Abstract
Penicillium and Talaromyces species are frequently isolated from the respiratory tracts of cystic fibrosis (CF) patients, yet their diversity, ecological roles, and clinical significance remain poorly understood. In this study, we analyzed 521 fungal isolates (482 Penicillium and 39 Talaromyces) obtained from Dutch CF patients to investigate species diversity and prevalence. Using a combination of AFLP fingerprinting and DNA sequences analysis, we identified 57 Penicillium and 18 Talaromyces species, including a putatively new species named Penicillium subluteum sp. nov. The most commonly isolated Penicillium species included P. crustosum, P. frequentans, P. chrysogenum, P. rubens, and P. brevicompactum, while Talaromyces rugulosus was the most prevalent Talaromyces species. Our findings highlight the underestimated diversity of Penicillium and Talaromyces in CF patients and emphasize the importance of accurate species identification for understanding fungal colonization patterns and assessing pathogenic potential. This study provides the most comprehensive overview to date of Penicillium and Talaromyces diversity in the CF airway and contributes valuable taxonomic and ecological insights into the role of these fungi in patients with chronic airway disease.