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Veterinary Dermatology Feb 2020
Review
Topics: Animals; Antifungal Agents; Cat Diseases; Cats; Dermatitis; Dermatomycoses; Dog Diseases; Dogs; Malassezia; Veterinary Medicine
PubMed: 31957203
DOI: 10.1111/vde.12834 -
Clinical Microbiology Reviews Apr 1992The genus Malassezia contains three member species: Malassezia furfur and Malassezia sympodialis, both obligatory lipophilic, skin flora yeasts of humans, and Malassezia... (Review)
Review
The genus Malassezia contains three member species: Malassezia furfur and Malassezia sympodialis, both obligatory lipophilic, skin flora yeasts of humans, and Malassezia pachydermatis, a nonobligatory lipophilic, skin flora yeast of other warm-blooded animals. Several characteristics suggest the basidiomycetous nature of these yeasts, although a perfect stage has not been identified. Classically, these organisms are associated with superficial infections of the skin and associated structures, including pityriasis versicolor and folliculitis. Recently, however, they have been reported as agents of more invasive human diseases including deep-line catheter-associated sepsis. The latter infection occurs in patients, primarily infants, receiving parenteral nutrition (including lipid emulsions) through the catheter. The lipids presumably provide growth factors required for replication of the organisms. It is unclear how deep-line catheters become colonized with Malassezia spp. Skin colonization with M. furfur is common in infants hospitalized in neonatal intensive care units, whereas colonization of newborns hospitalized in well-baby nurseries and of older infants is rarely observed. Catheter colonization, which may occur without overt clinical symptoms, probably occurs secondary to skin colonization, with the organism gaining access either via the catheter insertion site on the skin or through the external catheter hub (connecting port). There is little information on the colonization of hospitalized patients by M. sympodialis or M. pachydermatis. Diagnosis of superficial infections is best made by microscopic examination of skin scrapings following KOH, calcofluor white, or histologic staining. Treatment of these infections involves the use of topical or oral antifungal agents, and it may be prolonged. Diagnosis of Malassezia catheter-associated sepsis requires detection of the organism in whole blood smears or in buffy coat smears of blood drawn through the infected catheter or isolation of the organism from catheter or peripheral blood or the catheter tip. Culture of M. furfur from blood is best achieved with Isolator tubes and plating onto a solid medium supplemented with a lipid source. Appropriate treatment of patients requires removal of the infected catheter with or without temporary stoppage of lipid emulsions; administration of antifungal therapeutic agents does not appear to be necessary. Because many patients who develop Malassezia catheter-associated sepsis have severe underlying illnesses, caution must be exercised in attributing all clinical deterioration to Malassezia infection. Our better understanding of how these organisms cause disease awaits the development of a useful typing scheme for epidemiologic studies and further studies on microbial virulence factors and the role of the immune response in pathogenesis.
Topics: Dermatomycoses; Humans; Malassezia; Mycoses; Skin
PubMed: 1576583
DOI: 10.1128/CMR.5.2.101 -
Current Opinion in Infectious Diseases Apr 2009The recent sequencing of the whole genome of Malassezia globosa and M. restricta forms the basis for molecular epidemiology studies and instigates investigations into... (Review)
Review
PURPOSE OF REVIEW
The recent sequencing of the whole genome of Malassezia globosa and M. restricta forms the basis for molecular epidemiology studies and instigates investigations into their respective virulence factors. Thus, reviewing current knowledge on Malassezia molecular typing methods would reveal the pros and cons of each method and would highlight potential scarcity of epidemiological data regarding this ubiquitous fungal commensal and pathogen.
RECENT FINDINGS
Methods employed for Malassezia molecular typing can be categorized into those detecting sequence variations of strains and those that selectively amplify polymorphic DNA markers for discriminating Malassezia species subtypes. The former exploit rRNA gene sequence variations in order to trace M. globosa, M. restricta and M.pachydermatis subtypes associated with specific skin diseases, or detect M. furfur geographical variations. Polymorphic DNA amplification methods, such as amplified fragment length polymorphism analysis, demonstrated association of M. furfur subtypes with the origin of the strain (skin or systemic isolate), whereas PCR-fingerprinting of the mini-satellite DNA clustered M. furfur strains according to their geographic origin and disease origin. Moreover, much typing work has already been performed regarding the zoophilic species M. pachydermatis and the relevant methods can be adapted for studying the anthropophilic Malassezia species.
SUMMARY
In the near future, molecular typing will be a powerful tool in epidemiological studies that could be employed for the elucidation of the pathobiology of Malassezia species in associated skin diseases
Topics: DNA Fingerprinting; DNA, Fungal; Dermatomycoses; Genotype; Humans; Malassezia; Mycological Typing Techniques; Polymorphism, Genetic
PubMed: 19283910
DOI: 10.1097/qco.0b013e328324ed19 -
Medical Mycology Aug 2020Malassezia dermatitis and otitis are recurrent features of canine atopic dermatitis, increasing the cost of care, and contributing to a reduced quality of life for the...
Malassezia dermatitis and otitis are recurrent features of canine atopic dermatitis, increasing the cost of care, and contributing to a reduced quality of life for the pet. The exact pathogenesis of secondary yeast infections in allergic dogs remains unclear, but some have proposed an overgrowth of M. pachydermatis to be one of the flare factors. The distribution of Malassezia populations on healthy and allergic canine skin has not been previously investigated using culture-independent methods. Skin swabs were collected from healthy, naturally affected allergic, and experimentally sensitized atopic dogs. From the extracted DNA, fungal next-generations sequencing (NGS) targeting the ITS region with phylogenetic analysis of sequences for species level classification, and Malassezia species-specific quantitative real-time polymerase chain reaction (qPCR) were performed. M. globosa was significantly more abundant on healthy canine skin by both methods (NGS P < .0001, qPCR P < .0001). M. restricta was significantly more abundant on healthy skin by NGS (P = .0023), and M. pachydermatis was significantly more abundant on naturally-affected allergic skin by NGS (P < .0001) and on allergen-induced atopic skin lesions by qPCR (P = .0015). Shifts in Malassezia populations were not observed in correlation with the development of allergen-induced skin lesions. Differences in the lipid dependency of predominant Malassezia commensals between groups suggests a role of the skin lipid content in driving community composition and raises questions of whether targeting skin lipids with therapeutics could promote healthy Malassezia populations on canine skin.
Topics: Allergens; Animals; Dermatitis, Atopic; Dog Diseases; Dogs; Dysbiosis; Female; High-Throughput Nucleotide Sequencing; Hypersensitivity; Malassezia; Male; Mycobiome; Phylogeny; Quality of Life; Skin
PubMed: 31782778
DOI: 10.1093/mmy/myz118 -
Mycoses Dec 2019Biofilm formation represents a major microbial virulence attribute especially at epithelial surfaces such as the skin. Malassezia biofilm formation at the skin surface...
BACKGROUND
Biofilm formation represents a major microbial virulence attribute especially at epithelial surfaces such as the skin. Malassezia biofilm formation at the skin surface has not yet been addressed.
OBJECTIVE
The present study aimed to evaluate Malassezia colonisation pattern on a reconstructed human epidermis (RhE) by imaging techniques.
METHODS
Malassezia clinical isolates were previously isolated from volunteers with pityriasis versicolor and seborrhoeic dermatitis. Yeast of two strains of M furfur and M sympodialis were inoculated onto the SkinEthic RHE. The tissues were processed for light microscopy, wide-field fluorescence microscopy and scanning electron microscopy.
RESULTS
Colonisation of the RhE surface with aggregates of Malassezia yeast entrapped in a multilayer sheet with variable amount of extracellular matrix was unveiled by imaging techniques following 24, 48, 72 and 96 hours of incubation. Whenever yeast were suspended in RPMI medium supplemented with lipids, the biofilm substantially increased with a dense extracellular matrix in which the yeast cells were embedded. Slight differences were found in the biofilm architectural structure between the two tested species with an apparently higher entrapment and viscosity in M furfur biofilm.
CONCLUSION
Skin isolates of M furfur and M sympodialis were capable of forming biofilm in vitro at the epidermal surface simulating in vivo conditions. Following 24 hours of incubation, without added lipids, rudimental matrix was barely visible, conversely to the reported at plastic surfaces. The amount of biofilm apparently increased progressively from 48 to 96 hours. A structural heterogeneity of biofilm between species was found.
Topics: Biofilms; Dermatitis, Seborrheic; Epidermis; Humans; Image Processing, Computer-Assisted; Malassezia; Microscopy, Electron, Scanning; Skin, Artificial; Tinea Versicolor
PubMed: 31556177
DOI: 10.1111/myc.13011 -
Clinics in Dermatology 2002
Review
Topics: Age Distribution; Female; Folliculitis; Humans; Malassezia; Male; Tinea Versicolor
PubMed: 11973054
DOI: 10.1016/s0738-081x(01)00240-1 -
Medical Mycology Journal 2013Malassezia species of lipophilic yeasts account for most fungal microbiota. Although they colonize healthy skin, they are also associated with several skin diseases,... (Review)
Review
Malassezia species of lipophilic yeasts account for most fungal microbiota. Although they colonize healthy skin, they are also associated with several skin diseases, including pityriasis versicolor, seborrheic dermatitis, Malassezia folliculitis, and atopic dermatitis. To date, 14 members of the Malassezia genus have been identified. Of these, both M. globosa and M. restricta predominate, regardless of skin-disease type. Comprehensive analysis of fungal microbiota in the skin of patients with atopic dermatitis using an rRNA clone library method revealed that fungal microbiota cluster according to disease severity. The external ear canal and sole of the foot are colonized by specific Malassezia microbiota.
Topics: Dermatitis, Atopic; Ear Canal; Extremities; Foot; Gene Library; Genes, rRNA; Head; Humans; Malassezia; Nasal Cavity; Neck; RNA, Fungal; Severity of Illness Index; Skin
PubMed: 23470953
DOI: 10.3314/mmj.54.39 -
Frontiers in Immunology 2023Head and neck dermatitis (HND) is a refractory phenotype of atopic dermatitis (AD) and can be a therapeutic challenge due to lack of responsiveness to conventional...
INTRODUCTION & OBJECTIVES
Head and neck dermatitis (HND) is a refractory phenotype of atopic dermatitis (AD) and can be a therapeutic challenge due to lack of responsiveness to conventional treatments. Previous studies have suggested that the microbiome and fungiome may play a role in inducing HND, but the underlying pathogenic mechanisms remain unknown. This study aimed to determine the link between HND and fungiome and to examine the contribution of .
MATERIALS AND METHODS
To identify the effect of the sensitization status of on HND, 312 patients diagnosed with AD were enrolled. To elucidate the mechanism underlying the effects of , human keratinocytes and dermal endothelial cells were cultured with and treated with Th2 cytokines. The downstream effects of various cytokines, including inflammation and angiogenesis, were investigated by real-time quantitative PCR. To identify the association between changes in lipid composition and sensitization status, D-squame tape stripping was performed. Lipid composition was evaluated by focusing on ceramide species using liquid chromatography coupled with tandem mass spectrometry.
RESULTS
Increased sensitization to was observed in patients with HND. Additionally, sensitization to was associated with increased disease severity in these patients. IL-4 treated human keratinocytes cultured with produced significantly more VEGF, VEGFR, IL-31, and IL-33. IL-4/ co-cultured dermal endothelial cells exhibited significantly elevated VEGFR, TGF-β, TNF-α, and IL-1β levels. Stratum corneum lipid analysis revealed decreased levels of esterified omega-hydroxyacyl-sphingosine, indicating skin barrier dysfunction in HND. Finally, growth was inhibited by the addition of these ceramides to culture media, while the growth of other microbiota, including , were not inhibited.
CONCLUSIONS
Under decreased levels of ceramide in AD patients with HND, would proliferate, which may enhance pro-inflammatory cytokine levels, angiogenesis, and tissue remodeling. Thus, it plays a central role in the pathogenesis of HND in AD.
Topics: Humans; Malassezia; Endothelial Cells; Interleukin-4; Cytokines; Dermatitis, Atopic; Ceramides; Lipids
PubMed: 36911720
DOI: 10.3389/fimmu.2023.1114321 -
Giornale Italiano Di Dermatologia E... Dec 2013Although Malassezia yeasts are a part of the normal microflora, under certain conditions they can cause superficial skin infection, such as pityriasis versicolor (PV)...
Although Malassezia yeasts are a part of the normal microflora, under certain conditions they can cause superficial skin infection, such as pityriasis versicolor (PV) and Malassezia folliculitis. Moreover the yeasts of the genus Malassezia have been associated with seborrheic dermatitis and dandruff, atopic dermatitis, psoriasis, and, less commonly, with confluent and reticulated papillomatosis, onychomycosis, and transient acantholytic dermatosis. The study of the clinical role of Malassezia species has been surrounded by controversy due to the relative difficulty in isolation, cultivation, and identification. This review focuses on the clinical, mycologic, and immunologic aspects of the various skin diseases associated with Malassezia. Moreover, since there exists little information about the epidemiology and ecology of Malassezia species in the Italian population and the clinical significance of these species is not fully distinguished, we will report data about a study we carried out. The aim of our study was the isolation and the identification of Malassezia species in PV-affected skin and non-affected skin in patients with PV and in clinically healthy individuals without any Malassezia associated skin disease.
Topics: Adolescent; Adult; Case-Control Studies; Dermatomycoses; Diagnosis, Differential; Female; Humans; Malassezia; Male; Middle Aged; Risk Factors
PubMed: 24442041
DOI: No ID Found -
Mycoses Feb 2015Malassezia yeast belongs to the normal cutaneous flora and under certain conditions it causes seborrhoeic dermatitis (SD). There is no culture-based study about the... (Review)
Review
Malassezia yeast belongs to the normal cutaneous flora and under certain conditions it causes seborrhoeic dermatitis (SD). There is no culture-based study about the presence and density of the Malassezia in SD patients in Serbia. Aim was to show the presence, species distribution and density of Malassezia in patients with SD on lesional skin (LS) and non-lesional skin (NLS) and healthy controls (HC) and to compare data between Serbia and other countries. The study included 70 HC and 60 patients with SD in the study group (SG). Isolation, identification and examination of density of Malassezia colony-forming units from LS and NLS were performed. Malassezia was found more frequently in the SG than in HC, 90% and 60%, respectively (P < 0.01). The most frequent isolates in SG on LS were M. slooffiae (26%), followed by M. globosa (17%) and M. sympodialis (17%). The yeast density was much higher on LS of SG than on NLS of SG or in the HC group (P < 0.05). Higher density of Malassezia was shown on LS of SG than on NLS of SG and HC. M. slooffiae is the most prevalent species in SD patients in Serbia. This study demonstrated a positive relationship between severity of SD and presence of Malassezia spp.
Topics: Adult; Aged; Aged, 80 and over; Case-Control Studies; Dermatitis, Seborrheic; Dermatomycoses; Female; Humans; Malassezia; Male; Middle Aged; Serbia; Young Adult
PubMed: 25590588
DOI: 10.1111/myc.12276