Fungal epidemiology and diversity in cystic fibrosis patients in Buenos Aires, Argentina?

BRITO DEVOTO T; POLA S; RUBEGLIO E; FINQUELIEVICH JL; GAMARRA S; GARCIA-EFFRON G; CUESTAS ML

Congreso; XVIII Congreso SADI; 2018

Fungal colonization of the respiratory tract is frequently found in cystic fibrosis patients (CF). However, the knowledge on prevalence of moulds and yeasts lung colonization in patients with this genetic disorder in Argentina is scarce. The aim of this work is to overview the epidemiology of fungal colonization in CF patients. Over a 3-year period, 121 fungal strains isolated from respiratory samples of 32 CF patients from Buenos Aires were studied. Isolates were identified by morphological criteria according to standard macroscopic and microscopic criteria. In order to identify species to subspecies level and uncover cryptic species, sequence analysis of the fungal ITS regions of the ribosomal DNA, beta-tubulin and calmodulin genes were performed. For identification of Scedosporium spp. in respiratory tract specimens, a multiplex PCR assay was also carried out targeting ITS region.Overall, about 65.6% of CF patients were colonized by Aspergillus spp. of the Fumigati section, 18.8% by Aspergillus section Flavi, 15.3 % by Penicillium/Talaromyces sp., 12.5% by Aspergillus section Nigri, Scedosporium sp., Exophiala sp., and 3.1% by Alternaria sp., Paecilomyces sp. and Geotrichum sp. The occurrence of rare fungi in CF patients like Ramsamsonia argillacea, Cephalotheca foveolata, Phoma haematocycla and Rhodothorula spp. was sporadically observed. Among Aspergillus spp., Aspergillus fumigatus was the most prevalent species, followed by Aspergillus terreus, Aspergillus pseudeoterreus, Aspergillus oryzae, Aspergillus flavus, Aspergillus niger, Aspergillus ustus, Aspergillus calidoustus, Aspergillus lentulus and Aspergillus parasiticus. Among the genera Scedoporium, the most common species were Scedosporium apiospermum and Scedosporium aurantiacum. In some cases, fungal coinfections were detected (eg, A. fumigatus and Exophiala dermatitidis; A. terreus/A. fumigatus and S. auarantiacum).The pathogenic role of fungal isolates has to be evaluated in accordance with clinical data, immune status of the patient and available data regarding the pathogenicity of each particular fungal species. Further studies are needed to evaluate the clinical implications of fungal coinfections and their contribution to inflammation and clinical deterioration in CF patients.