Isolation of Malassezia globosa and M. sympodialis from patients with pityriasis versicolor in Spain

Atypical and Unpredictable Superficial Mycosis Presentations: A Narrative Review

While typically exhibiting characteristic features, fungal infections can sometimes present in an unusual context, having improbable localization (eyelid, face, or joint); mimicking other skin diseases such as eczema, psoriasis, or mycosis fungoides; and appearing with unexpected color, shape, or distribution. The emergence of such a challenging clinical picture is attributed to the complex interplay of host characteristics (hygiene and aging population), environment (climate change), advances in medical procedures, and agent factors (fungal resistance and species emergence). We aim to provide a better understanding of unusual epidemiological contexts and atypical manifestations of fungal superficial diseases, knowing that there is no pre-established clinical guide for these conditions. Thus, a literature examination was performed to provide a comprehensive analysis on rare and atypical superficial mycosis as well as an update on certain fungal clinical manifestations and their significance. The research and standard data extraction were performed using PubMed, Medline, Scopus, and EMBASE databases, and a total of 222 articles were identified. This review covers published research findings for the past six months.

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

Background

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

Case presentation

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

Conclusions

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

Epidemiology and susceptibility profile to classic antifungals and over-the-counter products of Malassezia clinical isolates from a Portuguese University Hospital: a prospective study

PURPOSE

Clinical epidemiological data about the distinct Malassezia species remain scarce. The recurrence of Malassezia-related skin diseases, despite long-term use of antifungals, raises concern about the hypothetical emergence of antifungal resistance. We aimed to assess the distribution of Malassezia species among patients from a University Hospital with pityriasis versicolor, seborrheic dermatitis and healthy volunteers, and to evaluate the susceptibility profile to classic antifungals and over-the-counter compounds, searching for clinical associations.

METHODOLOGY

The enrollment of volunteers was conducted at the Dermatology Department of a University Hospital over a 3 year period. Malassezia culture isolates were identified to the species-level by sequencing. The drug susceptibility profile was assessed according to a broth microdilution assay, as recommended by the Clinical Laboratory Standards Institute.

RESULTS

A total of 86 Malassezia isolates were recovered from 182 volunteers. Malassezia sympodialis was the most frequent isolated species. We found high MIC values and a wide MIC range in the case of tested azoles, and very low terbinafine MIC values against most isolates. Previous topical corticosteroid therapy was associated with a significant increase of MIC values of fluconazole and of terbinafine.

CONCLUSION

Conversely to other European studies, M. sympodialis was the most common isolated species, which might be related to geographic reasons. The impact of previous topical corticotherapy upon the antifungal susceptibility profile was hereby demonstrated. In vitro susceptibility test results suggest that terbinafine might be a valid alternative for Malassezia-related skin diseases nonresponsive to azoles.

Eighty Years of Mycopathologia: A Retrospective Analysis of Progress Made in Understanding Human and Animal Fungal Pathogens

Mycopathologia was founded in 1938 to 'diffuse the understanding of fungal diseases in man and animals among mycologists.' This was an important mission considering that pathogenic fungi for humans and animals represent a tiny minority of the estimated 1.5-5 million fungal inhabitants on Earth. These pathogens have diverged from the usual saprotrophic lifestyles of most fungi to colonize and infect humans and animals. Medical and veterinary mycology is the subdiscipline of microbiology that dwells into the mysteries of parasitic, fungal lifestyles. Among the oldest continuing scientific publications on the subject, Mycopathologia had its share of 'classic papers' since the first issue was published in 1938. An analysis of the eight decades of notable contributions reveals many facets of host-pathogen interactions among 183 volumes comprising about 6885 articles. We have analyzed the impact and relevance of this body of work using a combination of citation tools (Google Scholar and Scopus) since no single citation metric gives an inclusive perspective. Among the highly cited Mycopathologia publications, those on experimental mycology accounted for the major part of the articles (36%), followed by diagnostic mycology (16%), ecology and epidemiology (15%), clinical mycology (14%), taxonomy and classification (10%), and veterinary mycology (9%). The first classic publication, collecting nearly 200 citations, appeared in 1957, while two articles published in 2010 received nearly 150 citations each, which is notable for a journal covering a highly specialized field of study. An empirical analysis of the publication trends suggests continuing interests in novel diagnostics, fungal pathogenesis, review of clinical diseases especially with relevance to the laboratory scientists, taxonomy and classification of fungal pathogens, fungal infections and carriage in pets and wildlife, and changing ecology and epidemiology of fungal diseases around the globe. We anticipate that emerging and re-emerging fungal pathogens will continue to cause significant health burden in the coming decades. It remains vital that scientists and physicians continue to collaborate by learning each other's language for the study of fungal diseases, and Mycopathologia will strive to be their partner in this increasingly important endeavor to its 100th anniversary in 2038 and beyond.

Malassezia species in students from universities of Sabzevar, Northeastern Iran

BACKGROUND

Malassezia species, usually part of normal human skin microbiota, may also cause cutaneous infections, mainly pityriasis versicolor (PV) which may rapidly spread in crowded communities, particularly in students' dormitories and sport leisure centers.

OBJECTIVE

Few studies have been conducted on PV in students in the Middle East. The present study was designed to determine prevalence of Malassezia species and related diseases in students from city of Sabzevar, Northeast Iran.

METHODS

Specimens were collected from 189 students and analyzed by direct microscopy and cultures. Following PCR amplification of the large subunit of ribosomal DNA, species were identified by restriction fragment length polymorphism analysis (RFL-PCR).

RESULTS

PV was suspected for 28 students which was confirmed by direct examination and cultures. Cultures also revealed positive for 13 students with healthy skin. Four Malassezia species were identified, with M. restricta as the most prevalent. A higher rate of PV was observed compared to other regions in Iran. However, despite the lipophilic feature of Malassezia species, no significant association was observed between PV or Malassezia species and fatty skin or gender.

CONCLUSION

This study determined the frequencies of Malassezia species in part of Northeast Iran, but further studies are needed to identify risk factors for PV.

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.

Treatment of pityriasis versicolor with topical application of essential oil of Cymbopogon citratus (DC) Stapf - therapeutic pilot study

BACKGROUND

Pityriasis versicolor is a fungal infection caused by Malassezia spp. that has frequent relapses.

OBJECTIVES

The main objective of this research was to perform phase I and II clinical studies, using formulations containing essential oil of Cymbopogon citratus in patients with pityriasis versicolor.

METHODS

Phase I study included twenty volunteers to ascertain the safety of the formulations. In phase II, 47 volunteers randomly received essential oil formulations at 1.25 μL/mL concentration, for forty days. The shampoo should be applied three times a week and the cream twice a day. A control group in phase II, consisting of 29 volunteers, received the same formulations but with 2% ketoconazole as the active ingredient.

RESULTS

No significant adverse events were observed in volunteers during Phase I. In Phase II, 30 (63.83%) volunteers using essential oil and 18 (62.07%) using ketoconazole remained until the end of the study. We observed a predominance of lesions in disseminated form, with M. sympodialis detected as the predominant agent identified in cultures. After 40 days of treatment, the rate of mycological cure was 60% (p <0.05) for the group treated with essential oil of C. citratus and over 80% (p <0.05) for the group treated with ketoconazole formulations.

CONCLUSIONS

Notwithstanding the safety and antifungal effects observed in this study after application of formulations containing the essential oil of C. citratus, further studies with larger populations should be performed to confirm the actual potential of these formulations in the treatment of patients with Pityriasis versicolor.

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.

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.

Molecular analysis of Malassezia species isolated from Israeli patients with pityriasis versicolor

BACKGROUND

Pityriasis versicolor (PV) is a common superficial fungal infection of the skin caused by Malassezia species. The clinical significance of each of these species is not fully understood. M. furfur has long been identified as the causative agent of PV. Several recent studies suggest that M. globosa is most frequently associated with PV.

OBJECTIVES

The aim of this study was to examine the prevalence of Malassezia species in affected and unaffected skin in Israeli patients with PV using a polymerase chain reaction (PCR)-based culture-independent method.

METHODS

Samples were taken from affected skin of 75 patients with PV (35 females and 40 males, age range 18-65 years) who visited our outpatient clinic and from unaffected skin in 26 patients for direct microscopy and detection of Malassezia species using a PCR-based method.

RESULTS

The major Malassezia species in PV was M. globosa, found in 97.3% (73 of 75) of samples from affected skin and 80.8% (21 of 26) samples of unaffected skin. M. restricta was associated with M. globosa in 1.3% (one of 75) of patients. No cases of M. furfur were detected in this study. There was no difference in the distribution of Malassezia species between affected and unaffected skin.

CONCLUSION

Based on the PCR test, we have shown that M. globosa is probably most frequently associated with PV.

Identification and speciation of malassezia in patients clinically suspected of having pityriasis versicolor

Background:

Malassezia is a lipid-dependent yeast known to cause Pityriasis versicolor, a chronic, recurrent superficial infection of skin and present as hypopigmented or hyperpigmented lesions on areas of skin. If not diagnosed and treated, it may lead to disfigurement of the areas involved and also result in deep invasive infections.

Aim:

The aim of the present study was to identify and speciate Malassezia in patients clinically suspected of having Pityriasis versicolor.

Materials and Methods:

Total 139 patients suspected of having Pityriasis versicolor were evaluated clinically and diagnosis was done by Wood's lamp examination, confirmed mycologically by using KOH, cultivation on Sabouraud's dextrose agar and modified Dixon agar at a tertiary care hospital in Mumbai. The total duration of study was 12 months.

Results:

Majority of the patients were males (59.71%) in the age group of 21-30 years (33.81%) who were students (30.21%) by profession. The incidence of Malassezia in Pityriasis versicolor was 50.35%. The most common isolate was M. globosa (48.57%), followed by M. furfur (34.28%). Majority of the patients had hypopigmented lesions, with M. globosa as the predominant isolate. Neck was the most common site affected; 88.48% were Wood's lamp positive of which 56.91% of Malassezia isolates grew on culture. KOH mount was positive in 82.01% of which 61.40% Malassezia isolates grew on culture.

Conclusions:

The procedure of culture and antifungal testing is required to be performed as different species of Malassezia are involved in Pityriasis versicolor and susceptibility is different among different species. Thus, it would help to prevent recurrences and any systemic complications.

Distribution of Malassezia species in patients with pityriasis versicolor in Northern Iran

PURPOSE

Malassezia yeasts are globally distributed agents of pityriasis versicolor and are implicated in the pathogenesis of seborrhoeic and atopic dermatitis. The aim of this study is to identify the Malassezia species obtained from pityriasis versicolor patients, using morphological, biochemical, physiological as well as Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) methods.

MATERIALS AND METHODS

The identification of Malassezia species is performed according to microscopic features and physiological characteristics, including catalase reaction and Tween assimilation tests. The DNA is extracted from cultured Malassezia using the glass bead, phenol-chloroform method. The internal transcribed spacer 1(ITS1) region is amplified and there is restricted digestion of the PCR products with two enzymes Cfo I and Bst F5I.

RESULTS

The most commonly isolated species is M. globosa (47.6%). RFLP analysis of the PCR products of the ITS1 region is in complete agreement with those from the DNA sequences of the internal transcribed spacer (ITS) 1 region and the biochemical tests.

CONCLUSION

Based on the findings of this study, it can be concluded that PCR-RFLP is a relatively simple and quick method, completely comparable to the routine methods used for Malassezia identification.

Malassezia yeast species isolated from Iranian patients with pityriasis versicolor in a prospective study

The goal of this study was to determine the prevalence of Malassezia species in pityriasis versicolor lesions and to examine if the range of species varies with patients characteristics such as: age, sex and family history and also clinical findings such as site and number of the lesions. In a prospective study from July 2006 to July 2007, the patients with a clinical diagnosis of pityriasis versicolor (n = 166) were asked to participate in the study. A total of 116 patients had positive culture for Malassezia species: M. globosa was found in 52 (31.3%) cases, M. furfur in 34 (20.5%) cases, M. pachydermatis in 12 (7.2%) cases, M. restricta in 12 (7.2%) cases, M. slooffiae in 6 (3.6%) cases. According to our data, M. globosa is the main species causing pityriasis versicolor, M. furfur was found to be the second-most frequent species. M. sympodialis and M. obtusa were not found in any case, and in 30.2% of patient's Malassezia culture was negative.

Molecular identification of Malassezia species isolated from dermatitis affections

The lipophilic yeast of the genus Malassezia are opportunistic microorganisms of the skin microflora but they can be agents of various dermatomycoses. The aim of this study was to perform molecular identification of the commonly isolated Malassezia species from various dermatomycoses in our region. Thirty strains of Malassezia were isolated from different dermatologic affections: pityriasis versicolor (17), dandruff (5), seborrheic dermatitis (4), onyxis (2), folliculitis (1) and blepharitis (1). These species were identified by their morphological features and biochemical characterisation. The molecular identification was achieved by amplification of the internal transcribed spacer region by simple PCR. PCR technique was used for molecular characterisation of four Malassezia species: Malassezia globosa (270 bp), Malassezia furfur (230 bp), Malassezia sympodialis (190 bp) and Malassezia restricta (320 bp). We have detected the association between M. furfur and M. sympodialis in 16% and confirmed presumptive identification in 70% of the cases. The phenotypic identification based on microscopic and physiological method is difficult and time consuming. The application of a simple PCR method provides a sensitive and rapid identification system for Malassezia species, which may be applied in epidemiological surveys and routine practice.

Distribution of Malassezia species in patients with psoriasis and healthy individuals in Tehran, Iran

BACKGROUND

Psoriasis is a non-contagious disorder that affects the skin as red scaly patches. Although the role of Malassezia species in the pathogenesis of psoriasis is still not fully understood, it is thought that these lipophilic yeasts might be a trigger factor in the exacerbation of psoriatic lesions.

METHODS

Using culture in a specific medium followed by the polymerase chain reaction-restriction fragment length polymorphism method, the presence of Malassezia species in the skin of 110 patients with psoriasis was compared with that in a control group of 123 healthy patients.

RESULTS

The recovery rate of Malassezia species from the skin of patients with psoriasis was significantly lower than that in the controls. In both psoriatic and healthy skin, Malassezia globosa was isolated as the predominant species. In psoriatic patients, the rate of colonization of Malassezia furfur and Malassezia restricta was almost twice that in the controls, whereas M. globosa was isolated more frequently from healthy individuals than from patients.

CONCLUSIONS

Considering the higher lipase activity secretion by M. furfur in comparison with other Malassezia species, the enzymatic release of arachidonic acid and its metabolites by M. furfur may exacerbate the inflammatory and hyperproliferative changes observed in psoriasis.

Molecular analysis of Malassezia species isolated from hospitalized neonates

Malassezia species are a part of the skin microflora of neonates. Under certain circumstances, they can cause diseases ranging from simple pustulosis to lifethreatening fungemia in newborn infants. Little information is available about the epidemiology of Malassezia species in neonates. In the present study, we successfully isolated Malassezia yeasts from 68.7% of hospitalized neonates. Using the polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFPL), M. furfur (88.06%) was identified as the most isolated species, followed in frequency by M. globosa (10.48%), M. obtusa (0.73%), and M. slooffiae (0.73%). Among the variables studied, only a longer stay in the ward resulted in a higher colonization rate. Using multiple logistic regression, only the type of hospital and ward had some effects on the colonization rate. Our results supported the hypothesis that neonates acquire Malassezia flora through direct contact with their mothers or hospital personnel.

[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.

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

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

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.

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.

Microreview of Pityriasis versicolor and Malassezia species

Recently 11 Malassezia species were isolated. Attention has focused on the relationship between Malassezia species and Malassezia-related disease. The causal fungus of Pityriasis versicolor is M. globosa. The conditions of mycelial form induction are not clear for M. globosa.

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.

Molecular Analysis of Malassezia Microflora from Patients with Pityriasis Versicolor

BACKGROUND

Pityriasis versicolor (PV) is a superficial infection of the stratum corneum caused by Malassezia species. Eleven species have been identified within this genus, namely M. globosa, M. restricta, M. sympodialis, M. furfur, M. obtusa, M. slooffiae, M. pachydermatis, M. dermatis, M. japonica, M. yamatoensis, M. nana. M. furfur has long been identified as the causative fungus of PV. However, recent studies using the culture and isolation identified by morphological and physiological characteristics suggest that M. globosa is the causative agent of PV.

OBJECTIVES

The aim of this study was to examine the distribution of PV microorganisms with a molecular-based non-culture method.

PATIENTS

The subjects were 49 patients with PV (32 males, 17 females; 16-83 years old) who visited our outpatient clinic.

METHODS

Samples were taken from lesions for direct microscopy with methylene blue and detected Malassezia species without M. pachydermatis and M. nana using a non-culture-based method consisting of nested PCR with specific primers.

RESULTS

The most frequently isolated species were M. globosa and M. restricta (both 93.9%). Only M. globosa was detected from the lesion in which the mycelial form alone was observed microscopically, but M. restricta was not.

CONCLUSIONS

Our results suggest that M. globosa is the causative agent of PV.

Hyperkeratotic head and neck Malassezia dermatosis

BACKGROUND

Pityriasis versicolor (tinea versicolor) is a common skin disorder due to Malassezia usually affecting adolescents and young adults, more frequently in the tropics. Facial involvement, isolated or not, is not frequent in white adults.

OBJECTIVE

Here, we report a possible atypical hyperkeratotic form of dermatosis of the face, in two young immunocompetent Caucasian patients, particularly recalcitrant to therapy.

RESULTS

Skin scrapings grew yeasts belonging to the genus Malassezia, including both M. globosa and M. sympodialis. This unusual variant needs long-term therapy with systemic and topical imidazoles together with facial cleansing.

CONCLUSION

We propose the name hyperkeratotic head and neck Malassezia dermatosis for this distinctive clinical entity. This variant of pityriasis versicolor should be considered in the differential diagnosis of seborrheic dermatitis and dermatitis neglecta.

A case of pityriasis versicolor atrophicans

A case of pityriasis versicolor atrophicans caused by Malassezia globosa is reported in a 49-year-old woman. Diagnosis was based on direct microscopic examination and culture. Differential diagnosis was performed with respect to other skin diseases manifesting with cutaneous atrophy.

Malassezia Baillon, emerging clinical yeasts

The human and animal pathogenic yeast genus Malassezia has received considerable attention in recent years from dermatologists, other clinicians, veterinarians and mycologists. Some points highlighted in this review include recent advances in the technological developments related to detection, identification, and classification of Malassezia species. The clinical association of Malassezia species with a number of mammalian dermatological diseases including dandruff, seborrhoeic dermatitis, pityriasis versicolor, psoriasis, folliculitis and otitis is also discussed.

Identification of Malassezia species from Tunisian patients with pityriasis versicolor and normal subjects

BACKGROUND

The genus Malassezia (Pityrosporum), recognized as a member of microbiological flora of the skin in humans and warm-blooded animals, has been recently revised to include 10 Malassezia species. The aim of the study was the isolation, identification and analysis of Malassezia species distribution in skin of healthy volunteers and lesions of pityriasis versicolor (PV).

MATERIAL AND METHODS

Specimens were taken from 100 patients with PV and 30 healthy volunteers. Cultures were made in modified Dixon agar medium and the isolates were identified by morphological and physiological methods: macroscopy, microscopy, catalase, beta-glucosidase and lipid assimilation tests.

RESULTS

Malassezia globosa was the predominant species in lesional skin of PV (65%). It was isolated alone in 47% of cases and associated in 18% with M. furfur (13%) or M. sympodialis (5%). In healthy skin M. globosa was found alone in 7.77% and associated in 15.54%, respectively, with M. furfur (4.44%), M. sympodialis (4.44%), M. restricta (3.33%) and M. slooffiae (1.11%).

CONCLUSION

From these findings it was suggested that M. globosa presents the main species implicated in the pathogenicity of PV and M. furfur as the second agent of importance.

Pityriasis versicolor alba

Pityriasis versicolor alba is a hypopigmented or depigmented variant of pityriasis versicolor characterized by maculous, partly pityriasiform, scaly depigmented lesions occurring particularly in seborrhoeic areas. Long-persisting hypopigmentation after healing of the pityriasis versicolor was first described by Gudden in 1853. Hypopigmentation and depigmentation were later differentiated as an independent variant of the disease. In 1848, Eichstedt recognized the pathogen-related character of pityriasis versicolor in its hyperpigmented form. Today it is generally accepted that the disease is caused by yeasts of the genus Malassezia, of which nine species are differentiated. It is controversial whether a single species is responsible for the disease. The pathogenesis of depigmentation has not been established. A screening effect by the scale layer as well as toxic effects on pigment synthesis by fungal metabolites have been discussed. With regard to the second mechanism, the newly discovered tryptophan-derived metabolites of M. furfur might be significant. Evidence-based data concerning the therapy of pityriasis versicolor alba do not exist. According to current recommendations, pityriasis versicolor should be rapidly treated with antimycotics, followed by ultraviolet therapy to induce maturation of existent melanosomes and accelerate repigmentation. However, depigmented lesions are difficult to improve by ultraviolet therapy.

DNA sequence diversity of intergenic spacer 1 region in the non-lipid-dependent speciesMalasseziapachydermatisisolated from animals

The non-lipid-dependent species Malassezia pachydermatis is frequently isolated from animals. We analyzed the DNA sequences of the intergenic spacer (IGS) 1 region, which is the most variable region in the rRNA gene, of 43 M. pachydermatis strains obtained from dogs or cats. The lengths of the IGS 1 regions ranged from 552 to 898 bp and, based on the nucleotide sequence, these IGS 1 regions were divided into three major groups with 10 subtypes. Group 1 (552-601 bp long) was characterized by the short sequence repeat (CAGCA)n and had four to 14 repeats, and Group 3 (749-898 bp long), which included the neotype strain of M. pachydermatis, was characterized by the sequence (CAGCATAACATAACACACAACA)n in the IGS1 region. Group 2 possessed partial sequences of both Groups 1 and 3. Each group shared only 41.7-55.4% similarity in the IGS1 region with the other groups. The internal transcribed spacer (ITS) region and D1/D2 26S rDNA in the rRNA gene were also sequenced for representative strains in each IGS group. The groups were distinguished by both ITS (698-712 bp long including 5.8S rDNA) and D1/D2 26S rDNA (624 bp long) sequences with sequence similarities of 91.7-96.0% and 99.7-99.0%, respectively. Our results indicate that the sequence of the IGS region of M. pachydermatis has a remarkable intraspecies diversity, compared with ITS or D1/D2 26S rDNA, and that multiple genotypic strains of M. pachydermatis colonize animal skin.

Study of the distribution of Malassezia species in patients with pityriasis versicolor and healthy individuals in Tehran, Iran

Background

Pityriasis versicolor is a superficial infection of the stratum corneum which caused by a group of yeasts formerly named pityrosporium. The taxonomy of these lipophilic yeasts has recently been modified and includes seven species referred as Malassezia. The aim of this study is to compare the distribution of Malassezia species isolated from pityriasis versicolor lesions and those isolated from healthy skins.

Methods

Differentiation of all malassezia species performed using morphological features and physiological test including catalase reaction, Tween assimilation test and splitting of esculin.

Results

In pityriasis versicolor lesions, the most frequently isolated species was M. globosa (53.3%), followed by M. furfur (25.3%), M. sympodialis(9.3%), M. obtusa (8.1%) and M. slooffiae (4.0%). The most frequently isolated species in the skin of healthy individuals were M. globosa, M. sympodialis, M. furfur, M. sloofiae and M. restricta which respectively made up 41.7%, 25.0%, 23.3%, 6.7% and 3.3% of the isolated species.

Conclusions

According to our data, M. globosa was the most prevalent species in the skin of healthy individuals which recovered only in the yeast form. However, the Mycelial form of M. globosa was isolated as the dominant species from pityriasis versicolor lesions. Therefore, the role of predisposing factors in the conversion of this yeast to mycelium and its subsequent involvement in pityriasis versicolor pathogenicity should be considered.

Description of a new yeast species, Malassezia japonica, and its detection in patients with atopic dermatitis and healthy subjects

Lipophilic yeasts of the genus Malassezia are part of the normal cutaneous microflora and are considered one of the factors that trigger atopic dermatitis (AD). We isolated two strains of Malassezia from a healthy Japanese female. Analysis of the D1/D2 26S ribosomal DNA and internal transcribed spacer region sequences of the isolates suggested that they are new members of the genus Malassezia. We propose the name Malassezia japonica sp. nov. for the isolates. M. japonica is easily distinguished from the seven known lipophilic species by its ability to assimilate Tween 40 and Tween 60 and its inability to assimilate Tween 20 and Tween 80 and to grow at 40 degrees C. Furthermore, by applying transparent dressings to the skin lesions of 36 patients with AD and the skin of 22 healthy subjects, M. japonica DNA was detected by a non-culture-based method consisting of nested PCR with M. japonica species-specific primers. M. japonica DNA was detected from 12 of the 36 patients (33.3%) and 3 of the 22 healthy subjects (13.6%). Although it is not known whether M. japonica plays a role in AD, this species was part of the microflora in both patients with AD and healthy subjects.

DNA base alignment and taxonomic study of genus Malassezia based upon partial sequences of mitochondrial large subunit ribosomal RNA gene

The sequences of the large subunit of mitochondrial ribosomal RNA (LsmtrRNA) gene of Malassezia species were analysed. The sequences of the seven species of Malassezia are well separated in each species. Therefore the LsmtrRNA gene is thought to be one of the gene targets for species identification in the genus Malassezia. The dendrogram obtained from this gene supports the previous study of Malassezia species based upon the chromosomal genes. This is the first report of taxonomic analysis of Malassezia species based upon the mitochondrial gene.

Superficial fungal infections: an update on pityriasis versicolor, seborrheic dermatitis, tinea capitis, and onychomycosis

The recent advances in pityriasis versicolor, seborrheic dermatitis, tinea capitis and onychomycosis are reviewed. Some highlighted points include the new classification of Malassezia species, and the association of Malassezia species with seborrheic dermatitis. The use of terbinafine, fluconazole, and itraconazole for the treatment of tinea capitis is discussed. The management of onychomycosis, highlighting the high efficacy rates obtained with terbinafine when used to treat dermatophyte toenail onychomycosis, is discussed. The use of combination therapies in some circumstances to maximize cure rates is reviewed.