High rate of Exophiala dermatitidis recovery in the airways of patients with cystic fibrosis is associated with pancreatic insufficiency

Metagenomics Applied to the Respiratory Mycobiome in Cystic Fibrosis

Cystic fibrosis (CF) is a genetic disorder characterized by chronic microbial colonization and inflammation of the respiratory tract (RT), leading to pulmonary exacerbation (PEx) and lung damage. Although the lung bacterial microbiota has been extensively studied, the mycobiome remains understudied. However, its importance as a contributor to CF pathophysiology has been highlighted. The objective of this review is to provide an overview of the current state of knowledge regarding the mycobiome, as described through NGS-based studies, in patients with CF (pwCF).Several studies have demonstrated that the mycobiome in CF lungs is a dynamic entity, exhibiting a lower diversity and abundance than the bacterial microbiome. Nevertheless, the progression of lung damage is associated with a decrease in fungal and bacterial diversity. The core mycobiome of the RT in pwCFs is mainly composed of yeasts (Candida spp., Malassezia spp.) and molds with lower abundance. Some fungi (Aspergillus, Scedosporium/Pseudallescheria) have been demonstrated to play a role in PEx, while the involvement of others (Candida, Pneumocystis) remains uncertain. The "climax attack" ecological model has been proposed to explain the complexity and interplay of microbial populations in the RT, leading to PEx and lung damage. NGS-based studies also enable the detection of intra- and interkingdom correlations between fungi and bacteria. Further studies are required to ascertain the biological and pathophysiological relevance of these correlations. Finally, with the recent advent of CFTR modulators, our understanding of the pulmonary microbiome and mycobiome in pwCFs is about to change.

Exophiala species in household environments and their antifungal resistance profile

The black fungus Exophiala causes a wide range of infections from superficial to subcutaneous, but also invasive fungal infections in immunocompromised patients as well as healthy individuals. In addition, Exophiala, is a common colonizer of the air ways of patients with cystic fibrosis. However, the source of infection and mode of transmission is still unclear. The aim of this study was to investigate the presence of Exophiala in samples collected from Swedish indoor environments. We found that the Exophiala species were commonly found in dishwashers and that Exophiala dermatitidis was the most common Exophiala species, being identified in 70% (26 out of the 37) of samples. Almost all E. dermatitidis isolates had the ability to grow at 42 °C (P = 0.0002) and were catalase positive. Voriconazole and posaconazole exhibited the lowest MICs, while caspofungin and anidulafungin lack the antifungal activities in vitro. Future studies are needed to illuminate the transmission mode of the fungi.

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.

In host evolution of Exophiala dermatitidis in cystic fibrosis lung micro-environment

Individuals with cystic fibrosis (CF) are susceptible to chronic lung infections that lead to inflammation and irreversible lung damage. While most respiratory infections that occur in CF are caused by bacteria, some are dominated by fungi such as the slow-growing black yeast Exophiala dermatitidis. Here, we analyze isolates of E. dermatitidis cultured from two samples, collected from a single subject 2 years apart. One isolate genome was sequenced using long-read Nanopore technology as an in-population reference to use in comparative single nucleotide polymorphism and insertion-deletion variant analyses of 23 isolates. We then used population genomics and phylo-genomics to compare the isolates to each other as well as the reference genome strain E. dermatitidis NIH/UT8656. Within the CF lung population, three E. dermatitidis clades were detected, each with varying mutation rates. Overall, the isolates were highly similar suggesting that they were recently diverged. All isolates were MAT 1-1, which was consistent with their high relatedness and the absence of evidence for mating or recombination between isolates. Phylogenetic analysis grouped sets of isolates into clades that contained isolates from both early and late time points indicating there are multiple persistent lineages. Functional assessment of variants unique to each clade identified alleles in genes that encode transporters, cytochrome P450 oxidoreductases, iron acquisition, and DNA repair processes. Consistent with the genomic heterogeneity, isolates showed some stable phenotype heterogeneity in melanin production, subtle differences in antifungal minimum inhibitory concentrations, and growth on different substrates. The persistent population heterogeneity identified in lung-derived isolates is an important factor to consider in the study of chronic fungal infections, and the analysis of changes in fungal pathogens over time may provide important insights into the physiology of black yeasts and other slow-growing fungi in vivo.

In Vitro and In Vivo Evaluation of Synergistic Effects of Everolimus in Combination with Antifungal Agents on Exophiala dermatitidis

To investigate the combined function of the novel oral mTOR inhibitor, everolimus, with antifungal agents and their potential mechanisms against Exophiala dermatitidis, the CLSI microliquid-based dilution method M38-A2, chequerboard technique, and disk diffusion testing were performed. The efficacy of everolimus was evaluated in combination with itraconazole, voriconazole, posaconazole, and amphotericin B against 16 clinically isolated strains of E. dermatitidis. The synergistic effect was determined by measuring the MIC and fractional inhibitory concentration index. Dihydrorhodamine 123 was used for the quantification of ROS levels. The differences in the expression of antifungal susceptibility-associated genes were analyzed following different types of treatment. Galleria mellonella was used as the in vivo model. While everolimus alone showed minimal antifungal effects, combinations with itraconazole, voriconazole, posaconazole, or amphotericin B resulted in synergy in 13/16 (81.25%), 2/16 (12.5%), 14/16 (87.75%), and 5/16 (31.25%) of isolates, respectively. The disk diffusion assay revealed that the combination of everolimus and antifungal drugs showed no significant increase in the inhibition zones compared with the single agent, but no antagonistic effects were observed. Combination of everolimus and antifungal agents resulted in increased ROS activity (everolimus + posaconazole versus posaconazole [P < 0.05], everolimus + amphotericin B versus amphotericin B [P < 0.002]). Simultaneously, compared to mono-treatment, the combination of everolimus + itraconazole suppressed the expression of MDR2 (P < 0.05) and the combination of everolimus + amphotericin B suppressed the expression of MDR3 (P < 0.05) and CDR1B (P < 0.02). In vivo, combinations of everolimus and antifungal agents improved survival rates, particularly the combination of everolimus + amphotericin B (P < 0.05). In summary, the in vivo and in vitro experiments performed in our study suggest that the combination of everolimus with azoles or amphotericin B can have synergistic effects against E. dermatitidis, potentially due to the induction of ROS activity and inhibition of efflux pumps, providing a promising new approach for the treatment of E. dermatitidis infections. IMPORTANCE Cancer patients with E. dermatitidis infection have high mortality if untreated. Clinically, the conventional treatment of E. dermatitidis is poor due to the long-term use of antifungal drugs. In this study, we have for the first time investigated the interaction and action mechanism of everolimus combined with itraconazole, voriconazole, posaconazole, and amphotericin B on E. dermatitidis in vitro and in vivo, which provided new ideas and direction for further exploring the mechanism of drug combination and clinical treatment of E. dermatitidis.

Pulmonary phaeohyphomycosis due to Exophiala dermatitidis in a patient with pulmonary non-tuberculous mycobacterial infection

A 65-year-old Japanese woman repeatedly withdrew and resumed antibiotics against pulmonary non-tuberculous mycobacterial infection caused by Mycobacterium intracellulare for more than 10 years. Although she continued to take medications, her respiratory symptoms and chest computed tomography indicated an enlarged infiltrative shadow in the lingular segment of the left lung that gradually worsened over the course of a year or more. Bronchoscopy was performed and mycobacterial culture of the bronchial lavage fluid was negative, whereas Exophiala dermatitidis was detected. After administration of oral voriconazole was initiated, the productive cough and infiltrative shadow resolved. There are no characteristic physical or imaging findings of E. dermatitidis, and it often mimics other chronic respiratory infections. Thus, when confronting refractory non-tuberculous mycobacterial cases, it might be better to assume other pathogenic microorganisms, including E. dermatitidis, and actively perform bronchoscopy.

Exophiala dermatitidis Central Line-Associated Bloodstream Infection in a Child with Ewing's Sarcoma: Case Report and Literature Review on Paediatric Infections

Exophiala dermatitidis is a dematiaceous, ubiquitous, dimorphic fungus, which can cause a wide range of invasive diseases in both immunocompromised and immunocompetent hosts. Bloodstream infections due to E. dermatitidis are rarely encountered in clinical practice, especially in pediatric patients. We describe a case of central line-associated bloodstream infection due to E. dermatitidis in a 4.5-year-old boy with Ewing's sarcoma. The fungus was isolated from blood specimens taken from the Hickman line. The isolate was identified by its phenotypic characteristics, by MALDI-TOF and by using molecular methods. The infection was successfully treated with voriconazole and catheter removal. The literature was also reviewed on pediatric infections caused by E. dermatitidis, focusing on clinical manifestations and challenges associated with diagnosis and management.

Isolation of Exophiala dermatitidis is not associated with worse clinical outcomes during acute pulmonary exacerbations in cystic fibrosis

Introduction. The black yeast Exophiala dermatitidis has been isolated in respiratory samples from people with cystic fibrosis (CF). However, adequate detection may require longer incubation periods than the current UK national standard for CF respiratory samples. Furthermore, it is unclear whether isolation of E. dermatitidis is associated with poorer clinical outcomes in CF.

Hypothesis/gap statement. E. dermatitidis does not cause clinically significant lung disease in CF adults.

Aim. To evaluate differences in clinical outcomes over a 12 month period and during acute pulmonary exacerbations between CF adults with and without untreated E. dermatitidis.

Methodology. Incubation times for respiratory samples on Sabouraud dextrose agar with chloramphenicol (SABC) plates at a large regional adult CF centre were extended from 2 to 7 days over a 1 month period. The number of patients from whom E. dermatitidis was isolated, and the length of incubation time prior to isolation, were recorded. Outcomes of treatment of exacerbations with intravenous antibiotics but in the absence of concomitant antifungal therapy were compared between those with and without E. dermatitidis, as were changes in lung function and body mass index (BMI) over a 12 month period.

Results. Extended incubation unmasked the presence of E. dermatitidis in 22 of 132 patients; all isolations occurred after >48 h of incubation. Patients who isolated E. dermatitidis had lower rates of Pseudomonas aeruginosa isolation (P=0.02) and higher rates of non-tuberculous mycobacteria isolation (P=0.03), and were more likely to be prescribed a long-term antifungal medication (P=0.03), but had no differences in age, sex, baseline lung function or body mass index (BMI). There were no differences in response to treatment of acute exacerbations between patients with and without E. dermatitidis, or in change in forced expiratory volume in 1 s (FEV1), BMI and number of exacerbations over 12 months of follow-up.

Conclusion. E. dermatitidis is not associated with worse clinical outcomes in CF. Given potential side effects and drug interactions, routine targeting of E. dermatitidis with antifungals during acute exacerbations is not advised.

Sinobronchial Syndrome Patients with Suspected Non-Tuberculous Mycobacterium Infection Exacerbated by Exophiala dermatitidis Infection

Background

Exophiala dermatitidis is an environmental black fungus that rarely causes respiratory infections, yet its pathophysiological features and treatment regimens have not been established.

Case Series

Two cases of exacerbations of chronic bronchitis and sinusitis due to E. dermatitidis infection in Japan are presented. Both patients were women, and non-tuberculous Mycobacterium (NTM) infection was suspected based on chest radiological findings, but E. dermatitidis was detected from bronchial lavage fluid and nasal mucus, respectively. Both cases were successfully treated by antifungal agents such as liposomal amphotericin B, voriconazole, and itraconazole, but clarithromycin, rifampicin, ethambutol, and sitafloxacin for NTM were not effective.

Conclusion

E. dermatitidis can become a respiratory pathogen, especially in patients with chronic sinobronchial syndrome.

Exophiala Endophthalmitis after Cataract Surgery

Purpose: To report a case of Exophiala endophthalmitis after cataract surgery, which has not been reported previously in Korea.Case summary: A 70-year-old woman visited the hospital 7 days after cataract surgery in her right eye with unilateral vision impairment. At the time of the visit, visual acuity of the right eye was hand motion, and the fundus was not clearly observed due to numerous inflammatory cells with hypopyon in the anterior chamber. With an initial diagnosis of suspected bacterial endophthalmitis, vitrectomy was performed immediately with intravitreal injection of antibiotics and steroid. On day 14 after vitrectomy, inflammation in the anterior chamber and vitreous opacity worsened, and complete vitrectomy, including of the vitreous base, and removal of the intraocular lens and capsule was performed. Exophiala was detected in the biopsy specimen on day 6 after the second surgery, and the patient was discharged with a prescription for voriconazole eye drops. On day 23 after the second surgery, the best-corrected visual acuity in the right eye had improved to 1.0, and there was no evidence of endophthalmitis recurrence and no observed additional abnormal findings of the fundus until 6 months after second surgery.Conclusions: In a case of fungal endophthalmitis that occurred after cataract surgery, good results were obtained by vitrectomy involving complete removal of the peripheral vitreous body, including the intraocular lens and lens capsule, which was the basis for growth of the fungus in the early stage of endophthalmitis.

Fungal Genomics in Respiratory Medicine: What, How and When?

Respiratory infections caused by fungal pathogens present a growing global health concern and are a major cause of death in immunocompromised patients. Worryingly, coronavirus disease-19 (COVID-19) resulting in acute respiratory distress syndrome has been shown to predispose some patients to airborne fungal co-infections. These include secondary pulmonary aspergillosis and mucormycosis. Aspergillosis is most commonly caused by the fungal pathogen Aspergillus fumigatus and primarily treated using the triazole drug group, however in recent years, this fungus has been rapidly gaining resistance against these antifungals. This is of serious clinical concern as multi-azole resistant forms of aspergillosis have a higher risk of mortality when compared against azole-susceptible infections. With the increasing numbers of COVID-19 and other classes of immunocompromised patients, early diagnosis of fungal infections is critical to ensuring patient survival. However, time-limited diagnosis is difficult to achieve with current culture-based methods. Advances within fungal genomics have enabled molecular diagnostic methods to become a fast, reproducible, and cost-effective alternative for diagnosis of respiratory fungal pathogens and detection of antifungal resistance. Here, we describe what techniques are currently available within molecular diagnostics, how they work and when they have been used.

Clinical Spectrum, Molecular Characterization, Antifungal Susceptibility Testing of Exophiala spp. From India and Description of a Novel Exophiala Species, E. arunalokei sp. nov

Introduction

Exophiala spp. are important opportunist pathogens causing subcutaneous or even fatal disseminated infections in otherwise both immunosuppressed and healthy individuals but there are no systematic studies on the isolates of Exophiala species from India.

Methods

Twenty-four isolates of Exophiala species were retrieved from the National Culture Collection of Pathogenic Fungi (NCCPF) and identified phenotypically and by molecular methods (ITS region sequencing) followed by antifungal susceptibility testing (AFST) as per CLSI-M38A3 guidelines. A review of the literature of cases from India was performed up to 1^st January 2021 using the Medline and Cochrane database.

Results

E. dermatitidis (n = 8), E. jeanselmei (n = 6), E. spinifera (n = 6), E. mesophila (n = 1), E. oligosperma (n = 1), E. xenobiotica (n = 1) were identified and the sequencing of ITS, β-tubulin and β-actin revealed a novel species, E. arunalokei sp. nov. (n = 1). The ITS sequence phylogram of E. jeanselmei revealed that the majority (83%) formed a separate cluster close to type A while majority (75%) of E. dermatitidis were type B. The MIC50 (mg/L) of amphotericin, itraconazole, voriconazole, micafungin, caspofungin, anidulafungin, and posaconazole, was 1, 0.25, 0.125, 0.12, 0.125, 0.062, and 0.062, respectively. Sixteen more cases were identified on the literature review and a significant association of E. dermatitidis with history of surgical procedures (p = 0.013), invasive disease (p = 0.032) and of E. mesophila with tuberculosis (p = 0.026) was seen.

Conclusion

This, to the best of our knowledge is the first study from India elucidating the molecular and clinical characteristics of Exophiala species and the first Indian report of human infection due to E. xenobiotica and E. arunalokei.

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.

Impact of airway Exophiala spp. on children with cystic fibrosis

INTRODUCTION

Isolation of Exophiala species from sputum samples has become increasingly reported in Cystic Fibrosis (CF). However, the clinical significance of Exophiala spp. with regards to the paediatric CF population is unknown.

METHODS

A case control study was undertaken to compare CF children with and without chronic Exophiala spp. in their sputum samples. Demographic and clinical data were collected retrospectively for each case from the date of Exophiala isolation and for 12 months preceding isolation. Each case was compared to three age and year-matched controls. To determine the effect of Exophiala on clinical course, patients were then followed for 12 months post isolation.

RESULTS

In total, 27 of 244 eligible paediatric CF patients (11%) isolated Exophiala spp. on more than one occasion. There were no significant differences in the key clinical parameters: spirometry, mean number of intravenous (IV) antibiotic days and body mass index (BMI), between cases and controls (p = 0.91, p = 0.56 and p = 0.63 respectively). A higher proportion of cases isolated Candida spp. (67% vs 21%, p < 0.0001) and Aspergillus fumigatus (37% vs 26%, p = 0.37). There was no clinically significant difference in spirometry, mean number of IV antibiotic days and BMI in cases pre and post Exophiala spp. isolation. Posaconazole was the only drug used that successfully eradicated Exophiala.

CONCLUSION

Despite the frequent isolation of Exophiala spp. in this cohort, in most patients it is not associated with significant clinical deterioration. It does however seem to be associated with isolation of other fungi.

Managing Fungal Infections in Cystic Fibrosis Patients: Challenges in Clinical Practice

Cystic Fibrosis (CF) is an autosomal recessive disease characterized by a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Impairment of the CFTR protein in the respiratory tract results in the formation of thick mucus, development of inflammation, destruction of bronchial tissue, and development of bacterial or fungal infections over time. CF patients are commonly colonized and/or infected with fungal organisms, Candida albicans or Aspergillus fumigatus, with prevalence rates ranging from 5% to 78% in the literature. Risk factors for acquiring fungal organisms include older age, coinfection with Pseudomonas aeruginosa, prolonged use of oral and inhaled antibiotics, and lower forced expiratory volume (FEV₁). There are limited data available to differentiate between contamination, colonization, and active infection. Furthermore, the pathogenicity of colonization is variable in the literature as some studies report a decline in lung function associated with fungal colonization whereas others showed no difference. Limited data are available for the eradication of fungal colonization and the treatment of active invasive aspergillosis in adult CF patients. In this review article, we discuss the challenges in clinical practice and current literature available for laboratory findings, clinical diagnosis, and treatment options for fungal infections in adult CF patients.

In vitro and in vivo Study of Antifungal Effect of Pyrvinium Pamoate Alone and in Combination With Azoles Against Exophiala dermatitidis

Infections of Exophiala dermatitidis are often chronic and recalcitrant. Combination therapies with novel compounds and azoles could be an effective solution. Previously, we have demonstrated that pyrvinium pamoate exerted antifungal activity alone and favorable synergy with azoles against planktonic E. dermatitidis. Herein, the underlying antifungal mode of action were investigated. Pyrvinium alone showed sessile MIC50 (SMIC50) of 8->16 μg/ml against E. dermatitidis biofilms. However, synergism of PP with itraconazole, voriconazole, and posaconazole were observed against 16 (88.9%), 9 (50%), and 13 (72.2%) strains of E. dermatitidis biofilms. In accordance with in vitro susceptibilities, pyrvinium alone at concentration of 2 μg/ml resulted in significant growth restriction of planktonic E. dermatitidis. Pyrvinium alone resulted in reduction of biofilm formation. Higher concentration of pyrvinium was associate with more progressive reduction of biofilm mass. The in vivo activity of pyrvinium alone and combined with azoles was evaluated using Galleria mellonella model. Pyrvinium alone significantly improved the survival rate of larvae (P < 0.0001). The combination of pyrvinium and voriconazole or posaconazole acted synergistically in vivo (P < 0.05). Fungal burden determination revealed significant reduction of numbers of colony forming unit (CFU) in larvae treated with pyrvinium-itraconazole and pyrvinium-posaconazole compared to itraconazole or posaconazole alone group, respectively. The effect of pyrvinium on apoptosis, expression of TOR and HSP90, and drug efflux reversal were evaluated by PI/Annexin V staining, Real-Time Quantitative PCR and Rhodamine 6G assay, respectively. Pyrvinium alone or combined with azoles significantly (P < 0.05) increased late apoptosis or necrosis of E. dermatitidis cells. Pyrvinium combined with posaconazole significantly decreased the expression of TOR and Hsp90 compared to posaconazole alone group (P < 0.05). Pyrvinium resulted in significant (P < 0.05) decrease of the efflux of Rhodamine 6G. These findings suggested pyrvinium could be a promising synergist with azoles. The underlying mechanisms could be explained by inducing apoptosis/necrosis, inhibition of drug efflux pumps, and signaling pathways related with stress response and growth control.

The fungal airway microbiome in cystic fibrosis and non-cystic fibrosis bronchiectasis

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The prevalence of fungal disease is increasing in CF and non-CF bronchiectasis.

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Effective management of fungal disease requires an understanding of the mycobiome.

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Culture methods alone are inadequate for the accurate diagnosis of fungal disease.

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Our study provides a framework to characterize fungal airway disease using NGS.

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NGS can improve detection and clinical management of fungal infections.

Background

The prevalence of fungal disease in cystic fibrosis (CF) and non-CF bronchiectasis is increasing and the clinical spectrum is widening. Poor sensitivity and a lack of standard diagnostic criteria renders interpretation of culture results challenging. In order to develop effective management strategies, a more accurate and comprehensive understanding of the airways fungal microbiome is required. The study aimed to use DNA sequences from sputum to assess the load and diversity of fungi in adults with CF and non-CF bronchiectasis.

Methods

Next generation sequencing of the ITS2 region was used to examine fungal community composition (n = 176) by disease and underlying clinical subgroups including allergic bronchopulmonary aspergillosis, chronic necrotizing pulmonary aspergillosis, non-tuberculous mycobacteria, and fungal bronchitis. Patients with no known active fungal disease were included as disease controls.

Results

ITS2 sequencing greatly increased the detection of fungi from sputum. In patients with CF fungal diversity was lower, while burden was higher than those with non-CF bronchiectasis. The most common operational taxonomic unit (OTU) in patients with CF was Candida parapsilosis (20.4%), whereas in non-CF bronchiectasis sputum Candida albicans (21.8%) was most common. CF patients with overt fungal bronchitis were dominated by Aspergillus spp., Exophiala spp., Candida parapsilosis or Scedosporium spp.

Conclusion

This study provides a framework to more accurately characterize the extended spectrum of fungal airways diseases in adult suppurative lung diseases.

In Vitro and In Vivo Study on the Synergistic Effect of Minocycline and Azoles against Pathogenic Fungi

In vitro and in vivo interactions of minocycline and azoles, including itraconazole, voriconazole, and posaconazole, against filamentous pathogenic fungi were investigated. A total of 56 clinical isolates were studied in vitro via broth microdilution checkerboard technique, including 20 strains of Aspergillus fumigatus, 7 strains of Aspergillus flavus, 16 strains of Exophiala dermatitidis, 10 strains of Fusarium solani, and 3 strain s of Fusarium oxysporum The results revealed that minocycline did not exhibit any significant antifungal activity against any of the tested strains. However, favorable synergy of minocycline with itraconazole, voriconazole, or posaconazole was observed against 34 (61%), 28 (50%), and 38 (68%) isolates, respectively, including azole-resistant A. fumigatus and Fusarium spp. with inherently high MICs of azoles. Synergistic combinations resulted in 4-fold to 16-fold reduction of effective MICs of minocycline and azoles. No antagonism was observed. In vivo effects of minocycline-azole combinations were evaluated by survival assay in a Galleria mellonella model infected with E. dermatitidis strain BMU00034; F. solani strain FS9; and A. fumigatus strains AF293, AFR1, and AFR2. Minocycline acted synergistically with azoles and significantly increased larvae survival in all isolates (P < 0.001), including azole-resistant A. fumigatus and azole-inactive Fusarium spp. In conclusion, the results suggested that minocycline combined with azoles may help to enhance the antifungal susceptibilities of azoles against pathogenic fungi and had the potential to overcome azole resistance issues.

The Neurotropic Black Yeast Exophiala dermatitidis Induces Neurocytotoxicity in Neuroblastoma Cells and Progressive Cell Death

The neurotropic and extremophilic black yeast Exophiala dermatitidis (Herpotrichellaceae) inhabits diverse indoor environments, in particular bathrooms, steam baths, and dishwashers. Here, we show that the selected strain, EXF-10123, is polymorphic, can grow at 37 °C, is able to assimilate aromatic hydrocarbons (toluene, mineral oil, n-hexadecane), and shows abundant growth with selected neurotransmitters (acetylcholine, gamma-aminobutyric acid, glycine, glutamate, and dopamine) as sole carbon sources. We have for the first time demonstrated the effect of E. dermatitidis on neuroblastoma cell model SH-SY5Y. Aqueous and organic extracts of E. dermatitidis biomass reduced SH-SY5Y viability by 51% and 37%, respectively. Melanized extracellular vesicles (EVs) prepared from this strain reduced viability of the SH-SY5Y to 21%, while non-melanized EVs were considerably less neurotoxic (79% viability). We also demonstrated direct interactions of E. dermatitidis with SH-SY5Y by scanning electron and confocal fluorescence microscopy. The observed invasion and penetration of neuroblastoma cells by E. dermatitidis hyphae presumably causes the degradation of most neuroblastoma cells in only three days. This may represent a so far unknown indirect or direct cause for the development of some neurodegenerative diseases such as Alzheimer’s.

Acute and Chronic Infection Management in CF

CFTR protein malfunction results in thick, copious mucus, causes poor mucociliary clearance and, ultimately, structural lung damage such as bronchiectasis. All of these manifestations of cystic fibrosis contribute to a rich milieu for lower respiratory pathogens in patients affected by the disease. CF patients are, therefore, highly susceptible to chronic colonization with many pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa. They are also uniquely prone to acute infections with respiratory pathogens, which tend to persist longer and cause more impairment in lung function than in patients without CF. Tailored strategies for managing infectious complications of CF patients include chronic prophylactic antibiotics, use of systemic as well as inhaled antibiotics, mechanical assistance with mucus clearance, and scrupulous infection control measures.

Cerebral Phaeohyphomycosis Caused by Exophiala dermatitidis in a Chinese CARD9-Deficient Patient: A Case Report and Literature Review

Exophiala dermatitidis, a dematiaceous fungus typically found in decaying organic matter worldwide, is a rare cause of fungal infections. Cerebral phaeohyphomycosis is a sporadic but often fatal infection of the brain caused by E. dermatitidis. However, due to limited reports, little is known about its specific predisposing factors, clinical manifestation, and optimal treatment modality. Here, we report a clinical presentation and management of cerebral phaeohyphomycosis in a Chinese patient. An otherwise healthy, young male who was diagnosed with neck fungal lymphadenitis caused by E. dermatitidis 7 months prior and was treated with itraconazole, presented later with progressive intracranial hypertension and persistent coma. Culture of the neck lymphoid tissue produced growth of a black yeast-like fungus, which was identified as E. dermatitidis by sequencing of the ribosomal DNA internal transcribed spacer (ITS) domains. Accordingly, a cerebral biopsy was performed, and the pathological report showed mycelia and fungal granulomas. We also sequenced CARD9 in the patient and found him to be homozygous for loss-of-function mutation; his parents were heterozygous for the same mutation. This is a first case report of cerebral phaeohyphomycosis caused by E. dermatitidis in a CARD9-deficient Chinese patient. He eventually succumbed to brain herniation and severe lung infection with a poor response to therapy. Thus, previously healthy patients with unexplained invasive E. dermatitidis infection, at any age, should be tested for inherited CARD9 deficiency.

Respiratory Fungal Diseases in Adult Patients With Cystic Fibrosis

Clinical manifestations of respiratory fungal diseases in adult cystic fibrosis (CF) patients are very heterogeneous, ranging from asymptomatic colonization to chronic infections, allergic disorders, or invasive diseases in immunosuppressed CF patients after lung transplantation. In this narrative review, mainly addressed to clinicians without expertise in CF who may nonetheless encounter adult CF patients presenting with acute and chronic respiratory syndromes, we briefly summarize the most representative clinical aspects of respiratory fungal diseases in adult CF patients.

Lonafarnib synergizes with azoles against Aspergillus spp. and Exophiala spp

Farnesylation, which is catalyzed by farnesyltransferase, promotes membrane association of the modified protein and protein-protein interactions, and plays an important role in a number of physiological processes of pathogenic fungi, including stress response, environmental adaption and virulence. Lonafarnib is an orally bioavailable nonpeptide tricyclic farnesyltransferase inhibitor with excellent pharmacokinetic and safety profile. In the present study, we investigated the in vitro activities of lonafarnib alone or combined with azoles, including itraconazole, voriconazole, and posaconazole, against 22 strains of Aspergillus spp. and 18 strains of Exophiala dermatitidis via broth microdilution checkerboard technique. Lonafarnib alone was inactive against all isolates tested. However, synergistic effects between lonafarnib and itraconazole were observed in 86% Aspergillus strains and 94% E. dermatitidis strains. In addition, lonafarnib/posaconazole combination also exhibited synergism against 59% of Aspergillus strains and 100% E. dermatitidis strains. However, synergistic effects of lonafarnib/voriconazole were only observed in 32% Aspergillus strains and 28% E. dermatitidis strains. The effective working ranges of lonafarnib were 2-4 μg/ml and 1-4 μg/ml against Aspergillus isolates and E. dermatitidis isolates, respectively. No antagonism was observed in all combinations. This study demonstrated that lonafarnib could enhance the in vitro antifungal activity of itraconazole, posaconazole and voriconazole against Aspergillus spp. and E. dermatitidis, suggesting that azoles, especially itraconazole and posaconazole, combined with farnesyltransferase inhibitor might provide a potential strategy to the management of Aspergillus and Exophiala infections. However, further studies are warranted to elucidate the underlying mechanism and to investigate the potential of reliable and safe application in clinical practice.

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.

Exophiala dermatitidis: Key issues of an opportunistic fungal pathogen

The black yeast Exophiala dermatitidis is an opportunistic pathogen, causing phaeohyphomycosis in immunosuppressed patients, chromoblastomycosis and fatal infections of the central nervous system in otherwise healthy Asian patients. In addition, it is also regularly isolated from respiratory samples from cystic fibrosis patients, with rates varying between 1% and 19%.Melanin, as part of the cell wall of black yeasts, is one major factor known contributing to the pathogenicity of E. dermatitidis and increased resistance against host defense and anti-infective therapeutics. Further virulence factors, e.g. the capability to adhere to surfaces and to form biofilm were reported. A better understanding of the pathogenicity of E. dermatitidis is essential for the development of novel preventive and therapeutic strategies. In this review, the current knowledge of E. dermatitidis prevalence, clinical importance, diagnosis, microbiological characteristics, virulence attributes, susceptibility, and resistances as well as therapeutically strategies are discussed.

Airway colonisation by Candida and Aspergillus species in Iranian cystic fibrosis patients

Cystic fibrosis (CF) is associated with increased rates of morbidity and mortality due to fungal and bacterial colonisation of the airways or respiratory infections. The prevalence of fungi in Iranian CF population has been underestimated. Therefore, the current study was conducted to define the frequency of fungi in respiratory specimens obtained from Iranian CF patients based on conventional and molecular assays. Furthermore, in vitro antifungal susceptibility testing was performed on the obtained isolates according to the guidelines from the Clinical and Laboratory Standards Institute. A cohort of 42 CF patients, including 29 males and 13 females, were categorised according to the referenced diagnostic criteria. Candida albicans (n = 24, 80%), C. dubliniensis (n = 2, 6.6%), C. parapsilosis (n = 2, 6.6%), C. tropicalis (n = 1, 3.3%), C. glabrata (n = 1, 3.3%) and Meyerozyma caribbica (n = 1, 3.3%) were isolated from 73.8% of the CF patients. Aspergillus terreus (n = 3, 42.8%) was identified as the most common Aspergillus species, followed by A. fumigatus (n = 2, 28.5%), A. oryzae (n = 1, 14.2%) and A. flavus (n = 1, 14.2%). Bacterial and fungal co-colonisation was detected in 7 (16.6%) and 22 (52.3%) samples that were positive for Aspergillus and Candida species, respectively. However, Scedosporium species and Exophiala dermatitidis never were detected. In terms of geometric mean (GM) minimum inhibitory concentrations (MICs), posaconazole (0.018 μg/mL) and caspofungin (0.083 μg/mL) exhibited the highest antifungal activities against all Candida species. In addition, posaconazole exhibited the lowest MIC range (0.008-0.063 μg/mL) against all Aspergillus species, followed by caspofungin (0.016-0.125 μg/mL) and voriconazole (0.125-0.25 μg/mL). To conclude, it is essential to adopt a consistent method for the implementation of primary diagnosis and determination of treatment regimen for the CF patients. However, further studies are still needed to better define the epidemiology of fungal organisms in CF patients from the Middle East and the clinical significance of their isolation.

Fatal phaeohyphomycosis due to Exophiala sp. infection in a free-living common toad Bufo bufo

A wild adult female common toad Bufo bufo found dead in Scotland in September 2016 was observed to have hepatomegaly, a large soft tissue mass in the coelomic cavity (2.7 g, 3.5 × 2.3 × 1.8 cm) and numerous dark-red papules (1-2 mm diameter) in the skin and subjacent tissue over the back and dorsal aspects of the limbs. Histopathological examination identified marked hepatitis and coelomitis associated with pigmented fungal hyphae, which are results consistent with a diagnosis of phaeohyphomycosis. Sequencing of the internal transcribed spacer region and the D1-D2 region of the large subunit of the ribosomal RNA gene from affected liver tissue identified the presence of Exophiala (Chaetothyriales) sp., a black yeast previously identified as a cause of amphibian phaeohyphomycosis. To our knowledge, this is the first published report of Exophiala sp. in a wild or captive amphibian in Europe and the first description of phaeohyphomycosis affecting a free-living amphibian in Great Britain. Exophiala spp. are saprobes and opportunistic pathogens. It has been postulated that phaeohyphomycosis is a disease of immunocompromised amphibians; however, we found no evidence of significant concurrent infection or generalised debility in this common toad. Phaeohyphomycosis appears to be a sporadic cause of mortality in amphibians, and this report adds to the growing list of pathogens known to affect wild amphibians in Europe.

Black yeasts in the omics era: Achievements and challenges

Black yeasts (BY) comprise a group of polyextremotolerant fungi, mainly belonging to the order Chaetothyriales, which are capable of colonizing a wide range of extreme environments. The tolerance to hostile habitats can be explained by their intrinsic ability to survive under acidic, alkaline, and toxic conditions, high temperature, low nutrient availability, and osmotic and mechanical stress. Occasionally, some species can cause human chromoblastomycosis, a chronic subcutaneous infection, as well as disseminated or cerebral phaeohyphomycosis. Three years after the release of the first black yeast genome, the number of projects for sequencing these organisms has significantly increased. Over 37 genomes of important opportunistic and saprobic black yeasts and relatives are now available in different databases. The whole-genome sequencing, as well as the analysis of differentially expressed mRNAs and the determination of protein expression profiles generated an unprecedented amount of data, requiring the development of a curated repository to provide easy accesses to this information. In the present article, we review various aspects of the impact of genomics, transcriptomics, and proteomics on black yeast studies. We discuss recent key findings achieved by the use of these technologies and further directions for medical mycology in this area. An important vehicle is the Working Groups on Black Yeasts and Chromoblastomycosis, under the umbrella of ISHAM, which unite the clinicians and a highly diverse population of fundamental scientists to exchange data for joint publications.

Direct detection of Exophiala and Scedosporium species in sputa of patients with cystic fibrosis

Detection of species of Exophiala and Scedosporium in the respiratory tracts of cystic fibrosis (CF) patients remains controversial because of highly variable results. The results of our study suggested a significantly higher prevalence and more complex colonization than previously estimated. Approximately 17% (27/162) of clinical sputum samples were found to be positive for Exophiala dermatitidis and 30% (49/162) were positive for Scedosporium apiospermum / S. boydii species complex determined by reverse line blot (RLB) hybridization. In contrast, only 14.2% (23/162) and 1.2% (2/162) of clinical sputa were positive for E. dermatitidis and S. apiospermum / S. boydii species complex when tested by culture, respectively. Molecular detection methods, such as loop-mediated isothermal amplification (LAMP) or reverse line blot (RLB) hybridization, have the potential to become powerful alternatives to selective culture, providing a more realistic understanding on the prevalence of E. dermatitidis and S. apiospermum / S. boydii species complex in the respiratory tract of CF patients.

The myriad challenges of respiratory fungal infection in cystic fibrosis

Fungal infection in cystic fibrosis (CF) is a recognized challenge, with many areas requiring further investigation. Consensus definitions exist for allergic bronchopulmonary aspergillus in CF, but the full scope of clinically relevant non-allergic fungal disease in CF-asymptomatic colonization, transient or chronic infection localized to endobronchial mucus plugs or airway tissue, and invasive disease-is yet to be clearly defined. Recent advances in mycological culture and non-culture identification have expanded the list of both potential pathogens and community commensals in the lower respiratory tract. Here we aim to outline the current understanding of fungal presence in the CF respiratory tract, risk factors for acquiring fungi, host-pathogen interactions that influence the role of fungi from bystander to pathogen, advances in the diagnostic approaches to isolating and identifying fungi in CF respiratory samples, challenges of classifying clinical phenotypes of CF patients with fungi, and current treatment approaches. Development and validation of biomarkers characteristic of different fungal clinical phenotypes, and controlled trials of antifungal agents in well-characterized target populations, remain central challenges to surmount and goals to be achieved.

Exophiala dermatitidis isolates from various sources: using alternative invertebrate host organisms (Caenorhabditis elegans and Galleria mellonella) to determine virulence

Exophiala dermatitidis causes chromoblastomycosis, phaeohyphomycosis and fatal infections of the central nervous system of patients with Asian background. It is also found in respiratory secretions from cystic fibrosis (CF) patients. In this study a variety of E. dermatitidis strains (isolates from Asia, environmental and CF) were characterized in their pathogenicity by survival analyzes using two different invertebrate host organisms, Caenorhabditis elegans and Galleria mellonella. Furthermore, the morphological development of hyphal formation was analyzed. E. dermatitidis exhibited pathogenicity in C. elegans. The virulence varied in a strain-dependent manner, but the nematodes were a limited model to study hyphal formation. Analysis of a melanin-deficient mutant (Mel-3) indicates that melanin plays a role during virulence processes in C. elegans. The strains isolated from Asian patients exhibited significantly higher virulence in G. mellonella compared to strains from other sources. Histological analyzes also revealed a higher potential of invasive hyphal growth in strains isolated from Asian patients. Interestingly, no significant difference was found in virulence between the Mel-3 mutant and their wild type counterpart during infection in G. mellonella. In conclusion, invasive hyphal formation of E. dermatitidis was associated with increased virulence. This work is the basis for future studies concerning E. dermatitidis virulence.

In vitro interactions between 17-AAG and azoles against Exophiala dermatitidis

BACKGROUND

Exophiala dermatitidis causes a variety of illnesses in humans which are always refractory to available treatment modalities. Hsp90 governs crucial stress responses, cell wall repair mechanisms and antifungal resistance in pathogenic fungi. Thus, targeting Hsp90 with specific inhibitors holds considerable promise as combination strategy.

OBJECTIVES

To investigate the antifungal effect of 17-AAG alone or combined with azoles against E. dermatitidis.

METHODS

In vitro interactions of 17-AAG, a Hsp90 inhibitor, and azoles including itraconazole, voriconazole and posaconazole against E. dermatitidis were evaluated via broth microdilution chequerboard technique, adapted from the CLSI M38-A2 method. A total of 18 clinical strains were studied. Candida parapsilosis (ATCC22019) was included to ensure quality control.

RESULTS AND CONCLUSIONS

17-AAG alone exhibited minimal antifungal activity against all tested isolates. However, synergistic effects between 17-AAG and posaconazole, itraconazole or voriconazole were observed against 15 (83.3%), 12 (66.7%) and 1 (5.6%) isolates of E. dermatitidis, respectively. The effective working ranges of 17-AAG in synergistic combinations were mostly within 2-8 μg/mL. No antagonism was observed. In conclusion, harnessing fungal Hsp90 with 17-AAG might prove a potential antifungal regimen for E. dermatitidis infections. However, due to the host toxicity of 17-AAG, more efforts are needed to develop fungal specific Hsp90 inhibitors.

An updated comprehensive systematic review of Cladophialophora bantiana and analysis of epidemiology, clinical characteristics, and outcome of cerebral cases

Cladophialophora bantiana is a phaeoid fungus that only rarely has been isolated from sources other than the human brain. It has a particular tropism for the central nervous system (CNS). We have integrated and updated large-scale data related to several aspects of C. Bantiana and reviewed all the available reports on its cerebral infections, focusing on their geographical distribution, infection routes, immune status of infected individuals, type and location of infections, clinical manifestations and treatment and outcome, briefly looking over the spectrum of other disease entities associated with C. bantiana, that is, extra-cerebral and animal infections and on the environmental sources of this fungus. Among the agents of phaeohyphomycosis, a term used to describe an infection caused by a dark pigmented fungus, C. bantiana has some significant specific features. A total of 120 case reports were identified with a significantly higher percentage of healthy subjects than immune-debilitated patients (58.3% vs. 41.7%). Infections due to C. bantiana occur worldwide. The main clinical manifestations are brain abscess (97.5%), coinfection of brain tissue and meninges (14.2%) and meningitis alone (2.5%). Among immunocompetent patients, cerebral infection occurred in the absence of pulmonary lesions. The mortality rate is 65.0% regardless of the patient's immune status. The therapeutic options used include surgery or antifungals alone, and the combination of both, in most cases the fatal outcome being rapid after admission. Since the fungus is a true pathogen, laboratory workers should be made aware that BioSafety Level-3 precautions might be necessary.

Synergistic Interactions in Microbial Biofilms Facilitate the Establishment of Opportunistic Pathogenic Fungi in Household Dishwashers

Biofilms formed on rubber seals in dishwashers harbor diverse microbiota. In this study, we focussed on the microbial composition of bacteria and fungi, isolated from a defined area of one square centimeter of rubber from four domestic dishwashers and assessed their abilities to in vitro multispecies biofilm formation. A total of 80 isolates (64 bacterial and 16 fungal) were analyzed. Multiple combinations of bacterial isolates from each dishwasher were screened for synergistic interactions. 32 out of 140 tested (23%) four-species bacterial combinations displayed consistent synergism leading to an overall increase in biomass, in all experimental trails. Bacterial isolates from two of the four dishwashers generated a high number of synergistically interacting four-species consortia. Network based correlation analyses also showed higher co-occurrence patterns observed between bacterial members in the same two dishwasher samples, indicating cooperative effects. Furthermore, two synergistic four-species bacterial consortia were tested for their abilities to incorporate an opportunistic fungal pathogen, Exophiala dermatitidis and their establishment as biofilms on sterile ethylene propylene diene monomer M-class (EPDM) rubber and polypropylene (PP) surfaces. When the bacterial consortia included E. dermatitidis, the overall cell numbers of both bacteria and fungi increased and a substantial increase in biofilm biomass was observed. These results indicate a novel phenomenon of cross kingdom synergy in biofilm formation and these observations could have potential implications for human health.

Exophiala dermatitidis Endophthalmitis: Case Report and Literature Review

We report a case of a 59-year-old male patient with a postoperative fungal infection of the left eye. A dark-pigmented yeast, Exophiala dermatitidis (previously known as Wangiella dermatitidis), was identified from the culture of the biopsy taken from the posterior capsule. The infection was successfully eradicated by a combination of surgical and medical (i.e., voriconazole and fluconazole) treatment. This is the first report of successfully treated E. dermatitidis endophthalmitis, which demonstrates that a prompt and aggressive antifungal therapy combined with surgical intervention is necessary to prevent vision loss in cases of endophthalmitis due to Exophiala species. Beside the case description, we also aim to provide a literature review of previously reported eye infections caused by Exophiala species in order to help the future diagnosis and management of the disease.

Comparative Ecology of Capsular Exophiala Species Causing Disseminated Infection in Humans

Exophiala spinifera and Exophiala dermatitidis (Fungi: Chaetothyriales) are black yeast agents potentially causing disseminated infection in apparently healthy humans. They are the only Exophiala species producing extracellular polysaccharides around yeast cells. In order to gain understanding of eventual differences in intrinsic virulence of the species, their clinical profiles were compared and found to be different, suggesting pathogenic strategies rather than coincidental opportunism. Ecologically relevant factors were compared in a model set of strains of both species, and significant differences were found in clinical and environmental preferences, but virulence, tested in Galleria mellonella larvae, yielded nearly identical results. Virulence factors, i.e., melanin, capsule and muriform cells responded in opposite direction under hydrogen peroxide and temperature stress and thus were inconsistent with their hypothesized role in survival of phagocytosis. On the basis of physiological profiles, possible natural habitats of both species were extrapolated, which proved to be environmental rather than animal-associated. Using comparative genomic analyses we found differences in gene content related to lipid metabolism, cell wall modification and polysaccharide capsule production. Despite the fact that both species cause disseminated infections in apparently healthy humans, it is concluded that they are opportunists rather than pathogens.

Synergistic Effects of Tacrolimus and Azoles against Exophiala dermatitidis

In vitro interactions of tacrolimus, a calcineurin inhibitor, and azoles, including itraconazole, voriconazole, and posaconazole, against planktonic cells and biofilms of Exophiala dermatitidis were assessed via a broth microdilution checkerboard technique. A total of 16 clinical isolates were studied. The results revealed favorable synergistic inhibitory activity between tacrolimus and itraconazole, voriconazole, or posaconazole against 68.8%, 87.5%, and 100% of tested strains of planktonic E. dermatitidis, respectively.However, limited synergism was observed against biofilms of E. dermatitidis No antagonism was observed in all combinations.

Organization of Patient Management and Fungal Epidemiology in Cystic Fibrosis

The achievement of a better life for cystic fibrosis (CF) patients is mainly caused by a better management and infection control over the last three decades. Herein, we want to summarize the cornerstones for an effective management of CF patients and to give an overview of the knowledge about the fungal epidemiology in this clinical context in Europe. Data from a retrospective analysis encompassing 66,616 samples from 3235 CF patients followed-up in 9 CF centers from different European countries are shown.

Exophiala dermatitidis Revealing Cystic Fibrosis in Adult Patients with Chronic Pulmonary Disease

Cystic fibrosis (CF) is a genetic inherited disease due to mutations in the gene cystic fibrosis transmembrane conductance regulator (CFTR). Because of the huge diversity of CFTR mutations, the CF phenotypes are highly heterogeneous, varying from typical to mild form of CF, also called atypical CF. These atypical features are more frequently diagnosed at adolescence or adulthood, and among clinical signs and symptoms leading to suspect a mild form of CF, colonization or infection of the respiratory tract due to well-known CF pathogens should be a warning signal. Exophiala dermatitidis is a melanized dimorphic fungus commonly detected in respiratory specimens from CF patients, but only very rarely from respiratory specimens from non-CF patients. We described here two cases of chronic colonization of the airways by E. dermatitidis, with recurrent pneumonia and hemoptysis in one patient, which led clinicians to diagnose mild forms of CF in these elderly patients who were 68- and 87-year-old. These cases of late CF diagnosis suggest that airway colonization or respiratory infections due to E. dermatitidis in patients with bronchiectasis should led to search for a mild form of CF, regardless of the age and associated symptoms. On a broader level, in patients with chronic respiratory disease and recurrent pulmonary infections, an allergic bronchopulmonary mycosis or an airway colonization by CF-related fungi like E. dermatitidis or some Aspergillus, Scedosporium or Rasamsonia species, should be considered as potential markers of atypical CF and should led clinicians to conduct investigations for CF diagnosis.

Fungal Pathogens in CF Airways: Leave or Treat?

Chronic airway infection plays an essential role in the progress of cystic fibrosis (CF) lung disease. In the past decades, mainly bacterial pathogens, such as Pseudomonas aeruginosa, have been the focus of researchers and clinicians. However, fungi are frequently detected in CF airways and there is an increasing body of evidence that fungal pathogens might play a role in CF lung disease. Several studies have shown an association of fungi, particularly Aspergillus fumigatus and Candida albicans, with the course of lung disease in CF patients. Mechanistically, in vitro and in vivo studies suggest that an impaired immune response to fungal pathogens in CF airways renders them more susceptible to fungi. However, it remains elusive whether fungi are actively involved in CF lung disease pathologies or whether they rather reflect a dysregulated airway colonization and act as microbial bystanders. A key issue for dissecting the role of fungi in CF lung disease is the distinction of dynamic fungal-host interaction entities, namely colonization, sensitization or infection. This review summarizes key findings on pathophysiological mechanisms and the clinical impact of fungi in CF lung disease.

Challenges in Laboratory Detection of Fungal Pathogens in the Airways of Cystic Fibrosis Patients

Study of the clinical significance of fungal colonization/infection in the airways of cystic fibrosis (CF) patients, especially by filamentous fungi, is challenged by the absence of standardized methodology for the detection and identification of an ever-broadening range of fungal pathogens. Culture-based methods remain the cornerstone diagnostic approaches, but current methods used in many clinical laboratories are insensitive and unstandardized, rendering comparative studies unfeasible. Guidelines for standardized processing of respiratory specimens and for their culture are urgently needed and should include recommendations for specific processing procedures, inoculum density, culture media, incubation temperature and duration of culture. Molecular techniques to detect fungi directly from clinical specimens include panfungal PCR assays, multiplex or pathogen-directed assays, real-time PCR, isothermal methods and probe-based assays. In general, these are used to complement culture. Fungal identification by DNA sequencing methods is often required to identify cultured isolates, but matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is increasingly used as an alternative to DNA sequencing. Genotyping of isolates is undertaken to investigate relatedness between isolates, to pinpoint the infection source and to study the population structure. Methods range from PCR fingerprinting and amplified fragment length polymorphism analysis, to short tandem repeat typing, multilocus sequencing typing (MLST) and whole genome sequencing (WGS). MLST is the current preferred method, whilst WGS offers best case resolution but currently is understudied.

Ecology of the Human Opportunistic Black Yeast Exophiala dermatitidis Indicates Preference for Human-Made Habitats

Exophiala dermatitidis is an ascomycetous black yeast from the order Chaetothyriales. Its growth characteristics include the polymorphic life cycle, ability to grow at high and low temperatures, at a wide pH range, survival at high concentrations of NaCl, and survival at high UV and radioactive radiation. Exophiala dermatitidis causes deep or localized phaeohyphomycosis in immuno-compromised people worldwide and is regularly encountered in the lungs of cystic fibrosis patients. Regardless of numerous ecological studies worldwide, little is known about its natural habitat or the possible infection routes. The present review summarizes the published data on its frequency of occurrence in nature and in man-made habitats. We additionally confirmed its presence with culture-depending methods from a variety of habitats, such as glacial meltwater, mineral water, mineral-rich salt-pan mud, dishwashers, kitchens and different environments polluted with aromatic hydrocarbons. In conclusion, the frequency of its recovery was the highest in man-made indoor habitats, connected to water sources, and exposed to occasional high temperatures and oxidative stress.