牛乳腺炎的病原学调查及抗生素敏感性测试 -动物医学专业

摘要

本研究旨在系统调查中国某地区奶牛乳腺炎的病原菌分布特征及其对抗生素的敏感性，为临床治疗提供科学依据。通过采集2022年1月至12月期间该地区5个规模化奶牛场的乳腺炎奶样，共分离鉴定出286株病原菌，其中革兰氏阳性菌占68.5%，以金黄色葡萄球菌和无乳链球菌为主；革兰氏阴性菌占31.5%，主要为大肠杆菌和克雷伯菌属。采用微量肉汤稀释法对分离菌株进行16种常用抗生素的敏感性测试，结果显示金黄色葡萄球菌对青霉素的耐药率高达85.7%，但对头孢噻呋和恩诺沙星保持较高敏感性；无乳链球菌对四环素的耐药率为78.6%，而对阿莫西林-克拉维酸的敏感率达95.2%。革兰氏阴性菌中，大肠杆菌对氨苄西林的耐药率为82.1%，但对头孢曲松和庆大霉素的敏感率分别为88.9%和91.3%。本研究的创新点在于首次系统揭示了该地区乳腺炎病原菌的流行特征及耐药谱，并发现多重耐药菌株的比例显著上升，其中15.4%的金黄色葡萄球菌和12.8%的大肠杆菌表现出对3类及以上抗生素的耐药性。研究结果为优化乳腺炎治疗方案、制定合理的抗生素使用策略提供了重要参考，同时强调了加强牧场生物安全管理和规范抗生素使用的必要性。

关键词：奶牛乳腺炎；病原菌分布；抗生素敏感性；耐药性

ETIOLOGICAL INVESTIGATION AND ANTIBIOTIC SENSITIVITY TEST OF BOVINE MASTITIS

ABSTRACT

The purpose of this study was to systematically investigate the distribution characteristics of pathogenic bacteria and their sensitivity to antibiotics in dairy cows in a certain area of China, so as to provide scientific basis for clinical treatment. From January to December 2022, 286 strains of mastitis milk samples were collected from 5 large-scale dairy farms in the region. Among them, Gram-positive bacteria accounted for 68.5%, mainly Staphylococcus aureus and Streptococcus agalactia. Gram-negative bacteria accounted for 31.5%, mainly E. coli and Klebsiella. The results showed that the resistance rate of Staphylococcus aureus to penicillin was as high as 85.7%, but the sensitivity to ceftiofurme and enrofloxacin was high. The resistance rate of Streptococcus agalactis to tetracycline was 78.6%, while the sensitivity rate to amoxicillin and clavulanic acid was 95.2%. Among Gram-negative bacteria, the resistance rate of Escherichia coli to ampicillin was 82.1%, but the sensitivity rate to ceftriaxone and gentamicin were 88.9% and 91.3%, respectively. The innovation of this study is that the epidemic characteristics and drug resistance spectrum of mastitis pathogens in this region were systematically revealed for the first time, and the proportion of multi-drug resistant strains was significantly increased, among which 15.4% of Staphylococcus aureus and 12.8% of Escherichia coli showed resistance to class 3 or more antibiotics. The results of this study provide important references for optimizing mastitis treatment and formulating rational antibiotic use strategies, and emphasize the necessity of strengthening biosafety management and regulating antibiotic use in pasture.

KEY WORDS：Cow mastitis; Pathogenic bacteria distribution; Antibiotic sensitivity; Drug resistance

摘要 I

ABSTRACT II

第1章绪论 2

1.1 研究背景及意义 2

1.2 牛乳腺炎病原学及抗生素敏感性研究现状 2

第2章牛乳腺炎病原学调查与分析 4

2.1 牛乳腺炎主要病原菌的分离与鉴定 4

2.2 不同地区牛乳腺炎病原菌分布特征 4

2.3 牛乳腺炎病原菌的分子生物学特性分析 5

第3章牛乳腺炎病原菌的抗生素敏感性测试 7

3.1 常用抗生素对牛乳腺炎病原菌的抑菌效果评估 7