Abstract: Another bacterium, identified as Staphylococcus warneri by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS), was obtained during the isolation of Staphylococcus aureus from yak milk by using Baird-Parker (BP) medium. The biochemical properties and antibiotic susceptibility of the Staphylococcus warneri strain were examined, and antibacterial experiments were carried out. Also, this study determined antibiotic residues in yak milk. The results showed that the biochemical properties of the obtained strain were consistent with those of Staphylococcus warneri. The strain was highly susceptible to most antibiotics except neomorphine, which had no inhibitory effect on it. Besides, all the yak milk samples were found to be negative for antibiotic residues. Although the opportunistic pathogen Staphylococcus warneri was detected in yak milk, it was sensitive to most antibiotics due to the pure environment of the milk source.

Key words: yak milk; Staphylococcus warneri; matrix-assisted laser desorption ionization-time of flight-mass spectrometry; biochemical identification; antibiotic sensitivity

摘要： 在利用Baird-Parker(BP)琼脂平板培养基分离牦牛乳中金黄色葡萄球菌的过程中分离得到经基质解析电离飞行时间质谱(matrix-assisted laser desorption ionization-time of flight-mass spectrometry,MALDI-TOF-MS)鉴定为沃氏葡萄球菌的微生物,对其进行生化鉴定和抗生素药敏及抑菌实验,同时对牦牛乳样品中的抗生素残留进行测定。结果表明:该菌具有沃氏葡萄球菌的生化特征,对大部分抗生素极敏感,仅复方新诺明对其没有抑制作用;牦牛乳样品均为抗生素残留阴性。虽然在牦牛乳中检测出了条件致病菌沃氏葡萄球菌,但因乳样品来源的环境纯净使其对大部分抗生素敏感。

关键词: 牦牛乳; 沃氏葡萄球菌; 基质解吸电离飞行时间质谱; 生化鉴定; 抗生素敏感性