# Global response to antibiotic exposure uncovers a critical role for nucleotide metabolism in high-level β-lactam tolerance

## TL;DR

This study reveals that nucleotide metabolism is crucial for bacterial survival during antibiotic exposure, offering new strategies to enhance antibiotic effectiveness.

## Contribution

The study identifies nucleotide synthesis as a key metabolic pathway in antibiotic tolerance and shows that targeting it can synergize with penicillin.

## Key findings

- Transcriptomics and metabolomics in Vibrio cholerae reveal altered pathways including nucleotide synthesis during antibiotic exposure.
- Nucleotide levels decrease with antibiotic exposure, and purine and pyrimidine synthesis functions are upregulated.
- Targeting nucleotide synthesis synergizes with penicillin, suggesting new drug development opportunities.

## Abstract

Antibiotic tolerance, the ability to survive lethal antibiotics for a prolonged period of time is a rising threat due to its role as a steppingstone towards antibiotic resistance. While tolerance has been recognized as a severe clinical threat, little is known about the mechanisms promoting tolerance. Here, we delineated the physiology of antibiotic tolerance to the classic β-lactam antibiotic, penicillin, to discover the metabolic underpinnings of how tolerant bacteria survive ordinarily lethal antibiotic exposure. We used transcriptomics and metabolomics in the hypertolerant Gram-negative cholera pathogen, Vibrio cholerae, to identify the global regulatory and metabolic response to antibiotic exposure. Key pathways like central carbon metabolism, cell wall synthesis, heat shock, two-component systems, and particularly nucleotide synthesis were significantly altered in response to PenG. Most notably, nucleotide levels were depleted upon antibiotic exposure, concomitant with upregulation of both purine and pyrimidine synthesis functions. Consistent with a crucial role for nucleotide synthesis in tolerance, we find that targeting nucleotide synthesis synergizes with penicillin. These datasets thus reveal new vulnerabilities in tolerant bacteria that can serve as conceptual scaffolds for drug development and for improving antibiotic efficacy.