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目的研究1/2最小抑菌浓度(MIC)剂量的克雷霉素和头孢噻肟对中国艰难梭菌A-B+高分离株BJ08的生长、毒力基因转录和毒素分泌的影响。方法 BJ08菌株分别生长在含有1/2 MIC的克雷霉素或头孢噻肟以及无抗生素的脑心浸液肉汤(BHI)液体培养基中。每4个小时,通过检测其OD值以确定其生长曲线;通过实时荧光定量PCR检测其毒力基因的表达;通过酶联免疫吸附测定法(ELISA)检测上清和细胞内B毒素的表达。结果 BJ08在1/2 MIC剂量的克雷霉素存在的情况下,菌株的生长和毒素表达几乎不受影响;但是在1/2 MIC剂量的头孢噻肟存在的情况下,菌株生长变慢,到达对数期的时间延迟;毒力基因和B毒素的表达提前且增加。结论实验证明:在亚MIC剂量的不同的抗生素存在的情况下对中国株A-B+艰难梭菌的生长和毒力基因表达影响不同。我们的研究对于临床医师规范治疗CDAD和合理应用抗生素有一定的参考价值。
Objective To investigate the effects of 1/2 MIC on the growth, virulence genes transcription and toxin secretion of CJ in the BJ08 isolates from Chinese Clostridium difficile A-B +. Methods BJ08 strains were grown in liquid medium containing 1/2 MIC of crescosin or cefotaxime and antibiotic-free brain heart infusion broth (BHI). Every 4 hours, the growth curve was determined by measuring its OD value; the virulence gene expression was detected by real-time fluorescence quantitative PCR; and the expression of B toxin in supernatants and cells was detected by enzyme-linked immunosorbent assay (ELISA). Results BJ08 strain growth and toxin expression was virtually unaffected in the presence of ½ MIC doses of cresstin; however, strain growth was slower in the presence of cefotaxime at a ½ MIC dose, Time delay of reaching logarithmic phase; expression of virulence genes and B toxin increased earlier and more. Conclusions Experiments have shown that the effects of different antibiotics at submicrobial doses on the growth and virulence of C. difficile in Chinese strains A-B + are different. Our research has certain reference value for clinicians to standardize the treatment of CDAD and rational use of antibiotics.