Genetic variability and phospholipase production of Malassezia pachydermatis isolated from dogs with diverse grades of skin lesions.

Little detailed information is available on the association of Malassezia pachydermatis genotypes and the extent of skin damage that they cause. In the present study, isolates of M. pachydermatis, recovered from the skin of healthy dogs and dogs with dermatitis in Brazil, were characterized on the basis of partial sequencing of the large subunit (LSU), first internal transcribed spacer (ITS-1) and chitin synthase 2 gene (chs-2). The determination of phospholipase production was also included in the investigations. The severity of lesions and hyperpigmentation of dogs with skin disease were evaluated. For each locus, two main sequence types were designated as genotypes A and C. Two other minor sequence types (A2(I)-C2(I)) were also recorded and defined for the ITS-1. Genotype A isolates were the most prevalent, being recovered from healthy and diseased animals. No significant difference was detected among genotypes or ITS-1 sequence types and grades of skin damage or hyperpigmentation in the dogs with skin lesions. The number of M. pachydermatis isolates that produced phospholipase was statistically higher for diseased dogs than for strains found in healthy animals. The present study reveals that multiple genetic variants of M. pachydermatis occur in dogs and that the distribution patterns of particular genotypes on the skin of dogs in Brazil might be related to environmental and ecological factors which maintain distinctive genotype assemblages in specific geographical areas.