Polymicrobial infections: Do bacteria behave differently depending on their neighbours?

Area of Science:

• Microbiology
• Infectious Diseases
• Proteomics

Background:

• Polymicrobial infections involve complex interactions affecting pathogenicity and antibiotic response.
• Current antibiotic therapies often target single pathogens, neglecting interspecies dynamics.
• Chronic wounds, like those in epidermolysis bullosa, frequently harbor multiple bacterial species.

Purpose of the Study:

• To investigate the interactions between Staphylococcus aureus, Bacillus thuringiensis, and Klebsiella oxytoca in chronic wound environments.
• To analyze the exoproteomes of S. aureus in monoculture and co-culture conditions.
• To understand the implications of these interactions for pathogenicity and treatment.

Main Methods:

• Replica plating of wound dressing samples to identify coexisting bacterial strains.
• Laboratory culture to assess bacterial growth inhibition.
• Top-down proteomics using Mass Spectrometry to characterize bacterial exoproteomes.

Main Results:

• Identified S. aureus coexisting with B. thuringiensis and K. oxytoca in chronic wounds.
• Observed no mutual growth inhibition between these species in vitro, suggesting a lack of competition via inhibitory compounds.
• Characterized the exoproteomes of S. aureus isolates in monoculture and co-culture.

Conclusions:

• Bacterial species in chronic wounds may coexist without direct competition.
• Proteomic analysis provides insights into interspecies relationships in polymicrobial infections.
• Further research is needed to understand how these interactions influence disease progression and therapeutic outcomes.