# Expression patterns of core metabolic genes and elevated intracellular ROS confer drug tolerance in Staphylococcus aureus

## TL;DR

This study identifies key metabolic genes and elevated ROS levels in Staphylococcus aureus that help it tolerate antibiotics, offering new strategies to combat drug resistance.

## Contribution

The study identifies seven core metabolic genes and links elevated ROS to antibiotic tolerance in S. aureus.

## Key findings

- Seven metabolic genes were confirmed as major contributors to antibiotic tolerance in S. aureus.
- Elevated intracellular ROS levels were observed in drug-tolerant strains.
- Treatment with ROS scavengers increased antibiotic sensitivity in tolerant strains.

## Abstract

Staphylococcus aureus exhibits remarkable tolerance to antibiotic stress, facilitated by a complex network of cellular responses and metabolism controlled by numerous gene expression patterns that can be rapidly remodeled. This tolerance can lead to treatment failure and the emergence of antibiotic resistance. However, the expression patterns of these genes caused by metabolic alterations driving antibiotic tolerance remain poorly understood. Our objective was to identify the core metabolic genes involved in the development of tolerance. Using proteomic analysis and gene complementation assays, we found that seven tolerant isolates shared similar protein expression profiles and mechanisms for tolerance. Seven metabolic genes, including NWMN_0676-0677, opuCB, gltD, adhE, clpP, and rarA, were confirmed as major contributors to tolerance. Notably, these genes were linked to elevated intracellular reactive oxygen species (ROS) levels in drug-tolerant strains. Treatment with ROS scavengers increased the sensitivity of these strains to antibiotics. These results demonstrate that changes in the expression of metabolic genes play a crucial role in the development of drug tolerance, and the regulation of ROS metabolism may be central to the broader metabolic alterations in drug-tolerant bacteria.

S. aureus poses a major public health threat due to its remarkable ability to develop antibiotic tolerance, often leading to treatment failure and resistance emergence. This study provides critical insights into the underlying metabolic mechanisms. Proteomic analysis revealed that different genetic mutations in tolerant isolates converged on similar gene expression changes, which directly impacted the tolerance phenotype. Notably, the tolerant strains exhibited elevated intracellular reactive oxygen species (ROS) levels, and ROS scavenger treatment increased their antibiotic susceptibility. These findings demonstrate that shifts in core metabolic gene expression are pivotal for S. aureus to withstand antibiotic stress, with ROS metabolism regulation being a central component of the broader metabolic adaptations conferring drug tolerance. Understanding these metabolic underpinnings is crucial for developing more effective treatments against persistent, tolerant S. aureus infections. The identified metabolic targets and ROS-modulating approaches offer promising strategies to combat escalating antibiotic resistance.