In recent years, increased rates of yeast infections in humans and animals have been recognized worldwide. Since animals may represent a source of yeast infections for humans, knowing the antifungal susceptibility profile of yeast isolates from milk and evaluating their pathogenic potential would be of great medical importance. Therefore, the aim of this survey was to study yeast diversity in milk samples, analyze the hemolytic and phospholipase activities of isolates and determine minimal inhibition concentration (MIC) for fluconazole, voriconazole and flucytosine. Out of 66 yeast isolates obtained from 910 individual raw milk samples from subclinically infected cows, 26 different yeast species were determined based on sequencing of the D1/D2 and ITS regions. Among them, Pichia kudriavzevii (formerly known as Candida krusei), Kluyveromyces marxianus (formerly known as Candida kefyr) and Debaryomyces hansenii (formerly known as Candida famata) were the most commonly identified. Hemolysin and/or phospholipase activity was observed in 66.7% of isolates. The elevated MIC for fluconazole was determined in 16 isolates from 11 species. The findings of this study demonstrate that yeast isolates from raw milk have the potential to express virulence attributes such as hemolysin and phospholipase, and additionally, some of these strains showed elevated MIC to fluconazole or to flucytosine. Lay summary We identified 66 yeast isolates, including 26 different yeast species from 910 individual milk samples. Our results indicate that individual milk samples may serve as a source of yeasts with the potential to trigger infection and may have reduced sensitivity to tested antifungal agents.

中文翻译：

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生牛奶作为酵母菌的储存库，具有毒力因子并降低对抗真菌剂的敏感性

近年来，人类和动物的酵母菌感染率增加已在世界范围内得到认可。由于动物可能是人类酵母菌感染的来源，因此了解牛奶中酵母菌的抗真菌敏感性特征并评估其致病潜力将具有重要的医学意义。因此，本次调查的目的是研究牛奶样品中酵母的多样性，分析分离物的溶血和磷脂酶活性，并确定氟康唑、伏立康​​唑和氟胞嘧啶的最小抑制浓度 (MIC)。在从来自亚临床感染奶牛的 910 个单独的原料奶样品中获得的 66 种酵母分离物中，根据 D1/D2 和 ITS 区域的测序确定了 26 种不同的酵母种类。其中，Pichia kudriavzevii（原名Candida krusei）、最常见的是马克斯克鲁维酵母（以前称为开菲尔念珠菌）和汉森德巴利酵母（以前称为法玛塔念珠菌）。在 66.7% 的分离物中观察到溶血素和/或磷脂酶活性。在来自 11 个物种的 16 个分离株中测定了氟康唑的 MIC 升高。这项研究的结果表明，从生乳中分离出的酵母菌具有表达溶血素和磷脂酶等毒力属性的潜力，此外，其中一些菌株对氟康唑或氟胞嘧啶的 MIC 升高。总结 我们从 910 个单独的牛奶样品中鉴定出 66 种酵母菌分离物，包括 26 种不同的酵母菌种。