a multicenter study of seifem/fungiscope

BACKGROUND

Our multicenter study aims to identify baseline factors and provide guidance for therapeutic decisions regarding Magnusiomyces-associated infections, an emerging threat in patients with hematological malignancies.

METHODS

HM patients with proven M. capitatus or M. clavatus (formerly Saprochaete capitata and Saprochaete clavata) infection diagnosed between January 2010 and December 2020 were recorded from the SEIFEM (Sorveglianza Epidemiologica Infezioni nelle Emopatie) group and FungiScope (Global Emerging Fungal Infection Registry). Cases of Magnusiomyces fungemia were compared with candidemia.

RESULTS

Among 90 Magnusiomycescases (60 [66%] M. capitatus and 30 (34%) M. clavatus), median age was 50 years (range 2-78), 46 patients (51%) were female and 67 (74%) had acute leukemia. Thirty-six (40%) of Magnusiomyces-associated infections occurred during antifungal prophylaxis, mainly with posaconazole (n=13, 36%) and echinocandins (n=12, 34%). Instead, the candidemia rarely occurred during prophylaxis (p<0.0001). First-line antifungal therapy with azoles, alone or in combination, was associated with improved response compared to other antifungals (p=0.001). Overall day-30 mortality rate was 43%. Factors associated with higher mortality rates were septic shock (HR 2.696, 95%CI 1.396-5.204, p=.003), corticosteroid treatment longer than 14 days (HR 2.245, 95%CI 1.151-4.376, p=.018), and lack of neutrophil recovery (HR 3.997, 95%CI 2.102-7.601, p<.001). The latter was independently associated with poor outcome (HR 2.495, 95%CI 1.192-5.222, p=.015).

CONCLUSIONS

Magnusiomyces-associated infections are often breakthrough infections. Effective treatment regimens of these infections remain to be determined, but neutrophil recovery appears to play an important role in the favorable outcome.

Unexpected Diversity of Yeast Species in Esophageal Mycosis of Waterfowls

This study was performed to evaluate the diversity and prevalence of yeasts associated with esophageal mycosis in domestic ducks and geese. Fungi were isolated from esophageal lesions of dead animals sent for microbiologic laboratory diagnosis. Species identification using a culture-dependent method was carried out by sequencing of the internal transcribed spacer (ITS)1-5.8S rRNA-ITS2 region. The most frequently isolated yeast was Candida albicans (43.1%) followed by Saccharomyces cerevisiae (17.6%), Candida kefyr (11.7%), Kazachstania bovina (11.7%), Candida lambica (3.9%), and single isolates (1.9%) representing Candida inconspicua, Candida rugosa, Candida pelliculosa, Candida krusei, Magnusiomyces capitatus, and Trichosporon asahii. Our results indicate that a number of potentially pathogenic yeast species can be isolated from esophageal mycosis of waterfowls, but additional studies are needed to make conclusions regarding their possible etiologic role in disease.

Where the infection is isolated rather than the specific species correlates with adherence strength, whereas biofilm density remains static in clinically isolated Candida and arthroconidial yeasts

To colonize and infect the host, arthroconidial yeasts must avoid being killed by the host's defenses. The formation of biofilms on implanted devices allows fungi to avoid host responses and to disseminate into the host. To better study the mechanisms of infection by arthroconidial yeasts, adherence and biofilm formation were assayed using patient samples collected over 10 years. In clinical samples, adherence varies within species, but the relative adherence is constant for those samples isolated from the same infection site. Herein we document, for the first time, in-vitro biofilm formation by Trichosporon dohaense, T. ovoides, T. japonicum, T. coremiiforme, Cutaneotrichosporon mucoides, Cutaneotrichosporon cutaneum, Galactomyces candidus, and Magnusiomyces capitatus on clinically relevant catheter material. Analysis of biofilm biomass assays indicated that biofilm mass changes less than 2-fold, regardless of the species. Our results support the hypothesis that most pathogenic fungi can form biofilms, and that biofilm formation is a source of systemic infections.

Yeast-like filamentous fungi: Molecular identification and in vitro susceptibility study

Yeast-like filamentous fungi, collected in Italy from 1985 to 2018, were submitted to molecular identification and antifungal susceptibility testings. Clinical isolates were identified as Magnusiomyces capitatus (28), M. clavatus (18), and Geotrichum candidum (2). M. clavatus was prevalent among blood isolates (18/24), M. capitatus among isolates from other biological materials. The intrinsic echinocandin resistance was confirmed. Both species had low minimum inhibitory concentrations (MICs) of itraconazole, posaconazole, and voriconazole, while M. clavatus had lower MIC of flucytosine and higher MIC of isavuconazole than M. capitatus. The intrinsic resistance of these species to echinocandins could be the reason of the recent increase of M. clavatus bloodstream infections.

Saprochaete clavata Invasive Infections - A New Threat to Hematological-Oncological Patients

Background

Saprochaete clavata (formerly Geotrichum clavatum, now proposed as Magnusiomyces clavatus) is a filamentous yeast-like fungus that has recently been described as an emerging pathogen mostly in patients with acute leukemia.

Methods

This is a retrospective study of patients diagnosed with proven and probable S. clavata infection at the University Hospital, Hradec Králové, Czechia between March 2005 and December 2017. Previous cases were identified from the literature and FungiScope^® database.

Results

Six new cases (5 females, 1 male) of blood-stream S. clavata infections at the hemato-oncological department were described including epidemiological data of additional 48 patients colonized with the species. Overall, 116 strains of S. clavata were isolated from different clinical specimens of 54 patients; most of them belonged to the respiratory tract (60.3%). S. clavata was the most frequent species among arthroconidial yeasts (Trichosporon, Galactomyces, Magnusiomyces) recovered from the blood. All our patients with S. clavata infection had profound neutropenia, a central venous catheter, broad-spectrum antibiotics and antifungal prophylaxis; four had a history of a biliary tract system disease. The diagnosis was based on a positive blood culture in all patients. Four patients died of multiorgan failure and sepsis despite treatment with lipid-based amphotericin B and/or voriconazole. From the literature and FungiScope database, 67 previous cases of S. clavata infections were evaluated in context of our cases.

Conclusion

Saprochaete clavata infection represents a life-threatening mycosis in severely immunocompromised patients. The successful outcome of treatment seems to be critically dependent on the early diagnosis and the recovery of underlying conditions associated with immune dysfunction or deficiency.

Genome sequence of the opportunistic human pathogen Magnusiomyces capitatus

The yeast Magnusiomyces capitatus is an opportunistic human pathogen causing rare yet severe infections, especially in patients with hematological malignancies. Here, we report the 20.2 megabase genome sequence of an environmental strain of this species as well as the genome sequences of eight additional isolates from human and animal sources providing an insight into intraspecies variation. The distribution of single-nucleotide variants is indicative of genetic recombination events, supporting evidence for sexual reproduction in this heterothallic yeast. Using RNAseq-aided annotation, we identified genes for 6518 proteins including several expanded families such as kexin proteases and Hsp70 molecular chaperones. Several of these families are potentially associated with the ability of M. capitatus to infect and colonize humans. For the purpose of comparative analysis, we also determined the genome sequence of a closely related yeast, Magnusiomyces ingens. The genome sequences of M. capitatus and M. ingens exhibit many distinct features and represent a basis for further comparative and functional studies.

Molecular Diagnostics of Arthroconidial Yeasts, Frequent Pulmonary Opportunists

Magnusiomyces capitatus and Saprochaete clavata are members of the clade of arthroconidial yeasts that represent emerging opportunistic pulmonary pathogens in immunocompromised patients. Given that standard ribosomal DNA (rDNA) identification often provides confusing results, in this study, we analyzed 34 isolates with the goal of finding new genetic markers for classification using multilocus sequencing and amplified fragment length polymorphism (AFLP). The interspecific similarity obtained using rDNA markers (the internal transcribed spacer [ITS] and large subunit regions) was in the range of 96 to 99%, whereas that obtained using protein-coding loci (Rbp2, Act, and Tef1α) was lower at 89.4 to 95.2%. Ultimately, Rbp2 was selected as the best marker for species distinction. On the basis of cloned ITS data, some strains proved to be misidentified in comparison with the identities obtained with phenotypic characters, protein sequences, and AFLP profiles, indicating that different copies of the ribosomal operon were present in a single species. Antifungal susceptibility testing revealed that voriconazole had the lowest MIC against M. capitatus, while amphotericin B had the lowest MIC against S. clavata Both species exhibited in vitro resistance to fluconazole and micafungin.

Flavour production by Saprochaete and Geotrichum yeasts and their close relatives

In this study, a total of 30 yeast strains belonging to the genera Dipodascus, Galactomyces, Geotrichum, Magnusiomyces and Saprochaete were investigated for volatile organic compound production using HS-SPME-GC/MS analysis. The resulting flavour profiles, including 36 esters and 6 alcohols compounds, were statistically evaluated by cluster and PCA analysis. Two main groups of strains were extracted from this analysis, namely a group with a low ability to produce flavour and a group producing mainly alcohols. Two other minor groups of strains including Saprochaete suaveolens, Geotrichum marinum and Saprochaete gigas were diverging significantly from the main groups precisely because they showed a good ability to produce a large diversity of esters. In particular, we found that the Saprochaete genus (and their closed relatives) was characterized by a high production of unsaturated esters arising from partial catabolism of branched chain amino-acids. These esters were produced by eight phylogenetically related strains of Saprochaete genus.

First case of invasive Magnusiomyces capitatus infection in Slovakia

Magnusiomyces capitatus (previously known as Geotrichum capitatum or Blastoschizomyces capitatus or Trichosporon capitatum) is a rare cause of fungal infection in immunocompromised patients. Most of these cases (87%) have been reported from the Mediterranean region, as it is extremely rare to recognize it in other regions. Here we report a first case of disseminated M. capitatus infection in Slovakia. The patient – 19 year old woman with myelodysplastic syndrome was diagnosed with M. capitatus fungemia after allogeneic stem cell transplantation. The infection occurred despite antifungal prophylaxis with micafungin, which was in vitro sensitive to the yeast. The treatment according to minimal inhibitory concentrations (micafungin, voriconazol) and granulocyte transfusions were administered. M. capitatus was cleared out from the bloodstream. However, patient died of multiple organ failure. Autopsy showed multiple lesions in organs, but did not prove presence of yeast by histopathology. M. capitatus was confirmed by polymerase chain reaction from all tested organs: heart, brain, lungs, spleen, liver and kidneys. We present the post mortem pictures showing the yeast lesions in affected organs. 2012 Elsevier Ltd. All rights reserved.