【作者】 钱科；

【导师】 孙怀昌；

【作者基本信息】 扬州大学 ， 预防兽医学， 2006， 硕士

【摘要】 奶牛乳房炎是最常见、防治最难、花费最多的奶牛疾病之一,至今仍无有效的根治手段。目前奶牛乳房炎的防治主要依赖抗菌素等常规药物,但由于抗菌素的长期和盲目使用,奶牛乳房炎病原菌耐药性问题日益严重。针对国内外奶牛乳房炎病原菌流行情况主要为链球菌、金黄色葡萄球菌和大肠杆菌的基础上,我们分别在营养肉汤培养基、Baird-parker培养基、麦康凯培养基基础上,研制出致奶牛乳房炎链球菌、金黄色葡萄球菌和大肠杆菌快速鉴别及药敏试验用选择培养液。分别命名为EN培养液、mBP培养液、MQQ培养液。在EN培养液中,除链球菌生长较好外,金黄色葡萄球菌等4种革兰氏阳性菌和大肠杆菌等6种革兰氏阴性菌均不生长;将10μl奶样接种EN培养液,37℃培养24h后即可根据培养液是否浑浊和由紫色变为黄色判断奶样中有无链球菌,检测无乳链球菌、停乳链球菌和粪链球菌的灵敏度分别为35、15和25个细菌;经与标准纸片法药敏试验对比证明,EN选择培养液对治疗奶牛乳房炎的7类8种抗菌素的抑菌活性有所影响,根据标准药敏试验结果进行调整,得出用EN培养液进行快速药敏试验的抗菌素浓度;将10μl奶样或初次选择培养物接种含适当浓度抗菌素的EN培养液,35℃培养24h后即能根据培养液是否浑浊和由紫色变为黄色判断奶样中链球菌对所试抗菌素的敏感性。在mBP培养液中,除金黄色葡萄球菌生长良好外,链球菌等4种革兰氏阳性菌和大肠杆菌等6种革兰氏阴性菌均不生长;将10μl奶样接种入mBP培养液,37℃培养24h后即可根据培养液是否浑浊和产生黑色产物判断奶样中有无金黄色葡萄球菌,检测灵敏度为60个细菌;经与标准纸片法药敏试验对比证明,mBP培养液对常用于奶牛乳房炎治疗的7类8种抗菌素的抑菌活性无明显影响;将10μl奶样或选择培养物接种入含标准抑菌浓度抗菌素的mBP培养液中,35℃培养24h后即能根据培养液是否浑浊和产生黑色产物判断奶样中金黄色葡萄球菌对所试抗菌素更多还原

【Abstract】 Bovine mastitis is the most costly disease in the dairy industry. Antibiotic resistance is a prevalent problem in dairy industry due to the continuous and inappropriate use of antibiotics for bovine mastitis control, particularly in developing countries.To develop a quick method for differentiation and antibiotic sensitivity test of Streptococci、Staphylococcus aureus and Escherichia coli from the diseased cows, three selective broth were developed based on the recipe of nutrient broth medium、Baird-parker medium and MacConkey medium.These three new selective broth were named EN、mBP and MQQ.Here we demonstrated that, among 10 species of Gram-positive and Gram-negative bacteria tested, only Streptococci could grow in the EN medium. Following inoculation with 10μl of milk samples and incubation overnight at 37℃, the presence or absence of Streptococci in milk could be identified based on the change of turbidity and color of the medium. The medium had some inhibitory effects on activities of antibiotics commonly used for treating bovine mastitis, which could be avoided by adjusting the concentrations of the antibiotics for quick antibiotic sensitivity test using EN medium. By inoculating the medium containing adjusted minimal inhibitory concentrations of antibiotics with milk samples,a quick antibiotic sensitivity test was developed and the results could be obtained following overnight incubation.We also demonstrated that, among 11 species of Gram-positive and Gram-negative bacteria tested, only Staphylococcus aureus could grow in the mBP medium. Following inoculation with 10μl of milk samples and incubation overnight at 37℃, the presence or absence of S. aureus in milk could be identified based on the turbidity and color更多还原