We investigated malassezia species and genotypes colonizing dogs, comparing those recovered from the ear canal with those from other anatomical body sites, as well as from diseased and healthy skin. The malassezia isolates were obtained from four types of skin samples, i. Biology, diagnosis and treatment of malassezia dermatitis. In fact, the genus malassezia is by far the most abundant eukaryotic member of the microbial flora of the skin in these organisms. The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of. Malassezia species can be involved in skin disorders, such as pityriasis versicolor, seborrheic dermatitis, atopic eczema, and folliculitis, and occur. Dichotomous response of malasseziainfected macrophages to. The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention. Malassezia is the name of a type of yeast fungus that lives on the surface of the skin of dogs. Dermatitis associated with malassezia pachydermatis in 11 dogs, j am animal hosp assoc 27. Owing to the slow growth and lipid requirements of these fastidious yeasts, convenient and reliable antifungal drug susceptibility testing assays for malassezia spp. The aim of this study was to get a further insight into pathogenetic and clinical aspects of malassezia dermatitis and otitis in the dog through a comparison between patients with malassezia overgrowth to those of a control group. The genus malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds objectives. Malassezia fungemia, antifungal susceptibility testing and epidemiology of nosocomial infections, in malassezia and the skin.
Human skin is naturally acidic with an average ph of 4. The human proteins are capable of inducing positive skin prick and atopy patch tests in patients sensitized to the malassezia proteins, indicating a role of ige. Malassezia spp in skin microbiome scalp has been implicated in seborrheic dermatitis. Although the in vitro susceptibility testing is not yet standardized for malassezia spp. Commonly used physiologic tests include urease, catalase, and. In the last 15 years, the genus malassezia has been a topic of intense basic research on taxonomy, physiology, biochemistry, ecology, immunology, and metabolomics. All species are lipiddependent, with the exception of m. In vitro susceptibility of malassezia pachydermatis. The malassezia genus in skin and systemic diseases. Canine atopic dermatitis ad is frequently treated with topical or oral azole antifungals, as the lipophilic yeast malassezia pachydermatis is recognized as an exacerbating factor of canine ad 6, 8. Covering all aspects of skin disease from basic science through pathology and epidemiology to clinical practice, the text is recognized for its unparalleled coverage of diagnosis. The fungal genus malassezia comprises lipiddependent and lipophilic yeast species that are part of the normal skin microbiota. Diagnosis and management of the itchy horse in practice. The proportion of malassezia species isolated from the skin varies considerably among different medical conditions and in healthy skin.
Rooks textbook of dermatology is the most comprehensive work of reference available to the dermatologist. Malassezia pachydermatis is a lipophilic yeast that colonizes the stratum corneum and mucosal sites of dogs. Molecular and conventional identification of malassezia. After test analysis for morphological, biochemical, and physiological characterization, 36. Management of skin diseases in dogs and cats, elsevier science, edinburgh. Molecular analysis of malassezia pachydermatis isolated. Dogs may present with malassezia otitis, dermatitis either localized or generalized or both.
Before we proceed, i need to give some contextual information about the acid mantle and skins ph so you can better understand this section. Malassezia and the skin science and clinical practice teun. A close association between skin and malassezia ige binding allergens in atopic. The 14 species are classified in class malasseziomycetes in the ustilaginomycotina of basidiomycota. In this book, the authors, all experts in malassezia research, cover the history of the fungal species, associated skin conditions, epidemiology, genomic data and current treatment options. The skin commensal yeast malassezia is associated with common skin disorders like atopic dermatitis, but how the mammalian host responds to malassezia remains unclear.
Skin test, introduction of a specific test substance into the skin of an individual, either by injection or by scratching the skin, to determine that individuals possible allergy to certain substances or his susceptibility or immunity to certain diseases. A color atlas and therapeutics guide, w b saunders, philadelphia. It is a normal inhabitant of the ear canal and some other parts of the skin, and in most dogs it does not cause a problem. In postpubertal adults, these areas are the scalp, face, neck, and upper torso with accentuation at the role of commensal skin flora in atopic dermatitis 43 anterior axillary line fig. Malassezia and the skin science and clinical practice. Malassezia furfur promoting growth of staphylococcus. Recently, their pathogenicity is being expanded to other skin disorders, such as atopic dermatitis, psoriasis, and acne vulgaris. All animals enrolled in the study were presented at the.
These yeasts may act as opportunistic pathogens and cause skin diseases in humans and animals under certain conditions. The absence of a transformation system hampered studies to. Pityriasis versicolor and other malassezia skin diseases. Its relative prevalence also varies with age, body site, and geographic location. The interaction of malassezia yeasts with the skin is complex and involves. Military medical university, shanghai, china, 6agency for science, technology, and research a. The history can be vague, the patient is large with a dense coat, and the microscope is located back at the practice. Phenotypic characterization of canine malassezia spp. It is associated with common skin diseases such as pityriasis versicolor and atopic dermatitis and can cause systemic infections in immunocompromised individuals. Boekhout t, gueho e, mayser p, velegraki a editors, pp 65119. Yeasts from the genus malassezia belongs to normal commensal skin flora of warmblooded vertebrates. Table i displays an overview of the distinct malassezia species isolated in distinct conditions.
In this case, more than 70 colonyforming units per sample might be. Pdf pityriasis versicolor and other malassezia skin diseases. A skin test is usually considered positive when the skin becomes red and swollen at the site of contact with the test material and is. Previously, we reported that a clinical isolate of m. In healthy skin, malassezia yeasts exploit essential nutrients for their. The 1996 revision of the genus resulted in seven accepted taxa. Studies utilising traditional cytological and cultural methods have clearly demonstrated that malassezia yeasts are normal inhabitants of healthy canine and feline skin and mucosae section 4. Methodological issues in antifungal susceptibility testing. In healthy subjects from canada, m globosa was the most common isolate in. Aspetti clinici ed eziopatogenetici della dermatite ed. Probiotics for skin health and increasing lactic acid production. Reference methods for antifungal susceptibility testing of yeasts have been developed by the clinical and laboratory standards institute clsi and the european committee on antibiotic susceptibility testing eucast. The malassezia genus in skin and systemic diseases clinical.
Frontiers malassezia yeasts in veterinary dermatology. Management can also cause frustration for both the clinician and the client, with tasks that may be manageable for dogs and cats proving impractical in ponies and horses. Extra resources for generalized dermatitis in clinical practice. Clinical studies have shown that the ph of the skin surface of individuals with sdd slightly altered towards alkalinity from a ph pdf 7. Azole resistance of malassezia pachydermatis causing. Using an epicutaneous infection model in mice, sparber et al. Malassezia skin infection yeast infection fungal infection what is malassezia. Favorable growth conditions in the local environment allow excessive multiplication of this organism, which may then function as an opportunistic secondary pathogen.