Prevalence of Malassezia spp. in healthy pigs

Yeasts of the Malassezia Genus – Recent Findings

The genus Malassezia is a medically important genus of yeasts that can colonize the skin of humans and other warm-blooded animals. The genus currently comprises 18 species of which four new species were identified recently. The most widely known species, M. pachydermatis, occurs in animals but was detected also in humans, namely at life endangering septicaemias and in prematurely born children. Proliferation of Malassezia occurs most frequently as a result of disturbances in the normal homeostasis of host immunity on the one hand and virulence of these yeasts on the other hand. The successful management of the disease depends on the therapeutic control of overgrowth of the yeasts and any concurrent bacterial infection by local or systemic anti microbial treatment, as well as, on identification and potential correction of the predisposing factors.

Malassezia: Zoonotic Implications, Parallels and Differences in Colonization and Disease in Humans and Animals

Malassezia spp. are commensals of the skin, oral/sinonasal cavity, lower respiratory and gastrointestinal tract. Eighteen species have been recovered from humans, other mammals and birds. They can also be isolated from diverse environments, suggesting an evolutionary trajectory of adaption from an ecological niche in plants and soil to the mucocutaneous ecosystem of warm-blooded vertebrates. In humans, dogs and cats, Malassezia-associated dermatological conditions share some commonalities. Otomycosis is common in companion animals but is rare in humans. Systemic infections, which are increasingly reported in humans, have yet to be recognized in animals. Malassezia species have also been identified as pathogenetic contributors to some chronic human diseases. While Malassezia species are host-adapted, some species are zoophilic and can cause fungemia, with outbreaks in neonatal intensive care wards associated with temporary colonization of healthcare worker’s hands from contact with their pets. Although standardization is lacking, susceptibility testing is usually performed using a modified broth microdilution method. Antifungal susceptibility can vary depending on Malassezia species, body location, infection type, disease duration, presence of co-morbidities and immunosuppression. Antifungal resistance mechanisms include biofilm formation, mutations or overexpression of ERG11, overexpression of efflux pumps and gene rearrangements or overexpression in chromosome 4.

Isolation and characterization of Malassezia spp. in healthy swine of different breeds

Malassezia spp. genus is represented by several lipophilic yeasts, normally present on the skin of many warm-blooded vertebrates, including man. Swine are one of the less investigated animal species. The aim of the present work was to study the occurrence of Malassezia spp. in the external ear canal of 408 healthy swine of different breeds, under different breeding conditions. For this purpose N. 185 free-ranging wild boars, N. 107 large size pigs and 116 Cinta Senese breed were selected. Animals were of both genders, with age ranging from 8 months to 4 years. The subjects were culturally and molecularly checked for Malassezia spp. Ninety-two out of 408 animals scored positive for Malassezia yeasts (22.5%). Malassezia pachydermatis, Malassezia sympodialis and Malassezia furfur were recognized. M. pachydermatis was the sole species isolated from wild boars (12.9%), Cinta Senese (20.7%) and juvenile large size pigs (13.6%); 88% of large size breeds adult subjects scored positive for M. sympodialis (63.6%) and M. furfur (22.7%), respectively. The study focus on scarcely investigated epidemiological aspects of Malassezia spp. in this animal species.

Carriage ofMalassezia spp.yeasts in healthy and seborrhoeic Devon Rex cats

Skin and anal mucosal carriage of Malassezia spp. yeasts was investigated in 21 healthy Devon Rex cats (DRC) and in 9 seborrhoeic DRC using swabs and contact plates. M. pachydermatis was isolated from 26 cats and lipid-dependent Malassezia spp. isolates were recovered from the claw fold of 5 healthy and 3 seborrhoeic DRC. The frequencies of isolation and population sizes of M. pachydermatis in the axillae, left groin and claw fold in seborrhoeic DRC significantly exceeded (P<0.05) those of healthy animals. The frequencies of isolation and population sizes of M. pachydermatis in the axillae and groin in both groups of DRC, and the frequencies of isolation and population sizes of M. pachydermatis in the claw fold of the seborrhoeic DRC, exceeded those of healthy Domestic short-haired cats. Using polymerase chain reaction--restriction enzyme analyses (PCR-REA) based on amplification of the large subunit rRNA gene, all eight lipid-dependent isolates had profiles that were indistinguishable from that of M. slooffiae CBS 7956. These data indicate that DRC are frequently colonized by M. pachydermatis and that the claw folds may also be colonized by M. slooffiae. The pathogenic significance of the high Malassezia spp. counts in the seborrhoeic DRC should now be determined.

Carriage ofMalasseziaspp. 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.