Phage-Bacterial Interaction Alters Phenotypes Associated with Virulence in Acinetobacter baumannii

Area of Science:

• Microbiology
• Bacteriology
• Genomics

Background:

• Bacteriophages drive bacterial resistance evolution.
• Phage resistance can impose fitness costs, potentially altering bacterial virulence.
• Understanding these costs is crucial for phage therapy efficacy.

Purpose of the Study:

• To investigate the impact of phage resistance on the in vitro virulence of Acinetobacter baumannii.
• To assess fitness costs associated with phage resistance in this nosocomial pathogen.

Main Methods:

• Generation of phage-resistant Acinetobacter baumannii variant (Ev5-WHG).
• Evaluation of in vitro virulence profiles, including adhesion, invasion, and phagocytosis assays.
• Whole-genome sequencing of the phage-resistant mutant.

Main Results:

• Phage resistance in Acinetobacter baumannii Ev5-WHG correlated with reduced fitness.
• The mutant displayed impaired adhesion and invasion capabilities towards mammalian cells.
• Increased susceptibility to macrophage phagocytosis was observed in the resistant mutant.

Conclusions:

• Phage resistance significantly alters virulence-associated phenotypes in Acinetobacter baumannii.
• Fitness costs associated with phage resistance may impact the therapeutic potential of phage therapy.
• Genomic analysis revealed mutations linked to both phage resistance and altered virulence.