本文選題：牛支原體 + 大環(huán)內酯類類抗生素��； 參考：《吉林農(nóng)業(yè)大學》2015年碩士論文

【摘要】：牛支原體(Mycoplasma bovis,M.bovis)是引起肉牛和奶牛多種疾病的重要病原體,其中以引發(fā)呼吸系統(tǒng)疾病(Bovine respiratory disease,BRD)最為常見。2008年,我國首次從患肺炎的犢牛肺臟中分離到M.bovis。由于M.bovis不具有細胞壁,因此β-內酰胺類抗生素對其治療無效,且近年來抗生素的廣泛及不合理使用,使M.bovis逐漸出現(xiàn)了耐藥株,其產(chǎn)生的耐藥性不僅給控制和治療該病帶來困難,而且加劇了抗生素在牛體內的殘留,嚴重的危害動物食品安全。對吉林省售出至他省后患BRD的病牛進行病料采集,經(jīng)過對分離菌進行純化、形態(tài)觀察及分子生物學鑒定共獲得32株M.bovis。采用改良的微量二倍稀釋法對臨床治療M.bovis有效的9種抗菌藥物進行抗菌藥物敏感性實驗,結果顯示,所分離的32株M.bovis有13株對紅霉素、阿奇霉素、吉他霉素、泰樂菌素耐藥(MIC≥64μg/m L),對克林霉素耐藥(MIC≥4μg/m L),占40.63%,且這13株M.bovis同時對泰樂菌素、克林霉素和十四元環(huán)、十五元環(huán)、十六元環(huán)大環(huán)內酯類抗生素耐藥,有1株對氟苯尼考耐藥(MIC≥8μg/m L);部分菌株對紅霉素、泰樂菌素、環(huán)丙沙星、恩諾沙星、氟苯尼考中度敏感;所有菌株均對多西環(huán)素敏感,多數(shù)菌株對恩諾沙星較敏感。對M.bovis上與大環(huán)內酯類抗生素耐藥相關的靶位包括23S rRNA結構域Ⅱ,23S rRNA結構Ⅴ,L4、L22核糖體蛋白的基因序列進行比對分析,發(fā)現(xiàn)13株對大環(huán)內酯類藥物高度耐藥的M.bovis,其23S rRNA rrnA 2058位的堿基都發(fā)生了A—G的突變,23S rRNA結構域Ⅱ、核糖體蛋白L4、L22均未發(fā)現(xiàn)其有耐藥相關的基因突變或氨基酸置換。對編碼甲基化酶的ermA、ermB、ermC基因及大環(huán)內酯類鈍化酶基因mphA、mphC基因和調控藥物主動外排系統(tǒng)的mefA、mefE、msrA、msrB基因進行檢測,所分離32株M.bovis上均未檢測到上述基因。采用微量稀釋法檢測敏感株Mb9、Mb10及耐藥株Mb1和Mb12加入CCCP、VP和SOV后MIC值的變化,對其體內存在的藥物主動外排系統(tǒng)進行初步確證,發(fā)現(xiàn)應用EPI前后抗菌藥物對M.bovis MIC值無明顯變化,提示M.bovis體內可能不存在對大環(huán)內酯類藥物的主動外排系統(tǒng),但還有待于進一步確證。
[Abstract]:Mycoplasma bovis-M.bovis) is an important pathogen causing many diseases in beef cattle and dairy cattle, among which the respiratory system disease caused by bovine respiratory disease (BRD) is the most common. In 2008, M. bovisis was first isolated from the lungs of calf infected with pneumonia in China. Because M.bovis does not have cell wall, 尾 -lactam antibiotics are not effective in its treatment, and the widespread and unreasonable use of antibiotics in recent years has led to the emergence of drug-resistant strains of M.bovis. The drug resistance produced by M.bovis not only makes it difficult to control and treat the disease. Moreover, the residues of antibiotics in cattle are aggravated, which seriously endangers the safety of animal food. A total of 32 strains of M.bovisis were collected from infected cattle sold to his province in Jilin province. After purification, morphological observation and molecular biological identification, 32 strains of M.bovisis were obtained. A modified microdilution method was used to test the antimicrobial susceptibility of 9 effective antimicrobial agents for M.bovis. The results showed that 13 of the 32 strains of M.bovis isolated were resistant to erythromycin, azithromycin, and guitar mycin, and the results showed that 13 of the 32 strains of M.bovis were resistant to erythromycin, azithromycin and guitar mycin. The MIC of tylosin resistance was 鈮，

本文編號：1860887