In polymicrobial infections, interactions between bacterial species can complicate both disease progression and treatment options. Pseudomonas aeruginosa and Staphylococcus aureus often occur together in such infections and tend to colonize surfaces to form aggregates and biofilms. This study addressed whether and how individual cells interact with each other on solid substrates, rather than in batch cultures. Single-cell time-lapse fluorescence microscopy, combined with automated image analysis, showed that, although P. aeruginosa is generally considered dominant over S. aureus based on batch culture studies, on surfaces the competitive balance tips in favor of S. aureus. Thus, quantitative single-cell live imaging offers the potential to reveal microbial behaviors that cannot be predicted from batch culture studies, advancing our understanding of pathogen interactions on host-associated surfaces during polymicrobial infections.
See Niggli, Wechsler & Kümmerli, Front. Cell. Infect. Microbiol