Genetic relationships and population structure of Malassezia pachydermatis strains isolated from dogs with otitis externa and healthy dogs

Abstract

Malassezia pachydermatis causes infections of the skin and mucous membranes, especially in animals. It is commonly accepted that symptom manifestation depends on the physiological status of the host (different metabolic, hormonal, and immunological disorders). However, it should be considered whether distinct strains of M. pachydermatis could have different pathogenic potential and maintain opposite relations with the host, such as commensalism or parasitism. The scope of this study was to explore the population structure, genetic diversity, and phylogenetic relationships of M. pachydermatis strains isolated from dogs with clinical symptoms of otitis externa and from healthy dogs in order to investigate their relationships and evolutionary history. For all tests, a group of 30 strains derived from dogs with otitis externa and 34 strains from healthy dogs were used. The level of genetic diversity was initially assessed by polymerase chain reaction (PCR)-based random amplification of polymorphic DNA (RAPD-PCR), whereas evolutionary history was assessed by comparison of the nucleotide sequences of the internal transcribed spacer ITS1 region of nuclear rDNA. RAPD-PCR fingerprinting revealed a high level of genetic polymorphism in both tested groups (85% of unique profiles), but clinical isolates usually grouped together with other strains from otitis externa cases. Sequencing analysis identified 17 distinct genotypes with 59 polymorphic sites within both populations; however, putatively virulent strains were more closely related, indicating a probable correlation between the genotype and the virulence potential. Therefore, the hypothesis that M. pachydermatis virulence depends solely on the host's properties should be reconsidered including evolutionary and epidemiological data.

Genotypic Analysis of the Population Structure in Malassezia globosa and Malassezia restricta

“…Few molecular methods have been used for typing Malassezia strains, such as RFLP and multigene sequence analysis [ 28 , 29 , 30 ]. In previous studies, various molecular techniques found genetic variability within M. globosa , M. restricta , M. furfur [ 31 ] and M. pachydermatis [ 32 ]. Different Malassezia genotypes were identified as strictly related to the host, geographical origin and/or clinical manifestations [ 31 , 33 ].…”

“…Czyzenwska et al identified 17 distinct genotypes of M. pachydermatis with 59 polymorphic sites by sequencing analysis; however, putatively virulent strains were more closely related, indicating a probable correlation between the genotype and the virulence potential [ 32 ].…”

Managing recurrent otitis externa in dogs: what have we learned and what can we do better?

“…In dogs, M. globosa and M. restricta predominate on healthy skin whereas M. pachydermatis were associated with atopic skin 24 . More virulent M. pachydermatis have also been associated with otitis externa in dogs 25 . Differences in lipid dependency and altered lipid profiles in healthy and affected skin and ears may therefore influence population shifts.…”

An alternative application of some SSR DNA markers in experimental mycology

“…Відмічаються суттєві труднощі з повторюванням результатів дослідів різними лабораторіями. Однак незважаючи на великі проблеми цього методу ПЛР, його продовжують широко застосовувати як для генетичної ідентифікації зразків (Wyss, 1996;Stefańska et al, 2022;Valencia-Ledezma et al, 2022), так і в популяційних дослідженнях (Czyzewska et al, 2018;García-Béjar et al, 2021;Wojciechowska-Koszko et al, 2022).…”