Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan; Diagnostic Center for Animal Health and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan; Medical Mycology Research Center, Chiba University, Chiba 260-8673, Japan.
Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan.
J Dairy Sci. 2022 Oct;105(10):8364-8370. doi: 10.3168/jds.2022-21781. Epub 2022 Aug 12.
Bovine mastitis, a major infectious disease affecting milking cows, leads to reduced milk yield and quality, reduced animal welfare, and an increased need for culling. Although its major causative agents are bacteria, yeast species and achlorophyllous algae of the Prototheca genus are well known as causative agents of bovine refractory mastitis. Nevertheless, few studies have analyzed specific yeasts and Prototheca in this context. Herein, we present survey data of yeast species and Prototheca species isolated from bulk tank milk in the Tokachi district of Japan from April 2020 through March 2021. The species of 276 isolates were determined. Yeast species accounted for 184 isolates, of which Pichia kudriavzevii was the most prevalent species. Regarding Prototheca species, only Prototheca bovis was isolated (92 isolates). Prototheca bovis and Pichia kudriavzevii were detected throughout the year and were detected repeatedly on the same farm. Kluyveromyces marxianus was the second most frequently isolated yeast species after Pichia kudriavzevii. Candida parapsilosis, the fourth most frequently isolated yeast species, was found discontinuously. Analysis of monthly data indicated that Kluyveromyces marxianus and Candida parapsilosis were mainly found during the winter and summer months, respectively. Candida akabanensis and Pichia cactophila were the third and fifth most frequently isolated yeast species, respectively. They were detected repeatedly in bulk tank milk samples from the same farms. Results obtained from bulk tank milk underscore the prevalence of these species. These study results are expected to contribute to the elucidation of problematic yeast and Prototheca species.
奶牛乳腺炎是一种影响奶牛产奶量和奶质、降低动物福利并增加淘汰率的主要传染病。尽管其主要病原体是细菌，但酵母属和 Prototheca 属的无叶绿素藻类也被认为是引起奶牛难治性乳腺炎的病原体。然而，很少有研究分析过这种情况下的特定酵母和 Prototheca。在此，我们介绍了 2020 年 4 月至 2021 年 3 月在日本十胜地区从批量奶罐奶中分离的酵母属和 Prototheca 属的调查数据。确定了 276 株分离株的种类。酵母属占 184 株，其中最常见的种是毕赤酵母属。关于 Prototheca 种，仅分离到 Prototheca bovis（92 株）。Prototheca bovis 和毕赤酵母属在全年都有检测到，并在同一农场反复检测到。仅次于毕赤酵母属的第二大常见酵母种是马克斯克鲁维酵母属。第四大常见酵母种近平滑假丝酵母属为间断性存在。对月度数据的分析表明，马克斯克鲁维酵母属和近平滑假丝酵母属分别主要在冬季和夏季出现。卡氏酵母属和仙人掌假丝酵母属分别是第三和第五大常见酵母种，它们在来自同一农场的批量奶罐奶样本中反复出现。批量奶罐奶的结果突出了这些种的流行程度。这些研究结果有望有助于阐明有问题的酵母和 Prototheca 种。
