Studies on the Yeast-Like Fungi Associated with Bovine Mastitis 2. Sensitivity of Yeast-Like Fungi to Antifungal Agents

유우유방염(乳牛乳房炎)에 관여(關與)하는 효모양진균(酵母樣眞菌)에 관한 연구(硏究) 2. 효모양진균(酵母樣眞菌)의 항진균성물질(抗眞菌性物質)에 대한 감수성(感受性)

A total of 133 isolates of yeast-like fungi was tested for sensitivity to seven different antifungal agents. The yeast-like fungi tested were isolated from the milk from normal or mastitic bovine quaters or from bovine feces. They were 5 Candida albicans (C. albicans) isolates, 63 C. krusei, 27 C. tropicalis, 5 C. parapsilosis, 10 Torulopsis glabrata, 6 Rhodotorula sp., 6 Hansenula sp. and 1 Pichia sp. isolate. The antifungal agents tested were nystatin, griseofulvin, cycloheximide, 5-fluorocytosine, miconazol, clotrimazole and tolnaftate. In general, clotrimazole, miconazol and 5-fluorocytosine were more effective in antifungal activity in vitro against the test organisms than the rest of the agents tested. However, some of the isolates showed higher resistance to certain antifungal agents compared to the other isolates of the some species. They were: 1 C. albicans isolate to 5-fluorocytosine; 1 C. albicans to 5-fluorocytosine, miconazol and clotrimazole; 1 C. krusei to 5-fluorocytosine and cycloheximide; and 11 C. tropicalis isolates to cycloheximide. The minimum inhibitory concentrations(MIC) of clotrimazole were $12.5{\mu}g/ml$ or lower for all isolates tested except one C. albicans isolate, for which MIC of the drug was $100{\mu}g/ml$. On the other hand, the MIC's of cycloheximide were $6.5{\mu}g/ml$ or lower for all isolates except the following; all isolates of C. albicans ($100{\mu}g/ml$), C. pseudotropicalis ($200{\mu}g/ml$) and Rhodotorula sp. ($25-50{\mu}g/ml$), 11 C. tropicalis isolates ($100{\mu}g/ml$) and 1 C. krusei isolate ($200{\mu}g/ml$).