Scedosporium Species Research Articles

Application of Diagnostic Stewardship to Fungal Polymerase Chain Reaction: Low Yield of Follow-up Testing on Plasma and Bronchoalveolar Lavage After a Negative Result.

Early diagnosis of invasive fungal disease is essential for optimizing management. Although the clinical utility of fungal polymerase chain reaction (PCR) testing on plasma and bronchoalveolar lavage (BAL) has been established, the role of follow-up testing remains unclear. This was a retrospective single-center study. The yield of follow-up PCR for Aspergillus species, Mucorales agents, Fusarium species, Scedosporium species, dimorphic fungi, Pneumocystis jirovecii, and Candida species on plasma and/or BAL was measured at intervals of 1, 2, 3, and 4 weeks following a negative result. A total of 1389 follow-up tests on 406 plasma specimens from 264 patients and 983 BAL specimens from 431 patients were evaluated. Overall, the positivity rate at 1, 2, 3, and 4 weeks was 2.7% (4/148), 3.3% (4/123), 5.1% (4/78), and 3.5% (2/57), respectively, on plasma, and 0% (0/333), 0.3% (1/288), 0.4% (1/228), and 0.7% (1/134), respectively, on BAL. Conversions occurred with Aspergillus species, Mucorales agents, and Fusarium species PCR on plasma and Aspergillus species and P jirovecii PCR on BAL. All patients who converted were immunocompromised. Within 1 week of a prior negative test, 2 Aspergillus and 2 Mucorales PCRs were positive on plasma, and zero tests were positive on BAL. In week 1, only 1 Aspergillus species that was positive on day 7 was classified as probable fungal disease. Fungal PCR follow-up testing on plasma and BAL within 4 weeks of a prior negative result was of low yield and rarely generated a positive result considered clinically significant in the first week.

In vitro activity of olorofim against 507 filamentous fungi including antifungal drug-resistant strains at a tertiary laboratory in Australia: 2020-2023.

New antifungal agents are required to mitigate against azole-resistant Aspergillus and drug-resistant non-Aspergillus moulds. The novel orotomide, olorofim (F2G, Manchester, UK), has potent fungicidal activity against Aspergillus including azole-resistant Aspergillus fumigatus, Lomentospora prolificans and Scedosporium spp. Development of olorofim-specific clinical breakpoints/epidemiological cut-off values requires reliable MIC data. Determine the in vitro activity of olorofim compared with standard antifungals against mould pathogens at an Australian hospital. Olorofim MICs were determined for 507 clinical mould isolates using the CLSI M38-A3 standard. MICs of amphotericin B, anidulafungin, posaconazole, voriconazole and isavuconazole were obtained using Sensititre™ YeastOne YO10 and AUSNMRCI panels (Thermo-Fisher Scientific). A. fumigatus sensu stricto was the commonest species (33.3%) followed by L. prolificans (18.3%), Scedosporium (11.4%) and Fusarium (6%) species. Olorofim modal MICs were ≤0.25 mg/L (MIC90 0.25 mg/L) for all Aspergillus except Aspergillus Section Usti (1 mg/L); MICs for nine azole-resistant/non-wild-type A. fumigatus ranged from 0.008 to 0.125 mg/L. The MIC90 of olorofim for L. prolificans was 0.5 mg/L, 0.25-0.5 mg/L for Scedosporium spp. and 8 mg/L for the F. solani complex but with modal MICs of 0.25 and 0.008 mg/L for F. oxysporum and F. proliferatum complexes, respectively. For Verruconis gallopava (n = 10), the olorofim MIC90 was 0.06 mg/L (voriconazole MIC90 2 mg/L, isavuconazole MICs of 4->8 mg/L). Olorofim had little activity against other dematiaceous moulds including Exophiala species. Olorofim was highly active against Aspergillus spp. including azole-resistant A. fumigatus, L. prolificans, Scedosporium spp. and some Fusarium species with the new finding of potent activity against V. gallopava.

A Lateral-Flow Device for the Rapid Detection of Scedosporium Species.

Scedosporium species are human pathogenic fungi, responsible for chronic, localised, and life-threatening disseminated infections in both immunocompetent and immunocompromised individuals. The diagnosis of Scedosporium infections currently relies on non-specific CT, lengthy and insensitive culture from invasive biopsy, and the time-consuming histopathology of tissue samples. At present, there are no rapid antigen tests that detect Scedosporium-specific biomarkers. Here, we report the development of a rapid (30 min) and sensitive (pmol/L sensitivity) lateral-flow device (LFD) test, incorporating a Scedosporium-specific IgG1 monoclonal antibody (mAb), HG12, which binds to extracellular polysaccharide (EPS) antigens between ~15 kDa and 250 kDa secreted during the hyphal growth of the pathogens. The test is compatible with human serum and allows for the detection of the Scedosporium species most frequently reported as agents of human disease (Scedosporium apiospermum, Scedosporium aurantiacum, and Scedosporium boydii), with limits of detection (LODs) of the EPS biomarkers in human serum of ~0.81 ng/mL (S. apiospermum), ~0.94 ng/mL (S. aurantiacum), and ~1.95 ng/mL (S. boydii). The Scedosporium-specific LFD (ScedLFD) test therefore provides a potential novel opportunity for the detection of infections caused by different Scedosporium species.

Scedosporiosis and lomentosporiosis: modern perspectives on these difficult-to-treat rare mold infections.

SUMMARYAlthough Scedosporium species and Lomentospora prolificans are uncommon causes of invasive fungal diseases (IFDs), these infections are associated with high mortality and are costly to treat with a limited armamentarium of antifungal drugs. In light of recent advances, including in the area of new antifungals, the present review provides a timely and updated overview of these IFDs, with a focus on the taxonomy, clinical epidemiology, pathogenesis and host immune response, disease manifestations, diagnosis, antifungal susceptibility, and treatment. An expansion of hosts at risk for these difficult-to-treat infections has emerged over the last two decades given the increased use of, and broader population treated with, immunomodulatory and targeted molecular agents as well as wider adoption of antifungal prophylaxis. Clinical presentations differ not only between genera but also across the different Scedosporium species. L. prolificans is intrinsically resistant to most currently available antifungal agents, and the prognosis of immunocompromised patients with lomentosporiosis is poor. Development of, and improved access to, diagnostic modalities for early detection of these rare mold infections is paramount for timely targeted antifungal therapy and surgery if indicated. New antifungal agents (e.g., olorofim, fosmanogepix) with novel mechanisms of action and less cross-resistance to existing classes, availability of formulations for oral administration, and fewer drug-drug interactions are now in late-stage clinical trials, and soon, could extend options to treat scedosporiosis/lomentosporiosis. Much work remains to increase our understanding of these infections, especially in the pediatric setting. Knowledge gaps for future research are highlighted in the review.

Fungal Colonization of the Airways of Patients with Cystic Fibrosis: the Role of the Environmental Reservoirs.

Filamentous fungi frequently colonize the airways of patients with cystic fibrosis and may cause severe diseases, such as the allergic bronchopulmonary aspergillosis. The most common filamentous fungi capable to chronically colonize the respiratory tract of the patients are Aspergillus fumigatus and Scedosporium species. Defining the treatment strategy may be challenging, the number of available drugs being limited and some of the causative agents being multiresistant microorganisms. The knowledge of the fungal niches in the outdoor and indoor environment is needed for understanding the origin of the contamination of the patients. In light of the abundance of some of the causative molds in compost, agricultural and flower fields, occupational activities related to such environments should be discouraged for patients with cystic fibrosis (CF). In addition, the microbiological monitoring of their indoor environment, including analysis of air and dust on surfaces, is essential to propose preventive measures aiming to reduce the exposure to environmental molds. Nevertheless, some specific niches were also identified in the indoor environment, in relation with humidity which favors the growth of thermotolerant molds. Potted plants were reported as indoor reservoirs for Scedosporium species. Likewise, Exophiala dermatitidis may be spread in the kitchen via dishwashers. However, genotype studies are still required to establish the link between dishwashers and colonization of the airways of CF patients by this black yeast. Moreover, as nothing is known regarding the other filamentous fungi associated with CF, further studies should be conducted to identify other potential specific niches in the habitat.

Development of a monoclonal antibody and a lateral-flow device for the rapid detection of a Mucorales-specific biomarker.

Mucoromycosis is a highly aggressive angio-invasive disease of humans caused by fungi in the zygomycete order, Mucorales. While Rhizopus arrhizus is the principal agent of mucoromycosis, other Mucorales fungi including Apophysomyces, Cunninghamella, Lichtheimia, Mucor, Rhizomucor and Syncephalastrum are able to cause life-threatening rhino-orbital-cerebral, pulmonary, gastro-intestinal and necrotising cutaneous infections in humans. Diagnosis of the disease currently relies on non-specific CT, lengthy and insensitive culture from invasive biopsy, and time-consuming histopathology of tissue samples. At present, there are no rapid antigen tests that detect Mucorales-specific biomarkers of infection, and which allow point-of-care diagnosis of mucoromycosis. Here, we report the development of an IgG2b monoclonal antibody (mAb), TG11, which binds to extracellular polysaccharide (EPS) antigens of between 20 kDa and 250 kDa secreted during hyphal growth of Mucorales fungi. The mAb is Mucorales-specific and does not cross-react with other yeasts and molds of clinical importance including Aspergillus, Candida, Cryptococcus, Fusarium, Lomentospora and Scedosporium species. Using the mAb, we have developed a Competitive lateral-flow device that allows rapid (30 min) detection of the EPS biomarker in human serum and bronchoalveolar lavage (BAL), with a limit of detection (LOD) in human serum of ~100 ng/mL serum (~224.7 pmol/L serum). The LFD therefore provides a potential novel opportunity for detection of mucoromycosis caused by different Mucorales species.

2758. Clinical Significance and Antifungal Susceptibility Profile of 103 Clinical Scedosporium Species Complex and Lomentospora prolificans Isolated from NIH Hospitalized Patients

Abstract Background Members of the fungal genera Scedosporium species complex and Lomentospora have been increasingly recognized as emerging opportunists affecting immunocompromised patients. Reduced susceptibility to systemic antifungals is common, and optimal treatments are incompletely described. Methods 103 clinical isolates from NIH, Bethesda, MD, were investigated. The identity of each isolate was confirmed at the species level via PCR-sequencing of internal transcribed spacer (ITS) of the ribosomal DNA (rDNA) region and the calmodulin gene. Antifungal susceptibility testing was conducted in accordance with the CLSI M38-A3 guidelines. Patient data were collected retrospectively. Results The frequency of Scedosporium species complex and Lomentospora prolificans isolates are detailed in Figure 1. In vitro susceptibility results of eight antifungals against all isolates are listed in Table 1. The novel antifungal olorofim showed the lowest MICs against all Scedosporium and L. prolificans, followed by micafungin. Among triazoles, voriconazole (VRC) showed lower MIC values against clinical members of Scedosporium. Amphotericin and posaconazole (POS) demonstrated species-specific and inter-species variable activity. Itraconazole, isavuconazole, and terbinafine had high MICs against Scedosporium and L. prolificans. Clinical data were available for 90 isolates. 9 patients (28 isolates) had disease or infection (Table 2). All but one case occurred in immunocompromised hosts, and all patients were treated with a regimen that included VRC or POS. Five patients died. Three patients with chronic granulomatous disease were cured following hematopoietic cell transplant. 24 patients (62 isolates) had colonization, of which 58 isolates reflected respiratory colonization in patients with bronchiectasis. Conclusion Our data support that species-specific and inter-species differences exist in the distribution of antifungal susceptibility patterns among Scedosporium and L. prolificans. Our in vitro data suggest that olorofim may be a promising therapy for Scedosporium and L. prolificans. Our clinical data suggest that host status, in conjunction with effective antifungal therapy, is an important determinant in treatment outcomes. Disclosures All Authors: No reported disclosures

Functional insights into human macrophage response against Scedosporium apiospermum and Scedosporium dehoogii

Fungal infections caused by Scedosporium species are rising among immunocompromised and immunocompetent patients. Within the immunocompetent group, patients with cystic fibrosis (pwCF) are at high risk of developing a chronic airway colonization by these molds. While S. apiospermum is one of the major species encountered in the lungs of pwCF, S. dehoogii has rarely been reported. The innate immune response is believed to be critical for host defense against fungal infections. However, its role has only recently been elucidated and the immune mechanisms against Scedosporium species are currently unknown. In this context, we undertook a comparative investigation of macrophage-mediated immune responses toward S. apiospermum and S. dehoogii conidia. Our data showed that S. apiospermum and S. dehoogii conidia strongly stimulated the expression of a set of pro-inflammatory cytokines and chemokines such as IL-1β, IL-8, IL-6 and TNFα. We demonstrated that S. dehoogii was more potent in stimulating the early release of pro-inflammatory cytokines and chemokines while S. apiospermum induced a late inflammatory response at a higher level. Flow cytometry analysis showed that M1-like macrophages were able to internalize both S. apiospermum and S. dehoogii conidia, with a similar intracellular killing rate for both species. In conclusion, these results suggest that M1-like macrophages can rapidly initiate a strong immune response against both S. apiospermum and S. dehoogii. This response is characterized by a similar killing of internalized conidia, but a different time course of cytokine production.

Antifungal susceptibility patterns for Aspergillus, Scedosporium and Exophiala isolates recovered from cystic fibrosis patients against amphotericin B, and three triazoles and their impact after long term therapies.

In cystic fibrosis (CF) patients, fungal colonization of the respiratory tract is frequently found. Aspergillus fumigatus, Scedosporium genus and Exophiala dermatitidis are the most commonly isolated molds from the respiratory tract secretions of patients with this genetic disorder. The aim of this 5-year surveillance study was to identify trends in species distribution and susceptibility patterns of 212 mold strains identified as Aspergillus spp., Scedosporium spp. and Exophiala spp., isolated from sputum of 63 CF patients who received long term therapy with itraconazole and/or voriconazole. The Aspergillus spp. isolates were identified as members of the sections Fumigati (n=130), Flavi (n=22), Terrei (n=20), Nigri (n=8), Nidulantes (n=1) and Usti (n=1). Among the 16 species of the genus Scedosporium, 9 were S. apiospermum, 3 S. aurantiacum and 4 S. boydii. Among the 14 Exophiala species, all were molecularly identified as E. dermatitidis. Overall, 94% (15/16) of Scedosporium spp., 50% (7/14) of E. dermatitidis, and 7.7% (14/182) of Aspergillus spp. strains, showed high MIC values (≥ 8 µg/ml) for at least one antifungal. Particularly, 8.9% (19/212) of isolates showed high MIC values to amphotericin B, 11.7% (25/212) itraconazole, 4.2% (9/212) to voriconazole and 3.3% (7/212) to posaconazole. In some cases, such as some A. fumigatus and E. dermatitidis isolates recovered from the same patient, susceptibility to antifungal azoles decreased over time. We show that the use of azoles for a long time in CF patients causes the selection/isolation of mold strains with higher MIC values.

Scedosporium species and Lomentospora prolificans fungaemia is uniformly fatal in patients with haematological malignancy.

Scedosporium and Lomentospora species are environmental moulds that are virulent in immunocompromised hosts and rarely cause bloodstream infection (BSI). Patients with Scedosporium and Lomentospora species BSI were identified by the state public laboratory service in Queensland, Australia, over a 20-year period. Twenty-two incident episodes occurred among 21 residents; one patient had a second episode 321 days following the first. Of these, 18 were Lomentospora prolificans, three were Scedosporium apiospermum complex and one was a nonspeciated Scedosporium species. Seventeen (81%) patients died during their index admission, and all-cause mortality at 30, 90 and 365 days was 73%, 82% and 91% respectively. All 20 patients with haematological malignancy died within 365 days of follow-up with a median time to death of 9 days (interquartile range, 6-20 days) following diagnoses of BSI.

Comparative pathogenicity of Scedosporium species in murine model of systemic scedosporiosis.

Systemic scedosporiosis is a devastating emerging fungal infection caused by several species of the genus Scedosporium in immunocompetent and immunocompromised individuals. In this study, we compared the virulence of different Scedosporium species in a murine model of systemic scedosporiosis by survival assays, fungal burden and histopathological analysis. We found that mice mortality was species-dependent, S. apiospermum, S. aurantiacum and S. dehoogii were the most virulent species. We also observed the dissemination and invasion of Scedosporium species to the brain, spleen and kidney by colony count and histopathological analysis at different times of infection. Particularly, the brain was the tissue most susceptible to invasion during systemic scedosporiosis. This study shows the virulence and pathophysiology of different Scedosporium species and will be useful in facilitating control and prevention strategies for systemic scedosporiosis.

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

Scedosporiosis/lomentosporiosis is a globally emerging and crucial fungal infection. However, clinical data on Scedosporium/Lomentospora infections in Taiwan are scarce. This study aimed to explore the clinical characteristics of Scedosporium/Lomentospora-infected patients and evaluate the susceptibility of these isolates to antifungal agents. 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. 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. 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.

Outcome of patients with cystic fibrosis colonized by Scedosporium and Lomentospora species: A longitudinal cohort study.

Scedosporium and Lomentospora species rank second among the filamentous fungi colonizing the airways of cystic fibrosis (CF) patients. These fungi could be responsible for allergic bronchopulmonary mycosis (ABPM) and bronchitis before lung transplantation and invasive infections after. However, their role in CF lung disease is debated. This study aimed to identify clinical or environmental factors associated with an airway colonization by Scedosporium/Lomentospora species in patients with CF over a period of 7 years. A longitudinal cohort study was conducted from 2008 to 2014 in the CF reference centre in Lyon, France, to compare the characteristics of patients with Scedosporium/Lomentospora colonized and non-colonized patients. During the study period, 283 patients completed the clinical and microbiological follow-up. The analysis revealed that a higher number and duration of hospitalizations, an increased number of courses of parenteral antibiotic therapy, a history of ABPA, and treatment by itraconazole were significantly associated with an airway colonization by Scedosporium/Lomentospora species. The rate of decline of forced expiratory volume in the first second was not statistically different between colonized and non-colonized patients. This study provides evidence that patients colonized by Scedosporium/Lomentospora species require more medical care than non-colonized patients. Additional care could be in part explained by the management of Scedosporium/Lomentospora-related diseases such as ABPM or bronchitis. However, we did not demonstrate a faster rate of decline of respiratory function or body mass index in colonized patients, suggesting, as previously reported, that colonization of the airways by these fungi does not play a significant role in the progression of CF disease.

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 species and one Lomentospora species. All four major clinical relevant species were isolated with high frequency, i.e. S. apiospermum (42.4%), S. boydii (21.8%), L. prolificans (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 to 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.

The outcome of microbiologically proven fungal keratitis following standard treatment protocol

To describe the baseline characteristics, microbiological spectrum, therapy and assess the visual outcome in patients proven with fungal keratitis following standard treatment protocol. This longitudinal study was reviewed all patients with culture-proven fungal keratitis over a year at a tertiary referral facility in Bangladesh. All of the patients who had corneal stromal infiltrates had their corneal scrapings subjected to the normal microbiologic examination process, as well as a smear and culture-guided antimicrobial medication. Epidemiological features of patients (n=100), the mean age of patients was 55.6±9.8 years. More in the age group 51 to 60 years (28%). Males were more predominant (67%), commonly come from rural areas (59%). More were agriculture in workers (57%). Predisposing factors in fungal keratitis were trauma with vegetative matter (58%), herpetic keratitis (16%), penetrating keratoplasty (10%), extended wear of contact lens(12%), LASIK(4%). Treatment taken by another ophthalmologist before the presentation (46%). Low vision (20/50 to 20/160) was found in 58% cases and legal blindness (20/200 to worse ) was 40% of cases on visual acuity test at presentation. Filamentous Aspergillus (68%), Fusarium (2%), Scedosporium species (6%) and Candida(20%) were found by doing culture. Surgical intervention was needed in 36% of cases with topical and systemic anti fungal medications for management. Visual acuity after treatment was 20/40 or better in 16% of cases, low vision (20/50 to 20/160) in 39% of cases and legal blindness (20/200 to worse) in 45% of cases. Fungal keratitis causes irreparable vision damage. Yeast infections were less common than infections with filamentous fungus, which were typically treated more aggressively through both medicinal and surgical means. Similar durations of infections and visual results were observed in filamentous and yeast keratitis. In 80% of the cases where it was done, antifungal susceptibility testing had an impact on the course of treatment.

Pandemic Response Box® library as a source of antifungal drugs against Scedosporium and Lomentospora species.

Scedosporium and Lomentospora species are opportunistic filamentous fungi that cause localized and disseminated infections in immunocompetent and immunocompromised patients. These species are considered resistant fungi due to their low susceptibility to most current antifungal agents used in healthcare settings. The search for new compounds that could work as promising candidate antifungal drugs is an increasing field of interest. In this context, in the present study we screened the Pandemic Response Box® library (Medicines for Malaria Venture [MMV], Switzerland) to identify compounds with antifungal activity against Scedosporium and Lomentospora species. An initial screening of the drugs from this collection at 5 μM was performed using a clinical Scedosporium aurantiacum isolate according to the EUCAST protocol. Compounds with activity against this fungus were also tested against four other species (S. boydii¸ S. dehoogii, S. apiospermum and L. prolificans) at concentrations ranging from 0.078 to 10 μM. Seven compounds inhibited more than 80% of S. aurantiacum growth, three of them (alexidine, amorolfine and olorofim) were selected due to their differences in mechanism of action, especially when compared to drugs from the azole class. These compounds were more active against biofilm formation than against preformed biofilm in Scedosporium and Lomentospora species, except alexidine, which was able to decrease preformed biofilm about 50%. Analysis of the potential synergism of these compounds with voriconazole and caspofungin was performed by the checkerboard method for S. aurantiacum. The analysis by Bliss methodology revealed synergistic effects among selected drugs with caspofungin. When these drugs were combined with voriconazole, only alexidine and amorolfine showed a synergistic effect, whereas olorofim showed an antagonistic effect. Scanning electron microscopy revealed that alexidine induces morphology alterations in S. aurantiacum biofilm grown on a catheter surface. Reactive oxygen species production, mitochondrial activity and surface components were analyzed by fluorescent probes when S. aurantiacum was treated with selected drugs and revealed that some cell parameters are altered by these compounds. In conclusion, alexidine, amorolfine and olorofim were identified as promising compounds to be studied against scedosporiosis and lomentosporiosis.

Lignin-Modifying Enzymes in Scedosporium Species.

Scedosporium species are usually soil saprophytes but some members of the genus such as S. apiospermum and S. aurantiacum have been regularly reported as causing human respiratory infections, particularly in patients with cystic fibrosis (CF). Because of their low sensitivity to almost all available antifungal drugs, a better understanding of the pathogenic mechanisms of these fungi is mandatory. Likewise, identification of the origin of the contamination of patients with CF may be helpful to propose prophylactic measures. In this aim, environmental studies were conducted demonstrating that Scedosporium species are abundant in human-made environments and associated with nutrient-rich substrates. Although their natural habitat remains unknown, there is accumulated evidence to consider them as wood-decaying fungi. This study aimed to demonstrate the ability of these fungi to utilize lignocellulose compounds, especially lignin, as a carbon source. First, the lignolytic properties of Scedosporium species were confirmed by cultural methods, and biochemical assays suggested the involvement of peroxidases and oxidases as lignin-modifying enzymes. Scedosporium genomes were then screened using tBLASTn searches. Fifteen candidate genes were identified, including four peroxidase and seven oxidase genes, and some of them were shown, by real-time PCR experiments, to be overexpressed in lignin-containing medium, thus confirming their involvement in lignin degradation.

In Vitro Activity of the Novel Antifungal Olorofim against Scedosporium and Lomentospora prolificans.

Scedosporium spp. and Lomentospora prolificans are an emerging group of fungi refractory to current antifungal treatments. These species largely affect immunocompromised individuals but can also be lung colonizers in cystic fibrosis patients. Although Scedosporium apiospermum is thought to be the predominant species, the group has been expanded to a species complex. The distribution of species within the S. apiospermum species complex and other closely related species in the United States is largely unknown. Here, we used β-tubulin and ITS sequences to identify 37 Scedosporium isolates to the species level. These Scedosporium isolates as well as 13 L. prolificans isolates were tested against a panel of nine antifungal drugs, including the first in novel class orotimide, olorofim. IMPORTANCE Scedosporium and Lomentospora infections are notoriously hard to treat as these organisms can be resistant to numerous antifungals. The manuscript contributes to our knowledge of the activity of the new antifungal agent olorofim and comparator agents against Lomentospora and against Scedosporium isolates that have been molecularly identified to the species level. The efficacy of olorofim against all species of Scedosporium and Lomentospora was confirmed.

Two Cases of Single-fingernail Fungal Leukonychia with Varying Manifestations

Leukonychia is the white discoloration of the nail, and it is a common chromatic abnormality of the nail. Leukonychia can be caused by various systemic conditions; however, a fungal infection is also a probable cause. Herein, we report two cases that presented with varying patterns of single-nail leukonychia and were diagnosed with fungal leukonychia based on potassium hydroxide (KOH) examination and fungal culture. A 59-year-old man presented with asymptomatic complete whitish discoloration of the right fourth fingernail. KOH examination revealed many septate hyphae, and Trichophyton rubrum was identified through fungal culture and 18S rRNA sequencing. A 32-year-old man presented with asymptomatic longitudinal ridges and pitting with partial whitish discoloration of the second left fingernail persistent for 5 years. KOH examination revealed many short hyphae, and Scedosporium species was identified on fungal culture.

A new record of Scedosporium dehoogii isolated from paddy field soil in Iran: Phylogeny and antifungal susceptibility profiles.

Scedosporium species are ubiquitous environmental fungi, which are considered emerging agents that trigger disease in humans and animals. The present study aimed to determine Scedosporium dehoogii strain isolated from paddy field soil samples using semi-selective media and evaluate its antifungal susceptibility profile. Three paddy field soil samples were collected during an investigation for the isolation of Scedosporium species in Mazandaran province, Iran. Morphological and molecular analyses based on ITS-rDNA sequencing were performed. Furthermore, in vitro antifungal susceptibility testing for conventional drugs and novel imidazole (luliconazole) was performed based on Clinical and Laboratory Standards Institute M38-A3 guidelines. In this study, S. dehoogii was isolated from the soil in paddy fields. Based on the results, itraconazole and luliconazole showed the least and most antifungal activity against this isolate, respectively. Based on the findings, molecular identification was essential for distinguishing the species of S. dehoogii. Remarkably, luliconazole showed potent activity against this strain.