Outer membrane vesicles (OMVs) are produced by all Gram‑negative bacteria, and have a major role in contributing to gene transfer, cell‑to‑cell communication and host‑pathogen interactions. Although numerous studies have examined the composition of OMVs, the impact of bacterial growth stage on regulating the size, composition and functions of OMVs has not been determined. This study aims to compare the quantity, size and composition of OMVs produced during various stages of bacterial growth.
In this study, we examined the production and composition of OMVs produced by Helicobacter pylori at 16, 48 and 72 hours of growth. We initially analysed the number, size and content of OMVs produced by H. pylori at 16 hours of bacterial growth. We found that H. pylori produce approximately 1000 OMVs per bacterium at 16 hours, ranging between 20-100 nm in size, and that these OMVs are enriched in DNA and RNA. Furthermore, proteomic analysis revealed that OMVs produced at 16 hours of growth were enriched in membrane proteins compared to cytoplasmic proteins. Preliminary characterisation of H. pylori OMVs produced at 48 and 72 hours of bacterial growth suggests that they contain less RNA and DNA compared to 16-hour OMVs. We are currently further investigating the composition and immunogenicity of OMVs produced at 16, 48 and 72 hours of H. pylori growth to elucidate the effect of bacterial growth stage on OMV size, function and composition.
Collectively, the findings generated as part of this study will provide a detailed analysis of how bacterial growth stage affects the size, composition and immunogenicity of OMVs produced. Ultimately, these findings will contribute to the development of a standardised method of OMV production that will allow for more accurate comparisons to be made between research groups.