论文部分内容阅读
目的对志贺菌敏感株进行诱导使其耐多药,研究其诱导耐药前后marOR基因的差异。方法用4类抗生素的次抑菌浓度对临床分离鉴定的志贺菌敏感株进行诱导耐多药试验。对志贺菌敏感株及诱导耐多药株的marOR基因进行聚合酶链反应(PCR)扩增后,测序比较其诱导耐药前后marOR基因序列的差异。结果成功获得志贺菌诱导耐多药株,命名为YD株;其最小抑菌浓度(MIC)分别为初始菌株的6～8倍;该诱导耐药株对庆大霉素、诺氟沙星、磺胺甲基异恶唑、头孢噻吩等均耐药;测序结果发现诱导耐药株marOR基因YD株有6个位点出现突变,其中5个为同义突变,1个为错义突变(1630位点A→G,赖氨酸→精氨酸)。结论 marOR基因的突变可能是志贺菌诱导耐药的调控机制之一。
Objective To induce the multi-drug resistance of Shigella sensitive strains and study the difference of marOR genes before and after induction of drug resistance. Methods Secondary antibacterial concentrations of antibiotics were used to induce multidrug-resistant multidrug-resistant clinical isolates of Shigella. The marOR genes of Shigella strains and multidrug-resistant strains were amplified by polymerase chain reaction (PCR) and sequenced to compare the marOR gene sequences before and after resistance. Results The multi-drug resistant strain Shigella was successfully obtained and named as YD strain. The minimum inhibitory concentration (MIC) was 6-8 times of that of the original strain. The induced drug-resistant strains were sensitive to gentamicin, norfloxacin , Sulfamethoxazole and cefalotin were all resistant. Sequencing results showed that there were six mutations in the mard gene YD strain, of which 5 were synonymous mutations and 1 was missense mutation (1630 Site A → G, Lysine → Arginine). Conclusion The mutation of marOR gene may be one of the regulatory mechanisms of Shigella resistance induction.