Bacterial efflux pump inhibitors
Barbara J Kamicker1, Michael T Sweeney, Frank Kaczmarek
1Pfizer Global R & D, MS, Groton, CT, USA.
Methods in Molecular Medicine
|April 26, 2008
Summary
Researchers developed a method to find new drugs targeting multidrug-resistant Gram-negative bacteria. This approach identifies compounds that block Resistance Nodulation Division (RND) efflux pumps, crucial for antibiotic resistance.
Area of Science:
- Microbiology
- Pharmacology
- Biochemistry
Background:
- Multidrug-resistant Gram-negative pathogens cause significant hospital-acquired infections.
- Increasing antibiotic resistance necessitates novel therapeutic strategies.
- Resistance Nodulation Division (RND) efflux pumps are a key mechanism of resistance in Gram-negative bacteria, expelling various antibiotic classes.
Purpose of the Study:
- To establish a multistep process for identifying inhibitors of RND-type efflux pumps.
- To validate compounds that specifically target RND efflux pumps without general toxicity.
Main Methods:
- Inhibition of ethidium bromide accumulation in bacterial cells (E. coli, H. influenzae).
- Genetic and biochemical assays to confirm efflux pump specificity and rule out non-specific effects (e.g., antibacterial activity, membrane disruption).
- Assessment of synergistic or antagonistic effects of inhibitors with antibiotics in liquid cultures, quantifying viable cells over 24 hours.
Main Results:
- A validated multistep screening process was developed.
- Compounds specifically inhibiting RND efflux pumps were identified.
- Synergistic effects of identified inhibitors with antibiotics were confirmed, demonstrating potential for overcoming resistance.
Conclusions:
- The described method effectively identifies specific inhibitors of RND efflux pumps.
- This approach provides a pathway for developing new agents to combat multidrug-resistant Gram-negative infections.
- Targeting RND efflux pumps offers a promising strategy to restore antibiotic efficacy.
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