20.6%), while M. globosa was the most common species (26.7%) in the controls. The rate of identification was the highest in the teens for the patient group, whereas it was the highest in the thirties for the control group. M. globosa was the most predominant species on the chest with 13 cases (21.7%), and M. restricta was the most commonly identified species, with 17 (28.3%) and 12 (20%) cases on the forehead and cheek, respectively, for the patient group.

CONCLUSION

Statistically significant differences were observed between the patient and control groups for the people in their teens and twenties, and in terms of the body site, on the forehead only.

Prevalence of Malassezia species in patients with pityriasis versicolor in Rosario, Argentina

BACKGROUND

Malassezia species are considered opportunistic yeasts of increasing clinical importance. These lipophilic yeasts are associated with various human diseases, especially pityriasis versicolor (PV), a chronic superficial scaling dermatomycosis.

AIMS

The aim of this study was to isolate, identify and analyze the distribution of the different species of Malassezia in patients with PV in Rosario city (Argentina).

METHODS

A total of 264 clinical samples were studied. Isolates were identified on the basis of microscopic observation of cells, and physiological properties, such as the presence of catalase, ability to use Tween compounds, splitting of esculin, and morphology, color and precipitate production on chromogenic agar CHROMagar-Malassezia medium (CHROMM).

RESULTS

The highest prevalence of PV in this study was observed in the 25- to 45-year-old group. No differences were found in the development of PV between sexes. The most affected areas of body were the trunk and face. Malassezia sympodialis (51%) was the most commonly isolated species, followed in frequency by M. globosa (40%), Malassezia furfur (7%), Malassezia obtusa (1%) and Malassezia slooffiae (1%).

CONCLUSIONS

The success for a correct identification of these yeasts is important to improve our knowledge about their epidemiological role in PV and also to detect the appearance of strains which are resistant to the commonly used antifungal drugs.

Pathogenesis of dermatophytosis and tinea versicolor

Dermatophytoses are infections caused by keratinophilic fungi known as dermatophytes. Several steps are required for infection to take place: contact, adherence, and invasion of keratin layers. The severity of the infection depends on the type of agent, environmental factors, and the host immunologic status. Tinea versicolor is caused by the Malassezia spp yeasts, which are microorganisms that belong to normal biota in seborrheic areas, but some contributing factors, such as the application of oily preparations, creams, an increase in ambient humidity, corticosteroid abuse, or genetic predisposition can induce its overgrowth in both filamentous and yeast structures. Exposure to sunlight stimulates the production of azelaic acid, which causes the appearance of hypopigmented spots. Currently, there is no scientific explanation for hyperpigmented lesions.

Pitiríase versicolor circinada: isolamento de Malassezia sympodialis - Relato de caso

Os autores descrevem caso de pitiríase versicolor circinada, cujo agente etiológico isolado foi Malassezia sympodialis em uma mulher de 34 anos. O isolamento e identificação da Malassezia sympodialis foi em ágar Dixon modificado e o método molecular para confirmação da espécie foi PCR-RFLP (polymerase chain reaction and restriction fragment length polymorphism analysis).

Pitiríase versicolor: isolamento e identificação das principais espécies de Malassezia

As espécies do gênero Malassezia isoladas foram: Malassezia sympodialis (16,66%), Malassezia furfur (12,50%), Malassezia globosa (11,45%) e Malassezia slooffiae (2,10%). A Malassezia sympodialis foi a espécie que predominou em nosso estudo. As espécies de Malassezia identificadas não mostraram correlação com as variantes clínicas e com a distribuição das lesões de pitiríase versicolor quanto às regiões do corpo.

Role of topical calcineurin inhibitors in the treatment of seborrheic dermatitis: a review of pathophysiology, safety, and efficacy

Seborrheic dermatitis (SD) is characterized by erythematous pruritic patches and plaques with greasy scale that occur in sebaceous areas. It is common, affecting up to 3% of the population. Past treatments have relied on a wide variety of anti-inflammatory and antifungal agents, but corticosteroids have limited use because of long-term adverse effects. Topical calcineurin inhibitors provide a safe alternative for the treatment of SD, as these drugs block the inflammatory cascade involved in the disease process and pose no risk of skin atrophy. Studies of topical pimecrolimus and tacrolimus in the treatment of SD have found that improvement occurred within 2 weeks, and if SD recurred after stopping treatment, it was significantly less severe. There have been no studies of the comparative efficacy of pimecrolimus versus tacrolimus for the treatment of SD. Common adverse effects of mild burning and irritation have been associated with the use of both of these agents. Safety profile studies are limited to studies of atopic dermatitis, which show no increase in infection rate, photocarcinogenicity, or signs of immunosuppression in patients using topical calcineurin inhibitors for long-term treatment. This article reviews the clinical trials of pimecrolimus and tacrolimus in the treatment of SD, focusing on efficacy and safety.

Physiological and molecular characterization of atypical isolates of Malassezia furfur

The species constituting the genus Malassezia are considered to be emergent opportunistic yeasts of great importance. Characterized as lipophilic yeasts, they are found in normal human skin flora and sometimes are associated with different dermatological pathologies. We have isolated seven Malassezia species strains that have a different Tween assimilation pattern from the one typically used to differentiate M. furfur, M. sympodialis, and M. slooffiae from other Malassezia species. In order to characterize these isolates of Malassezia spp., we studied their physiological features and conducted morphological and molecular characterization by PCR-restriction fragment length polymorphism and sequencing of the 26S and 5.8S ribosomal DNA-internal transcribed spacer 2 regions in three strains from healthy individuals, four clinical strains, and eight reference strains. The sequence analysis of the ribosomal region was based on the Blastn algorithm and revealed that the sequences of our isolates were homologous to M. furfur sequences. To support these findings, we carried out phylogenetic analyses to establish the relationship of the isolates to M. furfur and other reported species. All of our results confirm that all seven strains are M. furfur; the atypical assimilation of Tween 80 was found to be a new physiological pattern characteristic of some strains isolated in Colombia.

Analysis of Malassezia microbiota in healthy superficial human skin and in psoriatic lesions by multiplex real-time PCR

Yeasts from the genus Malassezia are members of the normal biota of human skin, and may play a role in dermatopathology. Our previous study of the fungal microbiota from healthy subjects and from patients with psoriasis using clone library analysis revealed the presence of five Malassezia species and four uncharacterized phylotypes. We now compared the Malassezia microbiota from six healthy body locations and two psoriatic lesions, and evaluated its stability over time using multiplex real-time PCR. Samples from each body location were obtained monthly, for 4 months. Dual-labeled probes were designed to recognize four Malassezia sp. and two uncharacterized groups, and a genus-specific probe was also developed. A good correspondence was obtained between real-time PCR data and clone library analyses. Malassezia restricta was the most abundant species in the majority of samples, and high amounts of Malassezia globosa were also detected. The uncharacterized phylotype 1 was usually detected in lower proportions, nevertheless it was present in most samples. The microbiota was host-specific and relatively stable over time. In accordance with our previous observations, no significant dichotomy between samples from healthy skin and from psoriatic lesions was found; the samples clustered according to the subject, rather than health status.

[Malassezia folliculitis: characteristics and therapeutic response in 26 patients]

BACKGROUND

Malassezia folliculitis is most often described in patients living in hot and humid countries or in immunocompromised patients. Its frequency in France is unknown. We report 26 cases diagnosed at Saint-Louis Hospital between May 2002 and April 2004. The clinical features, the contributing factors, the results of direct mycological examination and/or histology and the efficacy of antifungal treatments were compared to the literature.

PATIENTS AND METHODS

The inclusion criteria were the presence of folliculitis on the trunk confirmed by direct microscopy and/or histopathology showing abundant yeast cells in the follicles.

RESULTS

Patients comprised 22 men and 4 women (M/F sex ratio: 5: 5) with a mean age of 46 years. Five patients (19%) were immunocompromised. In normal patients, the duration of folliculitis was long with a mean of 61 months. The eruption was typical, with follicular papules and superficial pustules distributed predominantly on the trunk. Itching was frequent (70%). Direct microscopy was more often positive than histology (89% vs 33%). Some sixty-five percent of the patients had been previously treated by topical or systemic antibiotics or anti-acne drugs, which was ineffective in all cases. Cure with topical ketoconazole, oral ketoconazole alone or in combination with topical ketoconazole occurred respectively in 12%, 75% and 75% of patients, but with consistent recurrence within 3 to 4 months after cessation of treatment.

DISCUSSION

Malassezia folliculitis is probably misdiagnosed, as suggested by the long time between onset and diagnosis and the high frequency of non-antifungal treatments prescribed. In our study, direct mycological examination provided more effective diagnosis than histology. Treatment is difficult especially because of the high frequency of relapses.

CONCLUSION

A diagnosis of Malassezia folliculitis should be considered in young adults or immunocompromised patients with an itching follicular eruption. Further therapeutic trials are needed due to the frequency of relapse.

Colonization of neonate skin by Malassezia species: relationship with neonatal cephalic pustulosis

BACKGROUND

Colonization of neonate skin by Malassezia species and their causative role in neonatal cephalic pustulosis is unclear.

OBJECTIVES

We sought to determine the skin colonization by Malassezia in healthy newborns, and to investigate its association with neonatal cephalic pustulosis.

METHODS

Samples for Malassezia colonization were taken from cheeks and scalps of 104 neonates between 24 and 72 hours after birth, and again 2 or 4 weeks later. Pustules were sampled with concomitant nonlesional skin cultures if neonatal cephalic pustulosis was diagnosed.

RESULTS

Malassezia colonization increased significantly with age of the neonate (5% at the first week, 30% at 2-4 weeks). In all, 26 patients were given the diagnosis of neonatal cephalic pustulosis during follow-up. No correlation was found between the severity of the disease and Malassezia isolation. Skin colonization of patients with neonatal cephalic pustulosis (20.8%) was not higher than colonization of healthy newborns (37%).

LIMITATIONS

Not all of the neonates were examined by the authors at the second visit.

CONCLUSIONS

Malassezia colonization increases after the first week of life. No correlation was found between neonatal cephalic pustulosis and Malassezia.

Isolation and expression of a Malassezia globosa lipase gene, LIP1

Dandruff and seborrheic dermatitis (D/SD) are common hyperproliferative scalp disorders with a similar etiology. Both result, in part, from metabolic activity of Malassezia globosa and Malassezia restricta, commensal basidiomycete yeasts commonly found on human scalps. Current hypotheses about the mechanism of D/SD include Malassezia-induced fatty acid metabolism, particularly lipase-mediated breakdown of sebaceous lipids and release of irritating free fatty acids. We report that lipase activity was detected in four species of Malassezia, including M. globosa. We isolated lipase activity by washing M. globosa cells. The isolated lipase was active against diolein, but not triolein. In contrast, intact cells showed lipase activity against both substrates, suggesting the presence of at least another lipase. The diglyceride-hydrolyzing lipase was purified from the extract, and much of its sequence was determined by peptide sequencing. The corresponding lipase gene (LIP1) was cloned and sequenced. Confirmation that LIP1 encoded a functional lipase was obtained using a covalent lipase inhibitor. LIP1 was differentially expressed in vitro. Expression was detected on three out of five human scalps, as indicated by reverse transcription-PCR. This is the first step in a molecular description of lipid metabolism on the scalp, ultimately leading toward a test of its role in D/SD etiology.