Molecular Analysis of Malassezia sympodialis -Related Strains from Domestic Animals

Abstract

Recently, several new lipid-dependent species belonging to the genus Malassezia have been described. Some of them, such as Malassezia dermatis, Malassezia nana, and the tentatively named "Malassezia equi," have similar phenotypes and are genetically close to Malassezia sympodialis Simmons et Guého 1990. DNA characterization by D1/D2 26S rRNA gene and internal transcribed spacer (ITS)-5.8S rRNA gene sequencing analysis of lipid-dependent strains from different animal species close to M. sympodialis is described and illustrated. Phylogenetic analysis of both the D1/D2 regions of 26S rRNA gene and ITS-5.8S rRNA gene sequences showed four distinct clusters. Cluster I included isolates from different animal species (horse, pig, and lamb) and the type culture of M. sympodialis. Cluster II included isolates from horses grouping close to the "M. equi" AJ305330 sequence. Cluster III comprised isolates mainly from goats. Cluster IV contained isolates mainly from cats grouping together with the M. nana AB075224 sequence. This last cluster included isolates from healthy and external otitic ears. All of these strains had identical 26S rRNA gene and ITS regions. It is not clear whether the value of these genetic differences is for the definition of species or whether they only demonstrate genetic variation among strains from different origins within M. sympodialis, which are in the course of differentiation and probably adaptation to specific animal hosts.Malassezia species are lipophilic yeasts that are usually members of the normal mycobiota of the human skin and inhabit the skin of a variety of animal species. However, these yeasts are associated with a variety of dermatological disorders of the human skin, such as atopic dermatitis, dandruff, folliculitis, pityriasis versicolor or seborrheic dermatitis (13) and intravascular catheter-acquired infections (23). They have been implicated in different skin disorders in animals, mainly otitis externa and dermatitis (6,15).Since the genus Malassezia was created by Baillon in 1889, its taxonomy has been a matter of controversy. A few years ago, the genus was reclassified (14, 16) on the basis of studies of morphological, ultrastructural, physiological, and genetic characteristics, and seven species, which are now widely accepted, were proposed. They are the previously described Malassezia furfur, Malassezia pachydermatis, and Malassezia sympodialis and four new species, Malassezia obtusa, Malassezia globosa, Malassezia restricta, and Malassezia slooffiae.

Molecular Detection of Fungal Communities in the Hawaiian Marine Sponges Suberites zeteki and Mycale armata

“…Malassezia species are lipophilic yeasts that are members of the normal mycoflora of the human skin and are also found on the skin of a variety of animal species (13). They are associated with a variety of dermatological disorders of human skin, including but not limited to, atopic dermatitis, dandruff, and folliculitis, and they are also implicated in several skin disorders in animals, mainly otitis externa and dermatitis (13,19,27,28,53).…”

“…They are associated with a variety of dermatological disorders of human skin, including but not limited to, atopic dermatitis, dandruff, and folliculitis, and they are also implicated in several skin disorders in animals, mainly otitis externa and dermatitis (13,19,27,28,53). Malassezia species have been isolated from humans, animals, soils, house dust, and deep sea sediments (4-6, 13, 29, 45, 60, 63).…”

Isolation of Malassezia pachydermatis and M. sympodialis from the external ear canal of cats with and without otitis externa

“…in domestic animals are required to improve our current understanding of the role that these recently identified species could play in the veterinary dermatological clinic. Although the final characterisation of some lipodependent Malassezia species is based on the use of genetic studies (Cabañes et al, 2005;Mirhendi et al, 2005), phenotypic methods have still been used by several researchers because they permit a satisfactory identification of Malassezia species and are feasible in clinical diagnostic laboratories and not only at research level .…”

“…Conditions that aggravate otitis externa are lichenification, hyperplasia, ulceration, fibrosis and otitis media (Scott et al, 2001). Guého et al (1996) (Mirhendi et al, 2005), although their differentiation is carried out by genetic analysis (Cabañes et al, 2005;Mirhendi et al, 2005), a technique not incorporated in the routine of commercial veterinary laboratories.…”

Hyperkeratotic Head and Neck <i>Malassezia</i> Dermatosis

“…In typical cases, direct examination of skin scrapings shows a mixture of globose blastoconidia arranged in clusters constantly associated with hyphae. The taxonomy of the Malassezia genus has been revised using molecular biology techniques and now comprises twelve different species: M. globosa , M. restricta , M. obtusa , M. slooffiae , M. sympodialis , M. furfur , M. pachydermatis , M. dermatis , M. nana , M. japonica , M. yamatoensis and the tentatively named M. equi [2,3,4,5,6,7]. M. globosa in its mycelial phase is assumed to be the causative agent for PV [8], even though the role of the other species of Malassezia in this skin disorder is not yet completely settled, according to variations found according to ethnic or geographic background [9,10,11].…”