Frequency of yeasts and dermatophytes from healthy and diseased dogs

The aim of this study was to investigate the presence of dermatophytes and yeasts in healthy and diseased dogs. A total of 633 samples were collected from 26 healthy animals (104 samples), 131 with dermatitis (343 samples), 74 with otitis (148 samples), and 19 with ocular diseases (38 samples). Cultures from healthy animals were positive for Malassezia pachydermatis in 13.5% (7/52) of samples from skin, 42.3% (11/26) from ear, and 3.8% (1/26) from eye. Fungal growth was observed in 20.4% (70/343) samples from animals with dermatitis. Microsporum canis was the most isolated fungus (n = 39), followed by M. pachydermatis (n = 30) and Malassezia sp. (n = 3). Of the 148 samples from dogs with otitis, 90 (60.8%) were positive for M. pachydermatis, and of the clinical specimens from the conjunctiva of animals with ophthalmic disease, 2.6% (1/38) presented positive cultures for M. pachydermatis. Only 14.3% (2/14) of the positive cultures for M. pachydermatis and 40.9% (9/22) of those for M. canis were positive in the direct exam. Direct exams were positive in 84.3% (70/83) of the culture positive samples from affected ears of dogs with otitis. Malassezia pachydermatis may act as an aggravating factor in the occurrence of cutaneous diseases, or the isolation of M. canis may be associated with the onset of dermatophytosis. Fungal culture, rather than microscopic examination, should be used as the definitive diagnostic test for dermatomycoses and otitis.