Oral prevalence and antifungal susceptibility of Candida species in cystic fibrosis patients

Metagenomics Applied to the Respiratory Mycobiome in Cystic Fibrosis

Cystic fibrosis (CF) is a genetic disorder characterized by chronic microbial colonization and inflammation of the respiratory tract (RT), leading to pulmonary exacerbation (PEx) and lung damage. Although the lung bacterial microbiota has been extensively studied, the mycobiome remains understudied. However, its importance as a contributor to CF pathophysiology has been highlighted. The objective of this review is to provide an overview of the current state of knowledge regarding the mycobiome, as described through NGS-based studies, in patients with CF (pwCF).Several studies have demonstrated that the mycobiome in CF lungs is a dynamic entity, exhibiting a lower diversity and abundance than the bacterial microbiome. Nevertheless, the progression of lung damage is associated with a decrease in fungal and bacterial diversity. The core mycobiome of the RT in pwCFs is mainly composed of yeasts (Candida spp., Malassezia spp.) and molds with lower abundance. Some fungi (Aspergillus, Scedosporium/Pseudallescheria) have been demonstrated to play a role in PEx, while the involvement of others (Candida, Pneumocystis) remains uncertain. The "climax attack" ecological model has been proposed to explain the complexity and interplay of microbial populations in the RT, leading to PEx and lung damage. NGS-based studies also enable the detection of intra- and interkingdom correlations between fungi and bacteria. Further studies are required to ascertain the biological and pathophysiological relevance of these correlations. Finally, with the recent advent of CFTR modulators, our understanding of the pulmonary microbiome and mycobiome in pwCFs is about to change.

Prevalence, virulence factors and antifungal susceptibility of oral isolates of Candida albicans from patients with cystic fibrosis in Mexico

BACKGROUND

Candida species are frequently isolated from the oral cavity of patients with cystic fibrosis. However, the information on the role of Candida in cystic fibrosis is scarce.

AIMS

This study aimed to evaluate the prevalence, virulence profile and antifungal susceptibility of oral isolates of Candida albicans recovered from patients with cystic fibrosis.

METHODS

Oropharyngeal swab samples were collected from sixty-five cystic fibrosis patients and sixty-five healthy individuals. Candida isolates were identified by MALDI-TOF VITEK-MS. Proteinase, phospholipase and esterase activity, biofilm production and level expression of ALS, SAP and PLB genes in C. albicans were evaluated. Minimal inhibitory concentration values were determined by means of an antifungal susceptibility test.

RESULTS

Oral Candida colonization in cystic fibrosis patients was 66.15%, while in healthy individuals was 36.92%. C. albicans was the most frequently isolated species. C. albicans strains from cystic fibrosis patients were high producers of protease and biofilm, and had higher expression levels of adhesin and protease-associated genes in comparison with healthy subjects. Among the C. albicans strains isolated from cystic fibrosis patients, 18.91% were resistant to itraconazole, while 16.21% exhibited resistance to ketoconazole and fluconazole, and only one strain was resistant to voriconazole.

CONCLUSIONS

This work represents a surveillance study on virulence patterns and antifungal susceptibility of Candida from the oropharyngeal tract in cystic fibrosis.

Distinct community structures of the fungal microbiome and respiratory health in adults with cystic fibrosis

BACKGROUND

The respiratory tract fungal microbiome in cystic fibrosis (CF) has been understudied despite increasing recognition of fungal pathogens in CF lung disease. We sought to better understand the fungal communities in adults with CF, and to define relationships between fungal profiles and clinical characteristics.

METHODS

We enrolled 66 adults with CF and collected expectorated sputum, spirometry, Cystic Fibrosis Questionnaire-revised, and clinical data. Fungi were molecularly profiled by sequencing of the internal transcribed spacer (ITS) region. Total fungal abundance was measured by quantitative PCR. Relative abundance and qPCR-corrected abundances were determined. Selective fungus culture identified cultivable fungi. Alpha diversity and beta diversity were measured and relationships with clinical parameters were interrogated.

RESULTS

Median age was 29 years and median FEV1 percent predicted 58%. Members of the Candida genus were the most frequent dominant taxa in CF sputum. Apiotrichum, Trichosporon, Saccharomyces cerevisiae, and Scedosporium were present in high relative abundance in few samples; whereas, Aspergillus species were detected at low levels. Higher FEV1% predicted and CFTR modulator use were associated with greater alpha-diversity. Chronic azithromycin use was associated with lower alpha-diversity. Patients with acute pulmonary had distinct fungal community composition compared to clinically stable subjects. Differing yeast species were mainly responsible for the community differences.

CONCLUSION

The respiratory tract fungal microbiome in adults with CF is associated with lung function, pulmonary exacerbation status, macrolide use, and CFTR modulator use. Future work to better understand fungal diversity in the CF airway and its impact on lung health is necessary.

Citizen-science based study of the oral microbiome in Cystic fibrosis and matched controls reveals major differences in diversity and abundance of bacterial and fungal species

Introduction: Cystic fibrosis (CF) is an autosomal genetic disease, associated with the production of excessively thick mucosa and with life-threatening chronic lung infections. The microbiota of the oral cavity can act as a reservoir or as a barrier for infectious microorganisms that can colonize the lungs. However, the specific composition of the oral microbiome in CF is poorly understood.Methods: In collaboration with CF associations in Spain, we collected oral rinse samples from 31 CF persons (age range 7-47) and matched controls, and then performed 16S rRNA metabarcoding and high-throughput sequencing, combined with culture and proteomics-based identification of fungi to survey the bacterial and fungal oral microbiome.Results: We found that CF is associated with less diverse oral microbiomes, which were characterized by higher prevalence of Candida albicans and differential abundances of a number of bacterial taxa that have implications in both the connection to lung infections in CF, as well as potential oral health concerns, particularly periodontitis and dental caries.Conclusion: Overall, our study provides a first global snapshot of the oral microbiome in CF. Future studies are required to establish the relationships between the composition of the oral and lung microbiomes in CF.