A New Yeast,Malassezia yamatoensis, Isolated from a Patient with Seborrheic Dermatitis, and Its Distribution in Patients and Healthy Subjects

Case Report: Scalp pityriasis versicolor may be a neglected problem

Pityriasis versicolor, a common skin fungal infection, is typically observed on trunk and limb skin. Here, we highlight an unusual presentation: scalp involvement, often overlooked due to its asymptomatic, mildly scaly patches. We report four pediatric cases, emphasizing the potential underestimation of this scalp variant. This case series underscores the importance of considering this diagnosis in patients with unexplained scalp hypopigmentation, especially in males with short hair who may readily notice these subtle changes. The report contributes to the understanding of this variant's clinical presentation and emphasizes the need for awareness among clinicians to ensure accurate diagnosis and appropriate management.

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.

Yeasts of the Malassezia Genus – Recent Findings

The genus Malassezia is a medically important genus of yeasts that can colonize the skin of humans and other warm-blooded animals. The genus currently comprises 18 species of which four new species were identified recently. The most widely known species, M. pachydermatis, occurs in animals but was detected also in humans, namely at life endangering septicaemias and in prematurely born children. Proliferation of Malassezia occurs most frequently as a result of disturbances in the normal homeostasis of host immunity on the one hand and virulence of these yeasts on the other hand. The successful management of the disease depends on the therapeutic control of overgrowth of the yeasts and any concurrent bacterial infection by local or systemic anti microbial treatment, as well as, on identification and potential correction of the predisposing factors.

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.

Potential of propolis antifungal activity for clinical applications

The high incidence of skin diseases of microbial origin along with the widespread increase of microbial resistance demand for therapeutic alternatives. Research on natural compounds has been opening new perspectives for the development of new therapies with health positive impacts. Propolis, a resinous mixture produced by honeybees from plant exudates, is widely used as a natural medicine since ancient times, mainly due to its antimicrobial properties. More recently, antioxidant, anti-tumor, anti-inflammatory, hepatoprotective and immunomodulatory activities were also reported for this natural product, highlighting its high potential pharmacological interest. In the present work, an extensive review of the main fungi causing skin diseases as well as the effects of natural compounds, particularly propolis, against such disease-causing microorganisms was organized and compiled in concise handy tables. This information allows to conclude that propolis is a highly effective antimicrobial agent suggesting that it could be used as an alternative skin treatment against pathogenic microorganisms and also as a cosmeceutic component or as a source of bioactive ingredients.

Sociodemographic characteristics and spectrum of Malassezia species in individuals with and without seborrhoeic dermatitis/dandruff: A comparison of residents of the urban and rural populations

Seborrhoeic dermatitis/dandruff (SD/D) is a common, persistent, relapsing inflammatory condition affecting the areas rich in sebaceous glands. SD/D is widely prevalent in India but Malassezia species implicated are not well studied. To estimate the prevalence and spectrum of Malassezia species causing SD/D and understand the sociodemographic characteristics of SD/D in rural and urban populations, a total of 200 SD/D patients and 100 healthy controls (HC) from both rural and urban backgrounds were enrolled in this study. SD/D severity was clinically graded as mild, moderate, severe, and very severe. The isolates were identified by phenotypic characters and confirmed by ITS2 PCR-RFLP and sequencing of the ITS region of rDNA. Severe (59%) and very severe (71%) form of SD/D was higher in the rural population compared to the urban population (P = .004). The isolation rate of Malassezia was significantly higher in overall SD/D patients scalp (82%) compared to HC (67%) (P = .005). From the scalp of SD/D patients, M. globosa (36.2%) was predominantly isolated followed by M. restricta (31.3%), M. furfur (15.7%), a mixture of M. globosa and M. restricta (12%) or M. arunalokei (4.8%). Similarly, M. globosa (49.3%) was predominately isolated from the scalp of HC followed by M. restricta (22.4%). M. restricta was significantly higher in the scalp of SD/D patients compared to HC and/or nasolabial fold of both SD/D patients and HC (P = .0001). Our findings indicate that M. restricta has a high association with SD/D. More severe disease frequency was observed in the rural population.

PRECIS

Dandruff is associated with Malassezia restricta and very severe cases are higher in rural population, probably due the poor hygiene. Moderate to severe hair loss and itching were strongly associated with dandruff. Use of soaps to cleanse scalp appears to be better than shampoo in preventing dandruff.

Cutaneous Malassezia: Commensal, Pathogen, or Protector?

The skin microbial community is a multifunctional ecosystem aiding prevention of infections from transient pathogens, maintenance of host immune homeostasis, and skin health. A better understanding of the complex milieu of microbe-microbe and host-microbe interactions will be required to define the ecosystem's optimal function and enable rational design of microbiome targeted interventions. Malassezia, a fungal genus currently comprising 18 species and numerous functionally distinct strains, are lipid-dependent basidiomycetous yeasts and integral components of the skin microbiome. The high proportion of Malassezia in the skin microbiome makes understanding their role in healthy and diseased skin crucial to development of functional skin health knowledge and understanding of normal, healthy skin homeostasis. Over the last decade, new tools for Malassezia culture, detection, and genetic manipulation have revealed not only the ubiquity of Malassezia on skin but new pathogenic roles in seborrheic dermatitis, psoriasis, Crohn's disease, and pancreatic ductal carcinoma. Application of these tools continues to peel back the layers of Malassezia/skin interactions, including clear examples of pathogenicity, commensalism, and potential protective or beneficial activities creating mutualism. Our increased understanding of host- and microbe-specific interactions should lead to identification of key factors that maintain skin in a state of healthy mutualism or, in turn, initiate pathogenic changes. These approaches are leading toward development of new therapeutic targets and treatment options. This review discusses recent developments that have expanded our understanding of Malassezia's role in the skin microbiome, with a focus on its multiple roles in health and disease as commensal, pathogen, and protector.

Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

BACKGROUND

The genus Malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds.

OBJECTIVES

The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of skin diseases associated with Malassezia yeasts in dogs and cats.

METHODS AND MATERIAL

The authors served as a Guideline Panel (GP) and reviewed the literature available prior to October 2018. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. The document was presented at two international meetings of veterinary dermatology societies and one international mycology workshop; it was made available for comment on the WAVD website for a period of six months. Comments were shared with the GP electronically and responses incorporated into the final document.

CONCLUSIONS AND CLINICAL IMPORTANCE

There has been a remarkable expansion of knowledge on Malassezia yeasts and their role in animal disease, particularly since the early 1990's. Malassezia dermatitis in dogs and cats has evolved from a disease of obscurity and controversy on its existence, to now being a routine diagnosis in general veterinary practice. Clinical signs are well recognised and diagnostic approaches are well developed. A range of topical and systemic therapies is known to be effective, especially when predisposing factors are identified and corrected.

Identification of Malassezia species using direct PCR- sequencing on clinical samples from patients with pityriasis versicolor and seborrheic dermatitis

Background and Purpose :

Malassezia yeasts are lipophilic normal flora of the skin in humans and other warm-blooded vertebrates. This genus includes 18 species and is responsible for dermatological disorders, such as pityriasis versicolor, atopic dermatitis, seborrheic dermatitis, folliculitis, and dandruff. The aim of the present study was to identify the etiologic agents of Malassezia infections among the patients referring to the Referral Dermatology Clinic of Al-Zahra Hospital, Isfahan, Iran, during 2018-2019.

Materials and Methods:

For the purpose of the study, clinical specimens, including skin scrapings and dandruff, were collected and subjected to direct microscopy, culture, and polymerase chain reaction (PCR) sequencing. Direct PCR was performed on the clinical samples to amplify the D1/D2 region of 26S rDNA, using specific primers; subsequently, the amplicons were sent for sequencing.

Results:

This study was conducted on 120 patients with suspected pityriasis versicolor and seborrheic dermatitis, who referred to the Referral Dermatology Clinic of Al-Zahra Hospital, Isfahan, Iran, during 2018-2019. Out of this population, 50 (41.7%), 26 (52%), and 24 (48%) cases had Malassezia infection, pityriasis versicolor, and seborrheic dermatitis, respectively. Malassezia globosa was found to be the most prevalent species (n=29, 58%), followed by M. restricta (n=20, 40%), and M. arunalokei (n=1, 2%).

Conclusion:

The epidemiologic study was indicative of the frequency of some Malassezia species, such as M. globosa and M. restricta, in Isfahan, Iran. It can be concluded that direct PCR on clinical samples could be used as a simple, precise, effective, fast, and affordable method for research and even routine medical mycology laboratory studies.

Phenotypic and genetic diversity of Malassezia furfur from domestic and zoo animals

Malassezia furfur is traditionally associated to human skin, although more recent studies have been revealing its presence in a variety of animals. The aim of this study was to analyze phenotypically and genetically the diversity among strains isolated from animals of this species. We have examined 21 strains of M. furfur from domestic and wild animals held in captivity. On the one hand, their phenotypic characteristics were studied, by assessing its growth at different incubation temperatures, their catalase and β-glucosidase activities and the Tween diffusion test on Sabouraud glucose agar (SGA), and on yeast nitrogen base agar (YNBA), a synthetic medium without lipids. On the other hand, the large subunit (LSU) and the internal transcribed spacer (ITS) of ribosomal RNA and the β-tubulin gene were sequenced. Different sequence types were identified for each target gene, and fourteen genotypes were revealed. While several genotypes were obtained from the strains from domestic animals, the strains from zoo animals appeared to be genetically more stable. With ITS and β-tubulin gene, M. furfur strains grouped in two clades. One clade included the strains from domestic animals and the other clade included the strains from zoo animals. The phenotypic tests also revealed a remarkable diversity within this species, which appeared to be more significant among strains from domestic animals. Moreover, the Tween diffusion test using YNBA was more useful to observe differences among strains, which could not be perceived using SGA.

Identification of Malassezia species by MALDI-TOF MS after expansion of database

The taxonomy of Malassezia species is evolving with introduction of molecular techniques, and difficulty is faced to identify the species by phenotypic methods. Among 15 known Malassezia species, the present Bruker database could identify only 2 species. The present study was aimed to improve Matrix -assisted laser desorption ionization time-flight mass spectrometry (MALDI-TOF MS) based identification of Malassezia species. A total of 88 isolates (DNA sequencing confirmed) for database preparation and, for the validation of database, 190 isolates confirmed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) were used. The main spectrum profile dendrogram showed the sufficient discrimination between all the species by MALDI-TOF MS. The updated Malassezia database could identify 94.7% and 5.3% strains to the species and genus level, respectively. MALDI-TOF MS is a significantly reliable technique, and results were comparable with PCR-RFLP with kappa value 0.9. In conclusion, MALDI-TOF MS could be a possible alternative tool to other molecular methods for rapid and accurate identification of Malassezia species.

Malassezia species and their associated skin diseases

Malassezia spp. are lipophilic fungi that occur on all skin surfaces of humans and animals as commensal and pathogenic organisms. In the 2000s, several new species were added to the Malassezia genus by Japanese researchers. The genus Malassezia now includes 14 species of basidiomycetous yeast. Culture-independent molecular analysis clearly demonstrated that the DNA of Malassezia spp. was predominantly detected in core body and arm sites, suggesting that they are the dominant fungal flora of the human body. Malassezia spp. have been implicated in skin diseases including pityriasis versicolor (PV), Malassezia folliculitis (MF), seborrheic dermatitis (SD) and atopic dermatitis (AD). While Malassezia spp. are directly responsible for the infectious diseases, PV and MF, they act as an exacerbating factor in AD and SD. The fatty acids generated by Malassezia lipase can induce inflammation of the skin, resulting in development of SD. Patch and serum immunoglobulin E tests revealed that AD patients were hypersensitive to Malassezia. However, these findings only partially elucidated the mechanism by which Malassezia spp. induce inflammation in the skin; understanding of the pathogenetic role of Malassezia spp. in SD or AD remains incomplete. In this article, the latest findings of Malassezia research are reviewed with special attention to skin diseases.

Malassezia arunalokei sp. nov., a Novel Yeast Species Isolated from Seborrheic Dermatitis Patients and Healthy Individuals from India

The majority of species within the genus Malassezia are lipophilic yeasts that colonize the skin of warm-blooded animals. Two species, Malassezia globosa and Malassezia restricta, are implicated in the causation of seborrheic dermatitis/dandruff (SD/D). During our survey of SD/D cases, we isolated several species of Malassezia and noticed vast variations within a few lipid-dependent species. Variations observed in the phenotypic characteristics (colony morphology, absence of catalase activity, growth at 37°C, and precipitation surrounding wells containing Tween 20 or Cremophor EL) suggested the possible presence of a novel species. Sequence divergence observed in the internal transcribed spacer (ITS) region, the D1/D2 domain, and the intergenic spacer 1 (IGS1) region of rDNA and the TEF1 gene, PCR-restriction fragment length polymorphism (RFLP) analysis of the ITS2 region, and fluorescent amplified fragment length polymorphism analysis support the existence of a novel species. Based on phenotypic and molecular characterization of these strains, we propose a new species, namely, M. arunalokei sp. nov., and we designate NCCPF 127130 (= MTCC 12054 = CBS 13387) as the type strain.

Progress in Malassezia Research in Korea

Yeasts of the genus Malassezia are part of the normal flora of human skin. However, they are also associated with various skin diseases. Since the introduction of Malassezia to the Korean Dermatologic Society two decades ago, remarkable progress has been made in our knowledge of this genus. In this paper, we review recent developments in Malassezia research, including taxonomy and methods for species identification, recent genome analyses, Malassezia species distribution in healthy conditions and in specific skin diseases, trials investigating the mechanisms underlying Malassezia-related diseases, as well as therapeutic options. This review will enhance our understanding of Malassezia yeasts and related skin diseases in Korea.

Occurrence and distribution of Malassezia species on skin and external ear canal of horses

The aim of this study was to investigate the prevalence of Malassezia species from the body skin and external ear canal of healthy horses. The samples were obtained by scraping the skin surface from the nose, groin and dorsum and swabbing from the external ear canal of 163 animals, and then incubated on sabouraud dextrose agar and modified Dixon agar. Malassezia species were isolated from 34.9% of horses. The percentages of Malassezia species were 64.3% for Arab, 35.7% for Persian, 35.4% for Thoroughbred and 27.1% for Turkmen breeds. The greatest abundance of Malassezia species was found in the external ear canal (47.7%, representing significant difference with other sites), followed by nose (26.3%), groin (15.8%) and dorsum (10.5%) (P < 0.05). A total of 57 strains from six Malassezia species were detected with a frequency rate as follows: M. pachydermatis (33.3%), M. globosa (26.3%), M. sympodialis (14.1%), M. restricta (10.5%), M. obtusa (8.8%) and M. furfur (7%). The most common age-group affected was 1-3 years (59.4%). This study confirmed that cutaneous Malassezia microbiota in healthy horses varies by body site and age but not by breed and gender, representing M. pachydermatis as the most prevalent species on horse skin.

Malassezia intra-specific diversity and potentially new species in the skin microbiota from Brazilian healthy subjects and seborrheic dermatitis patients

Malassezia yeasts are part of the resident cutaneous microbiota, and are also associated with skin diseases such as seborrheic dermatitis (SD). The role these fungi play in skin diseases and why they are pathogenic for only some individuals remain unclear. This study aimed to characterize Malassezia microbiota from different body sites in healthy and SD subjects from Brazil. Scalp and forehead samples from healthy, mild SD and severe SD subjects were collected. Non-scalp lesions from severe SD patients were also sampled. 5.8S rDNA/ITS2 amplicons from Malassezia sp. were analyzed by RFLP and sequencing. Results indicate that Malassezia microbiota did not group according to health condition or body area. Phylogenetic analysis revealed that three groups of sequences did not cluster together with any formally described species, suggesting that they might belong to potential new species. One of them was found in high proportions in scalp samples. A large variety of Malassezia subtypes were detected, indicating intra-specific diversity. Higher M. globosa proportions were found in non-scalp lesions from severe SD subjects compared with other areas, suggesting closer association of this species with SD lesions from areas other than scalp. Our results show the first panorama of Malassezia microbiota in Brazilian subjects using molecular techniques and provide new perspectives for further studies to elucidate the association between Malassezia microbiota and skin diseases.

Dermatomycoses and inflammation: The adaptive balance between growth, damage, and survival

Dermatomycosis is characterized by both superficial and subcutaneous infections of keratinous tissues and mucous membranes caused by a variety of fungal agents, the two most common classes being dermatophytes and yeasts. Overall, the stepwise process of host infection is similar among the main dermatomycotic species; however, the species-specific ability to elicit a host reaction upon infection is distinct. Yeasts such as Candida albicans elicit a relatively low level of host tissue damage and inflammation during pathogenic infection, while dermatophytes may induce a higher level of tissue damage and inflammatory reaction. Both pathogens can, however, manipulate the host's immune response, ensuring survival and prolonging chronic infection. One common element of most dermatomycotic infections is the disease burden caused by inflammation and associated signs and symptoms, such as erythema, burning and pruritus. There is a strong clinical rationale for the addition of a topical corticosteroid agent to an effective antimycotic therapy, especially in patients who present with inflammatory dermatomycoses (e.g., tinea inguinalis). In this review, we aim to compare the pathogenesis of common dermatomycotic species, including Candida yeasts (Candida albicans), dermatophytes (Trichophyton, Epidermophyton or Microsporum species), and other pathogenic yeasts (Malassezia), with a special focus on unique species-specific aspects of the respective infection processes, the interaction between essential aspects of pathogenic infection, the different roles of the host inflammatory response, and the clinical consequences of the infection-related tissue damage and inflammation. We hope that a broader understanding of the various mechanisms of dermatomycoses may contribute to more effective management of affected patients.

Identification of Malassezia species in the facial lesions of Chinese seborrhoeic dermatitis patients based on DNA sequencing

The genus Malassezia is important in the aetiology of facial seborrhoeic dermatitis (FSD), which is the most common clinical type. The purpose of this study was to analyse the distribution of Malassezia species in the facial lesions of Chinese seborrhoeic dermatitis (SD) patients and healthy individuals. Sixty-four isolates of Malassezia were isolated from FSD patients and 60 isolates from healthy individuals. Sequence analysis of the internal transcribed spacer (ITS) region was used to identify the isolates. The most frequently identified Malassezia species associated with FSD was M. furfur (76.56%), followed by M. sympodialis (12.50%) and M. japonica (9.38%). The most frequently isolated species in healthy individuals were M. furfur (61.67%), followed by M. sympodialis (25.00%), M. japonica (6.67%), M. globosa (3.33%), and M. obtusa (3.33%). Overall, our study revealed that while M. furfur is the predominant Malassezia species in Chinese SD patients, there is no significant difference in the distribution of Malassezia species between Chinese SD patients and healthy individuals.

An analysis of the Malassezia species distribution in the skin of patients with pityriasis versicolor in Chengdu, China

Pityriasis versicolor (PV) is a common clinical problem associated with Malassezia species (Malassezia spp.). Controversies remain regarding the specific species involved in the development of PV. This study analyzed the difference in Malassezia spp. distribution in lesional and nonlesional skin in Chinese PV patients. A paired design was applied. Lesional and nonlesional scales from 24 cases were collected; real-time fluorescence quantitative PCR was used to detect 10 different Malassezia spp. In lesional skin, the highest detection rates were for M. globosa (95.8%), M. restricta (91.7%), and M. sympodialis (50.0%). In nonlesional skin, the highest detection rates were for M. globosa (87.5%), M. restricta (79.2%), and M. dermatis (33.3%). A significant difference in the detection rate was only found for M. sympodialis (50.8% versus 20.8%, P = 0.04). Compared with nonlesional skin, the amount of M. globosa, M. restricta, and M. sympodialis in lesional skin was significantly higher (3.8 ± 1.3,  2.5 ± 1.1, and 3.2 ± 1.6 times higher, resp.). The results of this study do not indicate that M. globosa and M. restricta are directly correlated with PV development; however, M. sympodialis is more likely related to PV development in Chinese individuals.

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.

Pityriasis versicolor: clinical-epidemiological characterization of patients in the urban area of Buerarema-BA , Brazil

BACKGROUND

Pityriasis versicolor (PV) is a cutaneous pigmentation disorder caused by a lipophilic yeast of the genus Malassezia sp. It is a superficial mycosis characterized by well-defined, slightly scaly skin lesions of variable color. In Brazil, the number of reported cases is small, and there are few epidemiological studies.

OBJECTIVES

to assess incidence, characteristics of the lesions, effectiveness of the Zileri's Sign procedure, and the epidemiological profile of PV in the urban area of Buerarema - Bahia.

METHODS

Biological samples were collected on pre-established days at Basic Health Care Units from July to September 2010. Sample collection was followed by laboratory diagnosis using Porto's Method.

RESULTS

Of the 158 patients with suspected PV participating in the study, 105 (66.5%) were positive; 72 (68.6%) were female and 33 (31.4%) were male. Sex and location of lesions showed statistically significant differences (p<0.05). The region with the highest rate of cases of PV was found to be the center of the city, with 40.9% of diagnosed cases. The most affected age group was between 10 and 19 years. There was a significant association between the results produced through Zileri's Sign and Porto's Method in relation to positive and negative results (p<0.05).

CONCLUSIONS

The results showed a higher prevalence of PV among individuals at puberty. The Zileri's Sign method proved to be counterproductive, because it showed low efficacy as a method for clinical diagnosis, yielding negative results for 36 (34.3%) patients who had been diagnosed with PV through laboratory examination.

Distribution of Malassezia species on the skin of patients with atopic dermatitis, psoriasis, and healthy volunteers assessed by conventional and molecular identification methods

Background

The Malassezia yeasts which belong to the physiological microflora of human skin have also been implicated in several dermatological disorders, including pityriasis versicolor (PV), atopic dermatitis (AD), and psoriasis (PS). The Malassezia genus has repeatedly been revised and it now accommodates 14 species, all but one being lipid-dependent species. The traditional, phenotype-based identification schemes of Malassezia species are fraught with interpretative ambiguities and inconsistencies, and are thus increasingly being supplemented or replaced by DNA typing methods. The aim of this study was to explore the species composition of Malassezia microflora on the skin of healthy volunteers and patients with AD and PS.

Methods

Species characterization was performed by conventional, culture-based methods and subsequently molecular techniques: PCR-RFLP and sequencing of the internal transcribed spacer (ITS) 1/2 regions and the D1/D2 domains of the 26S rRNA gene. The Chi-square test and Fisher’s exact test were used for statistical analysis.

Results

Malassezia sympodialis was the predominant species, having been cultured from 29 (82.9%) skin samples collected from 17 out of 18 subjects under the study. Whereas AD patients yielded exclusively M. sympodialis isolates, M. furfur isolates were observed only in PS patients. The isolation of M. sympodialis was statistically more frequent among AD patients and healthy volunteers than among PS patients (P < 0.03). Whether this mirrors any predilection of particular Malassezia species for certain clinical conditions needs to be further evaluated. The overall concordance between phenotypic and molecular methods was quite high (65%), with the discordant results being rather due to the presence of multiple species in a single culture (co-colonization) than true misidentification. All Malassezia isolates were susceptible to cyclopiroxolamine and azole drugs, with M. furfur isolates being somewhat more drug tolerant than other Malassezia species.

Conclusions

This study provides an important insight into the species composition of Malassezia microbiota in human skin. The predominance of M. sympodialis in both normal and pathologic skin, contrasts with other European countries, reporting M. globosa and M. restricta as the most frequently isolated Malassezia species.

Skin diseases associated with Malassezia yeasts: facts and controversies

The implication of the yeast genus Malassezia in skin diseases has been characterized by controversy, since the first description of the fungal nature of pityriasis versicolor in 1846 by Eichstedt. This is underscored by the existence of Malassezia yeasts as commensal but also by their implication in diseases with distinct absence of inflammation despite the heavy fungal load (pityriasis versicolor) or with characteristic inflammation (eg, seborrheic dermatitis, atopic dermatitis, folliculitis, or psoriasis). The description of 14 Malassezia species and subsequent worldwide epidemiologic studies did not reveal pathogenic species but rather disease-associated subtypes within species. Emerging evidence demonstrates that the interaction of Malassezia yeasts with the skin is multifaceted and entails constituents of the fungal wall (melanin, lipid cover), enzymes (lipases, phospholipases), and metabolic products (indoles), as well as the cellular components of the epidermis (keratinocytes, dendritic cells, and melanocytes). Understanding the complexity of their interactions will highlight the controversies on the clinical presentation of Malassezia-associated diseases and unravel the complexity of skin homeostatic mechanisms.

Identification of Malassezia species from pityriasis versicolor lesions with a new multiplex PCR method

Despite the fact that a range of molecular methods have been developed as tools for the diagnosis of Malassezia species, there are several drawbacks associated with them, such as inefficiency of differentiating all the species, high cost, and questionable reproducibility. In addition, most of the molecular methods require cultivation to enhance sensitivity. Therefore, alternative methods eliminating cultivation and capable of identifying species with high accuracy and reliability are needed. Herein, a multiplex polymerase chain reaction (PCR)-based method was especially developed for the detection of eleven Malassezia species. The multiplex PCR was standardized by incorporating a consensus forward primer, along with Malassezia species-specific reverse primers considering the sizes of the PCR products. In the method, the multiplex-PCR primer content is divided into three parts to circumvent the problem of increased nonspecific background resulting from the use of a large number of primers. DNA extraction protocol described by Harju and colleagues was modified using liquid nitrogen instead of -80 °C to break down the yeast membrane. By a modified extraction procedure followed by multiplex PCR and electrophoresis, the method enables identification and differentiation of Malassezia species from both of the samples obtained directly from skin and yeast colonies grown in culture. Fifty-five patients who were confirmed with pityriasis versicolor were enrolled in the study. Multiplex PCR detected and differentiated all 55 samples obtained directly from the patients' skin. However, 50 out of 55 samples yielded Malassezia colony in the culture. In addition, eight of 50 colonies were misdiagnosed or not completely differentiated by conventional methods based on the sequence analysis of eight colonies. The method is capable of identifying species with high accuracy and reliability. In addition, it is simple, quick, and cost-effective. More importantly, the method works efficiently for the diagnosis of Malassezia species obtained directly from patient samples.

Seborrheic dermatitis: predisposing factors and ITS2 secondary structure for Malassezia phylogenic analysis

Seborrheic dermatitis (SD) is a chronic, widespread skin condition, which is considered a multifactorial disease influenced, in part, by Malassezia spp. opportunistic activities, as well as various endogenous and exogenous factors. Malassezia species are lipophilic, lipid-dependent yeasts that are members of the normal mycobiota of the human skin. Their isolation from SD lesions varies around the world and the study of the relationship among factors such as gender, age, immunosuppressive condition of the patient and SD development, can lead to a better understanding of this disease. To elucidate the association of age and gender with the development of SD and to precisely determine the Malassezia species involved in the disease, samples were obtained from 134 individuals, including individuals without lesions, human immunodeficiency virus positive patients, individuals with seborrheic dermatitis, and HIV patients with seborrheic dermatitis. Malassezia spp. were identified by phenotypic and genotypic methods and a phylogenetic analysis was performed using Bayesian inference. This study revealed that age and gender are not predisposing factors for SD development, and that the most frequent species of Malassezia related to SD development among the Colombian population is M. restricta. We also report the isolation of M. yamatoensis for the first time in Colombia, and propose an ITS2 secondary structure from Malassezia taxa that can be used for precise identification and to establish more robust phylogenetic relationships.

[Pityriasis versicolor : new aspects of an old disease]

Pityriasis versicolor (PV) is one of the most common infectious skin diseases, as well as the most common dermatosis associated with pigmentation alterations of the skin. PV is prevalent in 1% of the population living in temperate climate zones and more common during the summer. In tropical areas, PV is found in up to 50% of all patients consulting a dermatologist. Of the known Malassezia species, M. globosa is currently felt to play a key role in the pathogenesis of PV, as it is most commonly found in PV lesions. In addition, its round-shaped cells may contribute to the characteristic histology of the disease ("spaghetti and meatballs"). However, the clinical appearance of PV including hyper- and hypopigmentation, fluorescence of the lesions, as well as a lack of inflammation despite high fungal load cannot fully be explained by the presence of M. globosa, which is also found on healthy skin. In M. furfur a tryptophan-dependent metabolic pathway generates a number of indole pigments, which may be associated with the clinical appearance of PV. In the model organism Ustilago maydis it was shown that the formation of the indole compounds occurs spontaneously after initial conversion of tryptophan into indole pyruvate controlled by the key enzyme aminotransferase Tam 1. We review the present knowledge of PV and highlight the potential role of Tam1 in explaining the poorly understood aspects of the disease. Promising therapeutic results using the application of Tam1 inhibitors to treat PV support the enzyme's important role in the disease pathogenesis.

Skin Characteristics in Patients with Pityriasis Versicolor Using Non-Invasive Method, MPA5

Background

Skin pigmentary changes of pityriasis versicolor may occur as either hyperpigmented or hypopigmented lesions, depending on the outcome of interactions between Malassezia yeasts and the skin, such as lipoperoxidation process, stimulus of inflammatory cell to melanocytes, and increased thickness of keratin layer.

Objective

To investigate skin characteristic factors that enhance the susceptibility to Malassezia yeasts and provoke different color changes of pityriasis versicolor patients.

Methods

To clarify these factors, we investigated the skin characteristics of pityriasis versicolor patients, using a non-invasive method known as MPA 5® (Courage and Khazaka, Germany). A total of 90 normal healthy subjects and 30 pityriasis versicolor patients were included in this study.

Results

Both hyperpigmented and hypopigmented pityriasis versicolor skin lesions showed higher humidity, increased sebum excretion rate and increased transepidermal water loss (TEWL) values than normal healthy subjects. But no significant difference of specific Malassezia yeasts species between hyperpigmented and hypopigmented skin lesions was evident.

Conclusion

These results indicate that higher humidity and increased sebum level provide a better growing environment of Malassezia yeasts in the skin, leading to the assumption that interaction between Malassezia yeasts and skin barrier materials makes disruption of skin barrier causing increased TEWL.

Increased hydrophobicity in Malassezia species correlates with increased proinflammatory cytokine expression in human keratinocytes

Malassezia cells stimulate cytokine production by keratinocytes, although this ability differs among Malassezia species for unknown reasons. The aim of this study was to clarify the factors determining the ability to induce cytokine production by human keratinocytes in response to Malassezia species. M. furfur NBRC 0656, M. sympodialis CBS 7222, M. dermatis JCM 11348, M. globosa CBS 7966, M. restricta CBS 7877, and three strains each of M. globosa, M. restricta, M. dermatis, M. sympodialis, and M. furfur maintained under various culture conditions were used. Normal human epidermal keratinocytes (NHEKs) (1 × 10(5) cells) and the Malassezia species (1 × 10(6) cells) were co-cultured, and IL-1α, IL-6, and IL-8 mRNA levels were determined. Moreover, the hydrophobicity and β-1,3-glucan expression at the surface of Malassezia cells were analyzed. The ability of Malassezia cells to trigger the mRNA expression of proinflammatory cytokines in NHEKs differed with the species and conditions and was dependent upon the hydrophobicity of Malassezia cells not β-1,3-glucan expression.

The Malassezia genus in skin and systemic diseases

In the last 15 years, the genus Malassezia has been a topic of intense basic research on taxonomy, physiology, biochemistry, ecology, immunology, and metabolomics. Currently, the genus encompasses 14 species. The 1996 revision of the genus resulted in seven accepted taxa: M. furfur, M. pachydermatis, M. sympodialis, M. globosa, M. obtusa, M. restricta, and M. slooffiae. In the last decade, seven new taxa isolated from healthy and lesional human and animal skin have been accepted: M. dermatis, M. japonica, M. yamatoensis, M. nana, M. caprae, M. equina, and M. cuniculi. However, forthcoming multidisciplinary research is expected to show the etiopathological relationships between these new species and skin diseases. Hitherto, basic and clinical research has established etiological links between Malassezia yeasts, pityriasis versicolor, and sepsis of neonates and immunocompromised individuals. Their role in aggravating seborrheic dermatitis, dandruff, folliculitis, and onychomycosis, though often supported by histopathological evidence and favorable antifungal therapeutic outcomes, remains under investigation. A close association between skin and Malassezia IgE binding allergens in atopic eczema has been shown, while laboratory data support a role in psoriasis exacerbations. Finally, metabolomic research resulted in the proposal of a hypothesis on the contribution of Malassezia-synthesized aryl hydrocarbon receptor (AhR) ligands to basal cell carcinoma through UV radiation-induced carcinogenesis.

[A study of culture-based easy identification system for Malassezia]

Most species of this genus are lipid-dependent yeasts, which colonize the seborrheic part of the skin, and they have been reported to be associated with pityriasis versicolor, Malassezia folliculitis, seborrheic dermatitis, and atopic dermatitis. Malassezia have been re-classified into 7 species based on molecular biological analysis of nuclear ribosomal DNA/RNA and new Malassezia species were reported. As members of the genus Malassezia share similar morphological and biochemical characteristics, it was thought to be difficult to differentiate between them based on phenotypic features. While molecular biological techniques are the most reliable methods for identification of Malassezia, they are not available in most clinical laboratories. We studied ( i ) development of an efficient isolation media and culture based easy identification system, ( ii ) the incidence of atypical biochemical features in Malassezia species and propose a culture-based easy identification system for clinically important Malassezia species, M. globosa, M. restricta, and M. furfur.

Malassezia globosa tends to grow actively in summer conditions more than other cutaneous Malassezia species

Malassezia globosa is a major pathogen of Malassezia folliculitis (MF) and the predominant species on human skin. The aim of this study was to clarify the differences between M. globosa and other cutaneous Malassezia species, M. restricta, M. dermatis, M. sympodialis and M. furfur. The optimum growth temperature, effects of compounds of sweat and free fatty acids on growth, and lipase activities of five cutaneous Malassezia species were determined. The growth of M. globosa was promoted strongly by the compounds of sweat and high temperature unlike that of other cutaneous Malassezia species. This result clarified that M. globosa tended to grow actively in summer conditions more than other cutaneous Malassezia species. Furthermore, M. globosa showed high lipase activity. We consider these characteristics of M. globosa to relate to the pathogenesis of MF.

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

Background

Although acne is a common follicular inflammatory dermatosis, studies of the relationship between Malassezia yeasts and acne have rarely been conducted.

Objective

We sought to identify Malassezia yeasts from acne patients and establish a relationship between specific types of species of Malassezia and acne.

Methods

Sixty acne patients were enrolled. Each strain obtained was identified as one of eleven species by 26S rDNA PCR-RFLP. We then compared these data with those of age- and sex-matched healthy subjects.

Results

Growth of Malassezia was evident in fewer patients with acne (50%) in comparison to controls (70.6%). M. restricta was dominant in patients with acne (23.9%), whereas M. globosa was most common (26.7%) in healthy controls. In the patients group, the rate was the highest (71.7%) in the twenties and, in terms of body site, the rate was the highest (60%) in the chest. In the control group, the rate was the highest (75.0%) in the thirties and in the forehead (85.0%).

Conclusion

The detection rate of Malassezia yeasts was conspicuously low in the acne patients group. Statistically significant differences were observed between the patient and the control groups in the twenties and thirties, and in terms of body site, in the forehead and chest.

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.

Extracellular phospholipase activity of Malassezia strains isolated from individuals with and without dermatological disease

BACKGROUND

The Malassezia genus includes mainly lipophilic yeasts belonging to the cutaneous microbiota of man and other mammals. Some Malassezia species have been associated with various dermatological diseases. The factors permitting the transformation of yeasts of the Malassezia genus from a commensal organism to a pathogenic agent are still little known but the production of various enzymes such as lipase, phospholipase and lipoxygenase could contribute to the pathogenic activity of these yeasts.

AIMS

Here we have determined and compared the extracellular phospholipase activity of sixty human isolates of Malassezia so as to relate this feature to the species of Malassezia and to the origin (from dermatological diseases or not) of the strains examined.

METHODS

Phospholipase production was determined using the semi-quantitative egg-yolk plate method.

RESULTS AND CONCLUSIONS

Malassezia obtusa, Malassezia slooffiae, Malassezia globosa, Malassezia restricta had difficulty developing in the chosen culture medium so that it was not possible to measure phospholipasic activity. Malassezia pachydermatis showed the highest phospholipase activity. Twenty-nine Malassezia sympodialis strains produced phospholipase; the isolates from patients with pityriasis versicolor had significantly higher phospholipasic activity than those isolated from healthy individuals. This observation suggests that the phospholipasic activity of Malassezia may play a role in the onset of skin lesions, especially in the case of pityriasis versicolor.

Malassezia virulence determinants

PURPOSE OF REVIEW

Malassezia yeasts are associated with a number of dermatologic and systemic diseases in humans and animals. Pityriasis versicolor is amongst these diseases and represents one of the most common human skin diseases. Beyond that, the role of Malassezia yeasts in the pathogenesis of other skin diseases such as psoriasis, seborrheic dermatitis and confluent and reticulate papillomatosis is discussed but remains less clear. Clear pathogenetic mechanisms of the above-mentioned diseases are not known so far. The review presents new findings on virulence factors of Malassezia yeasts, shedding light on the pathogenesis of Malassezia-associated diseases.

RECENT FINDINGS

Several virulence factors in Malassezia yeasts are known, based on their enzymatic lipolytic activity resulting in the production of distinct metabolites and special cell wall features. Recently, a secondary metabolic pathway possibly implicated in the pathogenesis of pityriasis versicolor was described.

SUMMARY

The article presents virulence factors of Malassezia yeasts ranging from irritant metabolic byproducts to highly bioactive indole derivatives and attempts to clarify their pathogenic implications in the different diseases. Special emphasis is given to the pathogenesis of pityriasis versicolor, as it represents the disease wherein the causative relationship with Malassezia yeasts appears the most obvious.

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.

Advances in the identification of Malassezia

Members of the genus Malassezia are lypophilic and/or lipid-dependent, unipolar budding yeasts that can become pathogenic under the influence of particular predisposing factors (e.g., changes in the cutaneous microenvironment and/or alterations in host defences). This genus comprises at least 14 species, which have been identified traditionally based on their morphology and biochemical features. However, phenetic characteristics often do not allow the identification or delineation of closely related Malassezia spp., such that molecular tools need to be used to assist in fundamental studies of the epidemiology and ecology of Malassezia as well as aspects of the pathogenesis and disease caused by members of this genus. This article briefly reviews the morphological and biochemical methods commonly used for the identification of Malassezia as well as DNA technological methods that have been established for the specific identification of members of this genus and the diagnosis of their infections. New avenues for the development of improved molecular-diagnostic methods to overcome diagnostic limitations and to underpin fundamental investigations of this interesting group of yeasts are proposed.

Cutaneous malasseziasis: four case reports of atypical dermatitis and onychomycosis caused by Malassezia

BACKGROUND

This study investigates four special cases associated with Malassezia.

METHODS

The special clinical manifestations, mycologic examination, and treatment were reviewed intensively.

RESULTS

An abundance of Malassezia hyphae were found in the scales of the three cases presenting with erythematous patches and in another case presenting with dystrophic nails. Malassezia globosa was identified and confirmed by culture. Antifungal agents were effective in the treatment of all cases.

CONCLUSIONS

Malassezia is an opportunistic fungus that may induce dermatosis other than classical pityriasis versicolor. Hyphae from the lesions may be induced by a change in the microenvironment of the fungus caused by the local application of corticosteroids.