本文選題：牛支原體 + 大環(huán)內(nèi)酯類類抗生素　； 參考：《吉林農(nóng)業(yè)大學(xué)》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(jiàn)。2008年,我國(guó)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(xì)胞壁,因此β-內(nèi)酰胺類抗生素對(duì)其治療無(wú)效,且近年來(lái)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(lái)困難,而且加劇了抗生素在牛體內(nèi)的殘留,嚴(yán)重的危害動(dòng)物食品安全。對(duì)吉林省售出至他省后患BRD的病牛進(jìn)行病料采集,經(jīng)過(guò)對(duì)分離菌進(jìn)行純化、形態(tài)觀察及分子生物學(xué)鑒定共獲得32株M.bovis。采用改良的微量二倍稀釋法對(duì)臨床治療M.bovis有效的9種抗菌藥物進(jìn)行抗菌藥物敏感性實(shí)驗(yàn),結(jié)果顯示,所分離的32株M.bovis有13株對(duì)紅霉素、阿奇霉素、吉他霉素、泰樂(lè)菌素耐藥(MIC≥64μg/m L),對(duì)克林霉素耐藥(MIC≥4μg/m L),占40.63%,且這13株M.bovis同時(shí)對(duì)泰樂(lè)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(nèi)酯類抗生素耐藥,有1株對(duì)氟苯尼考耐藥(MIC≥8μg/m L);部分菌株對(duì)紅霉素、泰樂(lè)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(duì)多西環(huán)素敏感,多數(shù)菌株對(duì)恩諾沙星較敏感。對(duì)M.bovis上與大環(huán)內(nèi)酯類抗生素耐藥相關(guān)的靶位包括23S rRNA結(jié)構(gòu)域Ⅱ,23S rRNA結(jié)構(gòu)Ⅴ,L4、L22核糖體蛋白的基因序列進(jìn)行比對(duì)分析,發(fā)現(xiàn)13株對(duì)大環(huán)內(nèi)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(jié)構(gòu)域Ⅱ、核糖體蛋白L4、L22均未發(fā)現(xiàn)其有耐藥相關(guān)的基因突變或氨基酸置換。對(duì)編碼甲基化酶的ermA、ermB、ermC基因及大環(huán)內(nèi)酯類鈍化酶基因mphA、mphC基因和調(diào)控藥物主動(dòng)外排系統(tǒng)的mefA、mefE、msrA、msrB基因進(jìn)行檢測(cè),所分離32株M.bovis上均未檢測(cè)到上述基因。采用微量稀釋法檢測(cè)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(duì)其體內(nèi)存在的藥物主動(dòng)外排系統(tǒng)進(jìn)行初步確證,發(fā)現(xiàn)應(yīng)用EPI前后抗菌藥物對(duì)M.bovis MIC值無(wú)明顯變化,提示M.bovis體內(nèi)可能不存在對(duì)大環(huán)內(nèi)酯類藥物的主動(dòng)外排系統(tǒng),但還有待于進(jìn)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(hào)：1860887