Abstract

A total number of 125 dogs were sampled, which were taken from the external canal of the left and right ear (n=250 ears), of which 180 were positive to Malassezia pachydermatis, representing 72% (180/250) and 70 negatives or 28% (70/250). Parameters considered for this study were: kind of ear, length of hair and size of the animal. Samples were taken using sterile cotton swaps. Samples were cultured in potato dextrose agar media with cycloheximide and chloramphenicol. Complementary tests according to Mayser et al. (1997) and Guého et al. (1996) were realized. PCR tests amplifying regions D1 and D2, coding for LSU rRNA were also performed and were compared with the reference strain CBS 1879^NT of M. pachydermatis. Amplified product yielded a 600 bp product characteristic for Malassezia. Most predominant dog breeds for external otitis were Cocker Spaniel, French Poodle and Criolla. In Mexico, as well as in the state of Nuevo Leon, no documented evidence exists about the presence of this yeast in dogs with external otitis. The objective was to analyze dogs with this pathology and to inform the presence of M. pachydermatis by means of culture and amplification of D1 and D2 regions of gen 26S rRNA.

Key words: Malassezia, external otitis, M. pachydermatis, LSU rRNA D1/D2 regions. 

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