Microbiology Department of the First Affiliated Hospital of Hebei North University, Zhangjiakou, Hebei, People's Republic of China.
Key Lab of Environmental Pollution and Microecology of Liaoning Province, Shenyang Medical College, No. 146, Huang he North Street, Shenyang, Liao Ning, People's Republic of China.
BMC Microbiol. 2023 Nov 16;23(1):339. doi: 10.1186/s12866-023-03066-7.
As probiotics protect host cells, they are used to treat bacterial infections. It has been indicated that probiotics may prevent or reduce the attachment of pathogens to host cells. In this study, Streptococcus strain D19 was isolated from the oropharynx of a healthy child, and its adhesion performance and Staphylococcus aureus adhesion inhibition effect were analysed using human bronchial epithelial (16-HBE) cells, as an in vitro cell model. We evaluated the probiotic properties of the D19 strain based on its acid-base, bile salt, and lysozyme tolerance; antibacterial activity; cytotoxicity; antibiotic sensitivity; in vitro adhesion to 16-HBE cells; and competitive, exclusion, and displacement effects against S. aureus.
Streptococcus strain D19 showed tolerance to a PH range of 2-5 and 0.5-1% bile. However, it was more tolerant to 0.5% bile than to 1% bile. The strain also demonstrated an ability to adapt to maladaptive oropharyngeal conditions (i.e., tolerating 200 µg/mL lysozyme). It was resistant to 0.8 mM HO. The results also demonstrated that D19 exhibited inhibitory activities against various common pathogenic bacteria. Furthermore, D19 was not toxic to 16-HBE cells at different multiplicities of infection and was sensitive to most antibiotics tested. The adhesion rate of D19 cells to 16-HBE cells was 47% ± 1.2%, which was significantly higher than that of S. aureus to 16-HBE cells. The competition, exclusion, and displacement assay results showed that D19 has good inhibitory effect against S. aureus adhesion.
The present study revealed that Streptococcus strain D19 has the potential to be developed as a respiratory microbiota preparations.
由于益生菌可以保护宿主细胞，因此被用于治疗细菌感染。有研究表明，益生菌可能预防或减少病原体与宿主细胞的附着。本研究从健康儿童的口咽部分离出链球菌 D19 菌株，并利用体外细胞模型人支气管上皮细胞（16-HBE）分析其黏附性能和对金黄色葡萄球菌的黏附抑制作用。我们基于 D19 菌株的酸碱、胆盐和溶菌酶耐受性、抗菌活性、细胞毒性、抗生素敏感性、体外与 16-HBE 细胞的黏附、对金黄色葡萄球菌的竞争、排除和置换作用来评估其益生菌特性。
链球菌 D19 株在 PH 值为 2-5 和 0.5-1%的胆汁中表现出耐受性。然而，其对 0.5%胆汁的耐受性高于 1%胆汁。该菌株还能够适应适应性较差的口咽部环境（即耐受 200µg/mL 溶菌酶）。其对 0.8 mM HO 也有抗性。结果还表明，D19 对各种常见的致病性细菌均表现出抑制活性。此外，D19 在不同感染复数下对 16-HBE 细胞均无毒性，且对大多数测试的抗生素敏感。D19 细胞对 16-HBE 细胞的黏附率为 47%±1.2%，明显高于金黄色葡萄球菌对 16-HBE 细胞的黏附率。竞争、排除和置换实验结果表明，D19 对金黄色葡萄球菌的黏附具有良好的抑制作用。
本研究表明，链球菌 D19 株具有作为呼吸道微生物群制剂开发的潜力。
