Outer membrane vesicles from beta-lactam-resistant Escherichia coli enable the survival of beta-lactamsusceptible E. coli in the presence of beta-lactam antibiotics

Abstract

Outer membrane vesicles (OMVs) containing various bacterial compounds are released from mainly gram-negative bacteria. Secreted OMVs play important roles in the ability of a bacterium to defend itself, and thus contribute to the survival of bacteria in a community. In this study, we collected OMVs from beta-lactam antibiotic-resistant Escherichia coli established by conjugation assay and the parental beta-lactam antibiotic-susceptible strain, and performed comparative proteomic analysis to examine whether these OMVs carried beta-lactam-resistant compounds. We also investigated whether both types of OMVs could protect susceptible cells from beta-lactam-induced death and/or directly degrade beta-lactam antibiotics. Several proteins that can be involved in degrading beta-lactam antibiotics were more abundant in OMVs from beta-lactam-resistant E. coli, and thus OMVs from beta-lactam resistant E. coli could directly and dose-dependently degrade beta-lactam antibiotics and fully rescue beta-lactam-susceptible E. coli and other bacterial species from beta-lactam antibiotic-induced growth inhibition. Taken together, present study demonstrate that OMVs from beta-lactam-resistant E. coli play important roles in survival of antibiotic susceptible bacteria against beta-lactam antibiotics. This finding may pave the way for new efforts to combat the current global spread of antibiotic resistances, which is considered to be a significant public health threat.