Invasion assay was carr ied out at MOI 30 (30 bacteria: 1 osteoblast) for 2h incubation.The excellular b acteria were killed by gentamicin.

• 侵入实验的细菌与细胞比例为30：1，侵入发生时间为2小时，细胞外细菌为庆大霉素杀灭。