Common Adaptive Strategies Underlie Within-Host Evolution of Bacterial Pathogens

Area of Science:

• Microbiology
• Genomics
• Evolutionary Biology

Background:

• Chronic bacterial infections involve significant genomic alterations as pathogens adapt within the host.
• Large-scale genomic data from prolonged infections enable the study of pathogen adaptive strategies.
• Investigating whether different bacterial species converge on similar adaptive strategies is crucial.

Purpose of the Study:

• To compile and analyze whole-genome sequences of diverse bacterial species from sequential clinical isolates.
• To identify common within-host adaptive strategies employed by different bacterial pathogens.
• To explore the role of host immune pressure in driving these shared adaptations.

Main Methods:

• Compilation of extensive whole-genome sequencing data from bacterial isolates across various species.
• Sequential sampling during clinical infections to capture within-host evolution.
• Comparative genomic analysis to identify shared and species-specific adaptive mutations and pathways.

Main Results:

• Different bacterial species share common adaptive strategies, often involving mutations in various genes.
• Shared strategies can involve different genes within the same functional pathway across species (e.g., flagellar genes).
• Identified ubiquitous adaptations, including shifts in iron scavenging and glycerol-phosphate metabolism, and alterations in virulence factors.

Conclusions:

• Within-host adaptation strategies are remarkably conserved across diverse bacterial species, frequently driven by non-species-specific host immune pressures.
• Common adaptive strategies, such as altered iron acquisition and virulence factor modulation, are widespread.
• This study provides a comprehensive overview of common within-host bacterial adaptations, serving as a resource for future research.