<p>Antimicrobial resistance and dysregulated inflammation drive mortality in multidrug-resistant (MDR) sepsis. We evaluated the cationic peptide TP2-5 as a low-dose antibiotic adjuvant. At sub-MIC concentrations, TP2-5 enhanced antibiotic susceptibility of <i>MDR E. coli</i> in broth and 50% human serum, and in combination with antibiotics was associated with attenuated MIC escalation during 21-day serial passage. Membrane potential assays and cryo-electron tomography showed envelope perturbation characterized by inner-membrane hyperpolarization. This biophysical state was temporally associated with preferential interactions with lipopolysaccharide (LPS) and anionic phospholipids rather than nonspecific permeabilization. TP2-5 neutralized LPS and reduced TLR4-dependent cytokine production. In our murine polymicrobial CLP sepsis model, TP2-5 alone or with meropenem achieved 100% survival, accompanied by reduced bacterial burden and systemic inflammatory cytokines, consistent with combined antibacterial and host-directed effects, supporting a multifunctional adjuvant profile. This study did not measure bacterial membrane potential in vivo, and the causal role of hyperpolarization in protection or attenuated MIC escalation remains to be determined.</p><p></p>

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Antimicrobial peptide-induced inner membrane hyperpolarization is associated with antibiotic sensitization and attenuated MIC escalation in multidrug-resistant Gram-negative pathogens

  • Jih-Chao Yeh,
  • Prakash Kishore Hazam,
  • You-Ying Lin,
  • Yuan-Chih Chang,
  • Sanjay Prasad Selvaraj,
  • Chao-Chin Li,
  • Po-Yen Lin,
  • Yi-Ping Huang,
  • Chi-Fon Chang,
  • Ming-Feng You,
  • Jyh-Yih Chen

摘要

Antimicrobial resistance and dysregulated inflammation drive mortality in multidrug-resistant (MDR) sepsis. We evaluated the cationic peptide TP2-5 as a low-dose antibiotic adjuvant. At sub-MIC concentrations, TP2-5 enhanced antibiotic susceptibility of MDR E. coli in broth and 50% human serum, and in combination with antibiotics was associated with attenuated MIC escalation during 21-day serial passage. Membrane potential assays and cryo-electron tomography showed envelope perturbation characterized by inner-membrane hyperpolarization. This biophysical state was temporally associated with preferential interactions with lipopolysaccharide (LPS) and anionic phospholipids rather than nonspecific permeabilization. TP2-5 neutralized LPS and reduced TLR4-dependent cytokine production. In our murine polymicrobial CLP sepsis model, TP2-5 alone or with meropenem achieved 100% survival, accompanied by reduced bacterial burden and systemic inflammatory cytokines, consistent with combined antibacterial and host-directed effects, supporting a multifunctional adjuvant profile. This study did not measure bacterial membrane potential in vivo, and the causal role of hyperpolarization in protection or attenuated MIC escalation remains to be determined.