Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil.
Laboratório de Farmacologia Molecular e Compostos Bioativos, Universidade São Francisco, Bragança Paulista, Brazil.
PLoS One. 2024 Aug 7;19(8):e0307573. doi: 10.1371/journal.pone.0307573. eCollection 2024.
Streptococcus pneumoniae is a bacterium of great global importance, responsible for more than one million deaths per year. This bacterium is commonly acquired in the first years of life and colonizes the upper respiratory tract asymptomatically by forming biofilms that persist for extended times in the nasopharynx. However, under conditions that alter the bacterial environment, such as viral infections, pneumococci can escape from the biofilm and invade other niches, causing local and systemic disease of varying severity. The polyamine transporter PotABCD is required for optimal survival of the organism in the host. Immunization of mice with recombinant PotD can reduce subsequent bacterial colonization. PotD has also been suggested to be involved in pneumococcal biofilm development. Therefore, in this study we aimed to elucidate the role of PotABCD and polyamines in pneumococcal biofilm formation. First, the formation of biofilms was evaluated in the presence of exogenous polyamines-the substrate transported by PotABCD-added to culture medium. Next, a potABCD-negative strain was used to determine biofilm formation in different model systems using diverse levels of complexity from abiotic surface to cell substrate to in vivo animal models and was compared with its wild-type strain. The results showed that adding more polyamines to the medium stimulated biofilm formation, suggesting a direct correlation between polyamines and biofilm formation. Also, deletion of potABCD operon impaired biofilm formation in all models tested. Interestingly, more differences between wild-type and mutant strains were observed in the more complex model, which emphasizes the significance of employing more physiological models in studying biofilm formation.
肺炎链球菌是一种具有重要全球意义的细菌，每年导致超过 100 万人死亡。这种细菌通常在生命的头几年获得，并通过形成生物膜无症状地定植在上呼吸道，这些生物膜在鼻咽部持续存在很长时间。然而，在改变细菌环境的条件下，如病毒感染，肺炎链球菌可以从生物膜中逃脱并侵入其他生态位，导致局部和全身疾病的严重程度不同。聚胺转运体 PotABCD 是该生物在宿主中最佳生存所必需的。用重组 PotD 免疫小鼠可以减少随后的细菌定植。也有人认为 PotD 参与了肺炎链球菌生物膜的形成。因此，在这项研究中，我们旨在阐明 PotABCD 和聚胺在肺炎链球菌生物膜形成中的作用。首先，在培养基中添加外源性聚胺（PotABCD 转运的底物）来评估生物膜的形成。接下来，使用缺乏 potABCD 的菌株，在不同的模型系统中确定生物膜的形成，这些模型系统的复杂性从非生物表面到细胞基质到体内动物模型各不相同，并与野生型菌株进行比较。结果表明，向培养基中添加更多的聚胺刺激了生物膜的形成，这表明聚胺与生物膜形成之间存在直接相关性。此外，potABCD 操纵子的缺失破坏了所有测试模型中的生物膜形成。有趣的是，在更复杂的模型中，观察到野生型和突变型菌株之间更多的差异，这强调了在研究生物膜形成时采用更生理模型的重要性。
