Interaction between Pseudomonas aeruginosa and Aspergillus fumigatus in cystic fibrosis

Background: Cystic fibrosis (CF) is a disease characterized by chronic airway infection with a high incidence and poor prognosis. Pseudomonas aeruginosa and Aspergillus fumigatus are pathogens commonly found in CF patients. Clinically, these two microorganisms often coexist in the airway of CF patients. Combined infection with P. aeruginosa and A. fumigatus results in worsening lung function and clinical condition. Methods: In this review, we focus on the mutual inhibition and promotion mechanisms of P. aeruginosa and A. fumigatus in CF patients. We also summarized the mechanisms of the interaction between these pathogenic microorganisms. Results: P. aeruginosa inhibits A. fumigatus growth through the effects of phenazines, the quorum sensing system, iron competition, bacteriophages, and small colony variants. P. aeruginosa induces A. fumigatus growth through volatile organic compounds and subbacteriostatic concentrations of phenazines. A. fumigatus interferes with P. aeruginosa, affecting its metabolic growth via phenazine metabolic transformation, gliotoxin production, and reduced antibiotic sensitivity. Discussion: Coexistence of P. aeruginosa and A. fumigatus can lead to both mutual inhibition and promotion. In different stages of CF disease, the interaction between these two pathogenic microorganisms may shift between promotion and inhibition. A discussion of the mechanisms of P. aeruginosa and A. fumigatus interaction can be beneficial for further treatment of CF patients and for improving the prognosis of the disease.