Numerous pathogenic bacteria are naturally competent and are therefore able to take up DNA and integrate it within their genome to promote genetic diversity and disseminate antimicrobial resistance (AMR). Helicobacter pylori is a human gastric pathogen that is highly diverse and relies on natural transformation to acquire antimicrobial resistance genes, adapt to the human host and promote lifelong colonisation. However, we have limited understanding of factors that influence the efficiency of H. pylori to naturally acquire DNA encoding AMR and promote genetic diversity. Bacterial membrane vesicles (BMVs) have recently emerged as a novel mechanism used to package DNA, mediate horizontal gene transfer (HGT) and disseminate AMR within and between bacterial species. However, the contribution of BMV to the development of AMR within H. pylori remains unknown and was examined as part of this study.
BMVs were isolated from E. coli or H. pylori strains harbouring AMR genes encoded on a plasmid, or within the genome, respectively. The size and morphology of BMVs isolated from each strain were examined by transmission electron microscopy and nanoparticle tracking analysis, and DNA associated with BMVs was quantified. Natural transformation of a range of H. pylori clinical isolates using BMVs isolated from either E. coli or H. pylori strains encoding AMR resulted in the generation of antimicrobial-resistant H. pylori transformants. Furthermore, BMVs showed greater efficiency in transforming H. pylori compared to transformation of H. pylori with DNA alone. Furthermore, the mechanisms whereby BMVs deliver AMR genes into recipient bacterial cells are currently being investigated using a range of molecular and imaging techniques.
Collectively, these findings reveal a novel mechanism whereby H. pylori can acquire AMR mediated by BMVs. Further understanding of the mechanisms whereby BMVs orchestrate horizontal gene transfer within and between bacterial species will advance knowledge regarding AMR transmission within and between microbial communities.