• Journal of Veterinary Clinics
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• v.13 no.2
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• pp.130-139
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• 1996

Malassezia pachydercatis균은 개 외이염의 주된 원인균으로 알려져 있으나, 그 감염률은 지역에 따라 많은 차이가 있다. 그러나 그 기병론적인 역할에 대해서는 아직 명확히 밝혀지지 않았다. 이에 본문에서는 국내에서 사육되는 개의 외이염에서 Malassezia pachydercatis 균의 분리율을 조사하고, Malassezia pachydercatis에 대한 혈중 항체와 외이염과의 연관성을 밝혀 Malassezia pachydercatis에 의한 외이염 진단을 위한 도구로서 간접 ELISA 법의 유용성을 평가해 보고자 본 연구를 수행하였다. 총 112두 중, 외이염에 감염된 개 44두와 정상견 68두를 대상으로, 심부외이도에서 취한 가검물을 배양검사하였고, Malassezia pachydercatis 항원에 대한 혈청내 IgG와 IgM 역가를 간접 ELISA법에 의해 측정하였다. 살아있는 Malassezia pachydercatis 균을 3두의 정상견 외이도에 접종하여 Malassezia pachydercatis 균의 실험적 감염에 대한 조직병리학적 소견, 조직내 침투 정도, 그리고 접종 후 시간경과에 따른 IgG와 IgM의 혈중 역가변화를 측정하였다. Malassezia pachydercatis 균은 외이염이 있는 개 귀에서 가장 높게 분리(50.0%)되었고, 정상귀에서는 낮게 분리(6.3%)되었다. Malassezia pachydercatis 항원을 이용한 간접 ELISA 법 진단에서, Malassezia pachydercatis 양성배양인 외이염 개체에서 IgG와 IgM에 대한 민감도는 각각 41.7%, 20.8%이었고 특이도는 88.2%, 85.2% 이었다. 실험적으로 Malassezia pachydercatis 를 접종한 3두중 1두에서만 조직병리학적 변화와 모낭에 Malassezia pachydercatis 균체가 확인되었으며, IgG와 IgM 혈중역가도 유의성 있게 증가하였다. 국내에서 사육되는 개 외이염의 주된 원인균은 Malassezia pachydercatis 균이었고 이 균의 혈중항체는 유의성 있게 증가하였으며(p<0.005), 간접 ELISA법은 Malassezia pachydercatis 에 의한 개외이염의 유용한 진단도구임을 증명하였다.

• Journal of Microbiology and Biotechnology
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• v.31 no.5
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• pp.637-644
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• 2021

Malassezia is the most abundant genus in the fungal microflora found on human skin, and it is associated with various skin diseases. Among the 18 different species of Malassezia that have been identified to date, M. restricta and M. globosa are the most predominant fungal species found on human skin. Several studies have suggested a possible link between Malassezia and skin disorders. However, our knowledge on the physiology and pathogenesis of Malassezia in human body is still limited. Malassezia is unable to synthesize fatty acids; hence, it uptakes external fatty acids as a nutrient source for survival, a characteristic compensated by the secretion of lipases and degradation of sebum to produce and uptake external fatty acids. Although it has been reported that the activity of secreted lipases may contribute to pathogenesis of Malassezia, majority of the data were indirect evidences; therefore, enzymes' role in the pathogenesis of Malassezia infections is still largely unknown. This review focuses on the recent advances on Malassezia in the context of an emerging interest for lipases and summarizes the existing knowledge on Malassezia, diseases associated with the fungus, and the role of the reported lipases in its physiology and pathogenesis.

• Journal of Veterinary Clinics
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• v.31 no.2
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• pp.156-158
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• 2014

Malassezia spp. was isolated from the skin lesion of a South American Sea Lion (Otaria byronia) in South Korea. Colonies were cream to yellowish with smooth margin on Sabouraud dextrose agar without lipid supplements. Yeast cells were ovoid to cylindrical in shape and budding daughter cells from broad base. We conducted 26s rRNA sequencing to specify the strain of the yeast and found out this isolate highly matched with Malassezia pachydermatis isolated from canine otitis. The pulse therapy of oral itraconazole was very effective in this case. M. pachydermatis has a wide range of host animals but this is the first report in a sea lion in South Korea.

• Journal of Veterinary Clinics
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• v.27 no.2
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• pp.130-135
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• 2010

Malassezia (M.) is a member of normal mycobiota in warm-blooded vertebrates. Increased humidity is likely to be crucial in this infection. We studied the proportion of the species infected in dog during summer of Korea. Fifty samples were analyzed by PCR-RFLP and direct sequencing from June 2006 to October 2006. The study showed that lipid-dependent species was main pathogen (M. furfur; 86%, M. obtusa; 10%) while M. pachydermatis (4%) has only small portion. This result suggests that Malassezia infection has endemic characters that can be affected by the climate (temperature and humidity) in dogs.

• Journal of Veterinary Clinics
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• v.19 no.1
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• pp.86-91
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• 2002

The inhibitory effect of pooled canine serum on the growth of ten strains of Malassezia pachydermatis in vitro was investigated. Studies were also carried out to observe the effect of different concentrations of unsaturated bovine transferrin on Malassezia growth in vitro. Ten strains of Malassezia pachygedrmatis in normal canine serum (11.1%, 44.4%) were found to significantly inhibit the growth (p<0.0005) not only in a dose dependent but also in a time dependent manner. The same strains of yeast treated with 1, 2, 4 and 8 times the normal value of serum transferrin (3.0 mg/ml, 6.0 mg/ml, 12.0 mg/ml, 24.0 mg/fl), were shown to have significantly lower OD readings (p<0.05) when compared to yeast treated in lower concentrations of transferrin (1.5 mg/ml). The optical density (OD) of the ten strains of yeast were significantly lower (p<0.005) when treated with various concentrations of transferrin than with the saline control except at 72 hours post incubation. These results indicate that serum has inhibitory effects on Malassezia pachydermatis growth in vitro, and transfferin is one of the components that contribute towards this inhibitory role. The inhibitions are dose and time dependent.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.88-93
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• 2007

The purpose of the study reported here was to test the hypotheses that clinically healthy dogs will not manifest immediate hypersensitivity responses to intradermal injection of Malassezia pachydermatis extracts but that affected dogs with Malassesia otitis will manifest such hypersensitivity. Wd desired to identify approximate molecular mass of any allergenic components of the yeast by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein profile of Malassezia pachydermatis extracts showed between 16 and 110 kDa. Especially, the intensity was strongest between 25 and 80 kDa. Mean wheal diameters in the affected groups of 20, 2, 0.2, and $0.02{\mu}g/ml$ were $13.36{\pm}0.67,\;5.33{\pm}0.67,\;5.47{\pm}0.82,\;and\;5.07{\pm}0.64$, respectively. Mean wheal thickness in the affected groups of 20, 2, 0.2, and $0.02{\mu}g/ml$ was $6.44{\pm}0.40,\;3.86{\pm}0.35,\;2.64{\pm}0.36,\;and\;2.60{\pm}0.44$, respectively. The difference of wheal diameters and thickness between healthy and affected groups was significant (p<0.05). In conclusion, the observations confirm that Malassezia pachydermatis-derived antigens may induce an immediate wheal response when intradermal injected in dogs. It seems reasonable to suggest that hypersensitivity to yeast may contribute to the development of clinical signs in dogs with immediate skin test reactivity, especially in dogs with Malassezia otitis extema.

• Mycobiology
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• v.37 no.1
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• pp.67-68
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• 2009

Antifungal activity of celery essential oil against Malassezia furfur was investigated using broth microdilution and vapor contact methods. Potent antifungal activity was evident using both methods. Fungicidal activity was revealed in the vapor contact method.

• Journal of Mycology and Infection
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• v.23 no.4
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• pp.111-114
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• 2018

A 19-year-old woman presented with an asymptomatic cutaneous discoloration on her nape. Dermatological examination revealed localized dark brown to dark pigmented velvety macules and patches. She denied a past medical history, except for a 7-kg weight gain over a 6-months period. Histopathologically, the specimen showed hyperkeratosis, epidermal hyperplasia, mild acanthosis, and papillomatosis. In addition, keratin material and fungal spore were noted between the papilloma ridges. Periodic acid-Schiff special stain showed a positive result for the fungal spore in the horny layer. She was treated with a daily oral dose of terbinafine and topical flutrimazole. After 12 weeks of treatment, she is currently under observation without pigmentation and adverse effect. We considered the initial diagnosis as acanthosis nigricans because of weight gain, similar clinical features, and histological findings. However, the final diagnosis was hyperkeratotic head and neck Malassezia dermatosis considering the presence of yeast and the dramatic improvement after antifungal treatment. To the best of our knowledge, hyperkeratotic head and neck Malassezia dermatosis is not well characterized in the literature. It is an unusual variant of pityriasis versicolor. The skin lesion appears brown to dark, scaly, and hyperkeratotic macules and patches located on the face and neck. Here, we reported an unusual case of hyperkeratotic head and neck Malassezia dermatosis.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.180-187
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• 2023

The skin is a dynamic ecosystem on which diverse microbes reside. The interkingdom interaction between microbial species in the skin microbiota is thought to influence the health and disease of the skin although the roles of the intra- and interkingdom interactions remain to be elucidated. In this context, the interactions between Malassezia and Staphylococcus, the most dominant microorganisms in the skin microbiota, have gained attention. This study investigated how the interaction between Malassezia and Staphylococcus affected the antifungal susceptibility of the fungus to the azole antifungal drug ketoconazole. The susceptibility was significantly decreased when Malassezia was co-cultured with Staphylococcus. We found that acidification of the environment by organic acids produced by Staphylococcus influenced the decrease of the ketoconazole susceptibility of M. restricta in the co-culturing condition. Furthermore, our data demonstrated that the significant increased ergosterol content and cell membrane and wall thickness of the M. restricta cells grown in the acidic environment may be the main cause of the altered azole susceptibility of the fungus. Overall, our study suggests that the interaction between Malassezia and Staphylococcus influences the antifungal susceptibility of the fungus and that pH has a critical role in the polymicrobial interaction in the skin environment.

• Journal of Mycology and Infection
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• v.23 no.4
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• pp.91-98
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• 2018

Background: Malassezia, a lipophilic yeast, is a causative agent for dandruff and seborrheic dermatitis. Many biological agents have been studied for anti-Malassezia effect but further studies are needed for their clinical application. Objective: The study was conducted to evaluate the inhibitory effect of different natural essential oils and a fruit extract on Malassezia species in an in vitro study and a clinical trial. Methods: The antifungal effects of natural essential oils and a fruit extract on Malassezia species (M. furfur and M. sympodialis) were evaluated by measuring the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) and using the disc diffusion method. Natural essential oils of citron seed, lavender, and rosemary and citrus junos fruit extract were used for the in vitro study. The clinical trial was conducted with a shampoo containing four ingredients. A total of 22 subjects used the shampoo every day for 4 weeks and were evaluated using clinical photography, trichoscopy, and sebumeter at baseline, 2 weeks, and 4 weeks after treatment. Results: Antifungal activity of agents was relatively lower in lavender and rosemary essential oils at MIC and MFC. Disc diffusion method revealed same results. In the clinical trial, the amount of sebum decreased statistically significantly and erythema, dandruff, and lesion extent also improved. Conclusion: The natural essential oils and fruit extract are effective for suppressing Malassezia activity, therefore these might be used as an alternative for treatment of dandruff and seborrheic dermatitis.