Pseudomonas aeruginosa Interstrain Dynamics and Selection of Hyperbiofilm Mutants during a Chronic Infection

• DOI: 10.1128/mbio.01698-19
• Publication Date: 2019-08-12T12:26:53Z
• Authors: Erin S. Gloag; Christopher W. Ma...; Daniel Snyder; Gina R. Lewin; Jacob S. Harris; Alfonso Santos-Lopez; Sarah B. Chaney; Marvin Whiteley; Vaughn S. Cooper; Daniel J. Wozniak
• Keywords: 0301 basic medicine; bacteriophages; Swine; RSCV; CRISPR-Associated Proteins; Microbiology; 03 medical and health sciences; Bacterial Proteins; Animals; Bacteriophages; Pseudomonas Infections; CRISPR-Cas; Cyclic GMP; Biological Evolution; Wsp; QR1-502; 3. Good health; Phenotype; Biofilms; Mutation; Pseudomonas aeruginosa; Wound Infection; Genetic Fitness; biofilms; Genome, Bacterial; Research Article

Bacteria adapt to infections by evolving variants that are more fit and persistent. These recalcitrant variants are typically observed in chronic infections. However, it is unclear when and why these variants evolve. To address these questions, we used a porcine chronic wound model to study the evolutionary dynamics of Pseudomonas aeruginosa in a mixed-strain infection. We isolated hyperbiofilm variants that persisted early in the infection. Interstrain interactions were also observed, where adapted variants acquired CRISPR-mediated immunity to phages. We show that when initiating infection, P. aeruginosa experiences strong positive selection for hyperbiofilm phenotypes produced by mutants of a single chemosensory system, the Wsp pathway. We predict that hyperbiofilm variants are early adaptations to infection and that interstrain interactions may influence bacterial burden and infection outcomes.