四川地区猪大肠杆菌的耐药性检测

发布时间：2018-10-13 09:33

【摘要】：大肠埃希氏菌(Escherichia coli)简称大肠杆菌,是人和动物肠道中最丰富的一种细菌。大肠杆菌多数菌株不具有致病性,但在一定条件下可引起肠道外感染。而某些血清型菌株致病力强,可引起人和多种动物的疾病,常常导致腹泻和败血症,并可发生致死性感染。临床上使用抗生素进行大肠杆菌病的治疗,但近年来随着抗生素的大量运用,多重耐药大肠杆菌菌株日益增多,给人和动物的安全带来了极大隐患。为掌握四川省规模化猪场大肠杆菌的耐药特性,本研究对采集于四川省多个规模化猪场的样品进行了大肠杆菌的分离鉴定和耐药性分析,对氟喹诺酮耐药细菌进行了耐药基因的检测,为四川省规模化猪场大肠杆菌病毒防控提供了科学的实验数据。1、规模化猪场大肠杆菌的分离与鉴定在四川省规模化猪场采集发病猪的粪便或肝脏等组织样品,采用常规细菌分离技术分离发病猪组织中的大肠杆菌,通过形态学、培养特性和生化特性对分离菌进行鉴定。使用小鼠作为动物模型,对分离均进行致病力分析,结果鉴定出198株大肠杆菌,其中26株分离均具有致病性,腹腔感染小鼠后可引起小鼠死亡。2、198株大肠杆菌对9种非喹诺酮和9种喹诺酮药物的耐药性分析按照CLSI推荐的Kirby-Bauer法,进行18种抗菌药物的药敏试验,结果显示,非喹诺酮药物中氟苯尼考耐药率最高为94.95%(188/198),阿米卡星耐药率最低为23.23%(46/198)；喹诺酮药物中恩诺沙星耐药率最高为87.88%(174/198),左氧氟沙星耐药率最低为71.21%(141/198)。不同地区分离的大肠杆菌耐药性有差异。分离自不同地区的耐药率也有差异,多重耐药率比较高,15、16、17重耐药最为严重,分别有26、32和38株。3、198株大肠杆菌喹诺酮耐药基因的检测根据喹诺酮耐药基因序列设计扩增qnr A、qnrB、qnrC、qnrD、qnrS、aac(6')-Ib、 qepA等基因的引物对所有分离菌进行耐药基因的PCR检测。结果显示,198株分离菌株均没有检测出qnrC基因,qnrA基因检出率11.11%(22/198),qnrB基因检出率7.58%(15/198),qnrS基因检出率9.09%(18/198),qnrD基因检出率1.01%(2/198), aac(6')-Ib-cr基因检出率12.12%(24/198), qepA基因检出率4.04%(8/198)。以上研究结果显示四川省规模化猪场中猪源大肠杆菌耐药性严重且存在多重耐药现象。四川省猪源大肠杆菌喹诺酮耐药性与质粒介导的qnrA、qnrB、qnrS、qnrD、aac(6')-Ib-cr及qepA基因有关。
[Abstract]:Escherichia coli (Escherichia coli) is one of the most abundant bacteria in human and animal intestines. Most strains of Escherichia coli are not pathogenic, but can cause extraintestinal infection under certain conditions. Some serotype strains are virulent and can cause human and many animal diseases, often lead to diarrhea and septicemia, and can cause fatal infection. Clinical use of antibiotics for the treatment of Escherichia coli disease, but in recent years with the use of a large number of antibiotics, multi-drug resistant Escherichia coli strains are increasing, to the safety of humans and animals has brought great hidden danger. In order to understand the drug resistance characteristics of Escherichia coli in large-scale pig farms in Sichuan Province, the Escherichia coli isolates and drug resistance analysis were carried out in several large-scale pig farms in Sichuan Province. The resistance genes of fluoroquinolone-resistant bacteria were detected. Scientific experimental data were provided for the prevention and control of Escherichia coli virus in large-scale pig farms in Sichuan Province. 1. Isolation and identification of E. coli from large-scale pig farms in Sichuan Province were conducted to collect feces or liver samples of infected pigs. E. coli isolated from infected pig tissues was isolated by routine bacterial isolation technique. The isolated bacteria were identified by morphology, culture and biochemical characteristics. Using mice as animal model, 198 strains of Escherichia coli were identified, of which 26 strains were pathogenicity. The drug resistance of 2198 strains of Escherichia coli to 9 kinds of non-quinolones and 9 quinolones were tested by Kirby-Bauer method recommended by CLSI. The results showed that 2198 strains of Escherichia coli were resistant to 9 kinds of non-quinolones and 9 kinds of quinolones. Among non-quinolones, the highest resistance rate of florfenicol was 94.95% (1888 / 198), the lowest resistance rate of amikacin was 23.23% (46 / 198), the highest resistance rate of enrofloxacin was 87.88% (174 / 198), and the lowest resistance rate of levofloxacin was 71.21% (141198). The drug resistance of Escherichia coli was different in different regions. There were also differences in drug resistance rates between different regions, and the multidrug resistance rate was higher, and the most serious was 15C16 / 17. 3198 strains of Escherichia coli quinolone resistance genes were amplified by primers of qnr AqnrBnrBnnrBPQnrDnnrDnnrSnSAAC (6')-Ib, qepA and other genes, respectively. 3198 strains of Escherichia coli were tested by PCR for their resistance genes according to the sequence of quinolone resistance genes. The results showed that qnrC gene was not detected in all the 198-isolated strains, and the detection rate of qnrA gene was 11.11% (22 / 198), qnrB gene 7.58% (15 / 198), qnrS) 9.09% (18 / 198), aac (6') -Ib-cr 12.12% (24 / 198), qepA) 4.04% (8 / 198). The detection rate of), qnrD gene was 1.01% (2 / 198), aac (6') and the detection rate of Ib-cr gene was 12.12% (24 / 198), qepA). The results showed that the drug resistance of Escherichia coli was serious and multidrug resistance existed in large-scale pig farms in Sichuan Province. The resistance of Sichuan porcine Escherichia coli to quinolone is related to plasmid mediated qnrA,qnrB,qnrS,qnrD,aac (6')-Ib-cr and qepA genes.
【学位授予单位】：四川农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S852.61

【相似文献】