• 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.

• Korean Journal of Veterinary Service
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• v.26 no.1
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• pp.57-65
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• 2003

The present study was conducted to examine the outbreak state of bovine dermatophytosis in 14 farms(4 dairy farms, 10 Korean indigenous cattle farms) in Gyeongbuk province from November 2000 to November 2001. The causative agents of dermatophytosis was identified by mycological examination. Antifungal susceptibility test of 26 isolates was performed by agar dilution method, using 5 antifungal drugs. Prevalence of bovine dermatophytosis was found to be 13.5%(90/665) in dairy cattle farms and 14.5%(220/1,520) in Korean indigenous cattle farms. The most common age at which this disease occurred was 2-12 months. This disease usually occurred from winter to spring and the occurrence subsequently decreased in the summer. But 4 Korean indigenous cattle farms with poorly hygienic status were occurred all the year round. The causative agent was identified as Trichophyton verrucosum exclusively in these case. Antifungal susceptibility test of T verrucosum (26 strains) was performed by agar dilution method, using 5 antifungal drugs including tolnaftate, griseofulvin, ketoconazole, amphotericin B and terbinafine. All isolates were highly sensitive to 5 antifungal drugs (geometric mean MICs 0.004∼0.032 $\mu\textrm{g}$/$m\ell$). The isolates were the most sensitive to especially tolnaftate.

• Journal of Veterinary Clinics
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• v.18 no.1
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• pp.1-6
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• 2001

The aim of this study was to determine optimal therapeutic dose of antifungal agents for dermatophytes. Forty nine dermatophytes were isolated form dogs and cats showing skin lesions and were tested for their in vitro susceptibility to nystatin, griseofulvin, terbinafine, ketoconazole and fluconazole by broth microdilution test. Terbinafine showed the lowest MIC value among the antifungal agents tested, and MIC values ranged from 0.002 to 0.016 $\mu\textrm{g}$/ml. Fluconazole showed the highest MIC values among the antifungal agents tested, and MIC values ranged from 32 to 512 $\mu\textrm{g}$/ml. MIC values of nystatin, griseofulvin and ketoconazole ranged from 1.12 to 4.48 $\mu\textrm{g}$/ml, 0.5 to 4.0 $\mu\textrm{g}$/ml, and 1.6 to 12.8 $\mu\textrm{g}$/ml, resistant to griseofulvin, and that antifungal susceptibility test was needed to determine optimal therapeutic dose of antifungal agents for each dermatophyte.

• YAKHAK HOEJI
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• v.57 no.2
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• pp.119-124
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• 2013

The aim of this present study was to investigate the antifungal effect of tanshinones isolated from Salvia miltiorrhiza against Candida ablicans, a polymorphic fungus. For the work, tanshinone IIA (TSN), cryptotanshinone (CTS), and dihydrotanshinone I (DTS) were chosen. Initially, their antifungal effect was analyzed by in-vitro susceptibility test. Data from the susceptibility test showed that while all of these three compounds had antifungal activity, DTS was the most potent. At $100{\mu}g$ DTS/ml, there was about 80% CFU (colony forming unit) reduction as compared to DTS-untreated C. albicans yeast cells (P<0.05). Thus, DTS was selected to determine its antifungal activity in a murine model of disseminated candidiasis due to C. albicans. Results showed that DTS enhanced resistance of mice against disseminated candidiasis. During the entire period of 30-day observation, 60% of DTS-given mice groups survived whereas control animals all died within 14 days (P<0.05). Moreover, DTS inhibited the hyphal production, one of the virulence factors of this fungus, from the blastoconidial form of the fungus. Therefore, the tanshinone appears to have antifungal activity specific for C. albicans infection, which could possibly be mediated by the blockage of hyphal production.

• YAKHAK HOEJI
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• v.57 no.6
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• pp.383-387
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• 2013

In the present study, we determined the antifungal effect of obacunone isolated from Phellodendri Cortex against Candida ablicans, a pathogenic fungus. The antifungal effect was analyzed by an in-vitro susceptibility test and in a murine model of disseminated candidiasis. Possible mechanism of the antifungal activity was also examined. Analyses of data resulting from the susceptibility test revealed that the compound inhibited C. albicans growth. At 25 ${\mu}g$ obacunone/ml, there was app. 45% reduction of CFUs (colony forming units) as compared to obacunone-untreated C. albicans yeast cells (P<0.01). In the murine model of disseminated candidiasis due to C. albicans, obacunone enhanced resistance of mice against disseminated candidiasis. During an entire period of 30-day observation, control animals all died within 14 days, whereas 60% of obacunone-treated mice survived (P<0.05). In addition, obacunone inhibited the hyphal production, a major virulence factor of C. albicans, from the blastoconidial form. Thus, obacunone appears to have antifungal activity for C. albicans infection. This may possibly be mediated by the blockage of hyphal production.

• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.173-176
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• 2001

The present study was conducted to examine the drug susceptibility of 57 strains of Microsporum canis isolated from dogs with dermatitis in Taegu, 1999. Antifungal susceptibility test was performed by the microdilution method, using 7 antifungal drugs as follows: itraconazole(I), terbinafine(T), ketoconazole(K), griseofulvin(G), amphotericin B(A), flucytosine(5-Fc)(F), tolnaftate(To). All tester strains of M canis were highly susceptible to T, I, K and To(geometric mean $MICs{\leq}0.007{\sim}0.155{\mu}g/ml$), while those were lowly susceptible to G, A and F(geometric mean MICs $0.285{\sim}26.430{\mu}g/ml$).

• Mycobiology
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• v.47 no.4
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• pp.449-456
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• 2019

Invasive fungal infections caused by Cyberlindnera fabianii have recently increased. However, biochemical kits such as API 20 C AUX and Vitek-2C have misidentified this species as other Candida spp. such as C. pelliculosa or C. utilis due to no information of Cy. fabianii in yeast database. During our 2016-2017 surveys, eleven isolates of Cy. fabianii were obtained in International St. Mary's Hospital in Korea. Here, we describe its morphological and molecular characteristics and tested its antifungal susceptibility against nine antifungal agents. The sequences of the ITS region and the D1/D2 region of LSU revealed 100% identity with the sequences of Cy. fabianii. In comparison with the results from MALDI-TOF mass spectrometry, we found that Cy. fabianii can be distinguished from other species. In antifungal susceptibility test, voriconazole and echinocandins exhibited good antifungal activities against the majority of Cy. fabianii isolates despite the absence of standard criteria.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.301-307
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• 1987

A total of 42 strains of Candida albicans were examined for susceptibility to three antifungal agents, amphotericin B(AMB), 5-fluorocytosine(5-FC), and ketoconazole(KTZ), using defined medium, synthetic amino acid medium-fungal(SAAM-F), supplemented yeast nitrogen base(SYNB) and undefined medium Sabouraud's dextrose broth(SDB) and Kimmig broth media. A tube dilution method was used with minimum inhibitory concentrations(MICs) determined after incubation for 24 hour and 48 hours. All testes were performed in duplicate. In general, MICs were more reproducible after 48 hour of incubation. Forthermore, MICs determined after incubation for 48 hours were significantly higher than those determined after 24 hours. The actural MICs obtained with the different antifungal agents were clearly influenced by the test medium used. The rank order of AMB MICs according to the test medium was as follows: SAAM-F>SYNB>SDB>Kimmig broth. With 5-FC, the following pattern was observed: SYNB>SAAM-F>SDB>Kimmig borth. For ketoconazole, the MICs according to the test medium was SAAM-F>SDB>SYNB> Kimmig broth. In amphotericin B, the MICs mean value with the test medium was as follows: SDB, 0.24 mcg/ml; Kimmig broth, 0.29 mcg/ml; SYNB, 0.21 mcg/ml and SAAM-F, 0.15mcg/ml. The actural value of 5-FC was; SDB, 37.20 mcg/ml; Kimmig broth, 67.41mcg/ml; SYNB, 21.29 mcg/ml and SAAM-F, 24.61 mcg/ml and in ketoconazole, the MICs value was; SDB, 1.83 mcg/ml; Kimmig broth, 4.08 mcg/ml; SYNB, 1.95 mcg/ml and SAAM-F, 1.41 mcg/ml. The results of this investigation suggested that broth dilution susceptibility testing of yeast and yeast-like fungi are best performed with an incubation period of 48 hours. Furthermore, medium composition can significantly influence the results of such testing.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.690-695
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• 2005

The purpose of this thesis is to dedicate to get the objectivity of herbal medicine treatments by choosing herbs likely to work as antifungal agents against Candida albicans which is the causes of Candida vaginitis, making experiments on them and getting the significant results. Each herb's efficacy on control the number of Candida vaginitis is noticed by using Disk Susceptibility test with six herbs medicine and Broth dilution assay of the culture. Cinamon Ramulus, Pulsatillae Radix, Dictamni Radicis Cortex, Paeoniae Radix, Arecae Semen, Artemisiae Capillaries Herba extracts experimented on the efficiency of antifungal activities against Candida albicans by disk susceptibility test. Pulsatillae Radix has the strongest efficiency. In Dictamni Radicis Cortex never appeared antifungal effect on treatment. MIC (minimal inhibition concentration) in vitro antifungal agents of Cinamon Ramulus, Pulsatillae Radix, Paeoniae Radix, Artemisiae Capillaries Herba extracts against Candida albicans was determined by broth dilution assay. MIC against Candida albicans is that Pulsatillae Radix is 2.5 mg/ml and Cinamon Ramulus is 5 mg/ml and Paeoniae Radix is 10 mg/ml and Artemisiae Capillaries Herba is 40 mg/ml.

• Microbiology and Biotechnology Letters
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• v.25 no.3
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• pp.335-337
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• 1997

In this study, we show a convenient MTT assay for detect the susceptibility of yeast-like form of Trichosporon beigelii against antifungal agents. This assay was developed based on mitocondrial respiration by determining reduction of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan. Cells of T beigelii are seeded into 96-well microtiter plates, and antifungal agents, amphotericin B, magainin and CA-ME hybrid peptide were added with various concentrations. After 24 hr incubation, MTT was added, then incubations were continued for 4 hr. Formazan formation was quantified photometrically after extraction of the formazan with acid sodium dodesyl sulfate (SDS). From this assay, we could obtained MICs of antifungal agents against T. beigelii. The presented method can easily be used as an effective methods to assess the antiftingal action of various agents on yeasts with minimal amounts of antifungal agents.