Variability of Malassezia pachydermatis: an italian experience and brief review of literature

Material and methods: This work described some experiences relating to the study of morphological, cultural, biochemical features and the RAPD profiles of 75 M. pachydermatis strains, isolates from symptomatic and asymptomatic dogs and cats from various provinces of Northern Italy, with the purpose to find any relation between the different characteristics. The Beta–glucosidase activity, catalase reaction, synthesis of pigments by use of tryptophan as the single nitrogen source, growth at 40°C, precipitate production on mDixon agar and lipid assimilation using Tween 20, 40, 60, 80 and Cremophor-EL were tested. The RAPD analysis was performed using FM1 primer. Results: The strains showed a high morphological, cultural and biochemical variability and no correlations among the different biological characteristics and among these and the presence/absence of lesions in the animals were found. At RAPD analysis, 44 different clusters were found. Only few relations were observed among biological variables and the presence/absence of the different RAPD bands but these features were not usable for a univocal differentiation of the strains. Conclusions: No correlations were found among biological variables and the RAPD tree clusters. A comparison among our results and the literature data confirm the extreme variability of this species