江西猪源产ESBLs ETEC流行及质粒相关性研究

发布时间：2018-06-30 20:03

本文选题：猪源ETEC + ESBLs　；参考：《江西农业大学》2016年硕士论文

【摘要】：近年来,产超广谱β-内酰胺酶(Extended Spectrum Beta-Lactamases,ESBLs)在猪源大肠杆菌中广泛流行,赋予细菌多重耐药性,给耐药性大肠杆菌防控工作带来巨大挑战。产肠毒素大肠杆菌(ETEC)是养猪业最常见的致病性大肠杆菌之一。江西是我国养猪大省,了解ESBLs在江西猪源ETEC的流行及其介导的耐药具有重大意义。本研究以从江西规模化养猪场腹泻仔猪直肠拭子中分离的146株大肠杆菌为受试菌。首先采用PCR和纸片法对ETEC和产ESBLs ETEC进行鉴定,并进行药敏试验。结果:1.ETEC检出率为65.07%(95/146),产ESBLs ETEC检出率为20.55%(30/146);2.ETEC对林可霉素、四环素、甲氧苄啶、头孢氨苄和阿莫西林耐药率均超过90%,分别为100.00%、94.74%、94.74%、91.58%和90.53%。对亚胺培南、头孢西丁、头孢他啶、头孢吡肟和氨曲南敏感;3.产ESBLs ETEC对β-内酰胺类抗生素的耐药率整体远高于非产ESBLs ETEC,非β-内酰胺类抗生素耐药情况相近。其次运用PCR方法对产ESBLs ETEC进行ESBLs分型、质粒分型和细菌进化分群研究。结果:1.TEM、CTX-M、SHV和OXA型ESBLs均有检出,检出率分别为70.00%、63.33%、16.67%和13.33%;2.共检出FIB、I1、HI2、FIA、Y、FIC、FrepB和N8种不同类型质粒复制子。产ESBLs ETEC以FrepB、FIB和I1型质粒为主,分别占66.67%、60.00%和46.67%。非产ESBLs ETEC除N和I1型质粒复制子检出率较低,为13.33%外,其余质粒复制子检出率在33.33%~53.33%之间;3.细菌进化分群研究发现,产ESBLs ETEC多为A群ETEC,占46.67%(14/30)。非产ESBLs ETEC各进化群所占比例相仿,A群占16.67%。最后,将ESBLs阳性质粒转至Top10感受态细胞,对转化子进行药敏试验。结果:共计获得19株转化子,这些转化子具有原菌株全部或部分耐药性。本研究夯实了我国猪源产ESBLs ETEC研究基础,丰富了江西产ESBLs ETEC研究数据,为进一步研究产ESBLs ETEC耐药机制和耐药修复奠定了理论基础。
[Abstract]:In recent years, extended Spectrum Beta-Lactamases ESBLs (ESBLs) have been widely used in porcine Escherichia coli, which endows the bacteria with multiple drug resistance and brings great challenge to the prevention and control of drug-resistant Escherichia coli. Enterotoxigenic Escherichia coli (ETEC) is one of the most common pathogenic Escherichia coli in pig industry. Jiangxi is a big pig raising province in China. It is of great significance to understand the prevalence of ESBLs in Jiangxi porcine ETEC and its mediated drug resistance. In this study, 146 strains of Escherichia coli isolated from the rectal swabs of piglets in a large scale pig farm in Jiangxi Province were selected as the tested bacteria. First, ETEC and ESBLs-producing ETEC were identified by PCR and disk method, and drug sensitivity test was carried out. Results the detectable rate of ETEC was 65.07% (95 / 146). The detection rate of ETEC in ESBLs was 20.55% (30 / 146). 2. The resistance rates of ETEC to lincomycin, tetracycline, trimethoprim, cefalexin and amoxicillin exceeded 90% (100.0094.7494.7474747.74 91.58% and 90.53%, respectively). It is sensitive to imipenem, cefxitin, ceftazidime, cefepime and aztreonam. The resistance rate of ESBLs-producing ETEC to 尾 -lactam antibiotics was much higher than that of non-ESBLs-producing ETEC, and the resistance of non-尾 -lactam antibiotics was similar. Secondly, ESBLs typing, plasmid typing and bacterial evolution were studied by PCR. Results 1. Both CTX-MN SHV and OXA ESBLs were detected, and the detectable rates were 70. 00% and 63. 33% and 13. 33%, respectively. A total of 8 different types of plasmids replicators were identified. The majority of ESBLs-producing ETEC were FrepBFIB and I1 plasmids, accounting for 66.67% and 46.67%, respectively. The detectable rate of non-ESBLs-producing ETEC plasmids was lower than that of N and I1 type plasmids (13.33%), and the detectable rate of other plasmids replicas was between 33.33% and 53.33%. The ESBLs-producing ETEC was mainly group A ETEC, accounting for 46.67% (14 / 30). The percentage of ESBLs-free ETEC was similar to that of ESBLs-A group (16.67%). Finally, the ESBLs positive plasmid was transferred to Top10 competent cells for drug sensitivity test. Results: a total of 19 transformants were obtained and the transformants were resistant to all or part of the original strain. This study consolidated the research foundation of ESBLs-producing ETEC in China, enriched the data of ESBLs ETEC from Jiangxi Province, and laid a theoretical foundation for further study on the mechanism of ESBLs-producing ETEC resistance and drug resistance repair.
【学位授予单位】：江西农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S852.61

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