Comparison of lipid profiles of Malassezia pachydermatis strains isolated from dogs with otitis externa and without clinical symptoms of disease.

Malassezia pachydermatis can cause infections of the skin and mucous membranes, especially in animals. It becomes a problem also in medicine. It is considered that metabolic disorders as well as hormonal and immunological status of the host promote diseases caused by M. pachydermatis. Here we consider whether specific features of fungi could also favour infections. We checked whether there are differences in lipid profiles between strains obtained from dogs with otitis externa and strains obtained from healthy dogs. Lipid profiles were determined using thin layer chromatography and gas chromatography-mass spectrometry. All analyses were carried out on 32 strains derived from dogs with otitis externa and 31 strains isolated from dogs without symptoms of disease. The results show that strains isolated from dogs without symptoms of otitis externa are characterised by a higher content of fatty acids. They contain significantly more behenic and lignoceric acids on medium without addition of lipids, and more oleic acid and total monounsaturated fatty acids on medium with lipids supplementation. These strains have also a higher content of esters of ergosterol and triglycerides. Data obtained show differences which may be specific features of M. pachydermatis-specific strains related to the ability of infection, which could be not directly related of the host condition.