Mixed Populations and Co-Infection: Pseudomonas aeruginosa and Staphylococcus aureus
Laura Camus1, Paul Briaud1, François Vandenesch1,2
1CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France.
Abstract:
The human pathogens Pseudomonas aeruginosa and Staphylococcus aureus are frequently co-isolated from chronic wounds or cystic fibrosis patient airways. Clinical studies analysing the impact of co-infection on patient clinical outcomes lead to contradictory results. However, laboratory approaches suggest that the two pathogens co-colonize the same infection niches and form a mixed-species biofilm, therefore favouring their resistance to antibiotics and immune response. In parallel, many recent studies have focused on the different interactions between the two bacterial species. It has long been recognized that P. aeruginosa usually outcompetes S. aureus, and the molecular mechanisms involved in this state of bacterial competition are now well understood. However, several recent studies show that interactions between P. aeruginosa and S. aureus can be diverse and evolve over time. Thus, many CF isolates of P. aeruginosa and S. aureus can coexist and develop cooperative behaviours. In this chapter, we will provide an overview of the current knowledge on the mixed populations of P. aeruginosa and S. aureus, from their mechanisms of establishment to their impacts on bacterial physiology and clinical outcomes.
Insights
Pseudomonas aeruginosa and Staphylococcus aureus often co-infect patients, forming biofilms that resist treatment. Their interactions are complex, ranging from competition to cooperation, impacting patient outcomes.
Area of Science:
- Microbiology
- Infectious Diseases
- Bacterial Pathogenesis
Background:
- Pseudomonas aeruginosa and Staphylococcus aureus are key human pathogens.
- They are frequently co-isolated from chronic wounds and cystic fibrosis airways.
- Co-infection outcomes in patients are often contradictory, despite laboratory evidence of mixed-species biofilms.
Purpose of the Study:
- To review current knowledge on Pseudomonas aeruginosa and Staphylococcus aureus mixed populations.
- To explore their interaction mechanisms, from establishment to cooperative behaviors.
- To understand the impact of these interactions on bacterial physiology and clinical outcomes.
Main Methods:
- Literature review of clinical and laboratory studies.
- Analysis of research on bacterial competition and cooperation.
- Synthesis of data on biofilm formation and resistance.
Main Results:
- P. aeruginosa typically outcompetes S. aureus, with understood mechanisms.
- Recent studies reveal diverse and evolving interactions, including cooperation.
- Mixed-species biofilms enhance resistance to antibiotics and immune responses.
Conclusions:
- The interactions between P. aeruginosa and S. aureus are dynamic and context-dependent.
- Understanding these mixed populations is crucial for managing chronic infections.
- Further research is needed to reconcile clinical observations with laboratory findings.
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