Epidemiological pattern of Malassezia, its phenotypic identification and antifungal susceptibility profile to azoles by broth microdilution method

Background

Malassezia though known for its cutaneous infections can potentially cause invasion. The skin infections caused by Malassezia have poor patient compliance due to its chronicity and recurrent nature of the disease. There is also a lack of standardised antifungal susceptibility profile for Malassezia due to its complex growth requirement.

Objective

This study was performed to understand the epidemiological pattern of disease and to study the antifungal susceptibility testing (AFST) profile so as to choose the appropriate drug/drugs to treat the infections caused by Malassezia.

Materials and Methods

Samples were collected and processed, species were identified by conventional method and AFST was done by broth microdilution method.

Results

The epidemiological pattern showed adolescent females commonly affected in torso. The most common lesion was pityriasis versicolor. The systemic antifungal of choice was itraconazole with the lowest minimum inhibitory concentration (MIC) of 0.125-1 μg/ml. The best topical drug with the lowest MIC value was clotrimazole 0.03-0.5 μg/ml.

Conclusion

AFST is important as it will help the dermatologist to choose the appropriate antifungal agents for the patient and thereby reduce the chronicity of the disease with good patient compliance.

Malassezia Yeasts in Veterinary Dermatology: An Updated Overview

Lipophilic yeasts of the genus Malassezia are important skin commensals and opportunistic skin pathogens in a variety of animals. The species M. pachydermatis was first isolated from the skin of a captive Indian rhinoceros with an exfoliative dermatitis in 1925, recognized as an important otic pathogen of dogs in the 1950's, and finally accepted, after several years of controversy, as a common cause of canine dermatitis in the 1990's. Since then, there has been considerable research into the biology of Malassezia yeasts and their interaction with their animal hosts. In dogs and cats, M. pachydermatis is associated with ceruminous otitis externa and a "seborrhoeic" dermatitis, wherein pruritic, erythematous skin lesions, often with brown/black greasy, malodourous material matting hairs, preferentially develop in intertriginous areas. Skin disease is favored by folds, underlying hypersensitivity disorders, endocrinopathies, defects of cornification, and in cats, various visceral paraneoplastic syndromes. Diagnosis is based on detecting the yeast in compatible skin lesions, usually by cytology, and observing a clinical and mycological response to therapy. Treatment normally comprises topical or systemic azole therapy, often with miconazole-chlorhexidine shampoos or oral itraconazole or ketoconazole. Management of concurrent diseases is important to minimize relapses. Historically, wild-type Malassezia isolates from dogs and cats were typically susceptible to azoles, with the exception of fluconazole, but emerging azole resistance in field strains has recently been associated with either mutations or quadruplication of the ERG11 gene. These observations have prompted increased interest in alternative topical antifungal drugs, such as chlorhexidine, and various essential oils. Further clinical trials are awaited with interest.

Loss of centromere function drives karyotype evolution in closely related Malassezia species

Genomic rearrangements associated with speciation often result in variation in chromosome number among closely related species. Malassezia species show variable karyotypes ranging between six and nine chromosomes. Here, we experimentally identified all eight centromeres in M. sympodialis as 3-5-kb long kinetochore-bound regions that span an AT-rich core and are depleted of the canonical histone H3. Centromeres of similar sequence features were identified as CENP-A-rich regions in Malassezia furfur, which has seven chromosomes, and histone H3 depleted regions in Malassezia slooffiae and Malassezia globosa with nine chromosomes each. Analysis of synteny conservation across centromeres with newly generated chromosome-level genome assemblies suggests two distinct mechanisms of chromosome number reduction from an inferred nine-chromosome ancestral state: (a) chromosome breakage followed by loss of centromere DNA and (b) centromere inactivation accompanied by changes in DNA sequence following chromosome-chromosome fusion. We propose that AT-rich centromeres drive karyotype diversity in the Malassezia species complex through breakage and inactivation.

The diversity and abundance of fungi and bacteria on the healthy and dandruff affected human scalp

Dandruff is a skin condition that affects the scalp of up to half the world's population, it is characterised by an itchy, flaky scalp and is associated with colonisation of the skin by Malassezia spp. Management of this condition is typically via antifungal therapies, however the precise role of microbes in the aggravation of the condition are incompletely characterised. Here, a combination of 454 sequencing and qPCR techniques were used to compare the scalp microbiota of dandruff and non-dandruff affected Chinese subjects. Based on 454 sequencing of the scalp microbiome, the two most abundant bacterial genera found on the scalp surface were Cutibacterium (formerly Propionibacterium) and Staphylococcus, while Malassezia was the main fungal inhabitant. Quantitative PCR (qPCR) analysis of four scalp taxa (M. restricta, M. globosa, C. acnes and Staphylococcus spp.) believed to represent the bulk of the overall population was additionally carried out. Metataxonomic and qPCR analyses were performed on healthy and lesional buffer scrub samples to facilitate assessment of whether the scalp condition is associated with differential microbial communities on the sampled skin. Dandruff was associated with greater frequencies of M. restricta and Staphylococcus spp. compared with the healthy population (p<0.05). Analysis also revealed the presence of an unclassified fungal taxon that could represent a novel Malassezia species.

Alterations in gut bacterial and fungal microbiomes are associated with bacterial Keratitis, an inflammatory disease of the human eye

Dysbiosis, or imbalance in the gut microbiome, has been implicated in auto-immune, inflammatory, neurological diseases as well as in cancers. More recently it has also been shown to be associated with ocular diseases. In the present study, the association of gut microbiome dysbiosis with bacterial Keratitis, an inflammatory eye disease which significantly contributes to corneal blindness, was investigated. Bacterial and fungal gut microbiomes were analysed using fecal samples of healthy controls (HC, n = 21) and bacterial Keratitis patients (BK, n = 19). An increase in abundance of several antiinflammatory organisms including Dialister, Megasphaera, Faecalibacterium, Lachnospira, Ruminococcus and Mitsuokella and members of Firmicutes, Veillonellaceae, Ruminococcaceae and Lachnospiraceae was observed in HC compared to BK patients in the bacterial microbiome. In the fungal microbiome, a decrease in the abundance of Mortierella, Rhizopus, Kluyveromyces, Embellisia and Haematonectria and an increase in the abundance of pathogenic fungi Aspergillus and Malassezia were observed in BK patients compared to HC. In addition, heatmaps, PCoA plots and inferred functional profiles also indicated significant variations between the HC and BK microbiomes, which strongly suggest dysbiosis in the gut microbiome of BK patients. This is the first study demonstrating the association of gut microbiome with the pathophysiology of BK and thus supports the gut-eye axis hypothesis. Considering that Keratitis affects about 1 million people annually across the globe, the data could be the basis for developing alternate strategies for treatment like use of probiotics or fecal transplantation to restore the healthy microbiome as a treatment protocol for Keratitis.

MALDI-TOF MS identification of Malassezia species isolated from patients with pityriasis versicolor at the seafarers' medical service in Dakar, Senegal

Pityriasis versicolor (PV) is a superficial mycosis caused by yeast of the genus Malassezia. The most common isolated Malassezia species in PV lesions differ among M. furfur, M. globosa and M. sympodialis. We purpose to determine the distribution of Malassezia species in PV patients at the seafarers' medical service in Dakar, Senegal and to examine whether any association between identified Malassezia species and patients' profile. From May 2017 to August 2017, first a questionnaire was filled to get informative data before collection of skin scrapings taken from most scaly site using sterile scalpel blade and application of scotch^® for direct examination (DE). At the laboratory, DE, culture and identification by MALDI-TOF MS were done. One hundred patients with PV - all men - were included with a mean age of 34 years. Among seafarers, 81% were sailors. Clinical prevalence of PV was highest in aged adults patients with ages of 31 to 60 years (56%). Seafarers with high level of education were less representative with only 2%. The mean duration of the PV was 26.83 months. 20% of subjects suffered lesions in more than one location. The chest was the most affected anatomical site. Furthermore, possible predisposing factors associated with PV were also detected. DE was positive in 95% but culture growth only in 46%. MALDI-TOF MS analysis of the positive cultures could be performed in 84.8% (39/46). Only M. furfur was identified in 100% (39/39). In definitive, M. furfur is the only causative agent of PV in Dakar.

The gut mycobiome of the Human Microbiome Project healthy cohort

BACKGROUND

Most studies describing the human gut microbiome in healthy and diseased states have emphasized the bacterial component, but the fungal microbiome (i.e., the mycobiome) is beginning to gain recognition as a fundamental part of our microbiome. To date, human gut mycobiome studies have primarily been disease centric or in small cohorts of healthy individuals. To contribute to existing knowledge of the human mycobiome, we investigated the gut mycobiome of the Human Microbiome Project (HMP) cohort by sequencing the Internal Transcribed Spacer 2 (ITS2) region as well as the 18S rRNA gene.

RESULTS

Three hundred seventeen HMP stool samples were analyzed by ITS2 sequencing. Fecal fungal diversity was significantly lower in comparison to bacterial diversity. Yeast dominated the samples, comprising eight of the top 15 most abundant genera. Specifically, fungal communities were characterized by a high prevalence of Saccharomyces, Malassezia, and Candida, with S. cerevisiae, M. restricta, and C. albicans operational taxonomic units (OTUs) present in 96.8, 88.3, and 80.8% of samples, respectively. There was a high degree of inter- and intra-volunteer variability in fungal communities. However, S. cerevisiae, M. restricta, and C. albicans OTUs were found in 92.2, 78.3, and 63.6% of volunteers, respectively, in all samples donated over an approximately 1-year period. Metagenomic and 18S rRNA gene sequencing data agreed with ITS2 results; however, ITS2 sequencing provided greater resolution of the relatively low abundance mycobiome constituents.

CONCLUSIONS

Compared to bacterial communities, the human gut mycobiome is low in diversity and dominated by yeast including Saccharomyces, Malassezia, and Candida. Both inter- and intra-volunteer variability in the HMP cohort were high, revealing that unlike bacterial communities, an individual's mycobiome is no more similar to itself over time than to another person's. Nonetheless, several fungal species persisted across a majority of samples, evidence that a core gut mycobiome may exist. ITS2 sequencing data provided greater resolution of the mycobiome membership compared to metagenomic and 18S rRNA gene sequencing data, suggesting that it is a more sensitive method for studying the mycobiome of stool samples.

Species composition of Malassezia yeasts in dogs in Slovakia

Malassezia (M.) pachydermatis is the lipophilic yeast, which is normally present on the skin and in the ear canal of dogs but under certain conditions it may cause dermatitis and otitis. There is less known about the occurrence of lipid-dependent Malassezia species in dogs. The aim of this study was to detect whether lipid-dependent yeasts are part of the normal microflora in dogs. Two groups of animals were selected for comparison. The group of healthy dogs contained samples of 118 individuals and the group of dogs with cutaneous lesions or otitis externa comprised 328 dogs. The isolates of Malassezia were identified by using genotypic methods that allow the precise identification. M. pachydermatis was the most frequently isolated species in this study (121 isolates). Only four isolates were identified as M. furfur and one isolate was identified as M. nana.

Genus-Wide Comparative Genomics of Malassezia Delineates Its Phylogeny, Physiology, and Niche Adaptation on Human Skin

Malassezia is a unique lipophilic genus in class Malasseziomycetes in Ustilaginomycotina, (Basidiomycota, fungi) that otherwise consists almost exclusively of plant pathogens. Malassezia are typically isolated from warm-blooded animals, are dominant members of the human skin mycobiome and are associated with common skin disorders. To characterize the genetic basis of the unique phenotypes of Malassezia spp., we sequenced the genomes of all 14 accepted species and used comparative genomics against a broad panel of fungal genomes to comprehensively identify distinct features that define the Malassezia gene repertoire: gene gain and loss; selection signatures; and lineage-specific gene family expansions. Our analysis revealed key gene gain events (64) with a single gene conserved across all Malassezia but absent in all other sequenced Basidiomycota. These likely horizontally transferred genes provide intriguing gain-of-function events and prime candidates to explain the emergence of Malassezia. A larger set of genes (741) were lost, with enrichment for glycosyl hydrolases and carbohydrate metabolism, concordant with adaptation to skin’s carbohydrate-deficient environment. Gene family analysis revealed extensive turnover and underlined the importance of secretory lipases, phospholipases, aspartyl proteases, and other peptidases. Combining genomic analysis with a re-evaluation of culture characteristics, we establish the likely lipid-dependence of all Malassezia. Our phylogenetic analysis sheds new light on the relationship between Malassezia and other members of Ustilaginomycotina, as well as phylogenetic lineages within the genus. Overall, our study provides a unique genomic resource for understanding Malassezia niche-specificity and potential virulence, as well as their abundance and distribution in the environment and on human skin.

Malassezia are the dominant eukaryotic residents of human skin and are associated with the most common skin disorders, including dandruff, atopic dermatitis, eczema, and others. Despite significant effort, the role of Malassezia in skin disease and homeostasis remains unclear. Malassezia are also unique among fungi by requiring lipids for growth, but the breadth and genetic basis of their lipophilic lifestyle has not been comprehensively studied. Here we report the complete genomes of all 14 Malassezia species (including multiple strains of the most common species found on humans) and systematically identify features that define the genus and its sub-lineages, including horizontally transferred genes likely to represent key gain-of-function events and which may have enabled evolution of the genus from plant to animal inhabitants. Genus wide expansion of lipid hydrolases and loss of carbohydrate metabolism genes underscore the entire genus’ gradual evolution to lipid-dependency, which was confirmed even in the previously thought to be lipophilic M. pachydermatis, via genomics with experimental confirmation. Finally, these reference genomes will serve as a valuable resource for future metagenomic investigations into the role of Malassezia species in normal healthy skin and diseases.

Genotyping and antifungal susceptibility testing of multiple Malassezia pachydermatis isolates from otitis and dermatitis cases in pets: is it really worth the effort?

A total of 216 colonies of Malassezia pachydermatis from 28 cases of fungal otitis or dermatitis in pets were genotyped by M13 fingerprinting and tested for antifungal susceptibility. A huge genetic diversity was found (157 M13 types in total), with all animals having a polyclonal pattern of infection (5.4 ± 1.5 genotypes/sample). Furthermore, analysis of molecular variance (AMOVA) revealed that most genetic diversity (44%) was found at the within sample level. In contrast, variability in antifungal susceptibility among isolates from the same sample was less important, with different M13 types displaying in most cases identical or very similar MIC results. Most isolates displayed high in vitro susceptibility to amphotericin B, terbinafine and all azoles tested except fluconazole, for which MIC values were always ≥4 μg/ml and a 26.9% of isolates displayed values ≥32 μg/ml. We conclude that although characterization of multiple yeast isolates results in a considerable increase in laboratory workload and expenses, it may help to get a better understanding of the epidemiology of M. pachydermatis in a given patient population.

Malassezia skin diseases in humans

Although Malassezia yeasts are a part of the normal microflora, under certain conditions they can cause superficial skin infection, such as pityriasis versicolor (PV) and Malassezia folliculitis. Moreover the yeasts of the genus Malassezia have been associated with seborrheic dermatitis and dandruff, atopic dermatitis, psoriasis, and, less commonly, with confluent and reticulated papillomatosis, onychomycosis, and transient acantholytic dermatosis. The study of the clinical role of Malassezia species has been surrounded by controversy due to the relative difficulty in isolation, cultivation, and identification. This review focuses on the clinical, mycologic, and immunologic aspects of the various skin diseases associated with Malassezia. Moreover, since there exists little information about the epidemiology and ecology of Malassezia species in the Italian population and the clinical significance of these species is not fully distinguished, we will report data about a study we carried out. The aim of our study was the isolation and the identification of Malassezia species in PV-affected skin and non-affected skin in patients with PV and in clinically healthy individuals without any Malassezia associated skin disease.

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

Over the last few years, new Malassezia species have been found regularly in Japanese subjects. We isolated another new Malassezia species from a Japanese patient with seborrheic dermatitis (SD), and named it M. yamatoensis. In its physiological characteristics and the utilization of Tween by M. yamatoensis is similar to that of M. furfur and M. dermatis. It is distinguished by its growth temperature. To examine the distribution of the microorganism in the skin of patients with SD and atopic dermatitis (AD), and healthy subjects, we applied transparent dressings to the skin, and detected M. yamatoensis DNA using a non-culture-based method that consisted of nested PCR with specific primers. M. yamatoensis DNA was detected from 3 of 31 SD patients (9.7%), 5 of 36 AD patients (13.9%), and 1 of 22 healthy subjects (4.6%). Therefore, M. yamatoensis is a rare member of the cutaneous microflora.

Genotype Analysis ofMalassezia restrictaas the Major Cutaneous Flora in Patients with Atopic Dermatitis and Healthy Subjects

Lipophilic yeasts of the genus Malassezia colonize the skin surface of humans and are an exacerbating factor in atopic dermatitis (AD). Two species, M. restricta and M. globosa are major cutaneous microflora in both AD patients and healthy subjects. We compared the DNA sequences of the intergenic spacer (IGS) region, located between the 26S and 5S rRNA genes of M. restricta colonizing the skin surfaces of 13 AD patients and 12 healthy subjects, and of three CBS stock strains as references. The IGS 1 sequences were divided into two major groups, corresponding to AD patients and healthy subjects. These findings suggest that a specific genotype of M. restricta plays a significant role in AD, although M. restricta commonly colonizes both AD patients and healthy subjects.

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.

Molecular epidemiology of Malassezia globosa and Malassezia restricta in Sudanese patients with pityriasis versicolor

Pityriasis versicolor is a superficial infection of the stratum corneum caused by Malassezia yeasts. The cutaneous Malassezia globosa and Malassezia restricta in Sudanese patients with pityriasis versicolor were elucidated using a molecular-based, culture-independent method and compared with that in healthy individuals. Scale samples were collected by applying an Opsite™ transparent dressing to lesional and non-lesional sites on 29 Sudanese patients with pityriasis versicolor and 54 healthy individuals. Malassezia DNA was extracted directly from the samples. The overall level of colonization by Malassezia globosa and Malassezia restricta was analyzed by real-time PCR using a TaqMan probe. The overall level of colonization by Malassezia at the lesional sites was higher than that at the non-lesional sites for all body sites, including the face, neck, cheeks, and trunk (2.7- to 6.0-fold increase). Both M. globosa and M. restricta were detected in patients and healthy individuals. However, M. globosa predominated at lesional sites, whereas the level of colonization by both species was similar in healthy individuals.

[Evaluation of Malassezia species by Fourier transform infrared (FT-IR) spectroscopy]

Malassezia species which are lipophilic exobasidiomycetes fungi, have been accepted as members of normal cutaneous flora as well as causative agent of certain skin diseases. In routine microbiology laboratory, species identification based on phenotypic characters may not yield identical results with taxonomic studies. Lipophilic and lipid-dependent Malassezia yeasts require lipid-enriched complex media. For this reason, Fourier transform infrared (FT-IR) spectroscopy analysis focused on lipid window may be useful for identification of Malassezia species. In this study, 10 different standard Malassezia species (M.dermatis CBS 9145, M.furfur CBS 7019, M.japonica CBS 9432, M.globosa CBS 7966, M.nana CBS 9561, M.obtusa CBS 7876, M.pachydermatis CBS 1879, M.slooffiae CBS 7956, M.sympodialis CBS 7222 and M.yamatoensis CBS 9725) which are human pathogens, have been analyzed by FT-IR spectroscopy following standard cultivation onto modified Dixon agar medium. Results showed that two main groups (M1; M.globosa, M.obtusa, M.sympodialis, M.dermatis, M.pachydermatis vs, M2; M.furfur, M.japonica, M.nana, M.slooffiae, M.yamatoensis) were discriminated by whole spectra analysis. M.obtusa in M1 by 1686-1606 cm-1 wavenumber ranges and M.japonicum in M2 by 2993-2812 cm-1 wavenumber ranges were identified with low level discrimination power. Discriminatory areas for species differentiation of M1 members as M.sympodialis, M.globosa and M.pachydermatis and M2 members as M.furfur and M.yamatoensis could not be identified. Several spectral windows analysis results revealed that FT-IR spectroscopy was not sufficient for species identification of culture grown Malassezia species.

Identification of Malassezia species from immunocompetent and immunocompromised patients with seborrheic dermatitis

BACKGROUND AND OBJECTIVES

Differences in prevalence, clinical and histological manifestations between seborrheic dermatitis (SD) in immunocompetent and immunocompromised patients suggest that these two populations might also differ in a spectrum of isolated Malassezia species. The purpose of our study was to analyse the prevalence of Malassezia species in immunocompromised and non-immunocompromised patients with SD and to examine if the range of isolated yeasts varies between these two study groups.

PATIENTS AND METHODS

Specimens were taken from 50 patients with SD: 30 without any underlying disease and 20 with confirmed immunosuppression. The samples were obtained by scraping the skin surface of the scalp and trunk lesions of all subjects and then incubated on modified Dixon agar. The yeasts isolated were identified by their morphological and physiological properties according to Guillot et al method.

RESULTS

In both groups, the most commonly isolated species from the scalp lesions were Malassenzia restricta and Malassenzia globosa, the later being the most common species isolated from lesional trunk skin. No significant differences were found between immunocompromised and immunocompetent patients from both sampled sites.

CONCLUSIONS

There is no difference in the distribution of Malassezia species isolated from SD lesions between immunocompetent and immunocompromised patients. However, the much higher percentage of positive cultures in immunocompromised patients confirms that impaired cellular immunity may facilitate fungal survival on the skin.

[Lipophilic yeasts of the genus Malassezia and skin diseases. I. Seborrhoeic dermatitis]

Recent technological advances have revived the interest in Malassezia yeasts and their clinical role, which has long been a matter of controversy because of their fastidious nature in vitro and relative difficulty in isolation, cultivation and identification. Lipophilic yeasts of the genus Malassezia form a part of normal microbial flora of healthy human (and animal) skin, but they also have been associated with several dermatological diseases, like seborrhoeic dermatitis and atopic dermatitis. Our understanding of the interactions between Malassezia and the host might provide new opportunities to better control these often chronically relapsing diseases.

[Cremophor EL test for identification of Malassezia species]

OBJECTIVE

To establish a new method using cremophor EL test for the identification of Malassezia.

METHODS

The suspension of Malassezia fur fur was incubated in a broth containing different concentrations of cremophor EL at 32 degrees C. Cell growth of the yeast was counted by hematocytometer at the 4th, 6th, 8th, 10th and 12th day, respectively. The optimum concentration of cremophor EL for Malassezia was determined by means of variance analysis. Then the 11 species of Malassezia were inoculate in the agar containing the optimum concentration of cremophor EL, and the growth of colony of each species were observed and compared with those inoculated under traditional conditions.

RESULTS

The optimum concentration of cremophor EL for Malassezia fur fur was 4% (P < 0.05). The growth of the 11 species in the agar containing 4% cremophor EL were identical with those inoculated under the traditional conditions. The new method was easy to perform and demanded less culture medium and strains of yeast.

CONCLUSION

The cremophor EL test can improve the efficiency and reduce the cost of identification of Malassezia species.

[Isolation and identification of Malassezia species isolated from healthy skin of malnourished and eutrophic children cared for in daycare centers in Venezuela]

The Malassezia genus contains a group of lipophilic yeasts that form part of the normal microbiota of human and animals skins. The presence of Malassezia species was studied on healthy skin in children, who attended day care centers, located in Maracaibo, Zulia state, Venezuela. Children without skin lesions that were anthropometrically classified as malnourished (48) and eutrophics (40), were studied. Samples were taken from different anatomic regions with a transparent plastic tape. The direct examination was done using blue methylene (0.25%) and then, samples were cultivated in Dixon medium with antibiotic. The identification of the isolated yeasts was done by classical methodology. The results obtained indicate that malnourished and eutrophics children were positive to Malassezia in relatively high prevalences (66.6% and 65.0% respectively). It is worthy of notice that M. furfur was predominantly present in malnourished children (77%). It was isolated from all the anatomic locations in both groups of children. M. slooffiae was mainly located in the back of the eutrophic children. M. furfur was isolated preferently in malnourished male children, while in the eutrophic children, it was observed in females. It was demonstrated that M. furfur was predominantly present in the healthy skin of malnourished and eutrophic children.

[Pityriasis versicolor and the yeasts of genus Malassezia]

Although pityriasis versicolor is the only human disease for which Malassezia yeasts have been fully established as pathogens, it is still not clear which species are implicated. Most studies carried out in recent years support our hypothesis - proposed in 1999 - that Malassezia globosa is the predominant species in pityriasis versicolor lesions, at least in temperate climates. Confirmation of this hypothesis could help us understand the conditions, as yet unclear, that induce transformation of this yeast from the saprophytic form present in healthy skin to the parasitic form, characterized by the formation of pseudomycelium, and could also guide therapy. In addition, isolation of another species, Malassezia furfur, which seems to be predominant in the tropics, raises the possibility of a second etiologic agent confined to certain areas, as occurs with some other human mycoses.

Assessing the relationship between Malassezia and leishmaniasis in dogs with or without skin lesions

The relationship among the frequency, population size and phospholipase activity of Malasseziapachydermatis was investigated for dogs with Leishmania infantum infection (Li+) and those without evidence of this infection (Li-). A group of 188 dogs (141 without and 47 with skin lesions) was examined clinically, and samples were taken for the detection of Malassezia and L. infantum using various diagnostic methods. Malassezia was cultured from skin samples from 101 (53.7%) dogs and classified biochemically and molecularly as M. pachydermatis. A significantly higher mean population size of M. pachydermatis was cultured from the skin of L+ dogs compared with L- dogs. For M. pachydermatis, most phospolipase-producing cultures and the highest phospholipase activity were recorded for L- dogs with lesions and L+ dogs without lesions. The results showed that M. pachydermatis was a common commensal on dogs with or without L. infantum infection and established that L. infantum infection in dogs without skin lesions was associated with increased growth of M. pachydermatis and production of phospholipase in vitro.

The genus Malassezia: old facts and new concepts

Lipophilic yeasts are being considered as major opportunistic pathogens for a very long time. Most of the yeasts show an absolute requirement for long fatty acid chains and specific procedures are required for their isolation, conservation and identification. For that reason, the history of the nomenclature used for the Malassezia genus is quite complex. Before 1996, only 3 species were recognized: Malassezia furfur, M. pachydermatis and M. sympodialis. To date, the genus is composed of one non lipid-dependent species (M. pachydermatis) and 12 lipid-dependent species. No doubt that additional new taxa will be described in close future. Very recently the genome and secretory proteome of two Malassezia species was described. This analysis demonstrated the presence of multiple secreted lipases to aid in harvesting host lipids. It also revealed the presence of mating-type genes, providing an indication that Malassezia yeasts may be capable of sex.

Epidemiology and variability of Malassezia spp

A short review on Malassezia spp., completed with our experience, is made. The main epidemiological characteristics with particular regard to the diffusion in several animal species, the characteristics of skin colonization (in particular of the dog) and the distribution of the different Malassezia spp. in some hosts are discussed. Lastly the main phenotypic and genotypic characteristics, referred to M. pachydermatis especially, were described, showing their high variability and differentiation.

[Concordance between phenotypical features and PCR-REA for the identification of Malassezia spp]

The genus Malassezia has been recently revised and nowadays includes 11 species that cannot always be differentiated from each other by physiological and morphological tests. This study was aimed to evaluate the correlation between a molecular method and conventional phenotypic features in the identification of Malassezia spp. To achieve this aim, 92 Argentinean clinical strains isolated between 2001 and 2005 were analyzed along with three reference strains (Malassezia furfur CBS 7019, Malassezia sympodialis CBS 7222 and Malassezia slooffiae CBS 7956). By using PCR and restriction enzyme analysis with three different DNA endonucleases (PCR-REA), the molecular method consistently identified all three reference strains and all 92 clinical isolates as follows: 63 M. sympodialis, 18 M. furfur, 10 Malassezia globosa and one Malassezia obtusa. Phenotypic studies undentified 85 clinical isolates and two of the reference strains (total agreement > 91%). In particular for M. sympodialis, M. furfur and M. globosa, the species more frequently involved in human pathology, the agreement ranged between 84 and 96%. This result suggests that phenotypic studies are suitable for the presumptive identification of important Malassezia species in the clinical medical mycology laboratories where molecular methodologies are not available.

Antifungal and antioxidant activities of the phytomedicine pipsissewa, Chimaphila umbellata

Bioassay-guided fractionation of Chimaphila umbellata (L.) W. Bart (Pyrolaceae) ethanol extracts led to the identification of 2,7-dimethyl-1,4-naphthoquinone (chimaphilin) as the principal antifungal component. The structure of chimaphilin was confirmed by 1H and 13C NMR spectroscopy. The antifungal activity of chimaphilin was evaluated using the microdilution method with Saccharomyces cerevisiae (0.05mg/mL) and the dandruff-associated fungi Malassezia globosa (0.39mg/mL) and Malassezia restricta (0.55mg/mL). Pronounced antioxidant activity of C. umbellata crude extract was also identified using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, suggesting this phytomedicine has an antioxidant function in wound healing. A chemical-genetic profile was completed with chimaphilin using approximately 4700 S. cerevisiae gene deletion mutants. Cellular roles of deleted genes in the most susceptible mutants and secondary assays indicate that the targets for chimaphilin include pathways involved in cell wall biogenesis and transcription.

Malassezia slooffiae-associated dermatitis in a goat

An adult male Pygmy goat with a history of losing hair and declining body condition was euthanized, and a complete diagnostic work-up was performed. The animal showed diffuse alopecia on the dorsal and lateral sides of thorax and abdomen, proximal legs, neck and face. Histology revealed diffuse orthokeratotic hyperkeratosis, epidermal hyperplasia and perivascular dermatitis. Broad-based budding yeasts and hyphae were visible in the keratin layer. Malassezia slooffiae was identified in the skin by polymerase chain reaction amplification of part of the large subunit rRNA gene using broad-range fungal primers and DNA sequencing. This is the first report of M. slooffiae-associated dermatitis in goats.

Molecular analysis of Malassezia microflora in the lesional skin of psoriasis patients

Systemic and focal infections by microorganisms have been known to induce or exacerbate psoriasis. To investigate the role of Malassezia species in the development of psoriasis, we analyzed the Malassezia microflora in psoriasis patients using a nested polymerase chain reaction (PCR) assay, and compared it with those in atopic dermatitis (AD) patients and healthy subjects. Fungal DNA was directly collected from the lesional and non-lesional skin of the trunk of 22 psoriasis patients by applying a transparent dressing. The extracted DNA was amplified by using specific primers designed for the PCR in the intergenic spacer or internal transcribed spacer area of the ribosomal RNA. All nine of the Malassezia species were detected at different rates from the 22 psoriasis patients. The overall detection rates in lesional and non-lesional skin of M. restricta, M. globosa and M. sympodialis were high (96%, 82% and 64%, respectively), whereas the detection rates of the other species were relatively low. However, there was no difference in the rates between lesional and non-lesional skin areas. The average number of Malassezia species detected in overall sites of the psoriasis patients was 3.7 +/- 1.6 species, although this fact showed no correlation with the severity of the symptoms. The number of Malassezia species detected was 4.1 +/- 1.9 in the AD patients, and 2.8 +/- 0.8 in the healthy subjects, suggesting that the skin microflora of psoriasis patients and AD patients show greater diversity than that of healthy subjects.

Quantitative analysis of Malassezia in the scale of patients with psoriasis using a real-time polymerase chain reaction assay

BACKGROUND

It has been suggested that Malassezia is associated with the development of skin lesions in psoriasis because of the response of the scalp lesions in psoriasis to antifungal agents. Malassezia restricta and M. globosa are the two major members of the cutaneous Malassezia flora in patients with psoriasis, although they have not been analysed quantitatively.

OBJECTIVES

This study quantified the two major cutaneous Malassezia species in psoriatic scale from different body sites using a real-time polymerase chain reaction (PCR) assay.

METHODS

Scale samples were collected from lesional and nonlesional skin of 20 Japanese patients with psoriasis and fungal DNA was extracted from the samples directly. All the Malassezia species, including the two major species M. globosa and M. restricta, were quantified with high accuracy, using a real-time PCR assay.

RESULTS

Colonization by M. restricta was approximately five times higher at all body sites than colonization by M. globosa. Malassezia colonization was significantly lower in patients with hyperlipidaemia than in patients with normolipidaemia.

CONCLUSIONS

Malassezia restricta is the predominant species in psoriatic scale.

Two new lipid-dependentMalasseziaspecies from domestic animals

During a study on the occurrence of lipid-dependent Malassezia spp. in domestic animals, some atypical strains, phylogenetically related to Malassezia sympodialis Simmons et Guého, were shown to represent novel species. In this study, we describe two new taxa, Malassezia caprae sp. nov. (type strain MA383=CBS 10434), isolated mainly from goats, and Malassezia equina sp. nov. (type strain MA146=CBS 9969), isolated mainly from horses, including their morphological and physiological characteristics. The validation of these new taxa is further supported by analysis of the D1/D2 regions of the 26S rRNA gene, the ITS1-5.8S-ITS2 rRNA, the RNA polymerase subunit 1 and chitin synthase nucleotide sequences, and the amplified fragment length polymorphism patterns, which were all consistent in separating these new species from the other species of the genus, and those of the M. sympodialis species cluster, specifically.

Prevalence of Malassezia spp. yeasts in feline nail folds: a cytological and mycological study

Malassezia spp. yeasts are commensal organisms of mammal and avian skin, but little is known about their presence on the skin of healthy cats. The purposes of this study were to evaluate the prevalence of Malassezia spp. yeasts in feline nail folds and to identify the different species. Forty-six cats of different breeds were evaluated by cytological examination, and Malassezia spp. yeasts were seen in 61% of them. Yeasts were found in 100% of Devon Rex cats [mean 8.63/oil immersion field (high-power field - HPF)]. Conversely, only 42% of cats of other breeds (domestic short-haired and Persian) were positive (mean 0.59/HPF). Twenty-one cats of different breeds were subsequently evaluated by fungal culture. Malassezia pachydermatis was isolated from 52%, M. furfur from 38%, and M. sympodialis from 9.5% of the cats. More than one species was observed in eight of 21 cats, six of which were Devon Rex. Malassezia spp. yeasts are common inhabitants of feline nail folds, especially in Devon Rex cats, and the presence of a high number of yeasts on cytology correlates with the clinical observation of brown, greasy material in the nail folds. M. pachydermatis and two lipid-dependent species were isolated from both Devon Rex cats and cats of other breeds.

Detection and quantification of specific IgE antibodies against eight Malassezia species in sera of patients with atopic dermatitis by using an enzyme-linked immunosorbent assay

The lipophilic yeast Malassezia, a member of the cutaneous microflora, is an exacerbating factor in atopic dermatitis (AD). Of the 11 currently recognized species, M. globosa and M. restricta are found to frequently colonize the skin of AD patients. In this study, we attempted to quantify specific IgE antibodies against eight Malassezia species, namely, M. dermatitis, M. furfur, M. globosa, M. obtusa, M. pachydermatis, M. slooffiae, M. sympodialis, and M. restricta, in sera from AD patients by using an enzyme-linked immunosorbent assay (ELISA). The specific IgE value against M. restricta was greater than those against other Malassezia species. Competitive ELISA inhibition tests revealed that M. restricta contained species specific as well as shared antigens. Therefore, M. restricta could be considered as a candidate diagnostic antigen for detecting anti-Malassezia IgE in sera from AD patients.

Carriage ofMalassezia spp.yeasts in healthy and seborrhoeic Devon Rex cats

Skin and anal mucosal carriage of Malassezia spp. yeasts was investigated in 21 healthy Devon Rex cats (DRC) and in 9 seborrhoeic DRC using swabs and contact plates. M. pachydermatis was isolated from 26 cats and lipid-dependent Malassezia spp. isolates were recovered from the claw fold of 5 healthy and 3 seborrhoeic DRC. The frequencies of isolation and population sizes of M. pachydermatis in the axillae, left groin and claw fold in seborrhoeic DRC significantly exceeded (P<0.05) those of healthy animals. The frequencies of isolation and population sizes of M. pachydermatis in the axillae and groin in both groups of DRC, and the frequencies of isolation and population sizes of M. pachydermatis in the claw fold of the seborrhoeic DRC, exceeded those of healthy Domestic short-haired cats. Using polymerase chain reaction--restriction enzyme analyses (PCR-REA) based on amplification of the large subunit rRNA gene, all eight lipid-dependent isolates had profiles that were indistinguishable from that of M. slooffiae CBS 7956. These data indicate that DRC are frequently colonized by M. pachydermatis and that the claw folds may also be colonized by M. slooffiae. The pathogenic significance of the high Malassezia spp. counts in the seborrhoeic DRC should now be determined.

Genetic and biochemical characterization ofMalassezia pachydermatiswith particular attention to pigment-producing subgroups

The aim of the study was the characterization of Malassezia pachydermatis and its pigment-producing subgroup using biochemical tests and RAPD. It was of interest to determine whether particular RAPD patterns could be used to indicate pigment production, as well as a close genetic relatedness to Malassezia furfur. Therefore, 210 strains of M. pachydermatis were examined for morphology, catalase and ss-glucosidase activity, lipid and carbohydrate assimilation and the tryptophan-dependent synthesis of pigments. Of these, 114 strains were subjected to RAPD analyses. A multivariate logistic regression model was applied to classify M. pachydermatis isolates regarding their pigment production by using genetic and biological parameters. Biological and RAPD findings showed a high biological and genetic diversity within the species M. pachydermatis and within pigment producers. RAPD analysis revealed 28 genotypes within 114 strains tested. Pigment producing strains could not be assigned to a common RAPD profile, but a genetic relatedness of pigment-producing M. pachydermatis with M. furfur can be assumed. A particular RAPD pattern allowed statistically significant probability of pigment production (P<0.001) and might be used as a tool to rapidly detect pigment producing M. pachydermatis, e.g. in Malassezia-associated pityriasis versicolor. The reported method is useful for identification of pigment producing M. pachydermatis isolates and has advantages over established tests.

Update on the genusMalassezia

Malassezia yeasts are commensals of normal human skin, but also cause pityriasis versicolor, seborrhoeic dermatitis and evidence is accumulating that they play a significant role in atopic eczema/dermatitis syndrome (AEDS; formerly atopic dermatitis). The taxonomy of the genus has changed considerably and is likely to change more in the future. Our understanding of the interaction between Malassezia and the host demonstrates that it has the paradoxical ability to both stimulate and suppress the immune response directed against it and there is a fine balance in its existence at the interface between commensalism and pathogenicity.

Malassezia species isolated from lesional and non-lesional skin in patients with pityriasis versicolor

Pityriasis versicolor (PV) is a superficial fungal infection where Malassezia species play a definite causative role, but the clinical significance of each of these species is not fully understood. The aim of our study was to analyse the prevalence of Malassezia species in PV lesions and to examine if the range of species varies with patient sex, age, direct microscopy findings and some clinical data. Ninety patients with PV completed the study. The samples were obtained by scraping the skin surface, both from lesional and non-lesional skin and then incubated on Sabouraud dextrose agar and modified Dixon agar. The yeast isolated were identified according to their macroscopic and microscoipic features and physiological characteristics. In PV lesions, the most common species was M. globosa (63%), followed by M. sympodialis (14%), M. furfur (10%), M. obtusa (8%) and M. slooffiae (4%). The most frequently isolated species from clinically healthy skin were M. globosa (49%), M. sympodialis (37%) and M. furfur (5%). We found significant difference in the distribution of Malassezia species between lesional and non-lesional skin and in the distribution of Malassezia species according to the direct microscopy findings. M. globosa in its mycelial phase is the predominant species involved in the aetiology of PV.

Carriage ofMalasseziaspp. yeasts in cats with diabetes mellitus, hyperthyroidism and neoplasia

The frequencies of isolation and population sizes of Malassezia spp. on skin and at mucosal sites in 16 cats with diabetes mellitus, 20 cats with hyperthyroidism and 8 cats with neoplasia did not vary significantly from those of healthy cats when measured with the use of contact plates and a swab technique. M. pachydermatis was isolated from nine sites in one cat with feline paraneoplastic alopecia and pancreatic adenocarcinoma, two cats with diabetes mellitus and five cats with hyperthyroidism. A polymerase chain reaction-restriction enzyme analysis (PCR-REA) method that differentiated the 11 species of Malassezia spp was used to identify the lipid-dependent isolates that were obtained from two cats with diabetes mellitus, two cats with hyperthyroidism and one cat with multicentric lymphoma. Six isolates had PCR-REA patterns that were indistinguishable from M. slooffiae CBS 7956 and three matched M. nana CBS 9557. Our data suggests that skin and mucosal counts of Malassezia spp. are not routinely increased in cats with diabetes mellitus or hyperthyroidism but we report a further example of an association between feline paraneoplastic alopecia and Malassezia spp. proliferation. To the authors' knowledge, this is the first report of the isolation of M. slooffiae from feline skin.

[Malassezia yeasts and their significance in dermatology]

Yeasts of the genus Malassezia belong to the normal microflora of the human skin. In addition they are known to cause a variety of skin diseases; the most frequent of which is pityriasis versicolor. Malassezia yeasts are also thought to be associated with seborrheic dermatitis, dandruff and Malassezia folliculitis. Recently the significance of Malassezia yeasts as a trigger factor for atopic dermatitis of the head and neck region has been pointed out. The role of the Malassezia yeasts in these different diseases has been controversial in the past and remains an issue because of difficulties in isolation, culture and differentiation of the organism. Thanks to molecular techniques, 10 species can actually be differentiated. The article presents the different Malassezia-associated diseases, their clinical picture, diagnosis and appropriate therapy. In addition the speciation of Malassezia is reviewed.

Identificação de espécies de Malassezia em pacientes com pitiríase versicolor em Goiânia-GO

O objetivo deste estudo foi verificar a freqüência de pitiríase versicolor e identificar leveduras do gênero Malassezia, de pacientes encaminhados ao laboratório de Micologia da Universidade Federal de Goiás em Goiânia. Foram diagnosticados 95 casos de pitíriase versicolor e identificados quatro espécies de Malassezia: Malassezia furfur, Malassezia sympodialis, Malassezia globosa e Malassezia obtusa.

Quantitative investigation on the distribution of Malassezia species on healthy human skin in Korea

This study concerns a culture research based on the data gathered from Korean subjects to examine distribution of Malassezia yeast. Malassezia yeast were cultivated out of samples from scalp, forehead, chest, arm and thigh. Malassezia restricta was recovered more frequently in the teens and young adults, while M. globosa was the predominant species in subjects older than 50 years of age. The population density of Malassezia yeast was significantly higher in the age group (AG) of 21-30 years compared with other AGs (P < 0.05). It was also significantly higher in the chest compared with the forehead, arm and thigh (P < 0.05). The key is to recognise the existence of a difference in the amount and type of Malassezia species in different AGs as well as body areas, which reflects differing skin lipid levels in various AGs and different body areas.

Molecular analysis of fungal microbiota in samples from healthy human skin and psoriatic lesions

Psoriasis, a common cutaneous disease of unknown etiology, may be triggered by infections, including those due to fungi. Since the fungal community of human skin is poorly characterized, we aimed to analyze the mycological microbiota in healthy skin and psoriatic lesions. Twenty-five skin samples from five healthy subjects (flexor forearm) and three patients with psoriasis were analyzed using broad-range 18S ribosomal DNA (rDNA) and 5.8S rDNA/internal transcribed spacer 2 (ITS2) Malassezia-specific PCR primers. Broad-range PCR analysis indicated that most organisms resembled Malassezia. Malassezia-specific 5.8S/ITS2 analysis of 1,374 clones identified five species and four unknown phylotypes, potentially representing new species. The species distribution appears largely host specific and conserved in different sites of healthy skin. In three subjects, the Malassezia microbiota composition appeared relatively stable over time. Samples of Malassezia microbiota from healthy skin and psoriatic lesions were similar in one patient but substantially different in two others. These data indicate the predominance of Malassezia organisms in healthy human skin, host-specific variation, stability over time, and as yet, no consistent patterns differentiating psoriatic skin from healthy skin.

A modified Christensen's urea and CLSI broth microdilution method for testing susceptibilities of six Malassezia species to voriconazole, itraconazole, and ketoconazole

Two supplemented broths (Christensen's urea with 0.1% Tween 80 and 0.5% Tween 40 and RPMI 1640 with 1% glycerol, 1% peptone, 1.8% glucose, and 0.05% Tween 80) were evaluated to determine voriconazole, itraconazole, and ketoconazole MICs for 200 Malassezia sp. isolates. Malassezia globosa and M. restricta were the least susceptible species (MICs at which 90% of the isolates tested were inhibited, 1 to >or=8 microg/ml versus 0.25 to 1 microg/ml).

Microcoding and flow cytometry as a high-throughput fungal identification system for Malassezia species

Yeasts of the genus Malassezia have been associated with a variety of dermatological disorders in humans and domestic animals. With the recent recognition of new members of the genus, new questions are emerging with regard to the pathogenesis and epidemiology of the new species. As new species are recognized, a precise and comprehensive identification system is needed. Herein is described a bead suspension culture-based array that combines the specificity and reliability of nucleic acid hybridization analysis with the speed and sensitivity of the Luminex analyser. The developed 16-plex array consisted of species- and group-specific capture probes that acted as 'microcodes' for species identification. The probes, which were designed from sequence analysis in the D1/D2 region of rRNA and internal transcribed spacer (ITS) regions, were covalently bound to unique sets of fluorescent beads. Upon hybridization, the biotinylated amplicon was detected by the addition of a fluorochrome coupled to a reporter molecule. The hybridized beads were subsequently analysed by flow cytometric techniques. The developed array, which allowed the detection of species in a multiplex and high-throughput format, was accurate and fast, since it allowed precise identification of species and required less than 1 h following PCR amplification. The described protocol, which can integrate uniplex or multiplex PCR reactions, permitted the simultaneous detection of target sequences in a single reaction, and allowed single mismatch discrimination between probe and non-target sequences. The assay has the capability to be expanded to include other medically important pathogenic species in a single or multiplex array format.

Malassezia yeasts and pityriasis versicolor

PURPOSE OF REVIEW

To analyze the relationships among different Malassezia species and pityriasis versicolor, the only human disease in which the etiologic role of these fungi is fully accepted (although the species implicated remains a matter of discussion).

RECENT FINDINGS

Since 1996, after the taxonomic revision of the genus, a limited number of papers analyzing the role of the different Malassezia species in pityriasis versicolor have been published or were the subject of presentations in congresses; there were only four in the past year. This paper discusses the results of these works, comparing them with results of the authors' most recent study in this field, conducted over the past 16 months.

SUMMARY

Most of the studies published thus far now show that Malassezia globosa is the predominant species found in the lesions of pityriasis versicolor, at least in temperate climates. The authors' recent findings confirm these results. The etiologic role of M. globosa in pityriasis versicolor is based, even more than on its isolation in a high percentage of cultures, on its identification by direct microscopy as typical globose yeast cells producing pseudohyphae in almost 100% of cases. The confirmation of the pathogenic role of this species in pityriasis versicolor could help in understanding these conditions, which are still unclear, which promote its transformation from the saprophytic stage present in healthy skin to the parasitic one, and could also help in selecting the best therapeutic measures.

[Malassezia related diseases]

The genus Malassezia is now divided into eleven species. Different species initiate or aggravate different skin diseases. In seborroheic dermatitis, M. restricta play an important role, while in atopic dermatitis, M. globosa and/or M. restricta are major cutaneous microflora. M. globosa is a causative species of tinea versicolor, and this species is also a causative species of malassezia folliculitis. We should therefore obtain better knowledge of the ecological and pathogenic roles of malassezia.

Speziesdifferenzierung von Hefen der Gattung Malassezia mittels Fourier-Transform-Infrarot-Spektroskopie

BACKGROUND

83 Malassezia strains (65 wild isolates and 18 reference strains) were differentiated to the species level using conventional methods including morphological and biochemical features. These strains were further analyzed by Fourier transform infrared spectroscopy (FT-IRS).

RESULTS

FT-IRS analysis allowed a clear separation of Malassezia strains according to species-specific cluster formation. The main differences were found between Malassezia furfur and other Malassezia species. In addition, within the species Malassezia furfur, a separation in two similar groups could be demonstrated. A disadvantage of FT-IRS is the relatively expensive apparatus. A great advantage is the speed and simplicity of the procedure, producing results within minutes.

CONCLUSION

In pityriasis versicolor, Malassezia globosa was the dominant species found in 62% of cases. In addition, Malassezia furfur was found in 60% of dandruff cases.

Distribution of Malassezia species in pityriasis versicolor and seborrhoeic dermatitis in Greece. Typing of the major pityriasis versicolor isolate M. globosa

BACKGROUND

The expansion of the genus Malassezia has generated interest in the epidemiological investigation of the distribution of new species in a range of dermatoses, on which variable results have been reported from different geographical regions. No data are thus far available from South-east Europe (Greece).

OBJECTIVES

To study the distribution of Malassezia species in pityriasis versicolor (PV) and seborrhoeic dermatitis (SD) and to investigate whether polymorphisms in the internal transcribed spacer (ITS) 1 region facilitate detection of M. globosa and M. sympodialis subtypes.

METHODS

In total, 109 patients with PV and SD and positive Malassezia cultures were included in the study. Age, gender, primary/recurrent episode, disease extent and clinical form of PV were recorded. ITS 1 polymorphisms of M. globosa and M. sympodialis type and clinical strains were investigated by polymerase chain reaction (PCR)-single-strand conformational polymorphism (SSCP) analysis.

RESULTS

Malassezia globosa was the prevalent species isolated from PV and SD either alone (77% and 39%, respectively) or in combination (13% and 18%, respectively) with other Malassezia species. The pigmented form of PV was strongly correlated with the female gender. PCR-SSCP differentiated five subgroups of M. globosa with one being associated with extensive clinical disease. All M. sympodialis isolates displayed a homogeneous ITS 1 PCR-SSCP profile.

CONCLUSIONS

Malassezia species isolation rates were in agreement with those reported from South-west Europe. PCR-SSCP of the ITS 1 is useful for highlighting prospective clinical implications of M. globosa subtypes.

[RAPD differentiation of yeast like fungi Malassezia pachydermatis]

The aim of the work was analyzing of genomic DNA of Malassezia pachydermatis isolates from clinical cases otitis externa from dogs using RAPD method with arbitrary primers Eric 1R, Eric2, BG2 and FM1.

MATERIALS AND METHODS

47 strains of M. pachydermatis isolates from clinical cases otitis externa from dogs were tested. Isolation of genomic DNA was provided according with MasterPureTM Yeast DNA Purification Kit EPICENTRE procedure. The quality of isolated genomic DNA was determined electrophoreticaly. For differentiation the following primers were used: Eric1R, Eric2, BG2 and FM1. Primers Eric 1R and Eric 2 were used together in one reaction or amplificated separately. Obtained products were analyzed electrophoreticaly in 1.5% agarose gel. For determination of phylogenic tree Quantity one VersaDoc (BioRad) and Statgraphics plus 4.1 programs were used.

RESULTS

High degree of heterogeneity of DNA among investigated isolates of M. pachydermatis was shown using FM1 primer. Dendrograms were prepared by calculation euclid's distance of different parameters (size and count of RAPD products) by nearest neighbor method. Basing on phylogenic tree four main types (phylogenic groups) of M. pachydermatis isolates were shown. The other five groups non-count was shown also.