奶山羊乳房炎的淋巴细胞凋亡变化

通过AnnexinⅤ-FITC/PI双染流式细胞术测定泌乳1、6、14、21、28、35、45 d(强制退化10 d)健康及乳房炎奶山羊血液、脾、乳上淋巴结及肠系膜淋巴结淋巴细胞凋亡率的变化。结果表明,乳房炎组(M)奶山羊血液、脾、乳上淋巴结及肠系膜淋巴结淋巴细胞凋亡率(%)显著或极显著高于对照组(C)奶山羊(P<0.05,P<0.01),表明乳房炎奶山羊通过增加淋巴细胞凋亡下调炎症反应以维护自身健康。     

大型奶牛场奶牛乳房炎情况调查

对贵州省某奶牛场奶牛乳房炎发病率、发病规律及其对乳业生产的影响进行了调查分析,为奶牛乳房炎的防治工作提供基础资料.     

新疆部分地区奶牛乳房炎大肠杆菌的分离鉴定及耐药性分析

[目的]为了解本地区奶牛乳房炎大肠杆菌的流行及耐药情况。[方法]对新疆部分地区奶牛乳房炎大肠杆菌进行分离培养、染色镜检、荧光PCR鉴定,并用纸片法对分离菌株开展药物敏感试验。[结果]从200 份奶牛乳房炎样品中分离出63 株大肠杆菌,分离率为31.5%。分离菌株对青霉素耐药率最高,达到了93.65%,对美罗培南敏感率最高,达到了98.14%,对其他抗生素均有不同程度的耐药。[结论]新疆部分地区奶牛乳房炎中大肠杆菌广泛流行,具有较高的耐药性。     

牛源耐药性金黄色葡萄球菌的分离鉴定及黏附因子基因FnBP和clfA的表达分析

为探究致奶牛乳房炎主要致病菌金黄色葡萄球菌(Staphylococcus aureus,S.aureus)的生物学特性,对新疆垦区部分奶牛场乳房炎奶样进行病原学分析,并对病原菌进行耐药性、毒力因子的表达分析。从乳房炎奶样中分离得到S.aureus,采用血浆凝固酶试验、KB法、琼脂筛选法、生化鉴定法(VITEK32)、聚合酶链式反应等法进行鉴定。针对毒力基因clfA(凝集因子A)和FnBP(纤维结合素结合蛋白)进行特异性PCR扩增,用T/A克隆法将其插入pMD18-T载体,并构建原核表达载体pET-28a(+)-FnBP和pET-28a(+)-clfA。转化BL21(DE3)菌,经IPTG诱导表达,通过SDS-PAGE和Western blot分析鉴定表达产物。常规鉴定出葡萄球菌105株,其中金黄色葡萄球菌(S.aureus)62株,从62株S.aureus中检出耐药性金黄色葡萄球菌(MRSA)13株,检出率为20.10%,2株未确检。经测序证实与GenBank中FnBP基因(J04151)和clfA基因(AB245457)序列同源性分别为100%和95.69%。SDS-PAGE显示,clfA和FnBP蛋白相对分子质量分别为45ku和58ku。Western blot分析显示,clfA蛋白和FnBP蛋白均可与金黄色葡萄球菌多克隆抗血清发生特异性反应。病畜奶样中MRSA检出率较高,新疆垦区部分牛场呈蔓延趋势,成功表达了clfA、FnBP蛋白,具有一定的免疫保护效果。     

腺苷酸活化蛋白激酶在奶牛疾病中的作用研究进展

随着奶牛养殖规模化、集约化程度的不断提高，奶牛养殖过程中乳腺炎、酮病和脂肪肝等疾病的发病率也逐年增加。腺苷酸活化蛋白激酶（AMP-activated protein kinase，AMPK）作为一种能量感受器可以反映细胞能量状态。AMPK在葡萄糖、脂质和蛋白质代谢以及线粒体生物发生和自噬等过程中发挥重要调控作用。AMPK被认为是多种疾病潜在的干预或治疗靶点，在奶牛代谢性疾病中的研究也较为广泛。综述了AMPK在奶牛乳腺炎、酮病、脂肪肝中的调控作用研究进展，以期为这些疾病的靶向治疗提供参考。     

Molecular epidemiology,characterization of virulence factors and antibiotic resistance profile of Streptococcus agalactiae isolated from dairy farms in China and Pakistan

Streptococcus agalactiae is one of the most common pathogens that cause bovine mastitis worldwide. Identifying pathogen prevalence and virulence factors is critical for developing prevention and control approaches. Herein, 1 161 milk samples from various dairy farms in China (n=558) and Pakistan (n=603) were collected between 2019–2021 and were subjected to S. agalactiae isolation. Prevalence, serotyping, virulence genes, and antibiotic-resistant genes of S. agalactiae were evaluated by PCR assay. All isolates were characterized for haemolysis, biofilm production, cytotoxicity, adhesion, and invasion on bovine mammary epithelial cells. The prevalence of S. agalactiae-induced mastitis in cattle was found to be considerably higher in Pakistan than in China. Jiangsu and Sindh provinces had the highest area-wise prevalence in China and Pakistan, respectively. Serotypes Ia and II were prevalent in both countries, whereas serotype III was found only in Pakistan. Moreover, all isolates tested positive for PI-2b gene but negative for PI-1 and PI-2a genes. All isolates harboured cfb, cylE, hylB, and fbsB virulent genes, whereas many of them lacked bibA, rib and bca. However, the absence of bac and scp genes in Chinese isolates and cspA in Pakistani isolates was noted, while spb1 and lmb were not detected in isolates of both countries. Pakistani isolates, particularly serotype Ia-positive, had a considerably higher ability to produce biofilm, haemolysis, cytotoxicity, adhesion, and invasion than Chinese isolates. Most of the isolates were phenotypically resistant to tetracycline, erythromycin, and clindamycin and genotypic resistance was confirmed by the presence of ermA, ermB, tetM and tetO genes. Our study highlights the antimicrobial resistance profile and virulence-related factors contributing to the epidemiological spread of mastitis-causing S. agalactiae in China and Pakistan. The findings may facilitate future studies designed to develop improved treatment and control strategies against this pathogen.     

奶牛乳房炎的诊疗与防治

奶业是现代农业的重要组成部分,也是农业发展的一大支柱产业。奶牛乳房炎又名奶牛乳腺炎,特征为乳汁中白细胞增多以及乳腺组织发生变化。在我国,据报道,奶牛乳房炎的阳性率在46.6%?85.7%,乳房炎严重危害着奶牛的生产性能并导致了大量奶牛的淘汰,给奶牛业造成巨大的损失。随着我国奶牛产业的快速发展,奶牛乳房炎泛滥问题日益突出,所以有效的控制奶牛乳房炎对于我国奶牛业快速健康发展有着重要意义。     

奶牛牧场养殖环境中产ESBL耐药菌的流行特征

本研究旨在探索奶牛养殖环境中产超广谱β-内酰胺酶（extended-spectrum beta-lactamases，ESBL）耐药菌的流行特征。2020-2021年，采集6个内蒙古和宁夏牧场共160份牛奶、乳区皮肤拭子和环境来源的多种类型样本，分别进行了β-内酰胺酶检测、产ESBL耐药菌的分离鉴定、药敏试验以及菌株的全基因组测序。结果显示：24份奶样的检测结果显示，各牧场β-内酰胺酶阳性率为75%~100%。其中，5个牧场的153份样本共分离出6种产ESBL耐药菌，这些产ESBL耐药菌对阿莫西林（100%）、头孢噻肟（91.0%）和头孢他啶（78.2%）均具有较高耐药率；全基因组显示，14株产ESBL大肠杆菌携带多种耐药基因，以bla_CTX-M（100%）携带率最高。通过对内酰胺酶阳性奶样进行分析，发现造成牧场奶样β-内酰胺酶阳性的主要菌株是产ESBL鲍曼不动杆菌，并且该耐药菌携带有bla_CTX-M、bla_TEM、bla_OXA型β-内酰胺类耐药基因。本研究明确了内蒙古和宁夏牧场养殖环境中产ESBL耐药菌的流行特征，并对造成内蒙古1个牧场牛奶内酰胺酶阳性原因进行了追溯研究。     

茶多酚调控机制及其对奶牛乳房炎的干预作用

茶多酚（tea polyphenols,TP）是茶叶中的多酚类物质,属于稠环芳香烃,在抗氧化、抗肿瘤、抑菌、抗病毒、抗辐射、抗心血管疾病等方面均发挥生物学作用。介绍了茶多酚的组成成分和理化性质,综述了茶多酚发挥抗炎作用主要涉及的信号通路及其在奶牛乳腺上皮细胞（bovine mammary epithelial cells,BMEC）炎性反应中的作用研究进展,以期为探究茶多酚在预防和治疗奶牛乳房炎中的应用价值提供参考。