Ampicillin triggers the release of Pal in toxic vesicles from Escherichia coli

Area of Science:

• Microbiology
• Immunology
• Pharmacology

Background:

• Outer membrane proteins of Escherichia coli, such as lipopolysaccharides (LPS) and peptidoglycan-associated lipoprotein (Pal), are implicated in sepsis-related inflammation.
• The release of these components can influence the host's inflammatory response.

Purpose of the Study:

• To investigate the effect of different antibiotics on the release of outer membrane proteins, specifically Pal, from E. coli.
• To determine if antibiotic-induced release of Pal and LPS in outer membrane vesicles (OMVs) could exacerbate sepsis-related inflammation.

Main Methods:

• E. coli were treated with ampicillin, gentamicin, or levofloxacin.
• Outer membrane vesicles (OMVs) containing Pal and LPS were purified using ultracentrifugation.
• OMVs were characterized by transmission electron microscopy and nanoparticle tracking analysis.
• Western blotting was used to detect Pal and other E. coli proteins.

Main Results:

• Ampicillin significantly enhanced the release of Pal from E. coli compared to gentamicin and levofloxacin.
• The majority of released Pal was found within OMVs, which also contained LPS and other proteins.
• These findings suggest a mechanism by which certain antibiotics might increase inflammatory triggers.

Conclusions:

• Ampicillin treatment promotes the release of Pal and LPS within OMVs from E. coli.
• This enhanced release may contribute to an over-exuberant inflammatory response in sepsis patients treated with certain β-lactam antibiotics.
• Further research is needed to fully understand the clinical implications of these findings in sepsis treatment.