Cryptic Diversity of Malassezia pachydermatis from Healthy and Diseased Domestic Animals

Abstract

Malassezia pachydermatis is part of the normal cutaneous microbiota of wild and domestic carnivores. However, under certain conditions this yeast can overproliferate and cause several diseases in its host, mainly otitis and dermatitis in dogs. The aim of this study was to conduct a molecular characterization of M. pachydermatis isolates from healthy and diseased domestic animals, in order to assess the molecular diversity and phylogenetic relationship within this species. The large subunit (LSU) and the internal transcribed spacer (ITS) of ribosomal RNA, chitin synthase 2 (CHS2) and β-tubulin genes from sixteen strains isolated from dogs, cats, a goat, a pig and a horse were sequenced. A different number of types of sequences were identified for each target gene, including some types described for the first time. Five sequence types were characterized for the LSU, eleven for the ITS region, nine for CHS2 and eight for β-tubulin. A multilocus analysis was performed including the four genes, and the resulting phylogenetic tree revealed fifteen genotypes. Genotypes were distributed in two well-supported clades. One clade comprised strains isolated from different domestic animals and a strongly supported cluster constituted by strains isolated from cats. The second clade included strains isolated mainly from dogs and an outlier strain isolated from a horse. No apparent association could be observed between the health status of the animal hosts and concrete strains. The multilocus phylogenetic analysis is a useful tool to assess the intraspecific variation within this species and could help understand the ecology, epidemiology and speciation process of M. pachydermatis.

Characterization of the species Malassezia pachydermatis and re-evaluation of its lipid dependence using a synthetic agar medium

“…Due to the genetic diversity observed in M . pachydermatis strains [18, 30–32], we also hypothesize that the same could happen within this species.…”

“…pachydermatis genotypes and the new ITS and beta-tubulin genotypes from these lipid-dependent strains did not exceed the variation generally observed to occur in M . pachydermatis [18]. Besides, in the phylogenetic tree of the LSU rRNA sequences, the lipid-dependent strains were grouped and interspersed with the non-lipid dependent M .…”

“…Internal transcribed spacer (ITS) region (including the genes ITS1, 5.8S rRNA and ITS2), large subunit of the ribosomal RNA (LSU rRNA) region, chitin synthase 2 (CHS2) and beta-tubulin genes were amplified and sequenced, using the primers and the protocols described previously [17]. Sequences of the four genes of the remaining strains had been characterized previously [18]. …”

Biology, diagnosis and treatment ofMalasseziadermatitis in dogs and cats Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

“…Amplification of the chitin synthase 2 ( CHS2 ) gene in seven Malassezia species yielded an ~620 bp fragment with 95% sequence homology between the species, although phylogenetic analyses indicated that each species was genetically distinct . Limited genetic variability in seen in the CHS2 gene amongst M. pachydermatis isolates from dogs in previous studies, although wider variation was observed in another study . Partial sequencing of the ß‐tubulin gene in Malassezia provides a further opportunity for species and genotype differentiation …”

“…Genotypic approaches involving analyses of sequences obtained from multiple loci on the Malassezia genome, such as combined analyses of D1/D2, ITS, CHS2 and ß‐tubulin sequences, has proven to be a powerful tool in the epidemiological assessment of the intraspecific variations and adaptation of these particular genotypes to specific hosts …”