Teramoto, Hideshi Shinchitose Animal Clinic|Osaka Prefecture University
Kumeda, Yuko Osaka Prefectural Institute of Public Health
Yokoigawa, Kumio University of Tokushima Tokushima University Educator and Researcher Directory KAKEN Search Researchers
Hosomi, Koji Osaka Prefecture University
Kozaki, Shunji Osaka Prefecture University
Mukamoto, Masafumi Osaka Prefecture University
Kohda, Tomoko Osaka Prefecture University
Introduction: Malassezia species are commensals of normal skin microbial flora of humans and animals. These may become pathogenic under certain conditions such as those associated with atopic dermatitis or otitis externa in dogs.
Material and methods: Isolates of Malassezia pachydermatis were obtained from 27 dogs with healthy external ears and 32 dogs with otitis externa. Isolates were characterised on the basis of their first internal transcribed spacer (ITS) and internal spacer 1 (IGS1) sequences. Their extracellular lipase and phospholipase activity were also analysed. Three types of phospholipase inhibitor were used to identify the subclasses of phospholipase associated with otitis externa.
Results: The clinical isolates were classified into three ITS and three IGS1 sequence types. No significant differences in pathogenicity were detected among the ITS or IGS1 genotypes, and all of the isolates exhibited similar levels of lipase activity. The isolates derived from the dogs with otitis externa showed significantly higher phospholipase activity than those obtained from the dogs with healthy external ears. A phospholipase D inhibitor reduced the phospholipase activity of the isolates obtained from the dogs with otitis externa.
Conclusions: This study did not show any significant differences in pathogenicity among the ITS or IGS1 genotypes but does suggest that phospholipase D might be one of the virulence factors involved in the inflammation of the external ear caused by M. pachydermatis.
Veterinary Record Open
British Veterinary Association|BMJ Publishing Group
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Bioscience and Bioindustry