Host Cell Oxidative Stress Induces Dormant Staphylococcus aureus Persisters.

Area of Science:

• Microbiology and Host-Pathogen Interactions
• Bacterial Physiology and Persistence
• Cellular Stress Responses

Background:

• Persisters are antibiotic-tolerant variants of pathogens like Staphylococcus aureus.
• Intracellular persisters within host cells are poorly understood, especially concerning stress responses.
• Reactive oxygen species (ROS) are key components of host defense but can also influence bacterial physiology.

Purpose of the Study:

• To investigate how host cell reactive oxygen species (ROS) levels influence the dormancy depth of intracellular Staphylococcus aureus.
• To elucidate the mechanisms underlying ROS-induced dormancy in S. aureus.
• To understand the implications of varied dormancy states for bacterial resuscitation and therapeutic strategies.

Main Methods:

• Utilized single-cell approaches to analyze intracellular S. aureus persisters in host cells with varying oxidative stress levels.
• Quantified dormancy depth by measuring lag times for resuscitation in liquid medium.
• Assessed bacterial metabolism (translation, ATP levels) and protein aggregation markers.

Main Results:

• Host ROS induce heterogeneous dormancy states in S. aureus persisters, characterized by increased resuscitation lag times.
• High ROS levels lead to ATP depletion and protein aggregation, forming visible dark foci and recruiting the DnaK-ClpB chaperone system.
• ATP depletion significantly increases dormancy fractions, while translational repression by ROS plays a pivotal role in the dormant phenotype.

Conclusions:

• Intracellular S. aureus persisters exhibit heterogeneous dormancy depths influenced by host oxidative stress.
• ROS, ATP depletion, and protein aggregation are linked to deep dormancy, affecting bacterial resuscitation.
• Findings inform strategies for treating S. aureus infections, highlighting the potential of single-cell analysis for studying host-pathogen interactions.