Hemolytic Membrane Vesicles of Group B Streptococcus Promote Infection
Hemolytic Membrane Vesicles of Group B Streptococcus Promote Infection
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DOI：
10.1093/infdis/jiaa548
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发表时间：
2021-04-15
影响因子：
6.4
通讯作者：
Rajagopal, Lakshmi
中科院分区：
文献类型：
--
作者：
Armistead, Blair;Quach, Phoenicia;Rajagopal, Lakshmi
背景。B群链球菌（GBS）是一种溶血性革兰氏阳性细菌，与胎儿损伤、早产、自然流产和新生儿感染有关。促进GBS毒力的一个关键因素是-溶血素/细胞溶血素，一种与细菌表面相关的色素鸟氨酸鼠李糖脂（也称为granadaene）。先前的一项研究表明，GBS产生称为膜囊泡（MVs）的小结构，其中含有毒力相关蛋白。在这项研究中，我们发现GBS MVs是色素化的和溶血的，这表明granadaene在MVs中具有功能活性。此外，与来自等高溶血性GBS的mv相比，来自高溶血性GBS的mv诱导了更多的中性粒细胞、T细胞和B细胞死亡，这表明mv是granadaene介导的毒力的潜在机制。最后，溶血性mv降低了GBS的氧化杀伤，并加重了GBS感染新生小鼠的发病率和死亡率。这些研究结合在一起，揭示了GBS利用关键毒力因子促进细菌传播和发病的新机制。
Background. Group B streptococci (GBS) are beta-hemolytic, Gram-positive bacteria associated with fetal injury, preterm birth, spontaneous abortion, and neonatal infections. A key factor promoting GBS virulence is the beta-hemolysin/cytolysin, a pigmented ornithine rhamnolipid (also known as granadaene) associated with the bacterial surface.Methods. A previous study indicated that GBS produce small structures known as membrane vesicles (MVs), which contain virulence-associated proteins. In this study, we show that GBS MVs are pigmented and hemolytic, indicating that granadaene is functionally active in MVs.Results. In addition, MVs from hyperhemolytic GBS induced greater cell death of neutrophils, T cells, and B cells compared with MVs from isogonic nonhemolytic GBS, implicating MVs as a potential mechanism for granadaene-mediated virulence. Finally, hemolytic MVs reduced oxidative killing of GBS and aggravated morbidity and mortality of neonatal mice infected with GBS.Conclusions. These studies, taken together, reveal a novel mechanism by which GBS deploy a crucial virulence factor to promote bacterial dissemination and pathogenesis.