Malassezia Spp Research Articles

Biochemical Characterizations and Genotyping by RAPD-PCR Analyses of Malassezia spp. From Pityriasis Versicolor and Seborrhoeic Dermatitis Patients

The Iranian Red Crescent Medical Journal (IRCMJ) is international, open access, peer-reviewed, monthly, and ISI- Journal, affiliated to Iranian Hospital- Dubai, publishes original scientific studies in English that have direct clinical significance on Basic Science, Clinical Medicine, and Disaster Management. The journal strives to release the original articles related to various disciplines of medicine, including Review Articles, Meta-Analysis, Systematic Reviews, Clinical and Experimental Trials, Case Reports, and Letters. All research articles published in the journal have undergone rigorous peer review, based on initial editor screening and anonymized refereeing by at least two anonymous referees. The journal strives to strengthen connections between research and practice, so enhancing professional development and improving practice within the field of medicine.

AVALIAÇÕES CITOLÓGICAS EM OTITES CANINAS POR MALASSEZIA SPP.: ESTUDO RETROSPECTIVO

Otitis externa is a condition frequently observed in dogs at the small animal clinics. Malassezia spp. is the most frequently isolated microorganism in the ears of dogs, which is one of the major etiologic agents of ear infections. Identification of this agent may be based on fungal culture or cytology, and the first method is longer and more expensive. The aim of this study was to conduct a retrospective study of the incidence of Malassezia spp. in cases of canine otitis by cytology, in a period of five years. Ear cytology samples from 249 dogs with suspected otitis were evaluated, and were observed positive samples for Malassezia spp. in 44 cases (17.67%), among these 35 dogs (79.5%) with positive cytology in both ears, and 9 dogs (20.5%) were positive for Malassezia in only one ear. In conclusion, dogs with suspected otitis present high incidence of positive Malassezia spp. cytology counts. Cytology revealed to be a useful tool for diagnosis of canine ear infections involving this pathogen, representing diagnostic alternative in cases where the culture is not feasible. However, one must consider that there is no national standard cytological counting yeast cells/field set for cases of canine otitis, which may represent possible misdiagnosis.

Diagnostic Exercise: Severe Bilaterally Symmetrical Alopecia in a Horse

A 9-year-old Tennessee Walking Horse gelding was presented for diagnosis of the cause of extensive alopecia. Complete hair loss was noted over the head, neck, shoulder, thigh, and proximal limbs, but the trunk, distal limbs, pelvic area, mane, and tail were unaffected. The alopecic areas were visually noninflammatory with no exudate or crust except on the shoulder and along the back, where multifocal patchy areas of alopecia with scales and crust were evident. The horse was slightly pruritic. Microscopically, the hair bulbs, inner and outer root sheaths of inferior segments, and perifollicular regions were infiltrated by small to moderate numbers of small lymphocytes. Similar inflammation was occasionally evident in isthmus follicular walls as well as some apocrine glands. No sebaceous glands were affected. Immunohistochemistry confirmed that the small lymphocytes were CD3(+) T lymphocytes. The epidermis from the skin with scale and crusts along the horse's back exhibited mild to moderate hyperplasia, mild lymphocytic exocytosis, mild eosinophilic dermatitis, and diffuse parakeratosis with numerous budding yeasts, consistent with Malassezia spp. The final disease diagnosis was made as alopecia areata with Malassezia dermatitis. Alopecia areata could be a contributing underlying factor for Malassezia dermatitis.

Molecular characterization of Malassezia nana isolates from cats

Malassezia nana ( M. nana) is a lipid-dependent yeast that has been isolated from cats and cows. Some sequence variability has been observed in the large subunit (LSU) and internal transcribed spacer (ITS) regions between strains isolated from cats and cows though these regions in M. nana isolates from cats alone have proven to be relatively conserved. In the present study, microsatellite PCR fingerprinting and β-tubulin gene sequence analysis were carried out on M. nana isolates from cats to investigate the genetic diversity of this species. Although a relatively small number of isolates were available, the similarity in the sequences of the β-tubulin and the microsatellite profiles indicate that a particular M. nana genotype colonizes cats. Moreover, all isolates obtained from animals with otitis externa had the same microsatellite fingerprinting pattern. Further studies of a wider population of M. nana isolates from other hosts and status disease are needed to establish that M. nana is a genetically homogeneous species. This is the first report of the characterization of the β-tubulin gene in Malassezia spp.

Superficial veterinary mycoses

Dermatophytes are significant pathogens in animal health due to their zoonotic potential, the economic consequences of infection in farm animal and fur production systems, and the distressing lesions they cause in small domestic pets. Malassezia spp are normal commensal and occasional pathogens of the skin of many veterinary species. Malassezia pachydermatis is a very common cause of otitis and pruritic dermatitis in dogs but is of less importance in other veterinary species. Dermatophytosis, and Malassezia otitis and dermatitis, represent the superficial mycoses of greatest significance in companion and farm animal health. Although the dermatophytes and Malassezia spp both exist in the stratum corneum of mammalian skin, there are important differences in the epidemiology, pathogenesis, and clinical consequences of infection. Dermatophytes are significant due to their zoonotic potential, the economic consequences of infection in farm animal and fur production systems, and the concern for owners of pets with inflammatory skin disease that is sometimes severe. Malassezia spp are normal commensals and occasional pathogens of the skin for many veterinary species, and M pachydermatis is a very common cause of otitis and pruritic dermatitis in dogs. This chapter will focus on the epidemiologic, clinical, diagnostic, and therapeutic aspects of dermatophytosis and Malassezia dermatitis in veterinary species. There are generally only sporadic reports of other superficial mycoses, such as candidiasis, piedra, and Rhodotorula dermatitis in veterinary medicine, and these are not included here.

Superficial mycoses in immunodepressed patients (AIDS)

HIV infection has the capacity to distort the epidemiology and clinical course of infectious diseases, producing atypical manifestations and changing diagnoses. Superficial fungal infections are frequent in HIV-positive/AIDS patients and are no exception. These infections are frequently different in immunodepressed patients (AIDS), with a modified course or exacerbations. This chapter discusses the diagnosis and treatment of superficial mycoses in HIV patients, including cutaneous alterations caused by Candida, dematiaceous fungi agents of phaeohyphomycosis, Malassezia spp, dermatophyte, and filamentous nondermatophyte fungi.

Pathogenesis of dermatophytosis and tinea versicolor

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

Novel presentation of immune reconstitution inflammatory syndrome: folliculitis secondary to Malassezia spp

Folliculitis, as a manifestation of immune reconstitution inflammatory syndrome (IRIS) during antiretroviral therapy, has only been described in its aseptic form. Here, we describe folliculitis associated with Malassezia spp. as a distinct manifestation of IRIS. The distinction between these two types of IRIS folliculitis is relevant for treatment.

Chronic otomycosis due to Malassezia Spp

We report the case of a 31-year-old male presenting with complaints of mild pain in the right ear for three months and hypoacusis for 10 days. On otoscopic examination, a thin, papery, white material was extracted from his ear and sent for fungal identification. This material revealed presence of Malassezia spp – with characteristic “spaghetti and meat ball appearance”. The patient was treated with 2% acetic acid, hydrocortisone and Clotrimazole powder for one week and he resolved completely.

An open-label, single-center pilot study to determine the antifungal activity of a new nonsteroidal cream (Promiseb Topical Cream) after 7 days of use in healthy volunteers

Topical corticosteroids are effective for the treatment of seborrheic dermatitis. The duration of treatment with mid- to high-potency formulations is limited by the well-known side effects associated with their long-term use; further, topical corticosteroids treat only the inflammation associated with the disease. This study assessed the antifungal activity of a new corticosteroid-free cream against Malassezia spp, which may be an important pathogenic factor in seborrheic dermatitis. This was a single-center, bilateral, open-label pilot study in 10 healthy volunteers. The nonsteroidal cream was applied twice daily to a designated target area on the chest for 7 days, and the number of colony-forming units of Malassezia spp taken by tape stripping after 7 days was compared with baseline. The percentage reduction from baseline to day 7 in the number of colony-forming units of Malassezia spp was 94% on the treated side versus 49% on the untreated side ( P = .03). This pilot study shows the nonsteroidal topical cream has antifungal activities. Further exploration into its potential as a therapeutic alternative for seborrheic dermatitis is warranted.

An investigator-blind, randomized, 4-week, parallel-group, multicenter pilot study to compare the safety and efficacy of a nonsteroidal cream (Promiseb Topical Cream) and desonide cream 0.05% in the twice-daily treatment of mild to moderate seborrheic dermatitis of the face

The treatment of seborrheic dermatitis includes topical antifungal agents to eradicate Malassezia spp, corticosteroids, which treat the inflammatory component of the disease and keratolytics which remove scale and crust. This study compared the efficacy of a nonsteroidal topical cream and a low-potency topical corticosteroid for the treatment of mild to moderate seborrheic dermatitis of the face in 77 volunteers randomized to twice-daily treatment with nonsteroidal cream or corticosteroid cream for up to 28 days. If the individual was rated clear by day 14, the study drug was collected and the participant was told not to use any topical products on the previously treated areas until after the 28-day follow-up visit. Both treatments were similarly effective in reducing disease severity, with approximately 90% of participants clearing or almost clear during the study. Both treatments demonstrated significant reductions in erythema, scaling, and pruritus ( P < .0001). Safety in both groups was rated as excellent in more than 90%. Those using the nonsteroidal cream who cleared after 14 days of treatment were more likely to remain clear than were participants using the corticosteroid cream ( P = .0173). Investigator global assessments of improvement found both study agents were essentially the same, and participants in both groups achieved clinically important improvement.

Isolation and characterization of Malassezia spp. in healthy swine of different breeds

Malassezia spp. genus is represented by several lipophilic yeasts, normally present on the skin of many warm-blooded vertebrates, including man. Swine are one of the less investigated animal species. The aim of the present work was to study the occurrence of Malassezia spp. in the external ear canal of 408 healthy swine of different breeds, under different breeding conditions. For this purpose N. 185 free-ranging wild boars, N. 107 large size pigs and 116 Cinta Senese breed were selected. Animals were of both genders, with age ranging from 8 months to 4 years. The subjects were culturally and molecularly checked for Malassezia spp. Ninety-two out of 408 animals scored positive for Malassezia yeasts (22.5%). Malassezia pachydermatis, Malassezia sympodialis and Malassezia furfur were recognized. M. pachydermatis was the sole species isolated from wild boars (12.9%), Cinta Senese (20.7%) and juvenile large size pigs (13.6%); 88% of large size breeds adult subjects scored positive for M. sympodialis (63.6%) and M. furfur (22.7%), respectively. The study focus on scarcely investigated epidemiological aspects of Malassezia spp. in this animal species.

Identification of Malassezia species from pityriasis versicolor in Indonesia and its relationship with clinical characteristics

Pityriasis versicolor (PV) is a chronic superficial fungal disease caused by Malassezia spp. The incidence is as high as 30-40% in tropical climates. Previous studies indicate that the geographic factor has influence on the main species isolated from PV. Our aim was to identify Malassezia spp. from PV patients in Indonesia and their correlation to clinical characteristics. Isolates of Malassezia were collected from 98 PV patients (62 males and 36 females). Identification was based on morphological observation and biochemical evaluation. Leeming Notman agar was used as isolation culture medium. The biochemical evaluation consisted of specimen culture onto Sabouraud dextrose agar, Cremophor EL, Esculin, Dixon's agar at 37 degrees C and catalase reaction. The isolates found were Malasseziafurfur (42.9%), M. sympodialis (27.5%), M. globosa (13.3%), M. slooffiae (7.7%), M. obtusa (7.7%) and M. restricta (2.2%), and 7.14% specimens were unidentified. There was no statistically significant association between Malassezia spp. and demographic characteristics and clinical characteristics of the patients. Unlike reports from temperate climate countries, this study in Indonesia found M. furfur as the most frequently isolated Malassezia spp. in PV patients.

TLR2/MyD88-Dependent and -Independent Activation of Mast Cell IgE Responses by the Skin Commensal Yeast Malassezia sympodialis

Atopic eczema (AE) is a chronic inflammatory skin disease. Approximately 50% of adult AE patients have allergen-specific IgE reactivity to the skin commensal yeast Malassezia spp. Due to the ruptured skin barrier in AE, it is likely that Malassezia can come into contact with mast cells, which are known to be involved in AE. We therefore hypothesized that Malassezia spp. can activate mast cells. Bone marrow-derived mast cells (BMMCs) were generated from wild type, TLR2, TLR4, and MyD88 gene-deleted mice and cocultured with Malassezia sympodialis extract. We recorded that M. sympodialis induced release of cysteinyl leukotrienes in a dose-dependent manner in nonsensitized and IgE-anti-trinitrophenyl-sensitized BMMCs, respectively, with three times higher levels in the latter type of cells. IgE-sensitized BMMCs also responded by degranulation as assessed by release of beta-hexosaminidase, increased MCP-1 production through a MyD88-independent pathway, and activated phosphorylation of the MAPK ERK1/2. Furthermore, M. sympodialis enhanced the degranulation of IgE receptor cross-linked wild-type BMMCs and altered the IL-6 release dose-dependently. This degranulation was independent of TLR2, TLR4, and MyD88, whereas the IL-6 production was dependent on the TLR2/MyD88 pathway and MAPK signaling. In conclusion, M. sympodialis extract can activate nonsensitized and IgE-sensitized mast cells to release inflammatory mediators, to enhance the IgE-mediated degranulation of mast cells, and to modulate MAPK activation and by signaling through the TLR2/MyD88 pathway to modify the IL-6 production of IgE receptor cross-linked mast cells. Collectively, these findings indicate that M. sympodialis can activate mast cells and might thus exacerbate the inflammatory response in AE.

Kopfschuppen erfolgreich behandeln

Für immer mehr Menschen ist eine saubere und schuppenfreie Kopfhaut ein zwingendes Bedürfnis. Neben ihrer Bedeutung für die Körperpflege und Verschönerung der äußeren Erscheinung, spielen Shampoos eine wichtige Rolle für die Behandlung auch pathologischer Zustände der Kopfhaut. Die Haarwäsche stellt die häufigste Form der Haarbehandlung dar. Das Anforderungsprofil an ein Shampoo übertrifft damit die Funktion der Reinigung, es soll gleichzeitig Probleme der Kopfhaut behandeln. Die Koinzidenz einer erhöhten Keimdichte von Malasseziahefen bei Kopfschuppen und seborrhoischem Ekzem wird als Hinweis auf eine pathogenetische Bedeutung dieses Keimes gewertet. Als Wirkstoffe gegen Kopfschuppen stehen antimikrobielle Wirkstoffe im Vordergrund, die über eine Hemmung der Malasseziahefen wirken. Durch eine verbesserte Technologie und Galenik wird eine besonders effektive Inhibition von Malasseziahefen auch nach kurzer Einwirkzeit des Shampoos bei gleichzeitig niedrigem Hautreizungspotenzial erreicht. Fortschritte der Shampootechnologie haben zudem Anwendungen ermöglicht, die nicht nur eine effektive Behandlung von Kopfschuppen bieten, sondern auch die Vorteile nichtmedizinischer Haarwaschmittel. In Antischuppenshampoos erlangt der Einsatz von Pflegestoffen zunehmend Bedeutung, um dem Haar nach der Wäsche auch Glanz, Glätte und Volumen zu verleihen. Rückwirkend erhöhen die kosmetischen Eigenschaften eines Shampoos, wie Konditioniereffekt oder Pflegewirkung, und Aspekte des Produktkomforts, wie hohe Verträglichkeit und kurze Kontaktzeit, die Patienten-Compliance im Hinblick auf eine regelmäßige Anwendung für eine erfolgreiche Bekämpfung von Kopfschuppen.

Distribution of Yeast-form Fungi in Oral Cavity of Dog

The purpose of this study was to isolate and identify of yeast-form fungi from the oral cavity of dogs. Oral samples from 38 dogs were cultured on Brucella-blood agar for total organisms, and selective media for fungi. The distribution and characterization of the isolates were studied. The fungi were present in 52.6% of the examined dogs. The average detection rate against total cultivable bacteria was 0.0018% (0∼0.013%). Most yeast-form fungi could grow on CHROMagar Candida medium for 5 days and formed small, smooth colonies. Malassezia spp. was detected from 52.6% of the tested subjects. The genera Candida, Trichosporon and Cryptococcus were identified at a low percentage. However, Candida albicans was not detected in any of the dogs. The conclusions of this study are that dog inherent C. albicans was absent, and the predominant fungus was Malassezia spp. These results suggest that the composition of yeast-form fungi in oral cavities of human and dogs differs.

Concordancia entre características fenotípicas y PCR-REA en la identificación de especies de Malassezia

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.

A new ketoconazole topical gel formulation in seborrhoeic dermatitis: an updated review of the mechanism

Seborrhoeic dermatitis (SD) is a chronic, inflammatory skin disorder, affecting areas of the head and body where sebaceous glands are most prominent and active. The disorder commonly affects hair-bearing areas of the head, including the scalp. Involvement on the face is usually limited to the hairline, eyebrows, nasolabial folds and ears, and may occur either with or without scalp involvement. Areas of the trunk where SD may occur include the body folds and the presternal area. The aetiology of SD is unknown, although hormones and the Malassezia spp., formerly known as Pityrosporum (naturally occurring yeasts), are thought to be involved in the development of the condition. SD responds to the use of antifungal medications such as ketoconazole, suggesting that the inflammation could be linked to the Malassezia spp. The mechanisms behind the therapeutic effect of ketoconazole for the management of SD form the basis of this review. The broad spectrum activity of Ketoconazole was reported in the early 1980s. Due to its potent effect against Malassezia spp. the development of ketoconazole for the treatment of various skin infections, in which a link was proposed with Malassezia spp., was initiated. Later on, a number of ancillary properties were described for ketoconazole, comprising antibacterial, anti-inflammatory, sebostatic and antiproliferative effects. The incorporation of ketoconazole in an adapted vehicle further promoted its efficacy. Recently, a new anhydrous gel containing 2% ketoconazole (Xolegel™) was launched, in which all of the above properties were optimised.

Shampoos: Ingredients, efficacy and adverse effects

Shampoos are the most frequently prescribed treatment for the hair and scalp. The different qualities demanded from a shampoo go beyond cleansing. A cosmetic benefit is expected, and the shampoo has to be tailored to variations associated with hair quality, age, hair care habits, and specific problems related to the condition of the scalp. The reciprocal relationship between cosmetic technology and medical therapy is reflected in the advances of shampoo formulation that has made applications possible that combine benefits of cosmetic hair care products with efficacy of medicinal products. A shampoo is composed of 10 to 30 ingredients: cleansing agents (surfactants), conditioning agents, special care ingredients, and additives. Since the cleansing activity depends on the type and amount of surfactants utilized, shampoos are composed of a blend of different surfactants, depending on the requirements of the individual hair type. Development time from the concept to the commercial shampoo may take longer than a year. Much effort is invested in the development of conditioning agents, which impart luster, smoothness, volume and buoyancy. Another prerequisite is a scalp free of scaling. Current anti-dandruff agents primarily have an antimicrobial mode of action, and inhibit growth of Malassezia spp. Recent developments in shampoo technology have led to increased efficacy of anti-dandruff agents, allowing shorter contact time, and reducing irritation.

A Pilot Study on Seborrheic Dermatitis Using Pramiconazole as a Potent Oral Anti-Malassezia Agent

Background: Seborrheic dermatitis is considered to be a Malassezia-driven disease. Little objective information is available so far from biometrological quantitative assessments of this skin condition. Pramiconazole is a novel triazole with potent in vitro antifungal activity, especially against Malassezia spp. Objective: To study the sequential effects of pramiconazole on Malassezia, inflammation and epidermal changes. Method:This study was performed in 2 groups of subjects suffering from seborrheic dermatitis. The first group (n = 17) remained untreated and was used as control. Clinical, mycological and biometrological assessments were performed at inclusion and during the following 2 weeks. The second group of subjects (n = 10) received a single 200-mg oral dose of pramiconazole at inclusion. Clinical, mycological and biometrological evaluations were performed before and during 1 month following the single antifungal intake. For both parts of the study, several parameters were assessed including yeast density, desquamation, erythema, itching and sebum excretion. Results: In the control group, no significant changes were observed in any of the parameters during the observation period. The findings were markedly different in the pramiconazole-treated subjects. The yeast density was significantly improved on days 3, 7 and 28. Desquamation, erythema, itching, and the global clinical evaluation as assessed by the patients and investigators became significantly improved on days 7 and 28. A trend in decrease of scaliness was noted. No effect on sebum excretion was evidenced. In conclusion, a single 200-mg dose of pramiconazole exhibitsin vivo efficacy in controlling some important clinical aspects of seborrheic dermatitis. Following a reduction in the number of yeasts on day 3, a decrease in the severity of clinical signs and symptoms occurred from day 7 onwards. Sebum excretion appeared uninvolved in the clearing process of seborrheic dermatitis. Conclusion: A single 200-mg dose of pramiconazole appears to abate seborrheic dermatitis. The density in Malassezia present on lesional skin is first decreased, followed by clearing of the clinical signs.