Sigma B对单核细胞增生李斯特菌耐受抗生素作用的影响  

Effects of σB on Listeria monocytogenes against Antibiotic Tolerance

作　　者：王莉[1] 冯飞飞[1] 张强[1] 冯晓琴[1] 尹晓蛟[1] 罗勤[1] 

机构地区：[1]华中师范大学生命科学学院遗传调控与整合生物学湖北省重点实验室,湖北武汉430079

出　　处：《微生物学杂志》2011年第2期1-6,共6页Journal of Microbiology

基　　金：国家自然科学基金(30970111);湖北省杰出青年基金(2009CDA124);华中师范大学科研项目(CCNU09Y01001);华中师范大学研究生自主科研项目(2009028)

摘　　要：单核细胞增生李斯特菌是重要的革兰阳性食源性致病菌。近年来的报道显示出该菌耐受抗生素的能力有不断增强的趋势,为了探讨其耐药机制,对Sigma B(σB,李斯特菌中应对环境胁迫的主要调控因子)在抗生素耐受性中的作用进行了初步研究。检测和比较单核细胞增生李斯特菌标准菌株EGDe和其σB缺失突变菌株EGDeΔsigB对盘尼西林青霉素、氨苄西林青霉素、利福平、硫酸庆大霉素、四环素盐酸和红霉素6种抗生素的最小抑菌浓度(MIC);在测定的MIC的基础上,利用MTT(噻唑蓝活体染色法)法比较EGDe和EGDeΔsigB在1×MIC、2×MIC和8×MIC的氨苄西林青霉素、红霉素和利福平3种抗生素中的生长活性。EGDe对盘尼西林青霉素(0.16μg/mL)、四环素盐酸(0.25μg/mL)和硫酸庆大霉素(0.5μg/mL)的MIC高于EGDeΔsigB(分别为0.08、0.125和0.125μg/mL);而对氨苄西林青霉素、红霉素和利福平的MIC 2种菌株没有差别,分别为0.19、0.125和0.032μg/mL;与EGDe相比,EGDeΔsigB在氨苄西林青霉素、红霉素和利福平培养基中的生长活性较差,对抗生素的抑制更为敏感,而且随着这3种抗生素浓度的增加,其抑制程度也随之增强。Sigma B在单核细胞增生李斯特菌对抗生素的耐受中起到重要调节作用。Listeria monocytogenes （Lm） is an important gram-positive foodborue pathogen. Recent reports have indicated that the antibiotic resistance ability of the bacterium has a trend of continuous enhancement. In order to investigate the mechanism of its drug-resistance, the role of sigma factor （ σB , the main regulatory factor of Lm to response the environmental intimidation） in the antibiotic tolerance was primarily studied. Susceptibilities （or resistance） of Lm wild type strain EGDe and its sigB deletion mutant EGDeAsigB to six antibiotics （penicillin G, erythromyein, gentamicin sulphate, tetracycline HCl, rifampicin and ampicillin） were tested and compared by measuring their MICs （minimal inhibitory concentration）, as well as comparison of their growth activities based on the measurement of their MICs and using MTT （thiazole blue staining in vivo） on the media with 1× MIC, 2 x MIC, and 8 × MIC of three antibiotics （erythromycin, rifampicin and ampicillin）. The results showed that MICs of EGDe against penicillin G, gentamicin sulphate and tetracycline HCI were higher than that of EGDeAsigB, with 0. 16 μg/mL vs 0.08 μg/mL, 0.5 μg/mL vs 0. 125 μg/mL and 0.25 μg/mL vs 0. 125 μg/mL, respectively; the MICs of two strains against ampicillin, erythromyein and rifampicin were not different, being 0.19 μg/mL, 0. 125 μg/mL and 0. 032 μg/mL, respectively. However, the growth activities of EGDe and EGDeAsigB on the media with three antibiotics were easily distinguish-able. The resumption of EGDeAsigB from tested antibiotics inhibition was longer than that of EGDe, and this difference became more accentuated at higher antibiotic concentrations. Therefore, σB plays an important role in Lm antibiotic tolerance.

关 键 词：单核细胞增生李斯特菌 抗生素 耐受性 SigmaB 最小抑菌浓度(MIC) 

分 类 号：Q939.92[生物学—微生物学]