Stationary-Phase Persisters to Ofloxacin Sustain DNA Damage and Require Repair Systems Only during Recovery.
Stationary-Phase Persisters to Ofloxacin Sustain DNA Damage and Require Repair Systems Only during Recovery.
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DOI：
10.1128/mbio.00731-15
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发表时间：
2015-09-01
期刊：
影响因子：
6.4
通讯作者：
Brynildsen MP
中科院分区：
文献类型：
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作者：
Völzing KG;Brynildsen MP
慢性感染是一个严重的卫生保健问题，细菌持续存在与感染复发有关。寻找抗持续性记忆疗法的进展一直很缓慢，部分原因是关于这些罕见表型变异的生理学知识缺口。有证据表明，生长状态对生存很重要，因为非生长的文化可以比生长的人群多100倍。然而，其他因素显然是重要的，因为即使在非增长的人群中，持久性仍然很罕见。除了生长抑制之外，还有什么特征可以让坚持者在抗生素压力下生存下来，而他们的大多数亲属却屈服于抗生素压力，这仍然是一个悬而未决的问题。为了研究这一点，我们使用固定相作为模型非生长环境，研究大肠杆菌持久性氧氟沙星。考虑到流行的持久性模型将生存归因于短暂的休眠和抗生素靶标的不活跃，我们预计持久性物种将比它们垂死的亲属遭受更少的伤害。然而，使用遗传突变体，流式细胞术，荧光激活细胞分选和持久性试验，我们发现，nongrowing氧氟沙星persisters的经验，是从nonpersisters难以区分的过敏性损伤。与此相一致，我们发现这些持续存在者需要DNA修复才能生存，并且修复机制在治疗后恢复期（氧氟沙星去除后）之前是不必要的。这些研究结果表明，氧氟沙星的持久性不仅仅是由于抗生素靶点腐败的减少，表明抗生素应激后发生的事情对持久性表型至关重要，并支持抑制DNA损伤修复系统可能是消除氟喹诺酮持久性的有效策略。在没有耐药突变体的情况下，感染复发仍然可能发生，因为持久性，罕见的细菌细胞在抗生素治疗后存活下来，重新填充感染部位。持续生存是由于一个短暂的休眠状态，其中细胞的生长和代谢显着减少，许多重要的过程被认为是不活跃的。因此，休眠被认为是保护持久性植物免受干旱诱导的损害和死亡。在这项工作中，我们表明，在非生长人口中，氧氟沙星的坚持者经历了相同水平的过敏性损伤的细胞，屈服于治疗，他们的生存严重依赖于治疗结束后修复这种损伤。这些发现表明，氧氟沙星的持久性不仅仅是由于减少抗生素靶标腐败而产生的，并强调了抗生素应激后的过程对生存很重要。我们假设，有效的抗持续性疼痛治疗可能会发展的基础上，这方面的知识。
Chronic infections are a serious health care problem, and bacterial persisters have been implicated in infection reoccurrence. Progress toward finding antipersister therapies has been slow, in part because of knowledge gaps regarding the physiology of these rare phenotypic variants. Evidence shows that growth status is important for survival, as nongrowing cultures can have 100-fold more persisters than growing populations. However, additional factors are clearly important, as persisters remain rare even in nongrowing populations. What features, beyond growth inhibition, allow persisters to survive antibiotic stress while the majority of their kin succumb to it remains an open question. To investigate this, we used stationary phase as a model nongrowing environment to study Escherichia coli persistence to ofloxacin. Given that the prevailing model of persistence attributes survival to transient dormancy and antibiotic target inactivity, we anticipated that persisters would suffer less damage than their dying kin. However, using genetic mutants, flow cytometry, fluorescence-activated cell sorting, and persistence assays, we discovered that nongrowing ofloxacin persisters experience antibiotic-induced damage that is indistinguishable from that of nonpersisters. Consistent with this, we found that these persisters required DNA repair for survival and that repair machinery was unnecessary until the posttreatment recovery period (after ofloxacin removal). These findings suggest that persistence to ofloxacin is not engendered solely by reduced antibiotic target corruption, demonstrate that what happens following antibiotic stress can be critical to the persistence phenotype, and support the notion that inhibition of DNA damage repair systems could be an effective strategy to eliminate fluoroquinolone persisters. In the absence of resistant mutants, infection reoccurrences can still occur because of persisters, rare bacterial cells that survive antibiotic treatments to repopulate infection sites. Persister survival is attributed to a transient state of dormancy in which a cell’s growth and metabolism are significantly reduced and many essential processes are thought to be inactive. Thus, dormancy is believed to protect persisters from antibiotic-induced damage and death. In this work, we show that in nongrowing populations, persisters to ofloxacin experience the same level of antibiotic-induced damage as cells that succumb to the treatment and that their survival critically depends on repair of this damage after the conclusion of treatment. These findings reveal that persistence to ofloxacin is not engendered solely by reduced antibiotic target corruption and highlight that processes following antibiotic stress are important to survival. We hypothesize that effective antipersister therapies may be developed on the basis of this knowledge.