Population-based surveillance for scedosporiosis in Australia: epidemiology, disease manifestations and emergence of Scedosporium aurantiacum infection

Deciphering Unexpected Vascular Locations of Scedosporium spp. and Lomentospora prolificans Fungal Infections, France

Scedosporium spp. and Lomentospora prolificans are emerging non-Aspergillus filamentous fungi. The Scedosporiosis/lomentosporiosis Observational Study we previously conducted reported frequent fungal vascular involvement, including aortitis and peripheral arteritis. For this article, we reviewed 7 cases of Scedosporium spp. and L. prolificans arteritis from the Scedosporiosis/lomentosporiosis Observational Study and 13 cases from published literature. Underlying immunosuppression was reported in 70% (14/20) of case-patients, mainly those who had solid organ transplants (10/14). Osteoarticular localization of infection was observed in 50% (10/20) of cases; infections were frequently (7/10) contiguous with vascular infection sites. Scedosporium spp./Lomentospora prolificans infections were diagnosed in 9 of 20 patients ≈3 months after completing treatment for nonvascular scedosporiosis/lomentosporiosis. Aneurysms were found in 8/11 aortitis and 6/10 peripheral arteritis cases. Invasive fungal disease--related deaths were high (12/18 [67%]). The vascular tropism of Scedosporium spp. and L. prolificans indicates vascular imaging, such as computed tomography angiography, is needed to manage infections, especially for osteoarticular locations.

A case of Lomentospora prolificans endophthalmitis treated with the novel antifungal agent Olorofim

PURPOSE

To report a case of endogenous Lomentospora prolificans endophthalmitis treated with the novel antifungal agent Olorofim.

CASE REPORT

A 57-year-old man developed disseminated Lomentospora prolificans with right endophthalmitis on the background of immunosuppression following lung transplantation for interstitial lung disease. He was treated with early vitrectomy, intravitreal voriconazole, and systemic Olorofim, voriconazole and terbinafine. His symptoms improved and remained stable in the right eye. Eight weeks later the patient represented with Lomentopora prolificans endophthalmitis in the left eye when systemic voriconazole and terbinafine treatment were withdrawn. Despite aggressive treatment he ultimately succumbed due to vascular complications of extensive disseminated disease.

CONCLUSION

We report a rare case of disseminated Lomentosporosis with panophthalmitis in an immunocompromised host with prolonged survival on systemic Olorofim, voriconazole and terbinafine in conjunction with pars plana vitrectomy and intravitreal voriconazole. Early suspicion of an opportunistic fungal infection is critical, as managing disseminated disease is often unsuccessful. Despite presumed inherent resistance, intravitreal and systemic voriconazole appeared to limit disease progression in the right eye. The potential synergistic effects of combined antifungal therapy with orotomides warrant further investigation.

Detection of Scedosporium spp.: Colonizer or pathogen? A retrospective analysis of clinical significance and management in a large tertiary center

Infections with Scedosporium spp. are emerging in the past two decades and are associated with a high mortality rate. Microbiological detection can be associated with either colonization or infection. Evolution from colonization into infection is difficult to predict and clinical management upon microbiological detection is complex. Microbiological samples from 2015 to 2021 were retrospectively analyzed in a single tertiary care center. Classification into colonization or infection was performed upon first microbiological detection. Clinical evolution was observed until July 2023. Further diagnostic procedures after initial detection were analyzed. Among 38 patients with microbiological detection of Scedosporium spp., 10 were diagnosed with an infection at the initial detection and two progressed from colonization to infection during the observation time. The main sites of infection were lung (5/12; 41.6%) followed by ocular sites (4/12; 33.3%). Imaging, bronchoscopy or biopsies upon detection were performed in a minority of patients. Overall mortality rate was similar in both groups initially classified as colonization or infection [30.7% and 33.3%, respectively (P = 1.0)]. In all patients where surgical debridement of site of infection was performed (5/12; 42%); no death was observed. Although death occurred more often in the group without eradication (3/4; 75%) compared with the group with successful eradication (1/8; 12.5%), statistical significance could not be reached (P = 0.053). As therapeutic management directly impacts patients' outcome, a multidisciplinary approach upon microbiological detection of Scedosporium spp. should be encouraged. Data from larger cohorts are warranted in order to analyze contributing factors favoring the evolution from colonization into infection.

Update on therapeutic approaches for invasive fungal infections in adults

Invasive fungal infections are increasingly encountered with the expansion of iatrogenic immunosuppression, including not only solid organ and hematopoietic stem cell transplant recipients but also patients with malignancies or autoimmune diseases receiving immunomodulatory therapies, such as Bruton Tyrosine Kinase (BTK) inhibitor. Their attributable mortality remains elevated, part of which is a contribution from globally emerging resistance in both molds and yeasts. Because antifungal susceptibility test results are often unavailable or delayed, empiric and tailored antifungal approaches including choice of agent(s) and use of combination therapy are heterogeneous and often based on clinician experience with knowledge of host's net state of immunosuppression, prior antifungal exposure, antifungal side effects and interaction profile, clinical severity of disease including site(s) of infection and local resistance data. In this review, we aim to summarize previous recommendations and most recent literature on treatment of invasive mold and yeast infections in adults to guide optimal evidence-based therapeutic approaches. We review the recent data that support use of available antifungal agents, including the different triazoles that have now been studied in comparison to previously preferred agents. We discuss management of complex infections with specific emerging fungi such as Scedosporium spp., Fusarium spp., Trichosporon asahii, and Candida auris. We briefly explore newer antifungal agents or formulations that are now being investigated to overcome therapeutic pitfalls, including but not limited to olorofim, rezafungin, fosmanogepix, and encochleated Amphotericin B. We discuss the role of surgical resection or debridement, duration of treatment, follow-up modalities, and need for secondary prophylaxis, all of which remain challenging, especially in patients chronically immunocompromised or awaiting more immunosuppressive therapies.

Clinical manifestations and susceptibility of Scedosporium/Lomentospora infections at a tertiary medical centre in Taiwan from 2014 to 2021: A retrospective cohort study

BACKGROUND

Scedosporiosis/lomentosporiosis is a globally emerging and crucial fungal infection. However, clinical data on Scedosporium/Lomentospora infections in Taiwan are scarce.

OBJECTIVES

This study aimed to explore the clinical characteristics of Scedosporium/Lomentospora-infected patients and evaluate the susceptibility of these isolates to antifungal agents.

METHODS

The clinical features of Scedosporium/Lomentospora-infected patients at a tertiary teaching hospital in Northern Taiwan between 2014 and 2021 were retrospectively reviewed; isolates from these patients were identified to species level for antifungal susceptibility testing.

RESULTS

Among 44 patients, 27 (61.4%) had scedosporiosis/lomentosporiosis, whereas 17 (38.6%) were colonised with Scedosporium/Lomentospora species. Scedosporium apiospermum was the main coloniser; scedosporiosis was primarily caused by S. boydii. Trauma history, steroid and immunosuppressant use were the most common risk factors for developing these infections. Among 27 patients with scedosporiosis/lomentosporiosis, one was lost to follow-up and seven (7/26, 26.9%) died. Most patients with S. apiospermum infection have a history of trauma, leading to cutaneous, bone and ocular infections. Pulmonary, sinus and disseminated infections and mortality were frequently reported in patients with S. boydii infection. Voriconazole's minimum inhibitory concentration was low for S. boydii, S. apiospermum and S. aurantiacum. Caspofungin, micafungin and anidulafungin were active against S. boydii and S. apiospermum. A potentially novel Scedosporium species was identified in this study, with distinct clinical manifestations and antifungal susceptibility.

CONCLUSIONS

At our centre, S. boydii is the main causative species of scedosporiosis; voriconazole could be the first-line treatment in Taiwan. Our study supports the importance of speciation, rather than only categorising these isolates into S. apiospermum species complex.

Skin lesions by Scedosporium apiospermum and Nocardia pulmonary infection in an oncologic patient: a case report

BACKGROUND

Fungal infections, other than candidiasis and aspergillosis, are an uncommon entity. Despite this, emerging pathogens are a growing threat. In the following case report, we present the case of an immunocompromised patient suffering from two serious opportunistic infections in the same episode: the first of these, Nocardia multilobar pneumonia; and the second, skin infection by Scedosporium apiospermum. These required prolonged antibacterial and antifungal treatment.

CASE PRESENTATION

This case is a 71-year-old oncological patient admitted for recurrent pneumonias that was diagnosed for Nocardia pulmonary infection. Nervous system involvement was discarded and cotrimoxazole was started. Haemorrhagic skin ulcers in the lower limbs appeared after two weeks of hospital admission. We collected samples which were positive for Scedosporium apiospermum and we added voriconazole to the treatment. As a local complication, the patient presented a deep bruise that needed debridement. We completed 4 weeks of intravenous treatment with slow improvement and continued with oral treatment until the disappearance of the lesions occurs.

CONCLUSIONS

Opportunistic infections are a rising entity as the number of immunocompromised patients is growing due to more use of immunosuppressive therapies and transplants. Clinicians must have a high suspicion to diagnose and treat them. A fluid collaboration with Microbiology is necessary as antimicrobial resistance is frequent.

The high diversity of Scedosporium and Lomentospora species and their prevalence in human-disturbed areas in Taiwan

Scedosporium and Lomentospora are important opportunistic pathogens causing localized or disseminated infection in humans. Understanding their environmental distribution is critical for public hygiene and clinical management. We carried out the first environmental survey in urbanized and natural regions in Taiwan. Overall, Scedosporium and Lomentospora species were recovered in 132 out of 273 soil samples (48.4%) across Taiwan. We morphologically and molecularly identified six Scedosporium and one Lomentospora species. All four major clinical relevant species were isolated with high frequency, i.e., Scedosporium apiospermum (42.4%), S. boydii (21.8%), Lomentosporaprolificans (14.5%), S. aurantiacum (8.5%); two clinically minor species, Pseudallescheria angusta (6.7%) and S. dehoogii (5.6%), and a saprobic species, S. haikouense (0.6%), had moderate to rare incidence. These fungal species had high incidence in urban (48.6%) and hospital (67.4%) soil samples, and had limited distribution in samples from natural regions (5%). Multivariate analysis of the fungal composition revealed strong evidence of the preferential distribution of these fungi in urban and hospital regions compared with natural sites. In addition, strong evidence suggested that the distribution and abundance of these fungal species were highly heterogeneous in the environment; samples in vicinity often yielded varied fungal communities. We concluded that these fungal species were prevalent in soil in Taiwan and their occurrences were associated with human activities. Although, hygiene sensitive sites such as hospitals were not harboring heavier fungal burdens than other urban facilities in our survey, still, aware should be taken for the high frequency of these clinical relevant species around hospital regions.

Scedosporium apiospermum infections in the middle ear and mastoid: case series and review of the literature

Objectives

To present our case series and management of Scedosporium apiospermum infections of the middle ear and mastoid, and review the current literature on this rare yet potentially life-threatening condition.

Methods

Medical records of patients treated at the Royal Victorian Eye and Ear Hospital for S apiospermum middle ear and mastoid infections between 2009 and 2019 were reviewed. A literature search was conducted using PubMed, Medline and Cochrane Library databases.

Results

Two patients were identified in our institution: a 62-year-old diabetic woman with otogenic skull base osteomyelitis, and a 12-year-old boy with unilateral chronic suppurative otitis media which developed after tympanostomy tube insertion. The persistence of otalgia and otorrhoea despite prolonged antibiotic treatment characterised these cases. Both patients received voriconazole, and achieved disease resolution without complications. Ten relevant cases were identified after review of the literature. Despite treatment, there were three patient deaths, and four patients with otological or neurological complications.

Conclusion

The presence of a middle ear or mastoid infection refractory to appropriate topical and systemic antibiotics should prompt clinicians to consider a fungal infection. The role of surgical debridement in the treatment of S apiospermum infection of the middle ear and mastoid is equivocal.

In depth search of the Sequence Read Archive database reveals global distribution of the emerging pathogenic fungus Scedosporium aurantiacum

Scedosporium species are emerging opportunistic fungal pathogens causing various infections mainly in immunocompromised patients, but also in immunocompetent individuals, following traumatic injuries. Clinical manifestations range from local infections, such as subcutaneous mycetoma or bone and joint infections, to pulmonary colonization and severe disseminated diseases. They are commonly found in soil and other environmental sources. To date S. aurantiacum has been reported only from a handful of countries. To identify the worldwide distribution of this species we screened publicly available sequencing data from fungal metabarcoding studies in the Sequence Read Archive (SRA) of The National Centre for Biotechnology Information (NCBI) by multiple BLAST searches. S. aurantiacum was found in 26 countries and two islands, throughout every climatic region. This distribution is like that of other Scedosporium species. Several new environmental sources of S. aurantiacum including human and bovine milk, chicken and canine gut, freshwater, and feces of the giant white-tailed rat (Uromys caudimaculatus) were identified. This study demonstrated that raw sequence data stored in the SRA database can be repurposed using a big data analysis approach to answer biological questions of interest.

Multilocus Sequence Typing Reveals Extensive Genetic Diversity of the Emerging Fungal Pathogen Scedosporium aurantiacum

Scedosporium spp. are the second most prevalent filamentous fungi after Aspergillus spp. recovered from cystic fibrosis (CF) patients in various regions of the world. Although invasive infection is uncommon prior to lung transplantation, fungal colonization may be a risk factor for invasive disease with attendant high mortality post-transplantation. Abundant in the environment, Scedosporium aurantiacum has emerged as an important fungal pathogen in a range of clinical settings. To investigate the population genetic structure of S. aurantiacum, a MultiLocus Sequence Typing (MLST) scheme was developed, screening 24 genetic loci for polymorphisms on a tester strain set. The six most polymorphic loci were selected to form the S. aurantiacum MLST scheme: actin (ACT), calmodulin (CAL), elongation factor-1α (EF1α), RNA polymerase subunit II (RPB2), manganese superoxide dismutase (SOD2), and β-tubulin (TUB). Among 188 global clinical, veterinary, and environmental strains, 5 to 18 variable sites per locus were revealed, resulting in 8 to 23 alleles per locus. MLST analysis observed a markedly high genetic diversity, reflected by 159 unique sequence types. Network analysis revealed a separation between Australian and non-Australian strains. Phylogenetic analysis showed two major clusters, indicating correlation with geographic origin. Linkage disequilibrium analysis revealed evidence of recombination. There was no clustering according to the source of the strains: clinical, veterinary, or environmental. The high diversity, especially amongst the Australian strains, suggests that S. aurantiacum may have originated within the Australian continent and was subsequently dispersed to other regions, as shown by the close phylogenetic relationships between some of the Australian sequence types and those found in other parts of the world. The MLST data are accessible at http://mlst.mycologylab.org. This is a joined publication of the ISHAM/ECMM working groups on “Scedosporium/Pseudallescheria Infections” and “Fungal Respiratory Infections in Cystic Fibrosis”.

Consensus guidelines for the diagnosis and management of invasive fungal disease due to moulds other than Aspergillus in the haematology/oncology setting, 2021

Invasive fungal disease (IFD) due to moulds other than Aspergillus is a significant cause of mortality in patients with malignancies or post haemopoietic stem cell transplantation. The current guidelines focus on the diagnosis and management of the common non-Aspergillus moulds (NAM), such as Mucorales, Scedosporium species (spp.), Lomentospora prolificans and Fusarium spp. Rare but emerging NAM including Paecilomyces variotii, Purpureocillium lilacinum and Scopulariopsis spp. are also reviewed. Culture and histological examination of tissue biopsy specimens remain the mainstay of diagnosis, but molecular methods are increasingly being used. As NAM frequently disseminate, blood cultures and skin examination with biopsy of any suspicious lesions are critically important. Treatment requires a multidisciplinary approach with surgical debridement as a central component. Other management strategies include control of the underlying disease/predisposing factors, augmentation of the host response and the reduction of immunosuppression. Carefully selected antifungal therapy, guided by susceptibility testing, is critical to cure. We also outline novel antifungal agents still in clinical trial which offer substantial potential for improved outcomes in the future. Paediatric recommendations follow those of adults. Ongoing epidemiological research, improvement in diagnostics and the development of new antifungal agents will continue to improve the poor outcomes that have been traditionally associated with IFD due to NAM.

Invasive scedosporiosis in lung transplant recipients: A nine-year retrospective study in a tertiary care hospital

BACKGROUND

Scedosporium species and Lomentospora prolificans (Sc/Lp) are emerging molds that cause invasive disease associated with a high mortality rate. After Aspergillus, these molds are the second filamentous fungi recovered in lung transplant (LT) recipients.

AIMS

Our objective was to evaluate the incidence, risk factors and outcome of Sc/Lp infections in LT recipients at a tertiary care hospital with a national reference LT program.

METHODS

A nine-year retrospective study was conducted.

RESULTS

During this period, 395 LT were performed. Positive cultures for Sc/Lp were obtained from twenty-one LT recipients. Twelve patients (incidence 3.04%) developed invasive scedosporiosis (IS). In 66.7% of the patients with IS the invasive infection was defined as a breakthrough one. The main sites of infection were lungs and paranasal sinuses. Most of the patients received combination antifungal therapy. The IS crude mortality rate after 30 days was 16.7%, and 33.3% after a year.

CONCLUSIONS

Our study highlights improved survival rates associated with combination antifungal therapy in LT recipients and underlines the risk of breakthrough infections in patients with allograft dysfunction on nebulized lipidic amphotericin B prophylaxis. In addition to pretransplant colonization, acute or chronic organ dysfunctions seem to be the main risk factors for IS.

Identification of Promising Antifungal Drugs against Scedosporium and Lomentospora Species after Screening of Pathogen Box Library

Fungal infections have been increasing during the last decades. Scedosporium and Lomentospora species are filamentous fungi most associated to those infections, especially in immunocompromised patients. Considering the limited options of treatment and the emergence of resistant isolates, an increasing concern motivates the development of new therapeutic alternatives. In this context, the present study screened the Pathogen Box library to identify compounds with antifungal activity against Scedosporium and Lomentospora. Using antifungal susceptibility tests, biofilm analysis, scanning electron microscopy (SEM), and synergism assay, auranofin and iodoquinol were found to present promising repurposing applications. Both compounds were active against different Scedosporium and Lomentospora, including planktonic cells and biofilm. SEM revealed morphological alterations and synergism analysis showed that both drugs present positive interactions with voriconazole, fluconazole, and caspofungin. These data suggest that auranofin and iodoquinol are promising compounds to be studied as repurposing approaches against scedosporiosis and lomentosporiosis.

Global guideline for the diagnosis and management of rare mould infections: an initiative of the European Confederation of Medical Mycology in cooperation with the International Society for Human and Animal Mycology and the American Society for Microbiology

With increasing numbers of patients needing intensive care or who are immunosuppressed, infections caused by moulds other than Aspergillus spp or Mucorales are increasing. Although antifungal prophylaxis has shown effectiveness in preventing many invasive fungal infections, selective pressure has caused an increase of breakthrough infections caused by Fusarium, Lomentospora, and Scedosporium species, as well as by dematiaceous moulds, Rasamsonia, Schizophyllum, Scopulariopsis, Paecilomyces, Penicillium, Talaromyces and Purpureocillium species. Guidance on the complex multidisciplinary management of infections caused by these pathogens has the potential to improve prognosis. Management routes depend on the availability of diagnostic and therapeutic options. The present recommendations are part of the One World-One Guideline initiative to incorporate regional differences in the epidemiology and management of rare mould infections. Experts from 24 countries contributed their knowledge and analysed published evidence on the diagnosis and treatment of rare mould infections. This consensus document intends to provide practical guidance in clinical decision making by engaging physicians and scientists involved in various aspects of clinical management. Moreover, we identify areas of uncertainty and constraints in optimising this management.

Antifungal susceptibilities of opportunistic filamentous fungal pathogens from the Asia and Western Pacific Region: data from the SENTRY Antifungal Surveillance Program (2011-2019)

Antifungal surveillance is an important tool to monitor the prevalence of uncommon fungal species and increasing antifungal resistance throughout the world, but data comparing results across several different Asian countries are scarce. In this study, 372 invasive molds collected in the Asia-Western Pacific region in 2011-2019 were susceptibility tested for mold-active triazoles (isavuconazole, posaconazole, voriconazole, and itraconazole). The collection includes 318 Aspergillus spp. isolates and 53 non-Aspergillus molds. The MIC values using CLSI methods for isavuconazole versus Aspergillus fumigatus ranged from 0.25 to 2 mg l^-1. Isavuconazole, itraconazole, posaconazole, and voriconazole acted similarly against A. fumigatus. The mold-active triazoles exhibited a wildtype phenotype to most of the Aspergillus spp. isolates tested (>94%), but poor activity against Fusarium solani species complex and Lomentospora prolificans. Voriconazole was most active against the Scedosporium spp. and posaconazole was most active against the Mucorales. In summary, isavuconazole displayed excellent activity against most species of Aspergillus and was comparable to other mold-active triazoles against non-Aspergillus molds.

Miltefosine Against Scedosporium and Lomentospora Species: Antifungal Activity and Its Effects on Fungal Cells

Scedosporium and Lomentospora species are filamentous fungi responsible for a wide range of infections in humans and are frequently associated with cystic fibrosis and immunocompromising conditions. Because they are usually resistant to many antifungal drugs available in clinical settings, studies of alternative targets in fungal cells and therapeutic approaches are necessary. In the present work, we evaluated the in vitro antifungal activity of miltefosine against Scedosporium and Lomentospora species and how this phospholipid analogue affects the fungal cell. Miltefosine inhibited different Scedosporium and Lomentospora species at 2–4 µg/ml and reduced biofilm formation. The loss of membrane integrity in Scedosporium aurantiacum caused by miltefosine was demonstrated by leakage of intracellular components and lipid raft disorganisation. The exogenous addition of glucosylceramide decreased the inhibitory activity of miltefosine. Reactive oxygen species production and mitochondrial activity were also affected by miltefosine, as well as the susceptibility to fluconazole, caspofungin and myoricin. The data obtained in the present study contribute to clarify the dynamics of the interaction between miltefosine and Scedosporium and Lomentospora cells, highlighting its potential use as new antifungal drug in the future.

Clinical relevance of Scedosporium spp. and Exophiala dermatitidis in patients with cystic fibrosis: A nationwide study

An increased prevalence of various filamentous fungi in sputum samples of patients with cystic fibrosis (CF) has been reported. The clinical significance, however, is mostly unclear. The aim of this study was to investigate the clinical relevance of Scedosporium spp. and Exophiala dermatitidis from sputum samples of patients with CF in the Netherlands. In this cross-sectional study, all CF patients of the Dutch national CF registry who were treated at five of the seven recognized CF centers during a 3-year period were included. We linked clinical data of the national CF registry with the national Dutch filamentous fungal database. We investigated the association between clinical characteristics and a positive sputum sample for Scedosporium spp. and E. dermatitidis, using logistic regression. Positive cultures for fungi were obtained from 3787 sputum samples from 699 of the 1312 patients with CF. Scedosporium spp. was associated with severe genotype, CF-related diabetes, several microorganisms, and inhaled antibiotics. E. dermatitidis was associated with older age, female sex, and Aspergillus spp. CF patients with and without Scedosporium spp. or E. dermatitidis seemed comparable in body mass index and lung function. This study suggests that Scedosporium spp. and E. dermatitidis are probably no major pathogens in CF patients in the Netherlands. Greater understanding of epidemiologic trends, risk factors, and pathogenicity of filamentous fungi in the respiratory tracts of patients with CF is needed.

Scedosporium spp. from Clinical Setting in Argentina, with the Proposal of the New Pathogenic Species Scedosporium americanum

Species of the genus Scedosporium (family Microascaceae, phylum Ascomycota) are responsible for a wide range of opportunistic human infections, and have a low susceptibility to most antifungal drugs. It is well known that the pattern of Scedosporium species distribution varies according to geographic region. To assess the diversity of Scedosporium species in Argentina involved in human infections, we carried out a retrospective study reviewing 49 strains from clinical samples sent for diagnosis to the National Clinical Mycology Reference Laboratory between 1985 and 2019. Then, a phenotypic characterization, a phylogenetic study and and in vitro susceptibility test to antifungals were carried out. An analysis of combined nucleotide sequences dataset of the internal transcribed spacer of the ribosomal DNA (ITS) and of a fragment of the β-tubulin gene (BT2) demonstrated that 92% of the strains belonged to the species S. boydii, S. apiospermum and S. angustum, all them pertaining to S. apiospermum species complex. However, two strains (4%) were identified as S. aurantiacum, a species never reported in clinical settings in the Americas’. Surprisingly, one of them displayed a polycytella-like conidiogenesis, up to date only reported for S. apiospermum. In addition, the strain DMic 165285 was phylogenetically located far away from the rest of the species, so is proposed as the novel species Scedosporium americanum. On the other hand, from all seven antifungals tested, voriconazole and posaconazole were the most active drugs against Scedosporium spp.

Scedosporium and Lomentospora Infections: Contemporary Microbiological Tools for the Diagnosis of Invasive Disease

Scedosporium/Lomentospora fungi are increasingly recognized pathogens. As these fungi are resistant to many antifungal agents, early diagnosis is essential for initiating targeted drug therapy. Here, we review the microbiological tools for the detection and diagnosis of invasive scedosporiosis and lomentosporiosis. Of over 10 species, Lomentospora prolificans, Scedosporium apiospermum, S. boydii and S. aurantiacum cause the majority of infections. Definitive diagnosis relies on one or more of visualization, isolation or detection of the fungus from clinical specimens by microscopy techniques, culture and molecular methods such as panfungal PCR or genus-/species-specific multiplex PCR. For isolation from respiratory tract specimens, selective media have shown improved isolation rates. Species identification is achieved by macroscopic and microscopic examination of colonies, but species should be confirmed by ITS with or without β-tubulin gene sequencing or other molecular methods. Matrix-assisted laser desorption ionization-time of flight mass spectrometry databases are improving but may need supplementation by in-house spectra for species identification. Reference broth microdilution methods is preferred for antifungal susceptibility testing. Next-generation sequencing technologies have good potential for characterization of these pathogens. Diagnosis of Scedosporium/Lomentospora infections relies on multiple approaches encompassing both phenotypic- and molecular-based methods.

Glucosylceramide Plays a Role in Fungal Germination, Lipid Raft Organization and Biofilm Adhesion of the Pathogenic Fungus Scedosporium aurantiacum

Infections caused by Scedosporium species present a wide range of clinical manifestations, from superficial to disseminated, especially in immunocompromised patients. Glucosylceramides (GlcCer) are glycosphingolipids found on the fungal cell surface and play an important role in growth and pathogenicity processes in different fungi. The present study aimed to evaluate the structure of GlcCer and its role during growth in two S. aurantiacum isolates. Purified GlcCer from both isolates were obtained and its chemical structure identified by mass spectrometry. Using ELISA and immunofluorescence techniques it was observed that germination and NaOH-treatment of conidia favor GlcCer exposure. Monoclonal anti-GlcCer antibody reduced germination when cultivated with the inhibitor of melanin synthesis tricyclazole and also reduced germ tube length of conidia, both cultivated or not with tricyclazole. It was also demonstrated that anti-GlcCer altered lipid rafts organization, as shown by using the fluorescent stain filipin, but did not affect the susceptibility of the cell surface to damaging agents. Anti-GlcCer reduced total biomass and viability in biofilms formed on polystyrene plates. In the presence of anti-GlcCer, germinated S. aurantiacum conidia and biofilms could not adhere to polystyrene with the same efficacy as control cells. These results highlight the relevance of GlcCer in growth processes of S. aurantiacum.

Dementia-Like Symptoms Associated With Posaconazole

Posaconazole is widely used in lung transplant recipients as pre-emptive therapy or universal fungal prophylaxis. In this patient group, posaconazole is increasingly used instead of voriconazole due to the concerns of an increased risk of squamous cell carcinoma (SCC) with voriconazole, particularly with its long-term use. Dose dependent toxicity has not been identified for posaconazole in the registration trials of intravenous (IV) and modified-release tablet formulations. This is supported by post-marketing experience. We describe a lung transplant recipient who experienced dementia-like symptoms almost 3 years after commencing posaconazole for treatment of Aspergillus fumigatus complex and Lomentospora prolificans (formerly Scedosporium prolificans) fungal infections. Symptoms resolved upon discontinuation of posaconazole, but recurred when re-challenged at a lower dose more than a year later. To the best of our knowledge, this is the first case reporting a dementia-like state with posaconazole.

Scedosporiosis/lomentosporiosis observational study (SOS): Clinical significance of Scedosporium species identification

Scedosporiosis/lomentosporiosis is a devastating emerging fungal infection. Our objective was to describe the clinical pattern and to analyze whether taxonomic grouping of the species involved was supported by differences in terms of clinical presentations or outcomes. We retrospectively studied cases of invasive scedosporiosis in France from 2005 through 2017 based on isolates characterized by polyphasic approach. We recorded 90 cases, mainly related to Scedosporium apiospermum (n = 48), S. boydii/S. ellipsoideum (n = 20), and Lomentospora prolificans (n = 14). One-third of infections were disseminated, with unexpectedly high rates of cerebral (41%) and cardiovascular (31%) involvement. In light of recent Scedosporium taxonomic revisions, we aimed to study the clinical significance of Scedosporium species identification and report for the first time contrasting clinical presentations between infections caused S. apiospermum, which were associated with malignancies and cutaneous involvement in disseminated infections, and infections caused by S. boydii, which were associated with solid organ transplantation, cerebral infections, fungemia, and early death. The clinical presentation of L. prolificans also differed from that of other species, involving more neutropenic patients, breakthrough infections, fungemia, and disseminated infections. Neutropenia, dissemination, and lack of antifungal prescription were all associated with 3-month mortality. Our data support the distinction between S. apiospermum and S. boydii and between L. prolificans and Scedosporium sp. Our results also underline the importance of the workup to assess dissemination, including cardiovascular system and brain.

The Incidence of Invasive Fungal Infections in Patients With AML Treated With a Hypomethylating Agent

BACKGROUND

Newly diagnosed patients with acute myeloid leukemia (AML) who receive induction with a hypomethylating agent (HMA) are often neutropenic with an increased risk for invasive fungal infections (IFIs). This study analyzed the incidence and risk factors for IFIs in these patients, evaluated clinical patterns in antifungal prophylaxis, and assessed the diagnostic utility of tests in this setting.

PATIENTS AND METHODS

We studied 117 newly diagnosed patients with AML treated with HMAs at our center, divided into groups based on concern for IFI (cIFI: all possible, probable, and proven IFIs) versus no concern for IFI. The Fisher exact test compared patients with cIFI versus without, and a multivariable logistic regression model estimated odds for cIFI.

RESULTS

Sixty-seven (57%) patients had cIFI, with 48 possible IFIs, 17 probable, and 2 proven cases. There was no difference in incidence based on home zip code, but the presence of chronic obstructive pulmonary disease was highly associated with cIFI (P = .001), as was male gender (P = .01). Neutropenia at treatment initiation was borderline in significance (P = .08). In diagnostics, 9% of patients had positive serum fungal markers, and 30 patients underwent bronchoscopy, with only 27% of cases yielding positive results. There was a difference in treatment regimens between patients receiving antifungal prophylaxis with mold coverage versus without mold coverage with respect to cIFI (P = .04).

CONCLUSIONS

cIFI in patients with AML treated with HMAs remains significant, especially in males and those with chronic obstructive pulmonary disease, who were found to be at higher risk. This may prompt clinicians to consider anti-mold prophylaxis in this setting.

Perspectives on Scedosporium species and Lomentospora prolificans in lung transplantation: Results of an international practice survey from ESCMID fungal infection study group and study group for infections in compromised hosts, and European Confederation of Medical Mycology

BACKGROUND

Scedosporium species and Lomentospora prolificans (S/L) are the second most common causes of invasive mold infections following Aspergillus in lung transplant recipients.

METHODS

We assessed the current practices on management of S/L colonization/infection of the lower respiratory tract before and after lung transplantation in a large number of lung transplant centers through an international practice survey from October 2016 to March 2017.

RESULTS

A total of 51 respondents from 45 lung transplant centers (17 countries, 4 continents) answered the survey (response rate 58%). S/L colonization was estimated to be detected in candidates by 48% of centers. Only 18% of the centers used a specific medium to detect S/L colonization. Scedosporium spp. colonization was a contraindication to transplantation in 10% of centers whereas L prolificans was a contraindication in 31%; 22% of centers declared having had 1-5 recipients infected with S/L in the past 5 years.

CONCLUSIONS

This survey gives an overview of the current practices regarding S/L colonization and infection in lung transplant centers worldwide and underscores the need of S/L culture procedure standardization before implementing prospective studies.

Emerging fungal infections in solid organ transplant recipients: Guidelines of the American Society of Transplantation Infectious Diseases Community of Practice

These updated AST-IDCOP guidelines review the epidemiology, diagnosis, and management of emerging fungi after organ transplantation. Infections due to numerous generally innocuous fungi are increasingly recognized in solid organ transplant (SOT) recipients, comprising about 7%-10% of fungal infections in this setting. Such infections are collectively referred to as emerging fungal infections and include Mucormycetes, Fusarium, Scedosporium, and dematiaceous fungi among others. The causative organisms are diverse in their pathophysiology, uncommon in the clinical setting, have evolving nomenclature, and are often resistant to multiple commonly used antifungal agents. In recent years significant advances have been made in understanding of the epidemiology of these emerging fungal infections, with improved diagnosis and expanded treatment options. Still, treatment guidelines are generally informed by and limited to experience from cohorts of patients with hematological malignancies and/or solid and stem cell transplants. While multicenter randomized controlled trials are not feasible for these uncommon infections in SOT recipients, collaborative prospective studies can be valuable in providing information on the epidemiology, clinical manifestations, treatment strategies, and outcomes associated with the more commonly encountered infections.

Interactions of an Emerging Fungal Pathogen Scedosporium aurantiacum with Human Lung Epithelial Cells

Scedosporium fungi are found in various natural and host-associated environments, including the lungs of cystic fibrosis patients. However, their role in infection development remains underexplored. Here the attachment of conidia of a virulent S. aurantiacum strain WM 06.482 onto the human lung epithelial A549 cells in vitro was visualized using microscopy to examine the initial steps of infection. We showed that 75-80% of fungal conidia were bound to the A549 cells within four hours of co-incubation, and started to produce germ tubes. The germinating conidia seemed to invade the cells through the intercellular space, no intracellular uptake of fungal conidia by the airway epithelial cells after conidial attachment. Transcriptomic analysis of the A549 cells revealed that the up-regulated genes were mainly associated with cell repair and inflammatory processes indicating a protective response against S. aurantiacum infection. Network analysis of the differentially expressed genes showed activation of the innate immune system (NF-kB pathway) leading to the release of pro-inflammatory cytokines. We believe this is the first report showing the transcriptomic response of human alveolar epithelial cells exposed to S. aurantiacum conidia paving a way for better understanding of the mechanism of the infection process.

Scedosporium and Lomentospora: an updated overview of underrated opportunists

Species of Scedosporium and Lomentospora are considered as emerging opportunists, affecting immunosuppressed and otherwise debilitated patients, although classically they are known from causing trauma-associated infections in healthy individuals. Clinical manifestations range from local infection to pulmonary colonization and severe invasive disease, in which mortality rates may be over 80%. These unacceptably high rates are due to the clinical status of patients, diagnostic difficulties, and to intrinsic antifungal resistance of these fungi. In consequence, several consortia have been founded to increase research efforts on these orphan fungi. The current review presents recent findings and summarizes the most relevant points, including the Scedosporium/Lomentospora taxonomy, environmental distribution, epidemiology, pathology, virulence factors, immunology, diagnostic methods, and therapeutic strategies.

Angioinvasive fungal infections impacting the skin: Diagnosis, management, and complications

As discussed in the first article in this continuing medical education series, angioinvasive fungal infections pose a significant risk to immunocompromised and immunocompetent patients alike, with a potential for severe morbidity and high mortality. The first article in this series focused on the epidemiology and clinical presentation of these infections; this article discusses the diagnosis, management, and potential complications of these infections. The mainstay diagnostic tests (positive tissue culture with histologic confirmation) are often supplemented with serum biomarker assays and molecular testing (eg, quantitative polymerase chain reaction analysis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry) to ensure proper speciation. When an angioinvasive fungal infection is suspected or diagnosed, further workup for visceral involvement also is essential and may partially depend on the organism. Different fungal organisms have varied susceptibilities to antifungal agents, and knowledge on optimal treatment regimens is important to avoid the potential complications associated with undertreated or untreated fungal infections.

Nodular Lymphangitis (Sporotrichoid Lymphocutaneous Infections). Clues to Differential Diagnosis

Nodular lymphangitis, also known as sporotrichoid lymphocutaneous infections, is characterized by suppurative inflammatory nodules along the lymphatic vessels. This manifestation is classic of sporotrichosis, however, other infections such as nocardiosis, atypical mycobacteriosis, leishmaniasis, among others, can also express this clinical pattern. Sporotrichosis, which often occurs in gardeners, remains the most recognized cause of nodular lymphangitis. The histopathological studies, as well as the culture are diagnostic standards of lesions that do not respond to empirical treatment. In this article, we will review the main causes of nodular lymphangitis or lymphocutaneous sporotrichoid infections.

Case of Scedosporium aurantiacum infection detected in a subcutaneous abscess

This is the case report of a Scedosporium aurantiacum infection in a subcutaneous abscess. The patient had underlying diabetes and malignant lymphoma. Scedosporium species occur widely in nature and are increasingly recognized as pathologies under specific conditions, such as in immunocompromised hosts.

A cluster of scedosporiosis in lung transplant candidates and recipients: The Zurich experience and review of the literature

Scedosporium species are fungal pathogens increasingly recognized in cystic fibrosis (CF). They can cause multiresistant, life-threatening infections that are of particular concern in CF patients undergoing lung transplantation, as optimal treatment remains unclear. Here, we describe our Zurich experience of CF patients with Scedosporium infection. Disseminated infection occurred in one patient after transplantation and was successfully treated. We propose a step-by-step approach to treat candidates with colonization, and discuss our cases in the context of the current literature.

Scedosporium boydii CatA1 and SODC recombinant proteins, new tools for serodiagnosis of Scedosporium infection of patients with cystic fibrosis

Scedosporium species rank the second among the filamentous fungi colonizing the airways of patients with cystic fibrosis (CF), after Aspergillus fumigatus. In CF, these fungi may cause various respiratory infections similar to those caused by A. fumigatus, including bronchitis and allergic broncho-pulmonary mycoses. Diagnosis of these infections relies on the detection of serum antibodies using crude antigenic extracts. However, many components of these extracts are common to Scedosporium and Aspergillus species, leading to cross-reactions. Here, 5 recombinant proteins from S. apiospermum or S. boydii were produced, and their value in serodiagnosis of Scedosporium infections was investigated by enzyme-linked immunosorbent assay. Two of them, corresponding to the Scedosporium catalase A1 or cytosolic Cu,Zn-superoxyde dismutase, allowed the detection of Scedosporium infection, and the differentiation with an Aspergillus infection. These recombinant proteins therefore may serve as a basis for the development of a standardized serological test.

Genetic variation analysis and relationships among environmental strains of Scedosporium apiospermum sensu stricto in Bangkok, Thailand

The Scedosporium apiospermum species complex is an emerging filamentous fungi that has been isolated from environment. It can cause a wide range of infections in both immunocompetent and immunocompromised individuals. We aimed to study the genetic variation and relationships between 48 strains of S. apiospermum sensu stricto isolated from soil in Bangkok, Thailand. For PCR, sequencing and phylogenetic analysis, we used the following genes: actin; calmodulin exons 3 and 4; the second largest subunit of the RNA polymerase II; ß-tubulin exon 2–4; manganese superoxide dismutase; internal transcribed spacer; transcription elongation factor 1α; and beta-tubulin exons 5 and 6. The present study is the first phylogenetic analysis of relationships among S. apiospermum sensu stricto in Thailand and South-east Asia. This result provides useful information for future epidemiological study and may be correlated to clinical manifestation.

Pseudomonas aeruginosa Inhibits the Growth of Scedosporium and Lomentospora In Vitro

In vitro bacterial-fungal interaction studies in cystic fibrosis (CF) have mainly focused on interactions between bacteria and Candida. Here we investigated the effect of Pseudomonas aeruginosa on the growth of Scedosporium/Lomentospora spp. Standard suspensions of P. aeruginosa (16 non-mucoid and nine mucoid isolates) were dropped onto paper disks, placed on lawns of Lomentospora prolificans (formerly Scedosporium prolificans) strain WM 14.140 or Scedosporium aurantiacum strain WM 11.78 on solid agar. The median inhibitory activity (mIz) was calculated for each fungal-bacterial combination. As a group, mIz values for non-mucoid phenotype P. aeruginosa strains were significantly lower than those for mucoid strains (P < 0.001); 14/16 (87.5%) non-mucoid strains had mIz <1.0 against both fungi versus just 3/9 mucoid strains (33.4%) (P = 0.01). One non-mucoid (PA14) and one mucoid (CIDMLS-PA-28) P. aeruginosa strain effecting inhibition were selected for further studies. Inhibition of both L. prolificans and S. aurantiacum by these strains was confirmed using the XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide) reduction assay. Following incubation with XTT, inhibition of fungal growth was determined as the ratio of absorbance in liquid culture with Pseudomonas to that in control fungal cultures. An absorbance ratio of <1.0 consistent with bacterial inhibition of fungal growth was observed for all four P. aeruginosa-fungal combinations (P < 0.05). Fluorescence microscopy, subsequent to co-culture of either fungal isolate with P. aeruginosa strain PA14 or CIDMLS-PA-28 revealed poorly formed hyphae, compared with control fungal cultures. P. aeruginosa inhibits growth of L. prolificans and S. aurantiacum in vitro, with non-mucoid strains more commonly having an inhibitory effect. As P. aeruginosa undergoes phenotype transitions from non-mucoid to the mucoid form with progression of CF lung disease, this balance may influence the appearance of Scedosporium fungi in the airways.

Recurrent Scedosporium apiospermum mycetoma successfully treated by surgical excision and terbinafine treatment: a case report and review of the literature

Background

Scedosporium apiospermum is an emerging opportunistic filamentous fungus, which is notorious for its high levels of antifungal-resistance. It is able to cause localized cutaneous or subcutaneous infections in both immunocompromised and immunocompetent persons, pulmonary infections in patients with predisposing pulmonary diseases and invasive mycoses in immunocompromised patients. Subcutaneous infections caused by this fungus frequently show chronic mycetomatous manifestation.

Case report

We report the case of a 70-year-old immunocompromised man, who developed a fungal mycetomatous infection on his right leg. There was no history of trauma; the aetiological agent was identified by microscopic examination and ITS sequencing. This is the second reported case of S. apiospermum subcutaneous infections in Hungary, which was successfully treated by surgical excision and terbinafine treatment. After 7 months, the patient remained asymptomatic. Considering the antifungal susceptibility and increasing incidence of the fungus, Scedosporium related subcutaneous infections reported in the past quarter of century in European countries were also reviewed.

Conclusions

Corticosteroid treatment represents a serious risk factor of S. apiospermum infections, especially if the patient get in touch with manure-enriched or polluted soil or water. Such infections have emerged several times in European countries in the past decades. The presented data suggest that besides the commonly applied voriconazole, terbinafine may be an alternative for the therapy of mycetomatous Scedosporium infections.

Secretion of Proteases by an Opportunistic Fungal Pathogen Scedosporium aurantiacum

Scedosporium aurantiacum is an opportunistic filamentous fungus increasingly isolated from the sputum of cystic fibrosis patients, and is especially prevalent in Australia. At the moment, very little is known about the infection mechanism of this fungus. Secreted proteases have been shown to contribute to fungal virulence in several studies with other fungi. Here we have compared the profiles of proteases secreted by a clinical isolate Scedosporium aurantiacum (WM 06.482) and an environmental strain (WM 10.136) grown on a synthetic cystic fibrosis sputum medium supplemented with casein or mucin. Protease activity was assessed using class-specific substrates and inhibitors. Subtilisin-like and trypsin-like serine protease activity was detected in all cultures. The greatest difference in the secretion of proteases between the two strains occurred in mucin-supplemented medium, where the activities of the elastase-like, trypsin-like and aspartic proteases were, overall, 2.5–75 fold higher in the clinical strain compared to the environmental strain. Proteases secreted by the two strains in the mucin-supplemented medium were further analyzed by mass spectrometry. Six homologs of fungal proteases were identified from the clinical strain and five from the environmental strain. Of these, three were common for both strains including a subtilisin peptidase, a putative leucine aminopeptidase and a PA-SaNapH-like protease. Trypsin-like protease was identified by mass spectrometry only in the clinical isolate even though trypsin-like activity was present in all cultures. In contrast, high elastase-like activity was measured in the culture supernatant of the clinical strain but could not be identified by mass spectrometry searching against other fungi in the NCBI database. Future availability of an annotated genome will help finalise identification of the S. aurantiacum proteases.

Cyclophilin and enolase are the most prevalent conidial antigens of Lomentospora prolificans recognized by healthy human salivary IgA and cross-react with Aspergillus fumigatus

PURPOSE

The study of the immunocompetent airways immune response may provide important information to improve the therapeutic efficacy against Lomentospora (Scedosporium) prolificans. So, this study aimed to identify the most prevalent conidial antigens of this multiresistant fungus recognized by healthy human salivary immunoglobulin A, and to study their expression and cross-reactivity with other fungal species.

EXPERIMENTAL DESIGN

Twenty saliva from immunocompetent donors were used to detect and identify the immunoreactive proteins by 2D immunoblotting and LC-MS/MS. Moreover, anti-Aspergillus antibodies were purified to study their cross-reactivity.

RESULTS

Ten proteins of L. prolificans conidia showed reactivity with more than 50% of the saliva samples. Among them, cyclophilin and enolase were the most prevalent antigens recognized by 85 and 80% of the samples, respectively. These enzymes were also identified on the cell wall surface of L. prolificans and on the immunomes of Scedosporium apiospermum and Scedosporium aurantiacum. Additionally, they showed cross-reactivity with the most common pathogenic filamentous fungus Aspergillus fumigatus.

CONCLUSION AND CLINICAL RELEVANCE

These results show that the immunocompetent immune response might offer a pan-fungal recognition of conserved antigens such as enolase and cyclophilins, making them potential candidates for study as therapeutic targets.

Performance of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Identification of Aspergillus, Scedosporium, and Fusarium spp. in the Australian Clinical Setting

We developed an Australian database for the identification of Aspergillus, Scedosporium, and Fusarium species (n = 28) by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In a challenge against 117 isolates, species identification significantly improved when the in-house-built database was combined with the Bruker Filamentous Fungi Library compared with that for the Bruker library alone (Aspergillus, 93% versus 69%; Fusarium, 84% versus 42%; and Scedosporium, 94% versus 18%, respectively).

Emerging infections caused by non-Aspergillus filamentous fungi

There are three broad groups of non-Aspergillus moulds: the mucormycetes, the hyalohyphomycetes and the phaeohyphomycetes. Infections with these pathogens are increasingly reported, particularly in the context of increasing use of immunosuppressant agents and improved diagnostics. The epidemiology of non-Aspergillus mould infections varies with geography, climate and level of immunosuppression. Skin and soft-tissue infections are the predominant presentation in the immunocompetent host and pulmonary and other invasive infections in the immunocompromised host. The more common non-Aspergillus moulds include Rhizopus, Mucor, Fusarium and Scedosporium species; however, other emerging pathogens are Rasamsonia and Verruconis species, which are discussed in this article. Outbreaks of non-Aspergillus mould infections have been increasingly reported, with contaminated medical supplies and natural disasters as common sources. Currently culture and other conventional diagnostic methods are the cornerstone of diagnosis. Molecular methods to directly detect and identify mould pathogens in tissue and body fluids are increasingly used.

In vitro antifungal activity of antipsychotic drugs and their combinations with conventional antifungals against Scedosporium and Pseudallescheria isolates

In the present study, in vitro antifungal activities of five antipsychotic drugs (i.e., chlorpromazine hydrochloride, CPZ; trifluoperazine hydrochloride, TPZ; amantadine hydrochloride; R-(-)-deprenyl hydrochloride, and valproic acid sodium salt) and five conventional antifungal drugs (i.e., amphotericin B, AMB; caspofungin, CSP; itraconazole; terbinafine, TRB and voriconazole, VRC) were investigated in broth microdilution tests against four clinical and five environmental Scedosporium and Pseudallescheria isolates. When used alone, phenothiazines CPZ and TPZ exerted remarkable antifungal effects. Thus, their in vitro combinations with AMB, CSP, VRC, and TRB were also examined against the clinical isolates. In combination with antifungal agents, CPZ was able to act synergistically with AMB and TRB in cases of one and two isolates, respectively. In all other cases, indifferent interactions were revealed. Antagonism was not observed between the tested agents. These combinations may establish a more effective and less toxic therapy after further in vitro and in vivo studies for Scedosporium and Pseudallescheria infections.