Abstract 1362 Investigating the effects of antibiotics on the production of extracellular vesicles in E. coli

Extracellular vesicles (EVs) are nano-sized, membrane-bound spheres constitutively released by most cell types, including Gram-negative bacteria. EVs contain many similar molecules to their cell "parent," some of which are toxic and have been shown to contribute to the inflammatory response in host tissue. Studies have shown that EV production is enhanced by the presence of environmental stressors, such as antibiotic exposure. We hypothesized that some antibiotics, depending on their mechanism of action, might enhance EV release from Gram-negative Escherichia coli (E. coli) more than other antibiotic types. After incubation of E. coli with nine antibiotics at their clinically relevant concentrations, we isolated the EVs using ultracentrifugation and characterized them using immunoblotting, nanoparticle tracking analysis, and transmission electron microscopy. The results of our study suggest that some antibiotics, specifically beta-lactams, do indeed enhance EV release more than others, such as aminoglycoside antibiotics. Since EVs, as well as the molecules inside EVs, can trigger inflammation, these results may have important implications for doctors who prescribe antibiotics to sepsis patients. This work was supported by NIAID of the National Institutes of Health under award number R21AI163782 to LVM and TG.