• 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.

• Journal of Veterinary Clinics
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• v.23 no.1
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• pp.1-5
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• 2006

This study investigated the prevalence of Malassezia pachydermatis (M. pachydermatis) in dogs which were presented with otitis externa at the Chonbuk area from January 2002 to December 2003. A total of 589 dogs were diagnosed with otitis externa among which 243 (37.6%) dogs were affected with M pachydermatis. In addition, the prevalence of mutual relationship between the M. pachydermatis infection and ages, seasonality, breeds and ear types in otitis externa was investigated. The highest prevalence of M. pachydermatis was observed in 1 to 2 years age group, this was not statistically significant in comparison to other age groups. In summer, the prevalence of M. pachydermatis was significantly (p<0.01) higher ($57.06{\pm}2.01$) as compared with than in the winter ($21.03{\pm}3.56$), spring ($36.4{\pm}6.95$) and fall ($35.9{\pm}6.24$). A significantly (p<0.01) higher prevalence of M. pachydermatis was observed in pendulous ear dogs (49.1%) as compared to that in the erect ear dogs (23.6%). These results suggest that M. pachydermatis, the dominant causative organism of ear canal disease, strongly depends upon the seasonality and ear types.

• 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 Microbiology and Biotechnology
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• v.28 no.11
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• pp.1937-1945
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• 2018

Malassezia pachydermatis is a commensal yeast found on the skin of dogs. However, M. pachydermatis is also considered an opportunistic pathogen and is associated with various canine skin diseases including otitis externa and atopic dermatitis, which usually require treatment using an azole antifungal drug, such as ketoconazole. In this study, we isolated a ketoconazole-resistant strain of M. pachydermatis, designated "KCTC 27587," from the external ear canal of a dog with otitis externa and analyzed its resistance mechanism. To understand the mechanism underlying ketoconazole resistance of the clinical isolate M. pachydermatis KCTC 27587, the whole genome of the yeast was sequenced using the PacBio platform and was compared with M. pachydermatis type strain CBS 1879. We found that a ~84-kb region in chromosome 4 of M. pachydermatis KCTC 27587 was tandemly quadruplicated. The quadruplicated region contains 52 protein coding genes, including the homologs of ERG4 and ERG11, whose overexpression is known to be associated with azole resistance. Our data suggest that the quadruplication of the ~84-kb region may be the cause of the ketoconazole resistance in M. pachydermatis KCTC 27587.

• Journal of Applied Biological Chemistry
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• v.53 no.3
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• pp.184-188
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• 2010

Effect of the plant essential oils on the growth of Malassezia pachydermatis was evaluated and the essential oils of Ocimum basilicum L., Melaleuca alternifolia (Maid. & Bet.) Cheel, and Rosa damascene Mill. were the most active against M. pachydermatis and their activity were high than that of itraconazole at 2 mg/mL. The major constituents of the three oils by GC-MS analysis were linalool (21.83%) and estragole (74.29%) for O. basilicum, a-terpinolene (17.96%) and terpinen-4-01 (45.54%) for M. alternifolia, and a-citronellol (59.98%) and geraniol (27.58%) for R. damascene. Results showed that these selected three oils could be effective toward controlling M. pachydermatis opportunistic infections.

• Journal of Veterinary Clinics
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• v.29 no.2
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• pp.141-147
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• 2012

This work describes the characteristics of $Malassezia$ $pachydermatis$ isolated from dog ear canals and the effect of essential oils on the growth of this organism. Sterile cotton swabs were used to collect specimens from the external ear canal and culture tests were performed to detect the population size of $Malassezia$ yeast. Using three different isolation media, included Sabouraud dextrose agar (SDA) to isolate common $M.$ $pachydermatis$, and SDA supplemented with olive oil (SDAO) and Leeming's medium (LM) to detect lipophilic yeast, $Malassezia$ spp were isolated from 14 of 18 dogs (77.8%); isolation rates were 33.3% in SDA, 72.2% in SDAO and 66.7% in LM media. All $Malassezia$ spp isolates were identified as $M.$ $pachydermatis$ according to results of PCR amplification, but gross colony morphology and SDA growth rates suggested four different subtypes. Large (LC) and medium colony (MC) types respectively describe large colony (diameter > 3 mm) and medium colony (around 2 mm) after 72 hour incubation, and small (SC) type refers to smaller colony (< 1 mm) even after 5 days incubation; lipid dependent colonies did not grow onto SDA. Large Colony type strains were isolated from 4, 11, and 11 samples, MC type strains from 2, 3 and 1 and SC type strains from 1, 2 and 1 in SDA, SDAO and LM, respectively. Lipid-dependent $M.$ $pachydermatis$ (Lipo) were isolated from 3 samples each in SDAO and LM. Anti-$M.$ $pachydermatis$ activity testing was done using disc-diffusion assays and well diffusion tests. Most essential oils inhibited the growth of $M.$ $pachydermatis$ in a range from 0.5% to 1.0% of essential oils. MIC90 and MIC50 were variable depending upon the nature of essential oils. Thyme oil was found to be highly effective in inhibiting the growth of $M.$ $pachydermatis$ in a range from 0.125% to 0.0625% while marjoram and then tea tree oil exhibited lower inhibitory capacity.

• 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.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.387-389
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• 2011

A previous study of ours indicated that Citrus auranifoli oil possesses antifungal activity against Malassezia furfur and Malassezia pachydermatis. In this study, we evaluated the anti-M. furfur and M. pachydermatis activities of limonene, which is a major component of C. aurantifolia oil, using the disk diffusion method. We also examined cytotoxicity against human normal epithelial (Beas-2B) cells using the cytopathic effect reduction (CPE) method. The results revealed that the minimum fungicidal concentration (MFC) value of limonene is lower than the value for itraconazole. The MFC value of limonene was seen to be 7.81 ${\mu}g$/mL against M. furfur and 3.90 ${\mu}g$/mL against M. pachydermatis. MFC values of itraconazole against M. furfur and M. pachydermatis were 62.50 ${\mu}g$/mL and 31.25 ${\mu}g$/mL, respectively. In addition, it was noted that limonene was not toxic to Beas-2B cells with normal morphology at a concentration of 100 ${\mu}g$/mL. However, itraconazole exhibited weak toxicity at the same concentration. Therefore, our results indicate that limonene could potentially be effective at controlling M. furfur and M. pachydermatis infections with no cytotoxicity.

• Mycobiology
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• v.33 no.3
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• pp.142-146
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• 2005

To produce a novel antihypertensive angiotensin I-converting enzyme (ACE) inhibitor from yeast, a yeast isolate, designated G-14 showing the highest ACE inhibitory activity was obtained and identified as Malassezia pachydermatis based on morphological, biochemical and cultural characteristics. The maximal extracellular ACE inhibitor production was obtained from M. pachydermatis G-14 when the strain was cultured in YEPD medium containing 0.5% yeast extract, 3.0% peptone and 2.0% glucose at $30^{\circ}C$ for 24 h and the final ACE inhibitory activity was 48.9% under the above condition.

• Journal of Veterinary Clinics
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• v.29 no.4
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• pp.323-327
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• 2012

The effect of pH of chitosan solution (w/v) on antifungal activity against Malassezia pachydermatis isolated from a dog with otitis externa was evaluated. This study was investigated to find out the optimal pH of chitosan solution that could be able to eliminate yeast cells. For comparison of antifungal activity of chitosan solution 2% chlorhexidine that have been already proved the antifungal effect against M. pachydermatis was used as positive control. The chitosan solution at different pH (2.5, 3.0, 3.5, 4.0, 4.5, 5.0) were involved this experiment. The chitosan solutions at each pH could eliminate a number of yeast cells when they were compared to other antifungal agents. In chitosan solution's antifungal effect of varying degrees according to the pH M. pachydermatis was inhibited at pH of < 5.0. Especially it has been proved an effective antifungal effect at pH 3.5. Therefore, the pH of chitosan solution had a effect on antifungal activity and the optimal pH was 3.5 in vitro. The possibility of topical therapy with acidific solution of chitosan has a potential in skin infection against M. pachydermatis.