Significant increase in the secretion of extracellular vesicles and antibiotics resistance from methicillin-resistant Staphylococcus aureus induced by ampicillin stress

Abstract

Extracellular vesicles (EVs) containing specific cargo molecules from the cell of origin are naturally secreted from bacteria. EVs play significant roles in protecting the bacterium, which can contribute to their survival in the presence of antibiotics. Herein, we isolated EVs from methicillin-resistant Staphylococcus aureus (MRSA) in an environment with or without stressor by adding ampicillin at a lower concentration than the minimum inhibitory concentration (MIC). We investigated whether EVs from MRSA under stress condition or normal condition could defend susceptible bacteria in the presence of several β-lactam antibiotics, and directly degrade the antibiotics. A comparative proteomic approach was carried out in both types of EVs to investigate β-lactam resistant determinants. The secretion of EVs from MRSA under antibiotic stressed conditions was increased by 22.4-fold compared with that of EVs without stress. Proteins related to the degradation of β-lactam antibiotics were abundant in EVs released from the stressed condition. Taken together, the present data reveal that EVs from MRSA play a crucial role in the survival of β-lactam susceptible bacteria by acting as the first line of defense against β-lactam antibiotics, and antibiotic stress leads to release EVs with high defense activity.

Extracellular Vesicles and Their Role in Staphylococcus aureus Resistance and Virulence

“…Likewise, in another study, S. aureus had a significant increase in EVs release after exposure to the β-lactam antibiotics flucloxacillin and ceftaroline due to their ability to weaken the PGN wall [68]. Again, addition of the β-lactam ampicillin increased S. aureus EV production in a dose-dependent manner, which corresponded to a 22.4-fold increase at 64 μg/mL concentration [71]. The PGN present in the bacterial cell wall of most bacteria has a rigid structure formed of highly cross-linked polymers composed of polysaccharide chains and short peptides [81].…”

“…Moreover, EVs derived from LB cultures were two-fold larger than those derived from BHI cultures, even though the latter presented higher protein diversity, which may also explain their significantly higher cytotoxicity towards neutrophils following brief exposure compared to LB-derived EVs [69]. In another study, proteomics identified 156 and 137 proteins in EVs derived from cultures in the presence and absence of a sub-inhibitory concentration of ampicillin, respectively, while only 67 proteins were shared by both conditions [71]. Another example of changes in EVs content was observed in the chemical composition of S. aureus EVs following treatment with vancomycin at 1 mg/ml.…”

“…In a more recent report by Kim et al, the protective effect of EVs derived from the methicillin-resistant S. aureus (MRSA) strain ST692 grown in the presence of ampicillin was evaluated. Accordingly, ST692 EVs were shown to protect susceptible ATCC29213 strain against six different β-lactam antibiotics in a dose-dependent manner [71]. In another study, the addition of exogenous EVs purified from the culture supernatant of strain BWMR22 grown in the presence of a sub-inhibitory concentration of vancomycin was able to increase S. aureus adhesion and cell aggregation, contributing to biofilm formation [67].…”

Extracellular vesicle formation in Lactococcus lactis is stimulated by prophage‐encoded holin–lysin system

“…The penicillin‐binding proteins are involved in peptidoglycan synthesis and cell division (David et al ., 2018 ), but also offer binding sites to penicillin and β‐lactam antibiotics. This observation supports previous findings where EVs have been considered to contribute to bacterial survival by removing the antibiotics from the extracellular environment, acting as the decoy of antibiotic targeting or containing antibiotic‐degrading enzymes (Lee et al ., 2009 ; Chattopadhyay and Jaganandham, 2015 ; Kim et al ., 2018 ; Sabnis et al ., 2018 ; Bose et al ., 2020 ; Kim et al ., 2020b ).…”

Bacterial Membrane-Derived Vesicles Attenuate Vancomycin Activity against Methicillin-Resistant Staphylococcus aureus

“…MVs can stimulate biofilm formation, act as immunomodulators, increase bacterial resistance to host whole-blood killing, neutrophil killing, serum-complement killing, endogenous antimicrobial peptides and pharmaceutical antibiotics, and may in part be mediated by phenol-soluble modulins [10,11]. Previous studies suggest MVs confer certain SA protection against the lipopeptide membrane-active antibiotic daptomycin in vitro and ex vivo in whole blood, and that certain antimicrobial agents (e.g., gentamicin, cefotaxime, ampicillin and imipenem) can trigger bacterial MV release, potentially yielding antimicrobial resistance [12][13][14]. However, the role of methicillin-resistant Staphylococcus aureus-(MRSA) derived MVs and its implications in resistance to the first line therapeutic glycopeptide antibiotic vancomycin (VAN) has yet to be explored.…”