Malassezia pachydermatis: enzymes production in isolates from external ear canal of dogs with and without otitis

The relationship between production of enzymes and pathogenicity of Malassezia pachydermatis strains was studied. Thirty strains of M. pachydermatis isolated from dogs were used: 15 originating from animals with external otitis and 15 obtained from ears of asymptomatic dogs. The samples, obtained by introduction of a sterile swab into the auditory canal after cleaning the auricle with alcohol-ether solution, were seeded onto Sabouraud dextrose agar with chloramphenicol (100mg/l) and were incubated at 37°C for up to two weeks. The colonies were identified according to their macro-and-micromorphology. All strains were investigated for the production of chondroitin-sulphatase, hyaluronidase, phospholipase and proteinase. Most of the strains showed a high production of the four enzymes. Statistical analysis did not show any differences in the enzymatic activity among the strains. M. pachydermatis originating in normal microbiota as well as in otic secretion from dogs with otitis could produce the four researched enzymes. Probably M. pachydermatis has other virulence factors that are involved in the parasitism