Different studies targeted various RNA or DNA regions in order to distinguish the molecular pattern of M. pachydermatis and to assess whether genotype classification was in accordance with host preferences. The authors approached the development of consensus guidelines on therapy on two levels. The case of Malassezia yeasts is rather complex because many of the 18 currently described species have been found on the skin of animals as well as of humans (Table 1). These diagnostic challenges are compounded by lack of direct correlation between yeast population density and clinical signs (Section 8.5). Therapeutic doses recommended are variable with 5 mg/kg once daily, or for two consecutive days a week, being most often used. However, enhanced IgG responses can be seen in dogs with Malassezia dermatitis and in humans and dogs with atopic dermatitis. Malassezia dermatitis typically presents as a pruritic dermatosis or otitis and it is a major differential diagnosis in any dog with those presenting signs. In 1989, the genus Malassezia (Baillon 1889), also known under the generic name Pityrosporum proposed by Sabouraud in 1904, comprised only two taxa: M. furfur (syn. In cats only open case series have been described, using oral itraconazole at varying doses and intervals (Table S7, LoE 3, SoR C‐weak).85, 86, 284 As for dogs, topical antifungal agents such as miconazole, chlorhexidine or climbazole are likely to be beneficial but there is no data to substantiate this, other than anecdotal reports. These mature dendritic cells are excellent antigen presenting cells and are capable of presenting peptides on MHC molecules to T cells.185 Dendritic cells have also been shown to be activated by interaction between Malassezia antigens and various members of the C type lectin class of receptors such as Mincle, Dectins 1 & 2, and Langerin.175 This results in the production of pro‐inflammatory cytokines such as IL‐1, IL‐6, IL‐8 and TNF‐α.175 A recombinant Mala f 1 gene fragment upregulated the production of IL‐6, TNF‐Alpha and IL‐10, but not IL‐12, from human leukaemia‐derived dendritic cells.184 Interestingly, dendritic cells that have been stimulated by Malassezia antigens appear to be resistant to lysis by Natural Killer cells, a mechanism that likely favours survival of the cells in order to maintain antigen presentation.186. Unlike the dermatophytes, which visit and potentially infect the non‐immune host, Malassezia yeasts are commensal organisms, forming a reservoir of potential pathogens in the stratum corneum or mucosae, that may induce disease whenever the homeostatic balance of yeast virulence, on the one hand, and host immunity, on the other, is disrupted in favour of the yeast. Dans une série d´articles de synthèse, la participation de cette levure au développement de plusieurs maladies de la peau, particulièrement chez le chat et le chien comme par exemple la dermatite séborrhéique, est évoquée. Malassezia pachydermatis has also been isolated with significantly higher prevalence from the sputum of asthmatic human patients (21.7%) than from healthy controls (0%).468 The clinicopathologic significance of this finding, if any, is unknown and data on pet ownership was not collected from the subjects studied. It is important to appreciate that these definitions are likely arbitrary unless previous studies established the likely values obtained with the identical sampling method in that particular anatomical site in that particular breed of dog or cat. Figure S2. Abundant ovoid to short cylindrical yeast cells with broad‐based budding amongst squames; modified Wright‐Giemsa stain (“Diff‐Quik”), x50. While this disease has been reported a number of times, only two reports confirmed associated Malassezia overgrowth.251, 406 The remaining reports could not definitively confirm the presence of a thymoma,83 or failed to demonstrate yeast on histopathology, though skin cytology and/or culture was not noted to be performed in all cases.407-410, A single cat with thymoma and confirmed Malassezia overgrowth (confluent growth on contact plates) that was treated surgically and followed up showed no yeast growth on contact plate culture six months following surgical removal. El documento fue presentado en dos reuniones internacionales de sociedades de dermatología veterinaria y un taller internacional de micología; estuvo disponible para comentarios en el sitio web de WAVD por un período de seis meses. This probably reflects exposure of the immune system to antigens produced by commensal organisms. Chez les chiens: - traitement et stabilisation de la dermatite séborrhéique associée à Malassezia pachydermatis et Staphylococcus intermedius. Malassezia dermatitis is often first diagnosed in dogs between one and three years of age,386 as might be expected in a disease that is frequently secondary to atopic dermatitis or due to genetic predisposition. Français. Mast cell exocytosis is rare but a linear array of mast cells at the dermo‐epidermal junction is not infrequent. Summary of reports on susceptibility testing of Malassezia pachydermatis using the broth microdilution method. Gustafson was able to induce a spontaneously‐resolving erythemato‐ceruminous otitis externa in healthy dogs by the application of a suspension of ‘P. isolation from the hair coat as compared to non‐infected cats.254, Antibacterial therapy has not been reported to be an independent risk factor for development of Malassezia dermatitis in any published studies. Many dogs with Malassezia dermatitis have concurrent dermatoses, especially hypersensitivity disorders, ectoparasitic infestation, bacterial pyoderma, endocrinopathies or cornification defects (Section 7). Researchers and clinicians have developed a range of semi‐quantitative and quantitative methods for enumeration of yeasts in skin, some of which have important applications in veterinary clinical practice for routine diagnosis, assessment of response to therapy, and in research and development of novel therapeutic agents and formulations. It is a non‐pruritic disease unless there is significant secondary Malassezia (or bacterial) infection, usually manifest by crusts and brown exudate.399-405 Systemic azoles (itraconazole 5–10 mg/kg once daily284 and ketoconazole 5 mg/kg twice daily401) have been used in a limited number of cases to successfully treat concurrent Malassezia infections, resulting in reduced pruritus, better quality of life and reduction of inflammatory changes on histopathology, albeit without improving the poor prognosis associated with frequently metastatic neoplasia.83, 401, Significant colonisation of the skin with Malassezia organisms may be associated with some cases of thymoma‐associated exfoliative dermatitis. Similar discussions ensued at a lecture in 1992 at the British Veterinary Dermatology Study Group spring meeting.67 One highlight of the debate was mention of Shuster's publication that showed that dandruff was clearly associated with “Pityrosporum ovale”, elegantly dismissing the distorted view that effective dandruff treatments were cytostatic rather than antimycotic in action.68. La dermatite à levures est une infection de la peau causée par Malassezia pachydermatis. Amplification of the chitin synthase 2 (CHS2) gene in seven Malassezia species yielded an ~620 bp fragment with 95% sequence homology between the species, although phylogenetic analyses indicated that each species was genetically distinct.34 Limited genetic variability in seen in the CHS2 gene amongst M. pachydermatis isolates from dogs in previous studies,315, 316 although wider variation was observed in another study.57 Partial sequencing of the ß‐tubulin gene in Malassezia provides a further opportunity for species and genotype differentiation.35, 112, 317, Genotypic approaches involving analyses of sequences obtained from multiple loci on the Malassezia genome, such as combined analyses of D1/D2, ITS, CHS2 and ß‐tubulin sequences, has proven to be a powerful tool in the epidemiological assessment of the intraspecific variations and adaptation of these particular genotypes to specific hosts.35, 57, 301, 318. Mais ny aurait-il pas un lien déterminant avec lalimentation moderne que nous leur donnons ? Development. 5 mg/kg once daily or two consecutive days/week, for 21 days, Median lesion score reduced by 60% (pulse) and 31% (daily), Small group sizes; two ITZ intervals compared, Combined with twice weekly selenium sulphide shampoo. Utility. The extent of any clinical benefit of anti‐Malassezia activity from gentamicin in otic formulations used in canine otitis externa requires further assessment. In a RCT involving 35 dogs, 20 received a commercially‐available mixture of essential oils (Malacalm, Flora Slr Oli essenziali, Lorenzana, Italy) twice daily for one month, 10 received oral ketoconazole 10 mg/kg orally once daily and 2% chlorhexidine twice weekly and five dogs served as untreated controls.438 Whilst the authors reported a >50% improvement in clinical scores in nine of 10 of dogs treated with essential oils, and in all of the dogs treated with ketoconazole and chlorhexidine, interpretation is limited by unclear randomisation and blinding procedures, and failure to report pre‐ and post‐treatment group clinical scores (mean or median, range) in the three treatment groups (LoE 2; SoR C‐weak). Os comentários foram compartilhados eletronicamente com o GP e as respostas incorporadas no documento final. Vous devez savoir que cette maladie de peau est plus fréquente chez les chiens que chez les chats. The general conclusion is that M. pachydermatis remains by far the most important and prevalent species in dogs while the other lipid‐dependent species are detected quite frequently in certain animal species (like cats) or body sites. Detergent scrub sampling is the ‘gold standard’ method for quantitative culture, although it is more suited to a research rather than diagnostic environment because it is suitable for only relatively flat skin on co‐operative patients and rapid sample processing is required. The concomitant presence of the same species or the same genotypes in humans and animals is a first indication but of course it is not absolute proof unless transmission from one host to another has been clearly demonstrated. One study identified Malassezia yeasts in 43 out of 52 healthy cats sampled in the winter months in north eastern USA.113 By contast, another study failed to identify yeasts in 20 health cats sampled in France; notably in the latter study, the presence of cerumen was an exclusion criterion whereas cerumen was noted in many of the US cats, especially amongst those with a purely indoor lifestyle.114 Malassezia yeasts were detected in 20% (six of 30) ear canals of 15 cats with disease and in 43% (13 of 30) ear canals of 15 allergic cats.114 Devon rex cats and sphynx cats, but not Cornish rex cats, are prone to high carriage rates of Malassezia yeasts and a generalised seborrhoeic dermatitis that responds to oral itraconazole.80, 86, 115, 116 Predisposing factors such as hypersensitivities and internal diseases that disrupt cornification are reviewed in Section 7. The before and after clinical photographs left no doubt about the dramatic health and welfare benefits of the antifungal therapy in these cases. In epidemiological studies, genotyping of Malassezia yeasts may be required in order to identify the source of infection and to discover possible connection of genotypes with particular diseases. Los comentarios se compartieron electrónicamente con el GP y las respuestas se incorporaron al documento final. In the case of absence of budding yeasts, those authors242 regarded the histopathological diagnosis as “presumptive” provided the first five criteria were fulfilled. Cytology using swabs is normally best restricted to use in the ear canal. This section reviews literature relevant to Malassezia spp. Despite these critical limitations, current data suggest that the vast majority of field isolates of M. pachydermatis are routinely susceptible to most relevant azoles (miconazole, clotrimazole, itraconazole, posaconazole and ketoconazole). Die GP erstellten eine detaillierte Literaturrückschau und machten Empfehlungen über ausgewählte Themen. The perianal skin and anal mucosa is a frequent (~55% of 73 dogs) carriage site whereas nasal and oral carriage is less frequent. Limbs, paws and ears may be variably affected and dry crusting and fissuring of the footpads is occasionally noted. This work was later confirmed by Moore et al.51. Le genre Malassezia est composé qu’un groupe de levures lipophiliques qui ont évoluées en tant que commensaux de la peau et pathogènes cutanés opportunistes chez de nombreux mammifères et oiseaux. Compounded formulations must be avoided due to unreliable bioavailability. The most commonly affected body regions include the face, chin, neck, limbs, abdomen and ear canals (see below). Elevated ALT in 1 dog. Compared with KTZ + cefalexin. Some Malassezia species are able to form filaments in cutaneous lesions but also in culture under specific conditions.11-13 Malassezia yeasts have a thick cell wall (~0.12 µm) whose innermost layer shows a characteristic serrated structure.12, 14-16. Systemic therapies are often more expensive than topical therapies but may be necessary in cases where topical therapy is challenging for the owner/patient affiliation or otherwise ineffective. For canine Malassezia dermatitis, there is moderate evidence (SoR B) for the use of ketoconazole at 5–10 mg/kg orally once or twice daily (five studies of LoE ≥ 2); and itraconazole at 5 mg/kg orally once daily or two consecutive days per week (two studies of LoE ≥ 2). The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. el género Malassezia está compuesto por un grupo de levaduras lipofílicas que han evolucionado como comensales cutáneos y patógenos cutáneos oportunistas de una variedad de mamíferos y aves. Skin colonization by Malassezia species in full term healthy newborns has been also investigated.464 Malassezia pachydermatis was not isolated from the skin of human neonates, while M. sympodialis and M. globosa colonisation begins at birth and increases in the first weeks of life. On le retrouve alors aux oreilles, aux commissures labiales, aux extrêmités des pattes, à l’anus…. Method for the determination of broth dilution minimum inhibitory concentrations of antifungal agents for yeasts, Assessment of the antifungal susceptibility of Malassezia pachydermatis in various media using a CLSI protocol, Genotyping and antifungal susceptibility testing of multiple, Methodological issues in antifungal susceptibility testing of, Diffusion Procedures for Susceptibility Testing of, European harmonization of MIC breakpoints for antimicrobial susceptibility testing of bacteria, Evaluation of the antifungal susceptibility of, Posaconazole (Noxafil): a new triazole antifungal agent, Antifungal activity of the allylamine derivative terbinafine in vitro, Comparison of in vitro antifungal activities of topical antimycotics launched in 1990s in Japan, Determining canine skin concentrations of terbinafine to guide the treatment of, Principles and practice of clinical mycology, Incidence and treatment of budding yeasts in canine otitis externa, Sterol composition in polyene antibiotic‐sensitive and resistant strains of, Activity of chlorhexidine shampoos in vitro against, In vitro antimicrobial activity of a commercial ear antiseptic containing chlorhexidine and Tris‐EDTA, Comparative in vitro efficacy of antimicrobial shampoos: a pilot study, In vitro growth versus inhibition of growth of, Blad‐containing oligomer: a novel fungicide used in crop protection as an alternative treatment for tinea pedis and tinea versicolor, Blad‐Containing Oligomer Fungicidal Activity on Human Pathogenic Yeasts. Microbial populations recovered using conventional swabs can be quantified by dispersing organisms from the swab tip using solutions containing detergents; counts can be achieved by plating serial dilutions onto relevant culture media. The result was a complete revision of the genus Malassezia and the description of four new species (M. obtusa, M. globosa, M. slooffiae and M. restricta).20 Eleven more species were described subsequently by different groups and from varied hosts: M. dermatis,21 M. japonica22 and M. yamatoensis23 from humans in Japan; M. nana24 from cases of otitis externa in cats and cattle; M. caprae25 from goats; M. equina25 from horses; M. cuniculi26 from rabbits; M. arunalokei27 from humans in India; M. brasiliensis and M. psittaci28 from domesticated parrots in Brazil; and M. vespertilionis from bats in the USA29. The outbreak resolved upon implementation of infection control measures, including withdrawal of lipid‐rich hand moisturisers from staff. Clinical efficacy with these products corresponds to multiple, systematic reports of low MICs in vitro with drugs of this class,329, 330, 334, 344 with the exception of fluconazole (see below). Utility. with atypical strains of M. pachydermatis that show inconsistent or stable lipid‐dependence.105, 106 However, the presence of M. furfur was confirmed by molecular biology in dogs with cutaneous lesions107 or otitis108 in Brazil. Development. However, it is important to recognise that each have limitations that affect the final count;261 methods suitable for rapid assessment of Malassezia populations by veterinary practitioners ‘on the clinic floor’ are not necessarily optimal for scientific research. Furthermore, the addition of recently identified species resulted in similar physiological patterns and thus in a doubtful identification (M. arunalokei and M. brasiliensis are closely related to M. restricta and M. furfur, respectively) (Table S1). Maladies cryptogamiques [Scalp Diseases. The authors thank Catherine Outerbridge and Wayne Rosencrantz, co‐chairs of the WAVD CCG committee, for facilitating the development of these guidelines. In addition to this neonatal syndrome, M. pachydermatis has been implicated in severe systemic infections of immunocompromised adult patients.478, 479, In a study designed to estimate the prevalence of M. pachydermatis hand carriage by dog owners, two groups of people were sampled by culture and PCR techniques: owners of 50 healthy dogs and owners of 75 atopic dogs with cytological evidence of Malassezia dermatitis and/or otitis.462 When detection rates by hand culture were compared, owners of affected dogs were 11 times more likely to be positive for yeast isolation than owners of healthy dogs. M. globosa] patch test‐positive atopic dermatitis patients, an infiltration of CD4+ T cells is seen at the patch test site,197 and the expression of intercellular adhesion molecule (ICAM)‐1 and human leucocyte antigen (HLA)‐DR in the dermis of these patients was also up‐regulated. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username, Presented in draft form at the 2018 North American Veterinary Dermatology Forum, Maui, Hawaii, USA, the 2018 International Society for Human and Animal Mycology. Pathogenic roles for various Malassezia species have been described in association with several human skin diseases including atopic dermatitis, seborrhoeic dermatitis, folliculitis, psoriasis and pityriasis versicolor.88, 459 Among these diseases, M. pachydermatis has been most commonly isolated from human patients with seborrhoeic dermatitis.460, 465, 466 However, it is difficult to assign a truly pathogenic role to M. pachydermatis in the context of these studies and its identification from surface samples of human skin is typically ascribed to contact with dogs (even though epidemiological data on pet contact is not always available). Microbiome studies utilising next‐generation sequencing have the potential to re‐define the microbial ecology of mammalian skin. Yeasts of Emerging Concern in Fungemia. Characterizing the zoonotic potential of pathogenic agents is always a difficult task. No clinical response, complete mycological ‐ consider yeast presence incidental to other inflammatory disease. Learn about our remote access options, Department of Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA UK, Correspondence: Ross Bond, Department of Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK. Many culture‐based studies have been carried out worldwide both in humans and in animals (especially in dogs) to better understand the ecology of Malassezia species on healthy skin and in cases with cutaneous lesions.33 Results are rarely comparable between studies because of the use of different sampling procedures, culture media and identification techniques.
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