Tug-of-war for iron between Aspergillus fumigatus and Pseudomonas aeruginosa

Author:

Rutuja H. Patil1, Tereza Juříková1, Andrea Palyzová1, and Vladimír Havlíček1,2

Author address:

1 Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
2 Department of Analytical Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12,
771 46 Olomouc, Czech Republic

Abstract:

Background:
Interspecies interactions in pathogenesis represent a complex network of communication and relationships between different microorganisms. The coexistence of Aspergillus fumigatus and Pseudomonas aeruginosa in individuals with cystic fibrosis may exacerbate the pathophysiology of the disease. Pathogens may work together through synergy, where they support each other and improve their survival. Conversely, competitive interactions may lead to mutual inhibition through competition for metal nutrients, which may affect the spread of infection. Both microorganisms rely heavily on the availability of free iron to fuel their metabolic processes and proliferation. The study presented here illustrates the emergence of pathogen-specific siderophores during the interaction between A. fumigatus and P. aeruginosa in liquid co-culture, with their appearance being dependent on growth dynamics.
Methods:
For the monoculture of each and co-culture, we grew the A. fumigatus EI278 clinical isolate and P. aeruginosa strain PAO1 (1:1) in an iron-limited mineral medium at 37°C. The microbial inoculates represented 105 bacterial cells or 105 fungal conidia. A. fumigatus (ferricrocin (Fc), triacetylfusarinine C (TafC)) and P. aeruginosa (pyoverdines (Pvd E and C)) siderophores were extracted using liquid-liquid extraction. All compounds were quantified utilising Acquity M-class liquid chromatography system connected to Synapt G2-Si Q-TOF mass spectrometer (Waters Corporation, Manchester, UK). The data was analyzed with MassLynx 4.1 software (Waters Corporation, Manchester, UK). Statistical analysis was carried out using GraphPad Prism version 8.0.1 software.
Results:
The Aspergillus transcellular Fc and extracellular TafC production were significantly reduced during co-culture with P. aeruginosa (Figure 1A,B). It is important to note that there is a difference of one order of magnitude in concentration range between Fc and TafC. Conversely, the behaviour of extracellular bacterial Pvds secretion was more intricate. During the initial stages of intermicrobial interaction (0-12 h), co-culture recorded a statistically higher secretion of PvdE and PvdC compared to monoculture, as shown in Figure 1C and D. The general decline in PvdE secretion from 18 h onwards was attributed to PvdE conversion to PvdD [1]. A statistically significant difference was observed in PvdE and PvdC secretion behaviour during the later phase (48-72 h) of the interaction between A. fumigatus and P. aeruginosa. While the production of PvdE was inhibited by Aspergillus interaction, the opposite was true for the PvdC secretion curve.
Conclusions:
In iron-limited host environments, a diverse range of synthesized pyoverdines may offer Pseudomonas producers a phylogenetic advantage in competing for the labile iron pool with the host and other rivals. The stability constants of siderophores and the time course of complexation reactions will define the gains or losses of the interacting microbial partners and deserve further study.

Abstract Number: 78

Conference Year: 2024

Conference abstracts, posters & presentations

Showing 10 posts of 17325 posts found.

  • Title

    Author

    Year

    Number

    Poster