耐特定抗菌药双歧杆菌的鉴定与特性研究

发布时间：2018-05-02 23:01

本文选题：双歧杆菌 + 耐药性　；参考：《内蒙古农业大学》2007年硕士论文

【摘要】： 本项研究以源自内蒙古呼和浩特婴儿及牛犊的10株双歧杆菌为试材,用传统鉴定法(气相色谱法和糖发酵法),进行双歧杆菌的属、种鉴定,同时用引物(Eu-01、Eu-02,Bif-03、Bif-04)对受试菌株DNA进行扩增,在电泳图上,各菌株均扩增出了预期大小的多重PCR产物,说明该PCR方法可将双歧杆菌鉴定到属水平,且结果稳定,特异性好。对双歧杆菌驯化后的耐氧菌株、实验的原始菌株以及传代30-40次以后的厌氧菌株的生长特性及其对头孢氨苄(cefalexin)、阿米卡星(Amikacin)、甲硝唑(Metronidazole)三种抗菌药的耐药性等特性进行了研究比较;同时研究了双歧杆菌的质粒与耐药性的关系。结果表明: 随着传代次数的增加,2株豚双歧杆菌由原来对头孢氨苄的耐药变为中度敏感,对其它两种抗生素仍然为耐药;虽然其它菌株的耐药性未发生改变,但耐药强度有所减弱,即对同种抗菌药同一浓度的抑菌圈直径增大,且差异显著(p0.05)。需氧驯化后双歧杆菌的耐药性变化不大,只是个体形态均变为短杆状或球状,生长速度减缓。采用碱裂解法提取并检测了双歧杆菌的耐药性质粒,仅在一株标准双歧杆菌B2778中发现有1条质粒带,其对应的核酸分子量大约是23kbps,其他受试菌株中未发现有质粒存在,从而表明这些菌株对多种抗菌药的耐药性并非由质粒介导,这些菌株不存在耐药因子传递的危险。
[Abstract]:In this study, 10 strains of Bifidobacterium from infants and calves in Hohhot, Inner Mongolia, were used to identify the genus and species of Bifidobacterium by traditional identification methods (gas chromatography and sugar fermentation). At the same time, the DNA of the tested strain was amplified by primer Eu-01and Eu-02Bif-03BIF-04. On the electrophoretic map, the expected size of multiple PCR products were amplified from each strain, indicating that the PCR method could identify Bifidobacterium to the generic level, and the results were stable and specific. After acclimation of Bifidobacterium, the growth characteristics of the original strain and the anaerobic strain after 30 to 40 times of passage were studied and compared with those of the three antimicrobial agents, such as cefalexin, Amikacinine, Metronidazole. etc. The relationship between plasmid and drug resistance of Bifidobacterium was also studied. The results show that: With the increase of the number of passages, two strains of bifidobacterium changed from resistance to cefalexin to moderate sensitivity, and remained resistant to the other two antibiotics. Although the resistance of other strains remained unchanged, the drug resistance of the other strains weakened. The diameter of bacteriostasis circle of the same concentration of the same antimicrobial drug increased, and the difference was significant (p 0.05). After aerobic acclimation, the drug resistance of Bifidobacterium changed little, but the individual morphology became short rod or globular, and the growth rate slowed down. The resistant plasmids of Bifidobacterium were extracted and detected by alkaline lysis method. Only one plasmid band was found in one standard strain B2778. The molecular weight of nucleic acid was about 23kbps. no plasmids were found in other strains. The results showed that the resistance of these strains to various antimicrobial agents was not mediated by plasmids, and there was no risk of drug resistance factor transmission in these strains.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2007
【分类号】：R371

【引证文献】