Extracellular vesicles and transformation of antimicrobial resistance genetic determinants in Streptococcus pneumoniae

We investigated the role of secreted extracellular vesicles (EVs) isolated from Streptococcus pneumoniae in disseminating antibiotic resistance determinants. Pneumococcal EVs were found to associate with extracellular DNA that confers antibiotic resistance and mediate transformation of planktonic and biofilm-associated S. pneumoniae. Whole genome sequence combined with SNP variant analyses demonstrated homologous recombination of donor DNA fragments in biofilm recombinant genomes, ranging from ~9 to ~26 kb in size.