Abstract：
Non-aureus staphylococci and mammaliicocci (NASM) are the most frequently isolated bacterial group from bovine milk samples. Most studies focus on subclinical mastitis caused by NASM; however, NASM can cause clinical mastitis (CM) as well. We evaluated retrospective data from 6 years (2017-2022) to determine the species and frequency of NASM isolated from quarter bovine CM. The data was comprised of microbiological results from quarter CM samples routinely submitted to Quality Milk Production Services at Cornell University for microbial identification by MALDI-TOF mass spectrometry. A total of 9,909 microbiological results from 410 dairy herds were evaluated. Our results showed that 29 distinct NASM species were identified, with the 8 most prevalent NASM species being Staphylococcus chromogenes, Staphylococcus haemolyticus, Staphylococcus simulans, Staphylococcus epidermidis, Staphylococcus sciuri (now Mammaliicoccus sciuri), Staphylococcus agnetis/Staphylococcus hyicus, Staphylococcus borealis, and Staphylococcus xylosus. The NASM distribution remained similar among seasons, but the frequency of NASM CM cases was higher during the summer. Our results showed different patterns of variations in the isolation frequency over time, depending on the bacterial species: increasing or decreasing trends, cyclic fluctuations, and, except for Staphylococcus borealis, a significant seasonality effect for our study\'s most prevalent NASM. This study showed that Staphylococcus chromogenes remains the most frequent (43%) NASM species identified from bovine CM, followed by Staphylococcus haemolyticus (18%), and Staphylococcus simulans (12%).
摘要：
非金黄色葡萄球菌和哺乳动物球菌（NASM）是从牛乳样品中最常见的细菌群。大多数研究集中在由NASM引起的亚临床乳腺炎，然而，NASM也可以引起临床乳腺炎（CM）。我们评估了6年（2017-2022年）的回顾性数据，以确定从四分之一牛CM分离的NASM的种类和频率。该数据包括常规提交给优质牛奶生产服务（QMPS）的季度CM样品的微生物结果，康奈尔大学,NY,US,通过MALDI-TOFMS进行微生物鉴定对来自410个奶牛群的总共9,909个微生物结果进行了评估。我们的结果表明，鉴定出29种不同的NASM物种，8个最普遍的NASM物种是葡萄球菌色基因，S、溶血病，S、模拟器，表皮葡萄球菌，S.sciuri（现为Mamaliicoccussciuri），S、磁炎/Shyicus,美国北极星，还有S.xylosus.NASM分布在季节之间保持相似，但夏季NASMCM病例的频率较高。我们的结果显示了隔离频率随时间变化的不同模式，取决于细菌种类：增加或减少的趋势，循环波动，除了S.Borealis,观察到我们研究中最普遍的NASM具有显著的季节性效应。这项研究表明，S.chromogenes仍然是最常见的（43％）从牛CM鉴定的NASM物种，其次是溶血链球菌（18%），和S.simulans（12%）。
