Group B Streptococcus (GBS) is an opportunistic pathogen found in the vaginal tract and is a leading cause of preterm birth and neonatal illness. Aside from GBS, the vaginal tract is predominantly colonized by commensal Lactobacillus species that are thought to protect the vaginal tract from pathogens, including GBS. Studies that examined if, and how Lactobacilli modulate GBS pathogenicity remain limited. This study sought to investigate the potential protective role of Lactobacillus rhamnosus against GBS, using an in vitro model system. Immunofluorescence microscopy and Scanning Electron Microscopy (SEM) captured images of infected HeLa cells and were analyzed using the image analysis program ImageJ. Results indicate that GBS causes HeLa cell detachment unless L. rhamnosus is present. SEM images show that GBS reduces length and number of microvilli on HeLa cell surface, as well as size of secreted vesicles. L. rhamnosus partially inhibits GBS-dependent microvilli and vesicle disruption. GBS also disrupts HeLa cell F-actin fibers unless L. rhamnosus is present. These results reveal effects of GBS infection on the host cell cytoskeleton and implies a protective role of L. rhamnosus against GBS colonization.

中文翻译：

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鼠李糖乳杆菌降低 B 组链球菌对 HeLa 细胞的细胞毒作用

B 组链球菌 (GBS) 是一种在阴道中发现的机会性病原体，是导致早产和新生儿疾病的主要原因。除了 GBS 之外，阴道主要被共生乳酸菌定植，这些乳酸菌被认为可以保护阴道免受包括 GBS 在内的病原体的侵害。检查乳酸杆菌是否以及如何调节 GBS 致病性的研究仍然有限。本研究试图通过体外实验研究鼠李糖乳杆菌对 GBS的潜在保护作用。模型系统。免疫荧光显微镜和扫描电子显微镜 (SEM) 捕获受感染 HeLa 细胞的图像，并使用图像分析程序 ImageJ 进行分析。结果表明，除非鼠李糖乳杆菌存在，否则 GBS 会导致 HeLa 细胞脱离。SEM 图像显示 GBS 减少了 HeLa 细胞表面微绒毛的长度和数量，以及分泌囊泡的大小。L. rhamnosus部分抑制 GBS 依赖性微绒毛和囊泡破坏。GBS 还会破坏 HeLa 细胞 F-肌动蛋白纤维，除非存在鼠李糖乳杆菌。这些结果揭示了 GBS 感染对宿主细胞骨架的影响，并暗示了鼠李糖乳杆菌对 GBS 定植的保护作用。