Abstract
Bacteria live in spatially organized aggregates during chronic infections, where they adapt to the host environment and evade immune responses and resist therapeutic interventions. Although it is known that environmental factors such as polymers influence bacterial aggregation, it is not clear how bacterial adaptation during chronic infection impacts the formation and spatial organization of aggregates. Here we show that in an in vitro model of cystic fibrosis (CF) containing the polymers eDNA and mucin, O-antigen is the major factor in determining the formation of two distinct aggregate assembly types of Pseudomonas aeruginosa due to alterations in cell surface hydrophobicity. Our findings highlight that during chronic infection, the interplay between cell surface properties and polymers in the environment determines the formation and structure of bacterial aggregates, and sheds new light on the fitness costs and benefits of O-antigen production in environments such as CF lungs.
Importance During chronic infection, several factors contribute to the biogeography of microbial communities. Heterogeneous populations of Pseudomonas aeruginosa form aggregates in cystic fibrosis airways, however, the impact of this population heterogeneity on spatial organization and aggregate assembly is not well understood. In this study we found that changes in O-antigen structure determine the spatial organization of P. aeruginosa cells by altering the relative cell surface hydrophobicity. This finding provides new insights into the role of O-antigen on the biogeography and structure of P. aeruginosa aggregates in cystic fibrosis airways.
Competing Interest Statement
The authors have declared no competing interest.