Contamination of bacterial extracellular vesicles (bEVs) in human urinary extracellular vesicles (uEVs) samples and their effects on uEVs study

Abstract Bacterial overgrowth is common for improperly stored urine. However, its effects on human urinary extracellular vesicles (uEVs) study had not been previously examined nor documented. This investigated the presence of bacterial EVs (bEVs) contaminated in uEVs samples and their study. Nanoscale were isolated from normal urine immediately after collection (0‐h) or 25°C‐storage with/without preservative (10 mM NaN 3 ) up to 24‐h. Turbidity, count total proteins abnormally increased 8‐h 24‐h‐stored without . NanoLC‐ESI‐LTQ‐Orbitrap MS/MS identified 6–13 these samples. PCR also detected DNAs Besides, derived 24‐h induced macrophage activation (CD11b phagocytosis) secretion cytokines (IFN‐α, IL‐8, TGF‐β) macrophages renal cells (HEK‐293, HK‐2, MDCK). All by contamination partially/completely prevented Interestingly, cytokine bEVs purified Escherichia coli clearly shows evidence when inappropriately stored, whereas can prevent such bEVs.