PDF(Pubmed)
Abstract：
Persister cells are transiently tolerant to antibiotics and are associated with recalcitrant chronic infections due to recolonization of host cells after antibiotic removal. Brucella spp. are facultative pathogens that establish intracellular infection cycles in host cells which results in chronic persistent infections. Brucella abortus forms multi-drug persister cells which are promoted by the (p)ppGpp synthetase Rsh during rifampicin exposure. Here, we confirmed that Rsh promoted persister cells formation in B. abortus stationary phase treated with rifampicin and enrofloxacin. Deletion of the gene for Rsh decreased persister cells level in the presence of these drugs in different growth phases. However, persister cells formation by deletion strain varied in different growth phases in the presence of other antibiotics. Rsh also was involved in persister cells formation during rifampicin treatment under certain stress conditions, including acidic conditions, exposure to PBS, and heat stress. Moreover, Rsh impacted persister cell levels during rifampicin or enrofloxacin treatment in RAW264.7 macrophages. Certain typeIItoxin-antitoxin modules were upregulated under various stress conditions in B. abortus. We established that Rsh positively regulated the type II toxin-antitoxin mbcTA. Moreover, rifampicin-tolerant persister cells formation was elevated and ATP levels were decreased when mbcTA promoter was overexpressed in Rsh deletion background in stationary phase. Our results establish that (p)ppGpp synthetase Rsh plays a key role in B. abortus persistence and may serve as a potent novel target in combination with rifampicin in the development of new therapeutic approaches and prevention strategies to treat chronic infections of Brucella.
摘要：
耐受细胞对抗生素具有短暂的耐受性，并且由于去除抗生素后宿主细胞的重新定殖而与顽固性慢性感染有关。布鲁氏菌属。是兼性病原体，在宿主细胞中建立细胞内感染周期，导致慢性持续感染。流产布鲁氏菌形成多药持久细胞，在利福平暴露期间，（p）ppGpp合成酶Rsh会促进这种细胞。这里,我们证实，在利福平和恩诺沙星处理的B.abortus静止期，Rsh促进了持久细胞的形成。在存在这些药物的情况下，在不同的生长期中，Rsh基因的缺失会降低持续细胞的水平。然而,在存在其他抗生素的情况下，缺失菌株形成的持久细胞在不同的生长阶段有所不同。在某些胁迫条件下，利福平治疗期间，Rsh还参与了持久细胞的形成，包括酸性条件，暴露于PBS，和热应力。此外，在RAW264.7巨噬细胞中，利福平或恩诺沙星治疗期间，Rsh会影响持续细胞水平。在流产芽孢杆菌的各种胁迫条件下，某些II型毒素-抗毒素模块被上调。我们确定Rsh正调节II型毒素-抗毒素mbcTA。此外，当mbcTA启动子在静止期的Rsh缺失背景中过表达时，耐利福平的持久细胞形成升高，ATP水平降低。我们的结果确定，（p）ppGpp合成酶Rsh在流产芽孢杆菌的持久性中起着关键作用，并且可能与利福平联合用作开发新的治疗方法和预防策略以治疗布鲁氏菌慢性感染的有效新靶标。
