Carriage of Malassezia spp. yeasts in cats with diabetes mellitus, hyperthyroidism and neoplasia.

The frequencies of isolation and population sizes of Malassezia spp. on skin and at mucosal sites in 16 cats with diabetes mellitus, 20 cats with hyperthyroidism and 8 cats with neoplasia did not vary significantly from those of healthy cats when measured with the use of contact plates and a swab technique. M. pachydermatis was isolated from nine sites in one cat with feline paraneoplastic alopecia and pancreatic adenocarcinoma, two cats with diabetes mellitus and five cats with hyperthyroidism. A polymerase chain reaction-restriction enzyme analysis (PCR-REA) method that differentiated the 11 species of Malassezia spp was used to identify the lipid-dependent isolates that were obtained from two cats with diabetes mellitus, two cats with hyperthyroidism and one cat with multicentric lymphoma. Six isolates had PCR-REA patterns that were indistinguishable from M. slooffiae CBS 7956 and three matched M. nana CBS 9557. Our data suggests that skin and mucosal counts of Malassezia spp. are not routinely increased in cats with diabetes mellitus or hyperthyroidism but we report a further example of an association between feline paraneoplastic alopecia and Malassezia spp. proliferation. To the authors' knowledge, this is the first report of the isolation of M. slooffiae from feline skin.