Starvation, together with the SOS response, mediates high biofilm-specific tolerance to the fluoroquinolone ofloxacin.
Starvation, together with the SOS response, mediates high biofilm-specific tolerance to the fluoroquinolone ofloxacin.
复制标题
DOI：
10.1371/journal.pgen.1003144
复制
发表时间：
2013
期刊：
影响因子：
4.5
通讯作者：
Beloin C
中科院分区：
文献类型：
--
作者：
Bernier SP;Lebeaux D;DeFrancesco AS;Valomon A;Soubigou G;Coppée JY;Ghigo JM;Beloin C
高水平的抗生素耐受性是细菌生物膜的标志。与充分表征的遗传抗生素耐药性相反，导致生物膜细菌显示的可逆和短暂抗生素耐受性的分子机制仍然知之甚少。生物膜的生理异质性影响了可能对抗生素更耐受的瞬时特化亚群的形成。在这项研究中，我们使用随机转座子诱变，以确定生物膜特异性耐受突变体通常表现出的亚群位于专门的生态位的异质性生物膜。使用大肠杆菌作为模式生物，我们证明，通过鉴定氨基酸营养缺陷型突变体，饥饿的生物膜表现出显着更大的耐受性，对氟喹诺酮氧氟沙星比他们的反式异构体。我们证明，生物膜相关的氧氟沙星耐受性完全取决于氨基酸和碳源饥饿时的功能性SOS反应，部分取决于亮氨酸饥饿时的严格反应。然而，生物膜特异性氧氟沙星增加耐受性不涉及任何SOS诱导的毒素-抗毒素系统先前与形成高度耐受持久性。我们进一步证明，氧氟沙星耐受性诱导作为生物膜年龄的函数，这是依赖于SOS反应。因此，我们的研究结果表明，在异质性和营养缺乏的生物膜微环境中诱导的SOS应激反应是导致生物膜特异性对氟喹诺酮氧氟沙星高耐受性的分子机制。生物膜表面附着的群落具有耐受高浓度抗生素的能力，留置医疗器械上形成的细菌生物膜难以根除，往往导致慢性或全身性感染的发生。多细胞生物膜的生理异质性与对多种抗生素高度耐受的亚群的发展有关。在这里，我们表明，饥饿特定的必需生长营养素，生物膜细菌成为高度耐受氟喹诺酮氧氟沙星。SOS反应在这一现象中起关键作用，而严格反应只起次要作用。两者合计，这些结果支持的假设，即细菌定位在营养有限的壁龛的生物膜结构可能暂时进入生理状态，使他们能够耐受杀菌浓度的抗生素。
High levels of antibiotic tolerance are a hallmark of bacterial biofilms. In contrast to well-characterized inherited antibiotic resistance, molecular mechanisms leading to reversible and transient antibiotic tolerance displayed by biofilm bacteria are still poorly understood. The physiological heterogeneity of biofilms influences the formation of transient specialized subpopulations that may be more tolerant to antibiotics. In this study, we used random transposon mutagenesis to identify biofilm-specific tolerant mutants normally exhibited by subpopulations located in specialized niches of heterogeneous biofilms. Using Escherichia coli as a model organism, we demonstrated, through identification of amino acid auxotroph mutants, that starved biofilms exhibited significantly greater tolerance towards fluoroquinolone ofloxacin than their planktonic counterparts. We demonstrated that the biofilm-associated tolerance to ofloxacin was fully dependent on a functional SOS response upon starvation to both amino acids and carbon source and partially dependent on the stringent response upon leucine starvation. However, the biofilm-specific ofloxacin increased tolerance did not involve any of the SOS-induced toxin–antitoxin systems previously associated with formation of highly tolerant persisters. We further demonstrated that ofloxacin tolerance was induced as a function of biofilm age, which was dependent on the SOS response. Our results therefore show that the SOS stress response induced in heterogeneous and nutrient-deprived biofilm microenvironments is a molecular mechanism leading to biofilm-specific high tolerance to the fluoroquinolone ofloxacin. Biofilm surface-attached communities have the capacity to tolerate high concentrations of antibiotics, and bacterial biofilms formed on indwelling medical devices are difficult to eradicate and often lead to the onset of chronic or systemic infections. The physiological heterogeneity of multicellular biofilms has been associated with development of subpopulations highly tolerant to multiple antibiotics. Here we demonstrate that, upon starvation for specific essential growth nutrients, biofilm bacteria become highly tolerant to fluoroquinolone ofloxacin. The SOS response plays a critical role in this phenomenon, while the stringent response plays only a minor role. Taken together, these results support the hypothesis that bacteria localized within nutrient-limited niches of the biofilm structure may temporarily enter a physiological state enabling them to tolerate bactericidal concentrations of antibiotics.
登录
查看更多内容
影响因子：
3.5
作者：
CHEREPANOV, PP;WACKERNAGEL, W
通讯作者：
WACKERNAGEL, W
影响因子：
64.8
作者：
Beaber, JW;Hochhut, B;Waldor, MK
通讯作者：
Waldor, MK
影响因子：
4.5
作者：
Baharoglu Z;Bikard D;Mazel D
通讯作者：
Mazel D
影响因子：
4.2
作者：
Agarwal, G;Kapil, A;Dwivedi, SN
通讯作者：
Dwivedi, SN
影响因子：
3.2
作者：
Da Re, S;Ghigo, JM
通讯作者：
Ghigo, JM