Engineering persister-specific antibiotics with synergistic antimicrobial functions

Area of Science:

• Microbiology
• Molecular Biology
• Drug Discovery

Background:

• Antibiotic resistance is a major global health threat, driven by persister cells that tolerate conventional antibiotics.
• Persister cells, with reduced metabolic activity, evade antibiotic action and serve as a reservoir for antibiotic resistance.
• Existing antibiotics are ineffective against these resilient persister cells, necessitating novel therapeutic strategies.

Purpose of the Study:

• To re-engineer tobramycin, a ribosome-targeting antibiotic, to effectively eliminate metabolically inactive bacterial persister cells.
• To develop a novel strategy for combating antibiotic resistance by specifically targeting persister populations.
• To create a modified antibiotic that can penetrate bacterial membranes and retain potent antimicrobial activity.

Main Methods:

• Tobramycin was chemically modified by adding a 12-amino acid sequence to induce negative Gaussian membrane curvature.
• The modified tobramycin was designed to function as a transporter sequence, enabling spontaneous membrane permeation.
• The efficacy of the engineered tobramycin against persister cells of E. coli and S. aureus was evaluated and compared to unmodified tobramycin.

Main Results:

• The engineered tobramycin demonstrated the ability to induce nanoscopic negative Gaussian membrane curvature.
• The modified antibiotic efficiently permeated bacterial membranes, overcoming a key limitation of traditional tobramycin.
• Engineered tobramycin exhibited significantly enhanced killing of E. coli and S. aureus persisters (4-6 logs greater efficacy) compared to native tobramycin.
• The modified antibiotic maintained high aminoglycoside antibiotic activity while showing no cytotoxicity to eukaryotic cells.

Conclusions:

• Re-engineering tobramycin with a membrane-permeating sequence offers a promising strategy to overcome antibiotic tolerance in persister cells.
• This approach represents a novel paradigm for renovating traditional antibiotics to combat the global challenge of antibiotic resistance.
• The developed modified antibiotic effectively targets persister cells without harming eukaryotic cells, suggesting potential therapeutic applications.