Effective management of infectious osteomyelitis relies on timely microorganism identification and appropriate antibiotic therapy. Extracellular vesicles (EVs) carry protein and genetic information accumulated rapidly in the circulation upon infection. Rat osteomyelitis models infected by Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli were established for the present study. Serum EVs were isolated 3 days after infection. The size and number of serum EVs from infected rats were significantly higher than those from controls. In addition, bacterial aggregation assay showed that the S. aureus and E. coli formed large aggregates in response to the stimulation of serum EVs from S. aureus-infected and E. coli-infected rats, respectively. Treatment of EVs-S. epidermidis led to large aggregates of S. epidermidis and E. coli, whereas stimulation of EVs-P. aeruginosa to large aggregates of S. aureus and P. aeruginosa. To evaluate the changes in EVs in osteomyelitis patients, 28 patients including 5 S. aureus ones and 21 controls were enrolled. Results showed that the size and number of serum EVs from S. aureus osteomyelitis patients were higher than those from controls. Further analysis using receiver operating characteristic curves revealed that only the particle size might be a potential diagnostic marker for osteomyelitis. Strikingly, serum EVs from S. aureus osteomyelitis patients induced significantly stronger aggregation of S. aureus and a cross-reaction with P. aeruginosa. Together, these findings indicate that the size and number of serum EVs may help in the diagnosis of potential infection and that EVs-bacteria aggregation assay may be a quick test to identify infectious microorganisms for osteomyelitis patients.

传染性骨髓炎的有效管理取决于及时的微生物鉴定和适当的抗生素治疗。细胞外囊泡（EV）携带受感染后迅速在循环中积累的蛋白质和遗传信息。大鼠骨髓炎模型感染金黄色葡萄球菌，表皮葡萄球菌，铜绿假单胞菌和 大肠杆菌为本研究建立。感染后3天分离出血清EV。来自被感染大鼠的血清EV的大小和数量显着高于对照组。此外，细菌聚集试验表明金黄色葡萄球菌 和 大肠杆菌 形成大的聚集体以响应来自 金黄色葡萄球菌感染和 大肠杆菌感染的大鼠。电动车的处理表皮葡萄球菌 导致大量的 表皮葡萄球菌 和 大肠杆菌，而刺激电动汽车铜绿假单胞菌 到大量的 金黄色葡萄球菌 和 铜绿假单胞菌。为了评估骨髓炎患者电动车的变化，包括28例患者中的5例金黄色葡萄球菌一个和21个对照组参加了研究。结果表明，血清电动汽车的大小和数量金黄色葡萄球菌骨髓炎患者高于对照组。使用接收器工作特征曲线的进一步分析表明，只有粒径可能是骨髓炎的潜在诊断标志。引人注目的是，来自金黄色葡萄球菌 骨髓炎患者诱导明显更强的聚集 金黄色葡萄球菌 并与 铜绿假单胞菌。总之，这些发现表明血清EV的大小和数量可能有助于诊断潜在的感染，并且EV-细菌聚集测定可能是鉴定骨髓炎患者感染性微生物的快速测试。