Abstract
Objectives Cystic fibrosis (CF) lung disease is characterised by mucus stasis, chronic infection and inflammation, causing progressive structural lung disease and eventual respiratory failure. CF airways are inhabited by an ecologically diverse polymicrobial environment with vast potential for interspecies interactions, which may be a contributing factor to disease progression. Pseudomonas aeruginosa and Aspergillus fumigatus are the most common bacterial and fungal species present in CF airways respectively and coinfection results in a worse disease phenotype.
Methods In this review we examine existing expert knowledge of chronic co-infection with P. aeruginosa and A. fumigatus in CF patients. We summarise the mechanisms of interaction and evaluate the clinical and inflammatory impacts of this co-infection.
Results P. aeruginosa inhibits A. fumigatus through multiple mechanisms: phenazine secretion, iron competition, quorum sensing and through diffusible small molecules. A. fumigatus reciprocates inhibition through gliotoxin release and phenotypic adaptations enabling evasion of P. aeruginosa inhibition. Volatile organic compounds secreted by P. aeruginosa stimulate A. fumigatus growth, while A. fumigatus stimulates P. aeruginosa production of cytotoxic elastase.
Conclusion A complex bi-directional relationship exists between P. aeruginosa and A. fumigatus, exhibiting both mutually antagonistic and cooperative facets. Cross-sectional data indicate a worsened disease state in coinfected patients; however, robust longitudinal studies are required to derive causality and to determine whether interspecies interaction contributes to disease progression.
Abstract
A complex relationship exists between P. aeruginosa and A. fumigatus and is associated with worsened clinical disease in cystic fibrosis. Further study of organism interactions, longitudinal outcomes and therapeutic strategies is warranted. https://bit.ly/2A161bh
Footnotes
Submitted article, peer reviewed
Conflict of interest: K. Keown has nothing to disclose.
Conflict of interest: A. Reid has nothing to disclose.
Conflict of interest: J.E. Moore has nothing to disclose.
Conflict of interest: C.C. Taggart has nothing to disclose.
Conflict of interest: D.G. Downey has nothing to disclose.
- Received January 14, 2020.
- Accepted May 16, 2020.
- Copyright ©ERS 2020.
This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0.