The Quantification of Drug Accumulation within Gram-Negative Bacteria

Area of Science:

• Microbiology
• Pharmacology
• Biochemistry

Background:

• Intrabacterial drug accumulation influences small molecule interactions with bacteria.
• This accumulation affects a molecule's utility as a chemical probe or antibacterial drug candidate.

Purpose of the Study:

• To present a general method for quantitatively measuring intrabacterial drug accumulation and metabolism (IBDM).
• To apply this method to Gram-negative bacteria, including *Escherichia coli*, *Acinetobacter baumannii*, *Klebsiella pneumoniae*, and *Pseudomonas aeruginosa*.
• To validate a high-throughput screening assay for broader applications.

Main Methods:

• Development of a liquid chromatography-mass spectrometry-based platform for IBDM analysis.
• The platform does not require drug labeling.
• Application in both single-compound and high-throughput formats.

Main Results:

• Quantitative interrogation of IBDM in multiple Gram-negative species.
• Exploration of the correlation between drug accumulation and minimum inhibitory concentration (MIC) in various *E. coli* and *K. pneumoniae* strains.
• Demonstration of drug synergy through enhanced accumulation of partner drugs.
• Validation of a high-throughput format for screening assays.

Conclusions:

• The developed platform provides a robust tool for studying drug-bacteria interactions.
• This method facilitates understanding drug accumulation, metabolism, resistance, and synergy.
• The high-throughput format is adaptable for screening assays in translational and fundamental research.