Wen Xueyi, Tang Tian, Bao Tingrui, Xu Tao, An Bei, Zhang Ying, Han Jian
Department of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China.
Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, School of Life Science, Fudan University, Shanghai, China.
Microbiol Spectr. 2025 Sep 2;13(9):e0051125. doi: 10.1128/spectrum.00511-25. Epub 2025 Aug 12.
Glutamate metabolism plays a pivotal role in linking the tricarboxylic acid cycle, arginine biosynthesis, and purine metabolism, and these pathways have been shown to be involved in persister formation. However, the relationship among glutamate metabolism, bacterial antibiotic tolerance, and virulence remains unclear. In this study, which encodes the large subunit of glutamate synthase in was knocked out. The ∆ mutant in the stationary phase showed less tolerance to antibiotics and was killed completely after exposure to lethal doses of ampicillin and norfloxacin after 11 and 6 days, respectively, while the parent strain still had abundant viable bacteria. The complemented strain restored antibiotic tolerance. Interestingly, exogenous glutamate supplementation of ∆ restored the tolerance to antibiotics. Moreover, ∆ is more susceptible to heat, carbon starvation, and oxidative stress. Furthermore, the ability of ∆ to coagulate plasma, produce staphyloxanthin, and form biofilms was significantly weakened. In addition, ∆ attenuated virulence in BALB/c mice, and its 50% lethal dose (LD50) (1.14 × 10 CFU/mL, 95% CI: 7.29 × 10-2.75 × 10) was higher than that of the parent strain (2.39 × 10 CFU/mL, 95% CI: 9.99 × 10-4.42 × 10). The expression levels of major virulence genes, including and as well as staphyloxanthin synthesis-related genes, including and c were significantly downregulated in ∆. This study revealed that is involved in both antibiotic tolerance and virulence in and provides new insights into the mechanism of persister formation and virulence, with implications for the development of novel drugs.IMPORTANCE is a leading bacterial cause of death, and persister formation renders it tolerant to antibiotics and is associated with its persistent infections. Glutamate metabolism plays a critical role in linking the tricarboxylic acid cycle, arginine biosynthesis, and purine metabolism, and these pathways have been shown to be involved in persister formation. This work first discovered that , the large subunit of glutamate synthase gene in , is involved in tolerance to antibiotics and heat, carbon starvation, and oxidative stress. Furthermore, the mutant attenuated virulence in mice, owing to the inhibition of glutamate synthesis, which significantly weakened the ability of to coagulate plasma, produce staphyloxanthin, form biofilms, and express virulence factors. These findings confirm the important role of glutamate metabolism in the formation of persister and virulence in and provide new targets for developing novel anti-persister and anti-virulence drugs.
谷氨酸代谢在连接三羧酸循环、精氨酸生物合成和嘌呤代谢中起关键作用，并且这些途径已被证明与持留菌的形成有关。然而，谷氨酸代谢、细菌抗生素耐受性和毒力之间的关系仍不清楚。在本研究中，编码谷氨酸合酶大亚基的基因在被敲除。处于稳定期的∆突变体对抗生素的耐受性较低，分别在暴露于致死剂量的氨苄青霉素和诺氟沙星11天和6天后被完全杀死，而亲本菌株仍有大量活菌。互补菌株恢复了抗生素耐受性。有趣的是，向∆补充外源谷氨酸恢复了其对抗生素的耐受性。此外，∆对热胁迫、碳饥饿和氧化应激更敏感。此外，∆凝固血浆、产生金黄色葡萄球菌素和形成生物膜的能力显著减弱。此外，∆在BALB/c小鼠中的毒力减弱，其50%致死剂量（LD50）（1.14×10CFU/mL，95%CI：7.29×10 - 2.75×10）高于亲本菌株（2.39×10CFU/mL，95%CI：9.99×10 - 4.42×10）。在∆中，包括和在内的主要毒力基因以及包括和c在内的金黄色葡萄球菌素合成相关基因的表达水平显著下调。本研究揭示了在抗生素耐受性和毒力方面均有作用，并为持留菌形成和毒力机制提供了新见解，对新型药物的开发具有重要意义。重要性是导致死亡的主要细菌原因，持留菌的形成使其对抗生素产生耐受性，并与其持续性感染有关。谷氨酸代谢在连接三羧酸循环、精氨酸生物合成和嘌呤代谢中起关键作用，并且这些途径已被证明与持留菌的形成有关。这项工作首次发现，中谷氨酸合酶基因的大亚基参与了对抗生素以及热胁迫、碳饥饿和氧化应激的耐受性。此外，由于谷氨酸合成受到抑制，突变体在小鼠中的毒力减弱，这显著削弱了凝固血浆、产生金黄色葡萄球菌素、形成生物膜和表达毒力因子的能力。这些发现证实了谷氨酸代谢在持留菌形成和毒力方面的重要作用，并为开发新型抗持留菌和抗毒力药物提供了新靶点。
