Occurrence of Malassezia species in healthy and dermatologically diseased dogs (original) (raw)
Related papers
2019
Yeasts of the genus Malassezia are commonly isolated from different areas of the body in dogs diagnosed with atopic dermatitis. The proliferation of these yeasts may trigger clinically relevant hypersensitivity responses in patients with CAD. There are also reports that there is some association with certain body areas and predisposing factors such as gender, race, or age, among others. The objective is evaluate the factors associated with the presence of Malassezia spp. yeasts in dogs with atopic dermatitis in Quito, Ecuador. A total of 800 patients who attended a dermatological clinic at Veterinary Care Centers in Quito were evaluated, among whom 10% (80 dogs) were diagnosed with CAD. Epidemiological data were collected and cytological samples comprising ear culture swabs, imprints, or Scotch tape samples from different areas of the body, were taken. Each sample was stained and analyzed under the microscope. The 86.2% of dogs with CAD presented Malassezia spp. Dogs aged less than ...
Journal of Veterinary Diagnostic Investigation, 2005
Malassezia species are commensal organisms of human and animal skin that occasionally act as opportunistic pathogens. The lipid-dependent species are associated with human skin disorders, whereas the non-lipid-dependent species (Malassezia pachydermatis) is considered as an opportunistic secondary pathogen affecting the canine skin surface and ear canal. This study evaluated the relationship between Malassezia yeasts, their population size, and the occurrence of skin lesions from healthy and skin-diseased dogs. The efficiency of cytological examination and fungal culture for Malassezia detection was also evaluated. From March 2002 to July 2003, 33 healthy dogs and 54 dogs with pruritic localized skin diseases were examined; skin swabs (1218) were collected from 7 anatomical sites for culture and cytological examination. Malassezia prevalence according to anatomical site and the agreement between cytological results and fungal cultures were statistically analyzed. Differences in mean colony forming unit counts between positive healthy and diseased dogs were evaluated using the Bonferroni test for post hoc pair-wise comparisons. In healthy dogs, Malassezia yeasts were most frequently isolated in the perianal and perioral areas. The frequency of isolation and population size of Malassezia species were higher in dogs with localized dermatitis, especially in affected areas, indicating a role for Malassezia in the occurrence of skin lesions. Malassezia pachydermatis was the species most commonly cultured from the skin and external ear canal of healthy and diseased dogs; isolation of lipid-dependent yeasts from healthy dogs was less frequent. Using fungal culture as the gold standard, cytological examination showed good relative specificity (95%) but very low relative sensitivity (30%).
Frequency of yeasts and dermatophytes from healthy and diseased dogs
Journal of Veterinary Diagnostic Investigation, 2008
The aim of this study was to investigate the presence of dermatophytes and yeasts in healthy and diseased dogs. A total of 633 samples were collected from 26 healthy animals (104 samples), 131 with dermatitis (343 samples), 74 with otitis (148 samples), and 19 with ocular diseases (38 samples). Cultures from healthy animals were positive for Malassezia pachydermatis in 13.5% (7/52) of samples from skin, 42.3% (11/ 26) from ear, and 3.8% (1/26) from eye. Fungal growth was observed in 20.4% (70/343) samples from animals with dermatitis. Microsporum canis was the most isolated fungus (n 5 39), followed by M. pachydermatis (n 5 30) and Malassezia sp. (n 5 3). Of the 148 samples from dogs with otitis, 90 (60.8%) were positive for M. pachydermatis, and of the clinical specimens from the conjunctiva of animals with ophthalmic disease, 2.6% (1/38) presented positive cultures for M. pachydermatis. Only 14.3% (2/14) of the positive cultures for M. pachydermatis and 40.9% (9/22) of those for M. canis were positive in the direct exam. Direct exams were positive in 84.3% (70/83) of the culture positive samples from affected ears of dogs with otitis. Malassezia pachydermatis may act as an aggravating factor in the occurrence of cutaneous diseases, or the isolation of M. canis may be associated with the onset of dermatophytosis. Fungal culture, rather than microscopic examination, should be used as the definitive diagnostic test for dermatomycoses and otitis.
Veterinary Dermatology, 2020
Background-The genus Malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds. Objectives-The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of skin diseases associated with Malassezia yeasts in dogs and cats. Methods-The authors served as a Guideline Panel (GP) and reviewed the literature available prior to October 2018. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. The document was presented at two international meetings of veterinary dermatology societies and one international mycology workshop; it was made available for comment on the WAVD website for a period of six months. Comments were shared with the GP electronically and responses incorporated into the final document. Conclusions and clinical importance-There has been a remarkable expansion of knowledge on Malassezia yeasts and their role in animal disease, particularly since the early 1990's. Malassezia dermatitis in dogs and cats has evolved from a disease of obscurity and controversy on its existence, to now being a routine diagnosis in general veterinary practice. Clinical signs are well-recognised and diagnostic approaches are well-developed. A range of topical and systemic therapies is known to be effective, especially when predisposing factors are identified and corrected. 1853 Charles Robin named Eichstedt's fungus as Microsporon furfur, believing it to be a dermatophyte, and termed the associated skin disease "Tinea versicolor". 39 1873 Sebastiano Rivolta, an Italian veterinarian, noticed a double-contour budding yeast in human "psoriatic" scales and gave them the name Cryptococcus psoriasis. 40 1874 Frenchman Louis Charles Malassez 41 suggested that Microsporon furfur caused dandruff and correctly differentiated the yeast into genus of single cell fungi ("Saccharomyces") rather than the dermatophyte complex. For this correction, his name was ultimately attached to the genus. 42 3.2.2. Attempts at classification without laboratory isolation 1884 Bizzozero studied these microbes and described them to be part of normal human skin flora. He claimed there were two different species and named them Saccharomyces ovalis and S. sphaericus. 43 However, these were later shown to be a single species. 44 1889 Baillon created the genus Malassezia to accommodate M. furfur, in honour of Malassez, who was already acknowledged as having described the new species-at least in the French-speaking scientific community. 17 However this particular yeast could not be grown and isolated in laboratory conditions because its lipid requirement in culture media were as yet unknown. 1910 Raymond Sabouraud, a prominent medical mycologist, proposed the name Pityrosporum malassezi for this bottle shaped yeast thought to cause human dandruff. 45 1913 Alfred Kraus was able to culture P. malassezi in a medium containing lanolin. 46 In a prime example of the effect of geography and historical events on scientific discovery, this German scientist's work was largely overlooked with the onset of the First World War. 3.2.3. Diseases associated with Malassezia 3.2.4. The controversy and 'Dark Years': 1940 to 1960 1940-1960 are known as the 'Dark Years' and spanned a period of more controversy. The hard won progress in the field was forgotten as a consequence of the Second World War and the overwhelming effect of cortisone treatment becoming available in the late 1940s, to which human seborrhoeic dermatitis responded. The role of Malassezia yeasts in the disease was thus forgotten. 1970 The systematics were rectified when Sloff in Lodder's 'The Yeasts, a taxonomic study' assigned all Pityrosporum that grew on media without lipid enrichment as single species of P. pachydermatis. 52, 53 1984 The third edition of 'The Yeasts, a Taxonomic Study' (Yarrow and Ahearn) referred to the new genus Malassezia and confirmed that one species grew without lipid enrichment. 54 This was later officially added into the taxonomical order. 55 1990 A new species, Malassezia sympodialis was described 19 and by 1996 four new species were added to the genus. 20 This species was later isolated from a cat by Bond et al. in 1996. 56 3.2.5 Modern approaches Currently there are 18 different species of Malassezia. 35,57 The genus continues to expand and this is likely to continue as the classical 'bottom-up' microbiological approaches merge with organism-level genomics and community or 'systems-level meta-genomics'.
Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats
Veterinary Dermatology, 2020
Background-The genus Malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds. Objectives-The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of skin diseases associated with Malassezia yeasts in dogs and cats. Methods and material-The authors served as a Guideline Panel (GP) and reviewed the literature available prior to October 2018. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. The document was presented at two international meetings of veterinary dermatology societies and one international mycology workshop; it was made available for comment on the WAVD website for a period of six months. Comments were shared with the GP electronically and responses incorporated into the final document. Conclusions and clinical importance-There has been a remarkable expansion of knowledge on Malassezia yeasts and their role in animal disease, particularly since the early 1990's. Malassezia dermatitis in dogs and cats has evolved from a disease of obscurity and controversy on its existence, to now being a routine diagnosis in general veterinary practice. Clinical signs are well recognised and diagnostic approaches are well developed. A range of topical and systemic therapies is known to be effective, especially when predisposing factors are identified and corrected.
Phenotypic characterization of canine Malassezia spp., isolates
Objective. To characterize and identify yeasts of the genus Malassezia by phenotypic features. Materials and methods. First, the macroscopic and microscopic morphological characteristics were described. In addition we performed biochemical and physiological assays as Tweens and Cremophor, including more. Results. Our results evidenced of 105 isolates obtained from dogs diagnosed with external otitis, it was possible to identify two distinct species from 46 isolates within the Malassezia genus: 36.19% (n=38) were identified as M. pachydermatis and 7.62% (n=8) as M. furfur. According to phenotypic patterns the remaining 56.19% (n=59) were reported as Malassezia spp., possibly corresponding to M. furfur and/or M. pachydermatis. Conclusions. Results emphasize the necessity to characterize according to species. It is not feasible to define Malassezia by species based on morphological, biochemical, and physiological findings. Therefore, molecular genotyping should be performed to identify markers allowing a more precise isolate identification. This would broaden our epidemiological knowledge regarding different species involved in canine otitis pathologies.
Malassezia Species Associated With Dermatitis in Dogs and Their Antifungal Susceptibility
International Journal of Current Microbiology and Applied Sciences
The present study was taken with the objective of isolation, characterization, molecular detection and antifungal sensitivity of Malassezia species from dermatitis cases from dogs in and around Pondicherry state. A total of 100 skin swabs were collected from the dogs showing dermatological problems suggestive of Malassezia. Out of 100 swabs, 41 Malassezia isolates were successfully isolated and had good growth on Sabouraud's Dextrose Agar (SDA) during the primary isolation from the skin swabs. Biochemical tests for catalase, β-glucosidase activities and the capability to grow with three water soluble lipid supplements, namely Tween 20, Tween 80 and Cremophor EL concluded that the M. pachydermatis was the sole species isolated from the cases of canine dermatitis in Pondicherry state. Cytological examination revealed that direct skin swab smear was more sensitive than adhesive tape technique and impression smear. The frequency of isolation of M. pachydermatis was higher in neck region (8) followed by other regions in canine. Out of 100 skin swabs screened using an M. pachydermatis species specific primers, 61 were identified positive. The study showed a higher sensitivity of PCR (61%) in detecting Malassezia dermatitis over culture (41%). Based on invitro antifungal susceptibility studies it can be concluded that Ketoconazole, Itraconazole, Fluconazole and Amphotericin B can be advocated as the drug of choice to treat Malassezia dermatitis in this geographical location.
The lipophilic yeasts of the genus Malassezia are opportunistic microorganisms of the skin microflora, but they can be agents of various dermatomycoses. In this study, random amplification of polymorphic DNA (RAPD)-PCR technique was applied to the genetic typing of Malassezia species isolated from dog with otitis and seborrhoeic dermatitis and healthy dog. The analysis of electrophoretic profiles on 1/5% agarose gel showed a total 890 clearly amplified PCR band in 176 different positions. The phenogram constructed from the pairwise similarity among all Malassezia isolates demonstrated that the tested isolates of Malassezia are grouped into 22 distinct groups. This study was able to assess some DNA polymorphism of different Malassezia isolates in dogs. The detection of these differences between the RAPD band patterns from dogs observed could facilitate the monitoring of spread and pathogenicity of Malassezia infections in these animals.
Research in veterinary science, 2000
Hair and hair follicle carriage of Malassezia pachydermatis was studied in 12 healthy beagle dogs. The yeast was isolated from hair clipped from the lip region at 13 sites in nine dogs but was less frequently recovered from the interdigital spaces on the forefeet and from two sites on the trunk. Population sizes at the lip were significantly greater (P < 0.01) than those at other sites. Skin biopsy specimens were obtained from the same sites and epidermal and follicular tissues dissected following immersion in 1 M CaBr(2). Epidermal carriage of M. pachydermatis was identified in nine biopsy specimens taken from five dogs. Hair follicle carriage was identified in five skin specimens (four foot, one lip) from three dogs. This study indicates that M. pachydermatis is readily recovered from the distal hair in healthy dogs and that hair follicle carriage is infrequent or that populations are low at that site.
Use of contact plates for the quantitative culture of Malassezia pachydermatis from canine skin
Journal of Small Animal Practice, 1994
The Malassezia pachydermatis populations of the axilla and groin of 1 2 normal and 1 2 atopic dogs were compared using tape-strips and contact plates. When assessed by either method, the mean density of yeasts in the groin of the atopic dogs was significantly greater (P<0.05) than that of the normal dogs, suggesting that the cutaneous microenvironment of the groin region of the atopic dogs favoured colonisation by this yeast. Differences between the counts from the axilla were not significant. The frequency of isolation of yeasts from both dogs and sites was significantly higher (P<0.05 and PeO.001, respectively) in the atopic group. There was a very highly significant correlation (P<O.o01) between the tapestrip counts and contact plate counts in the atopic group only. This study suggests that isolation of numerous M pachydermatis colonies from the axilla and groin of dogs using contact plates is indicative of elevated skin surface populations. The simplicity of the contact plate method makes it suitable for the routine quantitative culture of cutaneous M pachydermatis populations in dogs with dermatological disease. ~ i 62, 541-542 106, 143-153 BOOKS RECEIVED Why Does My Cat?