GB24 from bioaerosol attenuates -introduced inflammation through regulation of gut microbiota and acetic acid.

() is the most common respiratory pathogen causing community-acquired pneumonia. Probiotics represent a new intervention target for 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 GB24 that antagonizes at cellular and animal levels. The results revealed that GB24 strain inhibited the growth of 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, 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 GB24 for 1.5 h almost eliminated the cellular inflammation caused by infection. Additionally, male Sprague-Dawley rats infected with were randomly allocated into two groups: GB24 pre-infection and infection groups, with healthy rats as control. GB24 significantly alleviated inflammatory lung injury caused by 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 infection in cellular assays. Together, these findings highlight that GB24 strain is an important protective feature in the respiratory tract.