Molecular epidemiology of Aspergillus species and other moulds in respiratory samples from Argentinean patients with cystic fibrosis

Abstract

In cystic fibrosis (CF) patients, fungal colonization of the respiratory tract is frequently found. Aspergillus fumigatus is the most frequently recorded and is associated with loss of pulmonary function and allergic disease (ABPA). The knowledge on prevalence rates of filamentous fungi in CF patients in Latin America is scarce. One hundred and seventy-six fungal isolates recovered from the upper respiratory tract of CF patients from Argentina were identified to species by morphology and DNA sequencing. In total, 90% of CF patients were colonized by Aspergillus sp., followed by Exophiala sp. (14%) and Scedosporium sp. (10%). Among Aspergillus, six species complexes (Fumigati, Flavi, Terrei, Nigri, Usti, and Nidulante) and different cryptospecies were found. Among Scedosporium, three species were observed (Scedosporium apiospermum, Scedosporium aurantiacum and Scedosporium boydii). All Exophiala isolates were identified as Exophiala dermatitidis. Rare filamentous fungi were also found. All cases of ABPA were associated to the presence of A. fumigatus. Mixed colonization with other mould or rare fungi was observed in half of them. To our knowledge, this is the first prospective study of mould species in CF using molecular methods in Latin America. This study shows that Aspergillus sp., E. dermatitidis and Scedosporium sp. have a high frequency in CF patients from Argentina, and by far, A. fumigatus was the most commonly cultured species. Continuous clinical surveillance is required to detect the emergence of new fungal pathogens and to detect resistant or difficult-to-treat species capable of chronic colonizing the airways and of hematogenous dissemination in case of lung transplantation.

High prevalence of triazole‐resistant Aspergillus fumigatus sensu stricto in an Argentinean cohort of patients with cystic fibrosis

“…All sputum samples were processed using %5 N‐acetyl‐ l ‐cysteine at a 1:1 ratio for liquefying and then subsequently plated undiluted on culture media. Culture media for fungi included Sabouraud dextrose agar (SDA) supplemented with 500 mg/L chloramphenicol and selective media such as the Scedosporium ‐agar (SceSel+‐agar), the erythritol‐chloramphenicol agar (ECA) and the Remel inhibitory mould agar (IMA), as previously described 2 . All plates were incubated at 37°C for at least 10 days at 37°C.…”

“…Aspergillus fumigatus is the most frequently filamentous fungi recovered from the respiratory secretions of patients with cystic fibrosis (CF) 1,2 . A. fumigatus can cause several pulmonary manifestations in CF patients, including allergic bronchopulmonary aspergillosis (ABPA) and bronchitis 3 .…”

Phylogenetic Identification, Diversity, and Richness of Aspergillus from Homes in Havana, Cuba

“…Here, we identified Aspergillus isolates obtained from indoor and outdoor housing environments in Havana, Cuba, belonging to the following sections: Versicolores, Usti, Flavi, Aspergillus, Cremei, Fumigati, Clavati, Nigri, Candidi, Flavipedes, and Circumdati. Of these, species from the sections Fumigati, Flavi, and Nigri may cause allergic diseases [40]; they were also found to be the most abundant.…”

Exophiala dermatitidis

“…The most common forms of deep infections are respiratory system infections, due to inhalation, and pulmonary infections; the latter are mostly not invasive, but it seems likely that subclinical colonization may be involved in Europe or Latin America, as rates can vary from 1% to 19%[ 3 , 16 , 25 , 30 ]. This pathogen is known to cause deep or localized phaeohyphomycosis in immunocompromised people worldwide, and is regularly found in the lungs of cystic fibrosis (CF) patients, but only very rarely is it found in respiratory specimens from patients who do not suffer from CF[ 2 , 18 , 31 ].…”