Increased prevalence and altered species composition of filamentous fungi in respiratory specimens from cystic fibrosis patients

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.

Molecular epidemiology of Aspergillus species and other moulds in respiratory samples from Argentinean patients with cystic fibrosis

In cystic fibrosis (CF) patients, fungal colonization of the respiratory tract is frequently found. Aspergillus fumigatus is the most frequently recorded and is associated with loss of pulmonary function and allergic disease (ABPA). The knowledge on prevalence rates of filamentous fungi in CF patients in Latin America is scarce. One hundred and seventy-six fungal isolates recovered from the upper respiratory tract of CF patients from Argentina were identified to species by morphology and DNA sequencing. In total, 90% of CF patients were colonized by Aspergillus sp., followed by Exophiala sp. (14%) and Scedosporium sp. (10%). Among Aspergillus, six species complexes (Fumigati, Flavi, Terrei, Nigri, Usti, and Nidulante) and different cryptospecies were found. Among Scedosporium, three species were observed (Scedosporium apiospermum, Scedosporium aurantiacum and Scedosporium boydii). All Exophiala isolates were identified as Exophiala dermatitidis. Rare filamentous fungi were also found. All cases of ABPA were associated to the presence of A. fumigatus. Mixed colonization with other mould or rare fungi was observed in half of them. To our knowledge, this is the first prospective study of mould species in CF using molecular methods in Latin America. This study shows that Aspergillus sp., E. dermatitidis and Scedosporium sp. have a high frequency in CF patients from Argentina, and by far, A. fumigatus was the most commonly cultured species. Continuous clinical surveillance is required to detect the emergence of new fungal pathogens and to detect resistant or difficult-to-treat species capable of chronic colonizing the airways and of hematogenous dissemination in case of lung transplantation.

Fungal epidemiology in cystic fibrosis patients with a special focus on Scedosporium species complex

In this present study, for the first time, we evaluated the cystic fibrosis (CF) patients for the Scedosporium species and their antifungal susceptibility against eight antifungal agents. During one-year period, 90 Sputum samples were collected from Iranian CF patients. All samples were evaluated by direct microscopic examination, culture onto four different media including Malt extract agar, Inhibitory mold agar, Brain Heart Infusion and Scedo-Select III. The mold isolated fungi were identified by PCR-Sequencing of ITS and β-tubulin genes. In-vitro antifungal susceptibility was performed according to the Clinical & Laboratory Standards Institute (CLSI) M38-A2 guidelines. Out of 90 CF patients, 47 (52.2%) were male. The age of the patients ranged from 1 to 34 years (median of 15.84 ± 7.41 years). Overall, 3 (3.3%) cases were positive for Scedosporium spp. of which two isolates were characterized as Scedosporium boydii and one isolate as S. ellipsoideum. Among Aspergillus genus, A. flavus (29.4%) was the most prevalent species followed by A. tubingensis (24.7%), A. niger (17.0%) and A. fumigatus (14.5%). The minimum effective concentration ranges of micafungin, anidulafungin, and caspofungin were 0.008-0.031 μg/mL, 0.0625-0.25 μg/mL, and 0.0625-0.25 μg/mL, respectively. All isolates of Scedosporium species showed high minimum inhibitory concentration to the triazoles tested, except voriconazole. Our results showed that A. flavus and Scedosporium species are the most prevalent molds isolated from CF patient populations in Iran. Our findings have also showed that Scedo-Select III can be used as a reliable culture media for isolation of Scedosporium spp. in clinical samples.

Aspergillus Bronchitis in Patients with Cystic Fibrosis

Aspergillus fumigatus frequently colonizes the airways of patients with cystic fibrosis (CF) and may cause various severe infections, such as bronchitis. Serological data, sputum dependent markers and longitudinal data of treated cases of Aspergillus bronchitis were evaluated for further description of this infection. This study, which comprises three substudies, aimed to analyze epidemiological data of Aspergillus in CF and the entity of Aspergillus bronchitis. In a first step, data of the German Cystic Fibrosis Registry were used to evaluate the frequency of Aspergillus colonization in patients with CF (n = 2599). Then a retrospective analysis of 10 cases of Aspergillus bronchitis was performed to evaluate longitudinal data for lung function and clinical presentation parameters: sputum production, cough and physical capacity. Finally, a prospective cohort study (n = 22) was conducted to investigate serological markers for Aspergillus bronchitis: total serum IgE, specific serum IgE, specific serum IgG, as well as sputum galactomannan, real-time PCR detection of Aspergillus DNA in sputum and fungal cultures. Analysis of the German CF registry revealed an Aspergillus colonization rate of 32.5% among the 2599 patients. A retrospective data analysis of 10 treated cases revealed the clinical course of Aspergillus bronchitis, including repeated positive sputum culture findings for A. fumigatus, no antibiotic treatment response, total serum IgE levels <200 kU/l, no observation of new pulmonary infiltrates and appropriate antifungal treatment response. Antifungal treatment durations of 4 ± 1.6 (2-6) weeks significantly reduced cough (P = 0.0067), sputum production (P < 0.0001) and lung function measures (P = 0.0358) but not physical capacity (P = 0.0794). From this retrospective study, a prevalence of 1.6% was calculated. In addition, two cases of Aspergillus bronchitis were identified in the prospective cohort study according to immunological, molecular and microbiological parameters. A prevalence of 9% was assessed. Aspergillus bronchitis appears to occur in a minority of colonized CF patients. Antifungal treatment may reduce respiratory symptoms and restore lung function.

Allergic and Noninvasive Infectious Pulmonary Aspergillosis Syndromes

Aspergillus spp are ubiquitous in the environment, and inhalation of Aspergillus spores is unavoidable. An intact immune system, with normal airway function, protects most people from disease. Globally, however, the toll from aspergillosis is high. The literature has largely focused on invasive aspergillosis, yet the burden in terms of chronicity and prevalence is higher for noninvasive Aspergillus conditions. This article discusses allergic aspergilloses and provides an update on the diagnosis and management of allergic bronchopulmonary aspergillosis, including in patients with cystic fibrosis, and an update on severe asthma with fungal sensitization. In addition, the presentation, investigation, and management of noninvasive infectious aspergilloses are reviewed.

Proteomics as a Tool to Identify New Targets Against Aspergillus and Scedosporium in the Context of Cystic Fibrosis

Cystic fibrosis (CF) is a genetic disorder that increases the risk of suffering microbial, including fungal, infections. In this paper, proteomics-based information was collated relating to secreted and cell wall proteins with potential medical applications from the most common filamentous fungi in CF, i.e., Aspergillus and Scedosporium/Lomentospora species. Among the Aspergillus fumigatus secreted allergens, β-1,3-endoglucanase, the alkaline protease 1 (Alp1/oryzin), Asp f 2, Asp f 13/15, chitinase, chitosanase, dipeptidyl-peptidase V (DppV), the metalloprotease Asp f 5, mitogillin/Asp f 1, and thioredoxin reductase receive a special mention. In addition, the antigens β-glucosidase 1, catalase, glucan endo-1,3-β-glucosidase EglC, β-1,3-glucanosyltransferases Gel1 and Gel2, and glutaminase A were also identified in secretomes of other Aspergillus species associated with CF: Aspergillus flavus, Aspergillus niger, Aspergillus nidulans, and Aspergillus terreus. Regarding cell wall proteins, cytochrome P450 and eEF-3 were proposed as diagnostic targets, and alkaline protease 2 (Alp2), Asp f 3 (putative peroxiredoxin pmp20), probable glycosidases Asp f 9/Crf1 and Crf2, GPI-anchored protein Ecm33, β-1,3-glucanosyltransferase Gel4, conidial hydrophobin Hyp1/RodA, and secreted aspartyl protease Pep2 as protective vaccines in A. fumigatus. On the other hand, for Scedosporium/Lomentospora species, the heat shock protein Hsp70 stands out as a relevant secreted and cell wall antigen. Additionally, the secreted aspartyl proteinase and an ortholog of Asp f 13, as well as the cell wall endo-1,3-β-D-glucosidase and 1,3-β-glucanosyl transferase, were also found to be significant proteins. In conclusion, proteins mentioned in this review may be promising candidates for developing innovative diagnostic and therapeutic tools for fungal infections in CF patients.

Acute Scedosporium apiospermum Endobronchial Infection in Cystic Fibrosis

Fungi are known pathogens in cystic fibrosis patients. A boy with cystic fibrosis boy presented with acute respiratory distress. Bronchoscopy showed airways obstruction by mucus plugs and bronchial casts. Scedosporium apiospermum was identified as the only pathogen. Bronchoalveolar lavage successfully resolved the acute obstruction. Plastic bronchitis is a new clinical picture of acute Scedosporium endobronchial colonization in cystic fibrosis patients.

Infection in cystic fibrosis: impact of the environment and climate

In many countries numbers of adults with cystic fibrosis (CF) exceed that of children, with median survival predicted to surpass 50 years. Increasing longevity is, in part, due to intensive therapies including eradication of early infection and suppressive therapies and pulmonary exacerbations. Initial infections with common CF pathogens are thought to arise from the natural environment. We review the impact of climate and environment on infection in CF. Specifically, several studies indicate that higher ambient temperatures, proximity to the equator and the summer season may be linked to the increased prevalence of Pseudomonas aeruginosa in people with CF. The environment may also play an important role in the acquisition of Gram negative organisms other than P. aeruginosa. There is emerging data suggesting that climatic and environmental factors are likely to impact on the risk of infection with NTM and fungi in people which are found extensively throughout the natural environment.