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Isolation of Rasamsonia argillacea species complex in a Cystic Fibrosis Adult Patient - First Case in Portugal
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Advisor(s)
Abstract(s)
Objectives: Cystic fibrosis (CF) is the most common monogenetic autosomal reces sive disease in the human population. An important fungal biota has been described in
respiratory secretions of patients suffering from CF being Aspergillus fumigatus and Candida albicans the most common fungi found. We report the isolation, for the first time in
Portugal, of the emerging fungal pathogen Rasamsonia argillacea species complex, from a
respiratory sample of an adult patient with CF.
Material & Methods: A 51-year-old male patient with heterozygous CF due to muatations ΔF508/P205S, is being followed in Cystic Fibrosis Reference Center for about 10
years. In the last years, he has been consistently colonized with Methicilin-susceptible
Staphylococcus aureus, Pseudomonas aeruginosa and Aspergillus section Fumigati whereby is
under chronic suppression therapy with two inhaled antibiotics. Recently, there has been
a progressive clinical respiratory functional deterioration. In a periodic evaluation, a miccrobiology control sputum was requested. Sample was cultured, in parallel, for bacteriol ogy and mycology evaluation.
Results: Apart from detection of S. aureus and Raoultella ornithinolytica, after 3-5 days
of incubation at 37ºC, the cultures showed several cream-coloured colonies, powdery to
velvety. Microscopic examination showed hyaline septate hyphae, Penicillium-like conid iophores with rough wall, ovoid to cylindrical phyalides with a narrow neck and cylin drical unicellular smooth-walled microconidia, arranged in unbranched basipetal chains arising from phialides.
The isolate was identified as Rasamsonia argillacea species complex based on its mor phology and confirmed by MALDI-TOF mass spectrometry. As no septate hyphae were
seen on direct examination, a new sample was requested to exclude extrinsic contamina tion. The second sample was inoculated as previously, confirming the persistent presence
of Rasamsonia argillacea species complex in the sputum of this patient. The identification
of this isolate was further confirmed by sequencing the internal transcribed spacer (ITS)
region of ribosomal DNA, showing 100% homology with sequences deposited on data bases. Antifungal susceptibility testing showed high minimal inhibitory concentrations
(MIC) to almost all tested antifungals (posaconazole, voriconazole, amphotericin B) and
low MIC to anidulafungin. The patient had no great exacerbation of his respiratory prob lems and the isolated fungus was interpreted as colonization being the patient under more
frequent surveillance.
Conclusion: Although colonization of the upper respiratory tract in CF patients by
R. argillacea species complex has been described as an emerging situation, the role of these
fungi in clinical or functional deterioration of the disease remains controversial. Indeed,
data about its real prevalence in the CF population are lacking. However, taking into ac count the ability of this species to predominantly affect the lungs, to induce pneumonia and to disseminate to adjacent organs or even to the central nervous system (CNS) in imunocompromised patients, it is essential to promote its accurate identification that is often misidentified as Penicillium spp. or Paecilomyces species. Antifungal susceptibility
testing should be performed for epidemiological purposes and to guide therapy, as Rasamsonia spp. usually presents a marked antifungal resistance profile
Description
Abstract publicado em: J Fungi. 2021;7(11):263-64 (P176). https://doi.org/10.3390/jof7110916
Keywords
Cystic Fibrosis Rasamsonia argillacea Infecções Sistémicas e Zoonoses Portugal