The role of Treponema denticola motility in synergistic biofilm formation with Porphyromonas gingivalis

In the human oral cavity Porphyromonas gingivalis and Treponema denticola dominated biofilm communities are associated with the progression and severity of chronic periodontitis and these two species display synergistic virulence in animal models. These two phylogenetically distant bacteria have evolved in close contact over millennia. T. denticola is a motile spirochaete that is adapted to moving through viscous environments whilst P. gingivalis is nonmotile and highly proteolytic. Metabolically they co-operate and partition their environment to avoid competition. In this study we show that the motility of T. denticola is essential for synergistic polymicrobial biofilm development by these species which helps to explain their synergistic virulence in animal models and their intimate association during disease.

在人类口腔中，以牙龈卟啉单胞菌（Porphyromonas gingivalis）和齿垢密螺旋体（Treponema denticola）为优势菌群的生物膜（biofilm）群落，与慢性牙周炎的病情进展及严重程度密切相关；这两种菌种在动物模型中展现出协同毒力。这两类系统发育距离较远的细菌，历经数千年的紧密接触协同演化。齿垢密螺旋体（Treponema denticola）是一种运动型螺旋体，适配于在粘性环境中移动；而牙龈卟啉单胞菌（Porphyromonas gingivalis）不具备运动能力，且具有高度的蛋白水解活性。二者在代谢层面相互协作，通过划分各自的生存微环境以避免彼此竞争。本研究证实，齿垢密螺旋体的运动能力是这两种菌形成协同多菌种生物膜（polymicrobial biofilm）的必要条件，这一发现有助于解释它们在动物模型中的协同毒力，以及在疾病进程中的密切关联。