AUTHOR=Deng Songyun , Wang Yutian , Liu Shiluan , Chen Te , Hu Yanjun , Zhang Guangyan , Zhang Xianrong , Yu Bin 

TITLE=Extracellular Vesicles: A Potential Biomarker for Quick Identification of Infectious Osteomyelitis

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2020.00323

DOI=10.3389/fcimb.2020.00323

ISSN=2235-2988

ABSTRACT=<p>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 <italic>Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa</italic>, and <italic>Escherichia coli</italic> 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 <italic>S. aureus</italic> and <italic>E. coli</italic> formed large aggregates in response to the stimulation of serum EVs from <italic>S. aureus</italic>-infected and <italic>E. coli</italic>-infected rats, respectively. Treatment of EVs-<italic>S. epidermidis</italic> led to large aggregates of <italic>S. epidermidis</italic> and <italic>E. coli</italic>, whereas stimulation of EVs-<italic>P. aeruginosa</italic> to large aggregates of <italic>S. aureus</italic> and <italic>P. aeruginosa</italic>. To evaluate the changes in EVs in osteomyelitis patients, 28 patients including 5 <italic>S. aureus</italic> ones and 21 controls were enrolled. Results showed that the size and number of serum EVs from <italic>S. aureus</italic> 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 <italic>S. aureus</italic> osteomyelitis patients induced significantly stronger aggregation of <italic>S. aureus</italic> and a cross-reaction with <italic>P. aeruginosa</italic>. 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.</p>