Lysophosphatidylcholine Potentiates Antibacterial Activity of Polymyxin B

Area of Science:

• Microbiology and Infectious Diseases
• Pharmacology and Drug Discovery

Background:

• Polymyxin B is crucial for treating infections caused by antibiotic-resistant Gram-negative bacteria.
• Current Polymyxin B dosages are associated with significant nephrotoxicity.
• There is an urgent need for safer and effective treatments against multidrug-resistant bacteria.

Purpose of the Study:

• To investigate the efficacy of a combination therapy using a nonbactericidal concentration of Polymyxin B and lysophosphatidylcholine (LPC).
• To explore the mechanisms underlying the synergistic effect of the Polymyxin B-LPC combination against Gram-negative bacteria.
• To evaluate the potential of this combination as a safer alternative to conventional Polymyxin B treatment.

Main Methods:

• In vitro testing of the Polymyxin B-LPC combination against *Salmonella* and other Gram-negative bacteria.
• Analysis of bacterial membrane integrity following treatment with the combination.
• Assessment of the impact of the combination on DnaK, a key protein folding regulator.

Main Results:

• The combination of nonbactericidal Polymyxin B and LPC demonstrated potent inhibition of Gram-negative bacterial growth.
• This combination induced membrane porosity in bacteria.
• Degradation of DnaK, essential for protein folding, was observed in treated bacteria.

Conclusions:

• The Polymyxin B-LPC combination exhibits significant antimicrobial activity against drug-resistant Gram-negative bacteria.
• The mechanism involves disruption of bacterial membrane integrity and interference with protein homeostasis via DnaK degradation.
• This combination represents a potentially safer and effective therapeutic strategy for multidrug-resistant bacterial infections.