河北省不同地区奶牛乳房炎主要病原菌的分离鉴定和耐药性研究

发布时间：2018-07-11 10:14

本文选题：奶牛 + 乳房炎　；参考：《河北农业大学》2015年硕士论文

【摘要】：奶牛乳房炎是奶牛养殖业中最常见的一种疾病,同时也是制约乳业发展的重要因素。本研究利用DHI数据监测和LMT法相结合方法对河北省7个地区的420份乳样诊断奶牛乳房炎的发病情况。结果,DHI数据监测显示从420份样品中检测出126份阳性乳样,阳性率为30%,同时采用LMT诊断试剂进行检测,有128份阳性乳样,检出率30.48%,即本研究中DHI数据监测与LMT试剂诊断的相符率为98.42%。其中邢台、沧州、廊坊、唐山、保定、石家庄、张家口地区的乳样阳性检出率分别为35%、28%、24.44%、28.89%、30%、27.14%、33.33%。本研究利用微生物学和分子生物学相结合的方法,对河北省7个地区乳样进行乳房炎致病菌的分离培养鉴定。总共分离出4种主要致病菌,362株。引起奶牛乳房炎的主要致病菌分别为金黄色葡萄球菌、无乳链球菌、大肠杆菌、绿脓杆菌,其中金黄色葡萄球菌167株,占总菌株数的46%,无乳链球菌94株,占总菌株数的25.97%,大肠杆菌84株,占总菌株数的23%,绿脓杆菌17株,占总菌株数的5%。在检出的乳样中,几乎全部为金黄色葡萄球菌、无乳链球菌、大肠杆菌的混合感染,但其中检出的17株绿脓杆菌全部由张家口地区乳样中分离所得,为4种分离菌的混合感染。参照NCCLS推荐的K-B药敏纸片法对奶牛乳房炎的四种分离菌进行15种药物的敏感性试验,试验测定其抑菌圈大小。结果表明,七个地区致病菌对头孢噻肟、呋喃唑酮、恩诺沙星、氟苯尼考及磷霉素的敏感性较高;对卡那霉素、阿奇霉素、四环素和环丙沙星耐药严重。所有菌株对青霉素、链霉素几乎完全耐药。根据药敏结果,河北省7个地区的362株菌中存在多重耐药现象,约占全菌株数的86.46%。采用PCR方法,研究河北省奶牛乳房炎病原菌的耐药基因的携带情况,评估耐药表型与基因型的相关性。结果显示:金黄色葡萄球菌分离株、无乳链球菌、大肠杆菌和绿脓杆菌的分离株检测出的优势耐药基因分别为gyr A、erm B、Qnr B、Qnr B。前3种细菌的耐药表型与基因型的相符率高达85%以上。表明药敏试验结果准确,可以用于临床指导用药。用药后各地区的DHI数据监测9、10、11、12月份SCC水平均有显著差异(P0.01),其下降幅度在14.01%-45%之间。选取部分致病菌的PCR扩增产物进行胶回收、测序,并与Gene Bank中已发表的相关序列进行同源性比对,从而确定病原菌所属种类。综上所述,本研究通过对分离鉴定的致病菌进行药敏试验和耐药基因检测,将试验结果反馈回各奶牛场,指导其临床用药和饲养管理,同时为河北省不同地区奶牛乳房炎主要致病菌的防治提供了理论依据。
[Abstract]:Dairy cow mastitis is the most common disease in dairy farming, and it is also an important factor restricting the development of dairy industry. In this study, DHI data monitoring and LMT method were used to detect the incidence of Dairy Mastitis in 420 milk samples in 7 regions of Hebei province. Results, DHI data monitoring showed that 126 samples were detected from 420 samples. The positive rate of sex milk was 30%, and LMT diagnostic reagent was used to detect 128 positive milk samples. The detection rate was 30.48%. That is, the coincidence rate of DHI data monitoring and LMT reagent diagnosis in this study was 98.42%. in Xingtai, Cangzhou, Langfang, Tangshan, Baoding, Shijiazhuang and Zhangjiakou. The positive rates of milk samples were 35%, 28%, 24.44%, 28.89%, 30%, respectively. 27.14%, 33.33%. in this study, a combination of Microbiology and molecular biology was used to identify the isolation and culture of mammary mastitis pathogenic bacteria in 7 regions of Hebei province. A total of 4 main pathogens were isolated and 362. The main pathogenic bacteria causing cow mastitis were Staphylococcus aureus, Lactococcus lactis, Escherichia coli, and purulent purulent. Bacilli, including 167 strains of Staphylococcus aureus, accounted for 46% of the total number of bacteria, 94 strains of Streptococcus lactis, 25.97% of the total number of bacteria, 84 strains of Escherichia coli, 23% of the total number of bacteria, 17 strains of Pseudomonas aeruginosa, which accounted for 5%. in the total number of bacteria, almost all were Staphylococcus aureus, Streptococcus free Streptococcus and Escherichia coli. 17 strains of Pseudomonas aeruginosa isolated from the Zhangjiakou region were isolated from the milk samples of the Zhangjiakou region and were mixed infection of 4 isolated bacteria. The sensitivity tests of 15 kinds of drugs for four isolates of Dairy Mastitis in dairy cows were tested with reference to the K-B drug sensitive paper recommended by us, and the size of the bacteriostasis was tested. The results showed that seven regional pathogenic bacteria were to cefotaxime. Furazolidone, enrofloxacin, florfenicol and fosfomycin were more sensitive to kanamycin, azithromycin, tetracycline and ciprofloxacin. All strains were almost completely resistant to penicillin and streptomycin. According to the results of drug sensitivity, there were multiple resistance in 362 strains of 7 regions in Hebei Province, which accounted for the 86.46%. mining of the total number of bacteria. The PCR method was used to study the carrying status of the resistant genes of the pathogenic bacteria of dairy cow mastitis in Hebei Province, and to evaluate the correlation between the resistance phenotype and genotype. The results showed that the dominant resistance genes of Staphylococcus aureus isolates, Streptococcus lactis, Escherichia coli and Pseudomonas aeruginosa were Gyr A, ERM B, Qnr B, and Qnr B., respectively. The resistant phenotype of the bacteria was more than 85% of the genotype, indicating that the drug sensitivity test results were accurate and could be used for clinical guidance. The DHI data of 9,10,11,12 months after the drug use were significantly different (P0.01), and the decrease was between 14.01%-45%. The PCR amplification products of some pathogenic bacteria were selected for rubber recovery. Sequencing, and comparing the homologous sequences with the related sequences published in Gene Bank to determine the species of pathogenic bacteria. In summary, this study returns the results of the test to the dairy farms, directing the clinical medication and feeding management, and in Hebei province. It provides a theoretical basis for the prevention and treatment of the main pathogenic bacteria of dairy cow mastitis.
【学位授予单位】：河北农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S858.23

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