Impact of Artificial Sputum Medium Formulation on Pseudomonas aeruginosa Secondary Metabolite Production
Rachel L Neve1, Brent D Carrillo2, Vanessa V Phelan2
1Department of Immunology and Microbiology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA.
Abstract:
In vitro culture media are being developed to understand how host site-specific nutrient profiles influence microbial pathogenicity and ecology. To mimic the cystic fibrosis (CF) lung environment, a variety of artificial sputum media (ASM) have been created. However, the composition of these ASM vary in the concentration of key nutrients, including amino acids, lipids, DNA, and mucin. In this work, we used feature-based molecular networking (FBMN) to perform comparative metabolomics of Pseudomonas aeruginosa, the predominant opportunistic pathogen infecting the lungs of people with CF, cultured in nine different ASM. We found that the concentration of aromatic amino acids and iron from mucin added to the media contributes to differences in the production of P. aeruginosa virulence-associated secondary metabolites. IMPORTANCE Different media formulations aiming to replicate in vivo infection environments contain different nutrients, which affects interpretation of experimental results. Inclusion of undefined components, such as commercial porcine gastric mucin (PGM), in an otherwise chemically defined medium can alter the nutrient content of the medium in unexpected ways and influence experimental outcomes.
Insights
Artificial sputum media (ASM) used to study cystic fibrosis (CF) lung infections vary in nutrient content. Differences in amino acids and mucin-derived iron in ASM significantly alter Pseudomonas aeruginosa virulence factor production.
Area of Science:
- Microbiology and Immunology
- Biochemistry and Metabolomics
- Biotechnology and Bioengineering
Background:
- Artificial sputum media (ASM) are crucial for studying microbial pathogenicity in environments like the cystic fibrosis (CF) lung.
- Existing ASM formulations exhibit significant variability in nutrient concentrations, including amino acids, lipids, DNA, and mucin.
- This nutrient variability complicates the interpretation of experimental results concerning microbial behavior and virulence.
Purpose of the Study:
- To comparatively analyze the metabolomic profiles of Pseudomonas aeruginosa cultured in nine distinct ASM.
- To investigate how variations in nutrient composition within ASM influence the production of P. aeruginosa virulence factors.
- To elucidate the impact of specific nutrient concentrations, particularly aromatic amino acids and mucin-derived iron, on microbial secondary metabolite production.
Main Methods:
- Utilized feature-based molecular networking (FBMN) for comparative metabolomics.
- Cultured Pseudomonas aeruginosa in nine different ASM formulations.
- Analyzed the metabolic output and secondary metabolite production in response to varying nutrient profiles.
Main Results:
- Identified significant differences in P. aeruginosa secondary metabolite production across the nine ASM.
- Demonstrated that concentrations of aromatic amino acids and mucin-derived iron are key factors influencing virulence-associated metabolite production.
- Highlighted how undefined components like porcine gastric mucin (PGM) can unexpectedly alter the nutrient landscape of chemically defined media.
Conclusions:
- Media formulation critically impacts experimental outcomes when studying microbial pathogenicity in simulated infection environments.
- Nutrient composition, especially aromatic amino acids and iron, directly modulates P. aeruginosa virulence factor expression.
- Careful consideration of undefined components in ASM is essential for accurate interpretation of microbial ecology and pathogenicity studies.
