The Role of L-DOPA on Melanization and Mycelial Production in Malassezia Furfur

Melanins are synthesized by organisms of all biological kingdoms and comprise a heterogeneous class of natural pigments. Certain of these polymers have been implicated in the pathogenesis of several important human fungal pathogens. This study investigated whether the fungal skin pathogen Malassezia furfur produces melanin or melanin-like compounds. A melanin-binding monoclonal antibody (MAb) labelled in vitro cultivated yeast cells of M. furfur. In addition, melanization of Malassezia yeasts and hyphae was detected by anti-melanin MAb in scrapings from patients with pityriasis versicolor. Treatment of Malassezia yeasts with proteolytic enzymes, denaturant and concentrated hot acid yielded dark particles and electron spin resonance spectroscopy revealed that these particles contained a stable free radical compound, consistent with their identification as melanins. Malassezia yeasts required phenolic compounds, such as L-DOPA, in order to synthesize melanin. L-DOPA also triggered hyphal formation in vitro when combined with kojic acid, a tyrosinase inhibitor, in a dose-dependent manner. In this respect, L-DOPA is thought to be an essential substance that is linked to both melanization and yeast-mycelial transformation in M. furfur. In summary, M. furfur can produce melanin or melanin-like compounds in vitro and in vivo, and the DOPA melanin pathway is involved in cell wall melanization.     

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

Pityriasis versicolor is a superficial infection of the stratum corneum by several yeast species formerly collectively named Malassezia furfur. The genus Malassezia has been recently enlarged with new species. With the exception of M. pachydermatis, the remaining six species have an absolute requirement in vitro for supplementation of long-chain fatty acids in media. These lipophilic yeasts comprise six species: M. furfur, M. globosa, M. obtusa, M. restricta, M. slooffiae and M. sympodialis. The aim of this study was to establish whether there was any association between the various species of Malassezia and pityriasis versicolor lesions. Thus, we studied the isolates from 79 patients with pityriasis versicolor, both from lesions and from apparently healthy skin close to the visible lesions. In pityriasis versicolor lesions, the species most frequently isolated was M. globosa (90%), followed by M. sympodialis (41%). Almost all isolates (99%) belonged to one of these two species. The most frequent pattern was M. globosa as the sole species (58% of cases), although the association with M. sympodialis was also frequent (30%). These results confirmed M. globosa as the main agent of pityriasis versicolor and M. sympodialis as the second agent in importance. Malassezia globosa was found to be a species with high levels of esterase and lipase enzymes of probable importance in their pathogenicity. This revised version was published online in June 2006 with corrections to the Cover Date.     

Genotyping by RAPD-PCR analyses of Malassezia furfur strains from pityriasis versicolor and seborrhoeic dermatitis patients

Malassezia furfur is lypophilic yeast commonly associate with dermatological disorders. In the present work, we described the isolation of 47 M. furfur strains from three groups of patients: pityriasis versicolor (21 isolates), seborrhoeic dermatitis (15 isolates) and seborrhoeic dermatitis of the HIV positive patients (11 isolates). To investigate the identity of the strains at molecular level, DNA genomic of M. furfur strains were prepared and used to RAPD-PCR analyses. RAPD assay were carried out using two decamer primers and bands pattern generated were analyzed by an Unweighted Pair-Group Method (UPGMA). Dendrogram established a distinct differentiation between M. furfur isolates from pityriasis versicolor and seborrhoeic dermatitis patients with or without AIDS. We concluded that RAPD typing presented a high discriminatory power between strains studied in this work and can be applied in epidemiological investigation of skin disease causing by M. furfur.     

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

BackgroundMalassezia species are considered opportunistic yeasts of increasing clinical importance. These lipophilic yeasts are associated with various human diseases, especially pityriasis versicolor (PV), a chronic superficial scaling dermatomycosis.AimsThe aim of this study was to isolate, identify and analyze the distribution of the different species of Malassezia in patients with PV in Rosario city (Argentina).MethodsA total of 264 clinical samples were studied. Isolates were identified on the basis of microscopic observation of cells, and physiological properties, such as the presence of catalase, ability to use Tween compounds, splitting of esculin, and morphology, color and precipitate production on chromogenic agar CHROMagar-Malassezia medium (CHROMM).ResultsThe highest prevalence of PV in this study was observed in the 25- to 45-year-old group. No differences were found in the development of PV between sexes. The most affected areas of body were the trunk and face. Malassezia sympodialis (51%) was the most commonly isolated species, followed in frequency by M. globosa (40%), Malassezia furfur (7%), Malassezia obtusa (1%) and Malassezia slooffiae (1%).ConclusionsThe success for a correct identification of these yeasts is important to improve our knowledge about their epidemiological role in PV and also to detect the appearance of strains which are resistant to the commonly used antifungal drugs.     

The diversity of Pityrosporum (Malassezia) yeasts in vivo and in vitro

Conclusions In considering the diversity of the lipophilic yeasts it has been shown that in vivo both spherical and oval yeasts may be found in normal conditions on the skin and also associated with hyphae in scales from pityriasis versicolor. There is however generally a different distribution pattern on the body for two forms. This may indicate a different ecology for two distinct varieties or the varying conditions at each site may influence changes in the cell shape of a single species. It is striking that the spherical yeasts (P. orbiculare) have not been found in animals. In vitro, several morphological variants can be maintained, but the change from one form to another which is the subject of a number of reports will be one deciding factor leading to the opinion that P. orbiculare and P. ovale are synonymous. However, physiological differences such as growth rate, their viability in subculture and the analysis of proteins, are all characteristics which alone would be insufficient to support a taxonomic division but when added together confirm the morphological separation of isolates. It remains to be seen if DNA studies, which have so far unified the anthropophilic, lipid dependant Pityrosporum yeasts, will in fact continue to show that they should be confined to a single species.This paper was presented at the X^th congress of the International Society for Human and Animal Mycology at Barcelona, Spain from June 27 to July 1, 1988.     

Studies of the genus Pityrosporum in submerged culture

Differentiation betweenPityrosporum ovale andPityrosporum orbiculare is mainly based upon the morphological features of cells and on physiological characters such as the ability ofP. ovale of utilizing oleic acid (Marples, 1965). Our studies in submerged culture, however, have not shown remarkable differences between the two species: growth curves, nutritional requirements, lipid utilization and optimal temperature are practically the same. In some strains of both species (1 : 4) we did observe a limited growth capacity, associated with a lower utilization rate of lipids. But for the notably different morphological features of cells,P. ovale andP. orbiculare could be ascribed, as regards their cultural characteristics, to the same species. The search forP. orbiculare was successful in all the cases of Pityriasis versicolor, while all our attempts to isolateP. ovale from its usual areas (scalp, upper back and chest) from both healty and seborrhoic subjets, gave no results.P. orbiculare was found in the same areas in the greatest part (85 %) of these subjects. In order to explain these results, one could assume thatP. orbiculare is the only species ofPityrosporum widespread in our region.These studies were supported by grant of the Consiglio Nazionale delle Ricerche of Italy under contract n. 70.01023/115.2798.     

A reevaluation of the genus Malassezia by means of genome comparison

Results of a study of the genus Malassezia on the basis of genome characters confirm that two species should be maintained, M. furfur and M. pachydermatis. The two forms associated with skin disease, frequently referred to as Pityrosporum orbiculare and P. ovale, were found to be synonymous, the name M. furfur having priority. Malassezia pachydermatis, hitherto regarded as a strictly zoophilic species, may also be found on humans.     

Superficial mycoses observed at the Department of Dermatology of the University of Pavia

Over a period of 13 years, 4100 specimens were cultured for fungi. Pityriasis versicolor (Malassezia furfur) was demonstrated in 17.6%, dermatophytosis in 34.6% and candidiasis in 10.8%. The most frequently isolated strains were M. canis (31.5%), T. rubrum (26.3%), E. floccosum (19.7%), T. mentagrophytes (19.3%) for the dermatophytes and C. albicans (88.9%). Those rarely seen were: M. gypseum, T. violaceum, M. audouini, T. schoenleinii. We observed the absolutely complementary results of the microscopic examinations and the cultures of the specimens.Abbreviations D Direct microscopic observation of the specimen - C Culture of the specimen - * Position of the table     

Profile of Dermatophytic and Other Fungal Infections in Jaipur

The common cause of skin infections are dermatophytes and opportunistic fungi. Aim of present study is to find predominant etiological agent of dermatophytoses and to isolate various fungal agents from clinical samples of patients with different mycoses and Clinical samples from 260 patients were subjected to potassium hydroxide (KOH) examination and culture isolation; causative agents were identified macroscopically and microscopically. One hundred sixty three (62.7%) were found to be positive by KOH examination while 132 (50.8%) were culture positive. Dermatophytes were isolated in 90/140 (64.3%) specimens. Trichophyton rubrum (75.5%) was the commonest isolate among the patients suffering from dermatophytoses. Candida spp. and Malassezia furfur were isolated from patient suffering from candidiasis and pityriasis versicolor.     

Pityriasis Versicolor: Clinical Spectrum and Diagnosis

Pityriasis versicolor (PV) is caused by the fungus Malassezia, especially by Malassezia globosa. The predisposing factors for PV are heat, humidity, hyperhidrosis, oral contraceptives, stress, application of oily preparations, and treatment with corticosteroids. PV is found mainly on the seborrheic areas of the trunk, shoulders, upper aspects of the arms, and neck, but it may spread to the face, scalp, submammary areas, axillae, groin, skin folds, and buttocks. It is characterized by hyperpigmented, hypopigmented, or erythematous (versicolor), round-to-oval, finely scaling, thin plaques. Other less frequent clinical variants are papular, atrophic, imbricata, and pityriasis rubra pilaris-like presentations. The diagnosis of PV is usually made clinically with the aid of Wood’s light or dermoscopy. Direct microscopic examination, culture, biopsy, and molecular studies are among the laboratory diagnostic methods. Topical therapy is the treatment of choice for most patients. Systemic imidazole therapy is usually reserved for widespread or resistant cases.     

Pityrialactone- a new fluorochrome from the tryptophan metabolism of M. alassezia furfur

As the main nitrogen source in Malassezia (M.) furfur, tryptophan induces the formation of fluorochromes and pigments, which makes the yeast less sensitive towards UV light. For the investigation of the fluorochromes, M. furfur (CBS1878) was incubated at 32 °C for 14 days on a pigment-inducing medium, and the agar extract was purified by column chromatography, preparative TLC and HPLC. The structures of the pure metabolites were determined by mass spectrometry and NMR spectroscopy. A pale yellow compound eluting from the column with 22% acetonitrile was found to exhibit a strong green-yellow fluorescence. The fluorochrome is a new bisindolyl compound (C₂₀H₁₂N₂O₃, MW 328.33) named pityrialactone because of its furan-2,3-dione structure. The UV protective properties (λ_max 352, 292, 276, 224 nm) of this metabolite were confirmed in a yeast model. As shown by the fluorescence spectrum, pityrialactone appears to be responsible for the green-yellow fluorescence of pityriasis versicolor lesions under Wood light. Pityrialactone is accompanied by the isomeric bisindolylmaleic anhydride (pityriaanhydride), which has not yet been described as a natural product but is a known intermediate in the total synthesis of bisindolylmaleimides. This revised version was published online in August 2006 with corrections to the Cover Date.     

Selective and Differential Media for Isolation and Tentative Identification of Each Species of Pityrosporum Residing on Normal or Diseased Human Skin

Selective and differential media were designed for each species of Pityrosporum; P. pachydermatis, P. ovale, and P. orbiculare in order to make feasible a quantitative cultivation. Medium for P. pachydermatis (medium A) was composed of 1% trypticase peptone (BBL), 0.5% yeast extract (BBL), 0.3% glucose, 0.2% NaCl, 1.2% KH₂ PO₄ (anhydrous), 1.5% agar, 0.01% ampicillin, and 0.025% cycloheximide with a pH of 5.5. Medium for P. ovale (medium B) was medium A supplemented with 0.05% sodium acetate (anhydrous), 0.2% Tween 80, and 0.025% (selective medium) or 0.075% (differential medium) sodium laurate. Medium for P. orbiculare was medium B (devoid of laurate) supplemented with 2% olive oil, 0.25% glycerol, 0.25% gall powder, 0.05% sodium palmitate, 0.05% sodium stearate, 0.05% sodium oleate and 8% (selective medium) or 10% (differential medium) sodium lactate and an increase in Tween to 1%. For isolation of Pityrosporum, specimens were suspended in 0.1% Tween 80 solution and inoculated onto agar plates of three selective media. The plates were incubated aerobically at 37 C for 8–10 days under conditions of prevention of water loss from the media. The plating efficiency of each selective medium, expressed as a ratio of cultural counts to microscopic counts was generally over 70%. Species of Pityrosporum could also be identified when we inoculated the cell suspension onto differential agar plates and incubated the preparations at 37 C for 7 days.     

A study of pityriasis versicolor in Bangkok (Thailand)

A total of 410 cases of pityriasis versicolor were studied in the Division of Dermatology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, during January to December 1987. These comprised 1% of all skin disorders, while infection caused by fungus comprised 17%. Most persons infected with pityriasis versicolor were 12–21 years old (mean age 20 years) and 47% were male and 53% were female. The common sites of infection were back, arms, face and trunk. The colors of lesions found were white (83%), brown (7%), pink (6%) and ashy (4%). Both forms of M. furfur were isolated, the ovale form in 97% and the orbiculare form in 3% of cases. The colors of the lesions did not depend on the form of the organism. Mycological and immunological studies confirmed that the two forms were different stages in the complex developmental cycle of a single species.     

Otomycosis due to Filamentous Fungi

Otomycosis is common throughout the world but barely studied in Spain. Our objective was to determine the microbiological and epidemiological characteristics of this pathology in Cadiz (Spain) between 2005 and 2010. Samples from patients with suspicion of otomycosis underwent a direct microscopic examination and culture on different media for fungi and bacteria. Mycological cultures were incubated at 30°C for at least seven days. Identification of fungi was based on colonial morphology and microscopic examination of fungal structure. From a total of 2,633 samples, microbial growth was present in 1,375 (52.2%) and fungal isolation in 390 (28.4%). We identified 228 yeasts and 184 filamentous fungi (13.4% of positive cultures and 47.2% of otomycosis), associated with yeasts in 22 cases (5.6%). The most frequent species were Aspergillus flavus (42.4%), A. niger (35.9%), A. fumigatus (12.5%), A. candidus (7.1%), A. terreus (1.6%), and Paecilomyces variotii (0.5%). Infection was predominant in men (54.9%) and patients beyond 55 years old (46.8%). The most common clinical symptoms were itching (98.9%), otalgia (59.3%), and hypoacusis (56.0%). Fall season reported the lowest number of cases (20.1%). Incidence of otomycosis and fungi producing otomycosis vary within the distinct geographical areas. In Cadiz, this infection is endemic due to warm temperatures, high humidity, sea bathing, and wind, which contributes to disseminate the conidia. Despite Aspergillus niger has been reported as the main causative agent, A. flavus is predominant in Cadiz. Although infection is usually detected in warm months, we observed a homogeneous occurrence of otomycosis in almost all the seasons.     

Interactions Between Plant Growth Promoting Fungi and Arbuscular Mycorrhizal Fungus Glomus Mosseae and Induction of Systemic Resistance to Anthracnose Disease in Cucumber

Cucumber plants were treated with plant growth promoting fungi (PGPF), Phoma sp. (isolates GS8-2 and GS8-3) and Penicillium simplicissimum (isolate GP17-2) with or without the arbuscular mycorrhizal fungus (AMF) Glomus mosseae. Induction of systemic resistance in cucumber against the anthracnose disease caused by Colletotrichum orbiculare was tested to evaluate the nature of the interaction between the PGPF and AMF. Root colonizing ability of each fungal species as influenced by their interaction was also evaluated. Plant roots were pre-inoculated with each PGPF isolate and/or G. mosseae for four weeks and leaves were then challenge inoculated with the pathogen C. orbiculare. Plants treated with each PGPF isolate showed considerable protection against the disease, but the treatment of G. mosseae had no significant effect on disease development. However, combined inoculation of Phoma GS8-2 or GS8-3 with G. mosseae reduced the level of disease protection induced by single inoculation of each Phoma isolate. In contrast, the high levels of protection induced by the P. simplicissimum GP17-2 were not altered by combining it with G. mosseae. Root colonization of both Phoma sp. isolates was also suppressed by the presence of the G. mosseae, but such an effect was not found on the population development of P. simplicissimum. The percent cucumber root length colonized by G. mosseae was not affected by any of the PGPF isolates tested.     

Causative Agents of Superficial Mycoses in Istanbul,Turkey: Retrospective Study

The aim of the present study was to determine the percentage of agents, which can give rise to superficial fungal infections in Istanbul, Turkey. Between 2000 and 2007, the clinical samples collected from 8,200 patients attending the outpatient Dermatology Clinic at Mihrimahsultan Medical Center were examined by direct microscopy and culture. Pathogen fungi were detected in 5,722 of the patients. Of the isolates were 4,218 (74%) dermatophytes, 1,196 (21%) Candida sp., 170 (3%) Malassezia furfur, and 138 (2%) Trichosporon sp. Among the dermatophytes, Trichophyton sp. was the most common isolate followed by Epidermophyton floccosum (243) and Microsporum sp. Among the Candida species, C. albicans (549) was also frequently found. Onychomycosis was the most prevalent type of infection, followed by tinea pedis, tinea cruris, tinea corporis, and tinea capitis. In conclusion, our study showed that the most common isolated agents from superficial infections were T. rubrum being Candida sp. the second most prevalent.     

Pitiriasis versicolor por malassezia ovalis

In a randomly collected series of 175 cases of pityriasis versicolor in residents of the central-northern part of Venezuela, 13% of the patients were infected with ovoid unicellular units of the causal fungus (Malassezia ovalis) and 87% with globous unicellular units in the scales (M. furfur). Only globous unicellular units (Pityrosporum orbiculare) were seen outside the active lesions and in these, after the successful treatment with ketoconazole. The median age of 40 ovalis patients was 37.5 years; the same in 40 furfur patients was 24.5 years. The median age at the moment of discovering the first lesions among ovalis patients was 31; among furfur patients this was 20 years. There were 16 male patients among the ovalis and 24 among the furfur groups of 40. The topographic distribution of the lesions varied according to the type of the invader. M. ovalis prevailed on the trunk below the waist-line and on the limbs, mainly on buttocks and upper legs. M. furfur prevailed on the chest, neck, face and upper limbs.The hypothesis is offered that the ovoid agent of pityriasis versicolor preferentially occupies the less sweating and sebum-producing parts of the body in older (and drier) persons than the globous type does.     

Prevalence of dermatophytes and yeasts (Candida spp., Malassezia furfur) in HIV patients

The prevalence of dermatophytes and yeasts (Candida spp. and Pityrosporum spp.) was studied in 40 former drug-addicts, all of whom were HIV seropositive but otherwise had no other symptoms (2nd Stage CDC Atlanta, 1987). We considered 7 skin areas for dermatophytes and Pityrosporum spp. (scalp, forehead, nose, back, chest, groin, toe webs) and the mouth for yeasts. Dermatophytes were found in 8 (20%) and tinea pedis was the most common dermatophytosis: Tricophyton rubrum was the fungus most frequently isolated (6 cases or 15%). The HIV + group showed almost the same rate of dermatophytes colonisation compared to a group of 121 athletes and to the control group. Candida spp. was present in 27 cases (67.5%) but clinical oral lesions were evident only in 5 patients (12.5%). Statistically significant differences were found in the presence of Candida spp. in HIV patients and controls (p<0.05). The lipophilic yeast Pityrosporum ovale was evaluated with quantitative and qualitative methods. Quantitative variations were evident between HIV patients and controls. P. ovale was present in 10 cases: 3 (7.5%) of them showed dischromic lesions while in 7 cases (17.5%) no clinical symptoms were evident.     

Outbreak ofTinea capitis caused by Microsporum ferrugineum in Thailand

There was an outbreak ofTinea capitis at the Pak-kred Home for Mentally and Physically Handicapped Babies, Bangkok, Thailand in 1993. One hundred and thirty-eight cases were diagnosed as tinea capitis based on clinical signs and positive laboratory investigations. The results of Wood's light examination, KOH preparation and fungal culture were positive in 89.9, 75.9 and 27.4% respectively. The non-inflammatory form had a higher rate of positive KOH and culture than in the inflammatory form.Microsporum ferrugineum was the major pathogen (66.7%) and most of its infections (80.4%) caused a non-inflammatory type of tinea capitis. Griseofulvin, in a dosage of 10–15 mg/kg/day and selenium sulfide shampoos, yielded an 84.8% cure rate within 14.9 weeks. No recurrence or obvious adverse reactions were observed.     

Immunodiffusion test for diagnosing human pythiosis

An immunodiffusion test was developed for diagnosing subcutaneous and systemic pythiosis in humans. When culture filtrate antigen (CFA) from P. insidiosum was reacted against patient and rabbit antisera, 1–5 precipitin bands occured both in patient and rabbit antisera, and a line of identity also occured between patient and rabbit sera. When control P. insidiosum CFA was reacted with 30 apparently normal persons, 20 Thalassemia patients, 2 candidosis and 5 aspergillosis patients, no precipitin bands were found. P. insidiosum CFA also tested with rabbit antibodies to B. dermatitidis, C. immitis, H. capsulatum, P. brasiliensis, C. albicans, M. furfur and A. fumigatus revealed no cross reactions. This test is practical, sensitive and specific.