Identification des réservoirs du complexe Scedosporium apiospermum au Maroc

Communications libresNational audienc

Ecology of Scedosporium Species: Present Knowledge and Future Research

The genus Scedosporium, which comprises at least five clinically relevant species, i.e. Scedosporium apiospermum, Scedosporium boydii, Scedosporium aurantiacum, Scedosporium dehoogii and Scedosporium minutisporum, ranks the second among the filamentous fungi colonizing the airways of patients with cystic fibrosis (CF). This colonization of the airways is thought to contribute to the inflammatory reaction leading to a progressive deterioration of the lung function. Additionally, these colonizing fungi may lead to severe disseminated infections in case of lung transplantation. Therefore, considering the low susceptibility of Scedosporium species to all current antifungal drugs, preventive measures should be defined to reduce the risk of exposure to these fungi for non-colonized CF patients. With this in mind, several studies have been conducted to elucidate the ecology of these fungi and to define possible sources of patient contamination. This review will summarize the major outcomes of those studies, including: the clear demonstration that ecological niches of Scedosporium species are strongly impacted by human activities, and the ability of Scedosporium species to degrade aliphatic and aromatic pollutants which supports the high occurrence of these species in contaminated soils and polluted waters and makes them promising candidates for bioremediation purposes. Finally, prospects for future research in this field are proposed

Ecology of the Scedosporium apiospermum species complex and species distribution in Morocco

National audienc

Sequential variations of Rasamsonia spp. isolate genotypes in cystic fibrosis patients

International audienceRasamsonia species have been recently described as emergent pathogens in human and animals. Recent multilocus phylogenetic studies have shown that the genus Rasamsonia (R.) includes at least four phylogenetically related species forming the R. argillacea complex, R. argillacea sensu stricto, R. piperina, R. eburnea and R. aegroticola, which have been mostly reported in the clinical context of chronic granulomatous disease (CGD) and cystic fibrosis (CF). Differences in sensitivity to antifungal therapies which have been noted within the genus Rasamsonia underline the importance of early identification of clinical isolates for optimal treatment during the early stages of infection. In this context, the aim of this work was to obtain genotypic characterization of clinical Rasamsonia spp. isolates from 26 CF patients and one acutely infected CGD patient using PCR amplification of repetitive DNA sequences (rep-PCR) and to compare species distributionsdetermined by β tubulin sequencing with rep-PCR genotypes/clusters.One hundred and ten isolates were collected sequentially or simultaneously from 01/09/1998 to 08/2012 from sputum samples of 26 CF patients. One CGD patient (4 isolates) was studied in parallel. Two references strains (CBS #408.73 (R. piperina) and #432.62 (R. cylindrospora) were obtained from CBS. After extraction, PCR amplifications of repetitive DNA sequences were realized for each sample using the DiversiLab Fungal kit (bioMérieux). Amplicons were separated by capillary electrophoresis in an Agilent 2100 Bioanalyzer (Massy, France). Single electrophoretic profiles obtained for each isolate were compared using the DiversiLab Healthcare software (version 3.41).As previously reported in CF patients, beta-tubulin gene sequencing of 110 isolates identified more frequently R. aegroticola (72 isolates from 19 CF patients) than R. argillacea stricto sensu (30 isolates from 8 CF patients), and R. piperina (8 isolates from 5 CF patients), with 15, 6, and 7 distinct profiles, respectively. From the CGD patient, all isolates were identified as R. argillacea stricto sensu. Without exception, species identification according to rep-PCR genotypes was entirely consistent with beta-tubulin sequencing results.Present data provide the first description of sequential Rasamsonia spp. variations with time in CF patients. Rasamsonia argillacea sensu stricto isolates were found persistent for years in all sequentially sampled CF patients except 1 who presented 4 different successive genotypes. In contrast to R. argillacea sensustricto, sequential detection of R. aegroticola and R. piperina revealed frequent successive changes in isolate genotypes in most CF patients.</p

Rep-PCR (DiversiLab, bioMérieux), une méthode automatisée pour des études épidémiologiques de la colonisation fongique des voies respiratoires au cours de la mucoviscidose

International audienc

Ecologie des espèces du complexe Scedosporium apiospermum au Maroc

International audienc

[Tc-99m]Tc-HMPAO mu SPECT/CT highlights cerebral blood flow enhancement and correlates with cognitive function improvements of chronic resveratrol exposure in aged rats

International audienc

Rasamsonia species isolated from cystis fibrosis patients: MALDI-TOF/MS identification and antifungal susceptibility by EUCAST method

International audienceA wide variety of filamentous fungi are able to colonize respiratory tract of patients with cystic fibrosis (CF). Recently, fungi of the genus Rasamsonia (formely Geosmithia) have been described as a new emergent group of fungi pathogen in CF patients. The genus Rasamsonia comprises nine species including Rasamsonia argillacea (sensu lato) which is a complex of species (R. argillacea sensu stricto, R. piperina , R. eburnea, and R. aegroticola). Only species belonging to species complex R. argillacea have been yet isolated from patients with chronic granulomatous disease and CF. Accurate identification at the species level of the members of the Rasamsonia complex on the basis of morphology criteria is challenging, and frequent misidentification with a Penicillium emersonii have been reported.Matrix-assisted laser desorption ionization (MALDI)-time of flight (TOF)/mass spectrometry (MS) is a powerful tool to rapidly identify moulds at the species level. We investigated the potential of this technology to discriminate Rasamsonia species. Nine reference strains were used to build a reference database library. Profiles from 3-, 5- and 7-day-old cultures of each reference strain were analysed to identify species-specific discriminating profiles. The database was tested for accuracy using a set of 74 clinical isolates collected from 29 CF-patients in 4 French hospitals (Rouen, Giens, Angers and Paris). For each isolate, the species identification obtained using MALDI-TOF/MS was compared to this obtained by Diversilab method. Our results showed a high reliability of the MALDI-TOF analysis.Antifungal susceptibility testing was also performed for 20 isolates (identified as R. argillacea, R. aegroticola or R. piperina) from 13 patients using the microdilution broth reference method of the Antifungal Susceptibility Testing Subcommittee of EUCAST. All isolates tested showed a high MIC of &gt; 8 mg/L to voriconazole, and the majority also showed high MICs to itraconazole (MIC &gt; 8 mg/L), except for R. piperina strains (MIC 0.5 - 1 mg/L). The susceptibility to amphotericin B was variable (MIC: 0.5 - &gt; 8 mg/L), with no specific distinction according to Rasamsonia species. Finally, all isolates exhibited low MICs to micafungin (0.0312 - 0.125 mg/L).Altogether, our results show that MALDI-TOF/MS is a powerful tool for rapid identification of Rasamsonia species that cannot be currently identified by morphological examination in the clinical setting, and confirm that the members of R. argillacea complex, colonizing respiratory tract in CF patients, have a very low susceptibility to available antifungal agents.</p