链球菌性肺炎是最常见的导致社区获得性肺炎的呼吸道病原菌。益生菌代表了链球菌感染的新干预靶点。因此，迫切需要发现和开发新的潜在益生菌菌株。本研究旨在调查一种名为Roseicella aerolata GB24T的新细菌在细胞和动物水平上与链球菌对抗的有益效果和机制。结果显示，GB24T菌株在绵羊血琼脂培养基上抑制了链球菌的生长，形成直径为20毫米的抑制圈。在经过Ad 12-SV40 2B (BEAS-2B)细胞转化的培养支气管上皮细胞中，链球菌感染导致白细胞介素-1β、白细胞介素-6和肿瘤坏死因子-α的表达水平分别增加到4.289±0.709、5.587±2.670和5.212±0.772倍，相比健康对照组。此外，GB24T预感染1.5小时几乎消除了链球菌感染引起的细胞炎症。此外，感染链球菌的雄性斯普拉格-道利大鼠被随机分为两组：GB24T预感染组和链球菌感染组，健康大鼠作为对照组。GB24T显著减轻了链球菌感染引起的炎性肺损伤，这与肠道菌群丰度明显变化和短链脂肪酸特别是乙酸分泌趋势增强有关。乙酸经细胞实验验证对缓解链球菌感染引起的炎症有效。综上所述，这些发现突出了GB24T菌株在呼吸道中的重要保护特性。版权所有©2023年秦，于，刘，吴，江和张。

Streptococcus pneumoniae (Spn) is the most common respiratory pathogen causing community-acquired pneumonia. Probiotics represent a new intervention target for Spn infection. Hence, the discovery and development of new potential probiotic strains are urgently needed. This study was designed to investigate the beneficial effect and mechanism of a new bacterium named Roseicella aerolata GB24T that antagonizes Spn at cellular and animal levels. The results revealed that GB24T strain inhibited the growth of Spn on sheep blood agar plates, forming inhibition circles with a diameter of 20 mm. In cultured bronchial epithelium transformed with Ad 12-SV40 2B (BEAS-2B) cells, Spn infection induced an elevation in the expression levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α to 4.289 ± 0.709, 5.587 ± 2.670, and 5.212 ± 0.772 folds compared to healthy controls, respectively. Moreover, pre-infection with GB24T for 1.5 h almost eliminated the cellular inflammation caused by Spn infection. Additionally, male Sprague-Dawley rats infected with Spn were randomly allocated into two groups: GB24T pre-infection and Spn infection groups, with healthy rats as control. GB24T significantly alleviated inflammatory lung injury caused by Spn infection, which was associated with obvious changes in the abundance of gut microbiota and a trend toward enhanced secretion of short-chain fatty acids, especially acetic acid. Acetic acid was validated to be effective in alleviating inflammation due to Spn infection in cellular assays. Together, these findings highlight that GB24T strain is an important protective feature in the respiratory tract.Copyright © 2023 Qin, Yu, Liu, Wu, Jiang and Zhang.