Fungal Pathogens in CF Airways: Leave or Treat?

Drivers of diversification in fungal pathogen populations

To manage and treat chronic fungal diseases effectively, we require an improved understanding of their complexity. There is an increasing appreciation that chronic infection populations are often heterogeneous due to diversification and drift, even within a single microbial species. Genetically diverse populations can contribute to persistence and resistance to treatment by maintaining cells with different phenotypes capable of thriving in these dynamic environments. In chronic infections, fungal pathogens undergo prolonged challenges that can drive trait selection to convergent adapted states through restricted access to critical nutrients, assault by immune effectors, competition with other species, and antifungal drugs. This review first highlights the various genetic and epigenetic mechanisms that promote diversity in pathogenic fungal populations and provide an additional barrier to assessing the actual heterogeneity of fungal infections. We then review existing studies of evolution and genetic heterogeneity in fungal populations from lung infections associated with the genetic disease cystic fibrosis. We conclude with a discussion of open research questions that, once answered, may aid in diagnosing and treating chronic fungal infections.

Exploring the dynamics of mixed-species biofilms involving Candida spp. and bacteria in cystic fibrosis

Cystic fibrosis (CF) is an inherited disease that results from mutations in the gene responsible for the cystic fibrosis transmembrane conductance regulator (CFTR). The airways become clogged with thick, viscous mucus that traps microbes in respiratory tracts, facilitating colonization, inflammation and infection. CF is recognized as a biofilm-associated disease, it is commonly polymicrobial and can develop in biofilms. This review discusses Candida spp. and both Gram-positive and Gram-negative bacterial biofilms that affect the airways and cause pulmonary infections in the CF context, with a particular focus on mixed-species biofilms. In addition, the review explores the intricate interactions between fungal and bacterial species within these biofilms and elucidates the underlying molecular mechanisms that govern their dynamics. Moreover, the review addresses the multifaceted issue of antimicrobial resistance in the context of CF-associated biofilms. By synthesizing current knowledge and research findings, this review aims to provide insights into the pathogenesis of CF-related infections and identify potential therapeutic approaches to manage and combat these complex biofilm-mediated infections.

Subtherapeutic triazole concentrations as result of a drug-drug interaction with lumacaftor/ivacaftor

Lumacaftor/ivacaftor (Orkambi®, LUM/IVA) is indicated for the treatment of cystic fibrosis (CF) patients aged ≥ 2 years with homozygous F580del mutation in the CFTR gene. Triazole fungal agents are used to treat fungal disease in CF. The use of triazoles is limited by pharmacokinetic challenges, such as drug-drug interactions. The most notable drug-drug interaction between triazoles and LUM/IVA is due to strong induction of CYP3A4 and UGT by LUM. In this real-world retrospective observational study, we described the effect of LUM/IVA on the trough concentration of triazoles. Concomitant use of LUM/IVA with itraconazole, posaconazole or voriconazole resulted in subtherapeutic triazole levels in 76% of the plasma samples. In comparison, in patients with triazole agents without LUM/IVA only 30.6% of the plasma samples resulted in subtherapeutic concentrations. Subtherapeutic plasma concentrations of triazoles should be considered in CF patients on LUM/IVA and further research is warranted for other dosing strategies and alternative antifungal therapy.

Pulmonary Aspergillosis in People with Cystic Fibrosis

In the last decade, fungal respiratory diseases have been increasingly investigated for their impact on the clinical course of people with cystic fibrosis (CF), with a particular focus on infections caused by Aspergillus spp. The most common organisms from this genus detected from respiratory cultures are Aspergillus fumigatus and Aspergillus terreus, followed by Aspergillus flavus, Aspergillus niger, and Aspergillus nidulans. These species have been identified to be both chronic colonizers and sources of active infection and may negatively impact lung function in people with CF. This review article discusses definitions of aspergillosis, challenges in clinical practice, and current literature available for laboratory findings, clinical diagnosis, and treatment options for pulmonary diseases caused by Aspergillus spp. in people with CF.

Dual species sphingosine-1-phosphate lyase inhibitors to combine antifungal and anti-inflammatory activities in cystic fibrosis: a feasibility study

Cystic fibrosis (CF) is an autosomal recessive disorder characterized by respiratory failure due to a vicious cycle of defective Cystic Fibrosis Transmembrane conductance Regulator (CFTR) function, chronic inflammation and recurrent bacterial and fungal infections. Although the recent introduction of CFTR correctors/potentiators has revolutionized the clinical management of CF patients, resurgence of inflammation and persistence of pathogens still posit a major concern and should be targeted contextually. On the background of a network-based selectivity that allows to target the same enzyme in the host and microbes with different outcomes, we focused on sphingosine-1-phosphate (S1P) lyase (SPL) of the sphingolipid metabolism as a potential candidate to uniquely induce anti-inflammatory and antifungal activities in CF. As a feasibility study, herein we show that interfering with S1P metabolism improved the immune response in a murine model of CF with aspergillosis while preventing germination of Aspergillus fumigatus conidia. In addition, in an early drug discovery process, we purified human and A. fumigatus SPL, characterized their biochemical and structural properties, and performed an in silico screening to identify potential dual species SPL inhibitors. We identified two hits behaving as competitive inhibitors of pathogen and host SPL, thus paving the way for hit-to-lead and translational studies for the development of drug candidates capable of restraining fungal growth and increasing antifungal resistance.

Pathogenicity and virulence of Aspergillus fumigatus

Pulmonary infections caused by the mould pathogen Aspergillus fumigatus are a major cause of morbidity and mortality globally. Compromised lung defences arising from immunosuppression, chronic respiratory conditions or more recently, concomitant viral or bacterial pulmonary infections are recognised risks factors for the development of pulmonary aspergillosis. In this review, we will summarise our current knowledge of the mechanistic basis of pulmonary aspergillosis with a focus on emerging at-risk populations.

Allergic bronchopulmonary aspergillosis: A multidisciplinary review

Allergic bronchopulmonary aspergillosis (ABPA) is a rare disease characterized by a complex allergic inflammatory reaction of airways against Aspergillus affecting patients with chronic respiratory diseases (asthma, cystic fibrosis). Exacerbation is often the way to diagnose ABPA and marks its evolution by its recurrent character leading to cortico-requirement or long-term antifungal treatment. Early diagnosis allows treatment of ABPA at an initial stage, preventing recurrence of exacerbations and long-term complications, mainly represented by bronchiectasis. This review of the literature aims to present the current state of the art in terms of diagnosis and treatment of ABPA from a multidisciplinary perspective. As there is no clinical, biological nor radiological specific sign, diagnostic criteria are regularly revised. They are mainly based on the elevation of total and specific IgE against Aspergillus fumigatus and the presence of suggestive CT abnormalities such as mucoid impaction and consolidations. ABPA management includes eviction of mold and pharmacological therapy. Exacerbations are treated in first line with a moderate dose of oral corticosteroids. Azole antifungal agents represent an alternative for the treatment of exacerbations and are the preferential strategy to reduce the future risk of exacerbations and for corticosteroids sparing. Asthma biologics may be of interest; however, their place remains to be determined. Avoiding complications of ABPA while limiting the side effects of systemic drugs remains a major challenge of ABPA management. Several drugs, including new antifungals and asthma biologics, are currently being tested and may be useful in the future.

Clinical Relevance of Fungi in Cystic Fibrosis

In cystic fibrosis, a new era has started with the approval and use of highly effective cystic fibrosis transport regulator (CFTR) modulator therapy. As pulmonary function is increasing and exacerbation rate significantly decreases, the current meaning of fungal pulmonary diseases is questioned. During the past couple of decades, several studies have been conducted regarding fungal colonization and infection of the airways in people with cystic fibrosis. Although Aspergillus fumigatus for filamentous fungi and Candida albicans for yeasts remain by far the most common fungal species in patients with cystic fibrosis, the pattern of fungal species associated with cystic fibrosis has considerably diversified recently. Fungi such as Scedosporium apiospermum or Exophiala dermatitidis are recognized as pathogenic in cystic fibrosis and therefore need attention in clinical settings. In this article, current definitions are stated. Important diagnostic steps are described, and their usefulness discussed. Furthermore, clinical treatment strategies and recommendations are named and evaluated. In cystic fibrosis, fungal entities can be divided into different subgroups. Besides colonization, allergic bronchopulmonary aspergillosis, bronchitis, sensitization, pneumonia, and aspergilloma can occur as a fungal disease entity. For allergic bronchopulmonary aspergillosis, bronchitis, pneumonia, and aspergilloma, clear indications for therapy exist but this is not the case for sensitization or colonization. Different pulmonary fungal disease entities in people with cystic fibrosis will continue to occur also in an era of highly effective CFTR modulator therapy. Whether the percentage will decrease or not will be the task of future evaluations in studies and registry analysis. Using the established definition for different categories of fungal diseases is recommended and should be taken into account if patients are deteriorating without responding to antibiotic treatment. Drug-drug interactions, in particular when using azoles, should be recognized and therapies need to be adjusted accordingly.

Dot Immunobinding Assay for the Rapid Serodetection of Scedosporium/Lomentospora in Cystic Fibrosis Patients

The detection of Scedosporium/Lomentospora is still based on non-standardized low-sensitivity culture procedures. This fact is particularly worrying in patients with cystic fibrosis (CF), where these fungi are the second most common filamentous fungi isolated, because a poor and delayed diagnosis can worsen the prognosis of the disease. To contribute to the discovery of new diagnostic strategies, a rapid serological dot immunobinding assay (DIA) that allows the detection of serum IgG against Scedosporium/Lomentospora in less than 15 min was developed. A crude protein extract from the conidia and hyphae of Scedosporium boydii was employed as a fungal antigen. The DIA was evaluated using 303 CF serum samples (162 patients) grouped according to the detection of Scedosporium/Lomentospora in the respiratory sample by culture, obtaining a sensitivity and specificity of 90.48% and 79.30%, respectively; positive and negative predictive values of 54.81% and 96.77%, and an efficiency of 81.72%. The clinical factors associated with the results were also studied using a univariate and a multivariate analysis, which showed that Scedosporium/Lomentospora positive sputum, elevated anti-Aspergillus serum IgG and chronic Pseudomonas aeruginosa infection were significantly associated with a positive result in DIA, while Staphylococcus aureus positive sputum showed a negative association. In conclusion, the test developed can offer a complementary, rapid, simple and sensitive method to contribute to the diagnosis of Scedosporium/Lomentospora in patients with CF.

Effect of Flagellin Pre-Exposure on the Inflammatory and Antifungal Response of Bronchial Epithelial Cells to Fungal Pathogens

Bronchial epithelial cells (BEC) play a crucial role in innate immunity against inhaled fungi. Indeed, in response to microorganisms, BEC synthesize proinflammatory cytokines involved in the recruitment of neutrophils. We have recently shown that BEC exert antifungal activity against Aspergillus fumigatus by inhibiting filament growth. In the present study, we first analyzed the inflammatory and antifungal responses of BEC infected by several fungal species such as Aspergillus spp., Scedosporium apiospermum and Candida albicans, which are frequently isolated from the sputum of people with chronic pulmonary diseases. The airways of these patients, such as people with cystic fibrosis (pwCF), are mainly colonized by P. aeruginosa and secondary by fungal pathogens. We have previously demonstrated that BEC are capable of innate immune memory, allowing them to increase their inflammatory response against A. fumigatus following a previous contact with Pseudomonas aeruginosa flagellin. To identify the impact of bacteria exposure on BEC responses to other fungal infections, we extended the analysis of BEC innate immune memory to Aspergillus spp., Scedosporium apiospermum and Candida albicans infection. Our results show that BEC are able to recognize and respond to Aspergillus spp., S. apiospermum and C. albicans infection and that the modulation of BEC responses by pre-exposure to flagellin varies according to the fungal species encountered. Deepening our knowledge of the innate immune memory of BEC should open new therapeutic avenues to modulate the inflammatory response against polymicrobial infections observed in chronic pulmonary diseases such as CF.

Culture-dependent evaluation of the respiratory microbiome in children with cystic fibrosis

The study aimed to assess the regional peculiarities of the respiratory profile of children with cystic fibrosis (CF) in the Dnipro region (Ukraine). Methods. Children living in the Dnipro region and aged younger than 18 years old with molecular-genetic confirmation of CF were enrolled in the study. Lung colonization was evaluated using a culture-dependent method. Sputum, mucus from the posterior pharyngeal wall and bronchoalveolar lavage fluid (BALF) were utilized. Results. The Firmicutes phylum was the most common and occupied 54.00 % of the general proportion. On the other hand, the Proteobacteria phylum demonstrated overexpression in CF airways and kept the second rank with 28.87 %. Sorensen's species similarity coefficient showed an allied affinity between the microbial burden of oropharyngeal samples with nasopharyngeal and sputum, QS = 0.61 and 0.91, respectively. However, the species composition within the nasal cavity was distinct from sputum and BALF (QS=0.47). The primary pathogens in childhood were S. aureus, H. influenza, P. aeruginosa and A. fumigatus. In contrast to gram-negative non-fermenters (GNNF), the prevalence of S. aureus isolates by age had a non-linear character. The commensal microbiota changed negatively with age. Among children under 12 years, the Streptococcus genus was identified in 23.08 % of the samples, but among the age category older than 15 – only in 9.22 %. 11.06 % of S. aureus had small colony variants (SCVs) morphotypes. Isolates of P. aeruginosa with the properties of SCVs were also found in children who underwent prolonged antimicrobial treatment. However, the most prominent was the mucoid phenotype – 34.31 % of isolates. Conclusions. Along with conventional microbiological properties, obligate pathobionts in children with CF exhibited changes, resulting in difficulties in identification. These included auxotrophic modification into SCVs and mucoid transformation. The culture-dependent technique gives crucial data about the profile of pathogens usually associated with CF, although it is sufficiently limited

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.

de la Pedrosa E, López-Campos JL, Máiz L, del Campo R, Martínez-García MÁ. The Human Mycobiome in Chronic Respiratory Diseases: Current Situation and Future Perspectives

Microbes play an important role in the pathogenesis of chronic lung diseases, such as chronic obstructive pulmonary disease, cystic fibrosis, non-cystic fibrosis bronchiectasis, and asthma. While the role of bacterial pathogens has been extensively studied, the contribution of fungal species to the pathogenesis of chronic lung diseases is much less understood. The recent introduction of next-generation sequencing techniques has revealed the existence of complex microbial lung communities in healthy individuals and patients with chronic respiratory disorders, with fungi being an important part of these communities' structure (mycobiome). There is growing evidence that the components of the lung mycobiome influence the clinical course of chronic respiratory diseases, not only by direct pathogenesis but also by interacting with bacterial species and with the host's physiology. In this article, we review the current knowledge on the role of fungi in chronic respiratory diseases, which was obtained by conventional culture and next-generation sequencing, highlighting the limitations of both techniques and exploring future research areas.

The Effects of Aspergillus fumigatus Colonization on Lung Function in Patients with Cystic Fibrosis

Aspergillus fumigatus is commonly isolated from CF airways. However, the impact on CF lung progression is not completely understood. In this study, using a 16-year retrospective observational cohort study (2000–2015) that included 132 patients, we determined the annual lung function, measured as percent predicted forced expiratory volume in the first second (ppFEV1), decline before and after the first colonization with A. fumigatus. Further, in the same individual, the ratios of lung function when patients were colonized with A. fumigatus and when they were not were calculated. The impact of eradication, with antifungal treatment or spontaneously, was assessed. The annual ppFEV1 was significantly lower after the first colonization with A. fumigatus. Furthermore, within the same individual, colonization with A. fumigatus for two and three years in a row was associated with 4.3% and 7.9% lower ppFEV1, respectively, compared to when not colonized. Finally, patients who eradicated A. fumigatus the following two years after colonization exhibited 9.9% and 14.5% higher ppFEV1 compared to patients who continued to produce cultures with A. fumigatus for two and three years. Our study demonstrated that A. fumigatus colonization was associated with a negative impact on lung function in the long term and eradication, spontaneously or with treatment, was associated with a better pulmonary outcome.

Cystic Fibrosis Clinical Isolates of Aspergillus fumigatus Induce Similar Muco-inflammatory Responses in Primary Airway Epithelial Cells

Aspergillus is increasingly associated with lung inflammation and mucus plugging in early cystic fibrosis (CF) disease during which conidia burden is low and strains appear to be highly diverse. It is unknown whether clinical Aspergillus strains vary in their capacity to induce epithelial inflammation and mucus production. We tested the hypothesis that individual colonising strains of Aspergillus fumigatus would induce different responses. Ten paediatric CF Aspergillus isolates were compared along with two systemically invasive clinical isolates and an ATCC reference strain. Isolates were first characterised by ITS gene sequencing and screened for antifungal susceptibility. Three clusters (A-C) of Aspergillus isolates were identified by ITS. Antifungal susceptibility was variable, particularly for itraconazole. Submerged CF and non-CF monolayers as well as differentiated primary airway epithelial cell cultures were incubated with conidia for 24 h to allow germination. None of the clinical isolates were found to significantly differ from one another in either IL-6 or IL-8 release or gene expression of secretory mucins. Clinical Aspergillus isolates appear to be largely homogenous in their mucostimulatory and immunostimulatory capacities and, therefore, only the antifungal resistance characteristics are likely to be clinically important.

Small Molecule CCR4 Antagonists Protect Mice from Aspergillus Infection and Allergy

The ability to regulate the recruitment of immune cells makes chemokines and their receptors attractive drug targets in many inflammatory diseases. Based on its preferential expression on T helper type 2 (Th2) cells, C-C chemokine receptor type 4 (CCR4) has been widely studied in the context of allergic diseases, but recent evidence on the expression of CCR4 in other cell types has considerably expanded the potential applications of CCR4 antagonism. However, the current number of approved indications, as well as the portfolio of CCR4-targeting drugs, are still limited. In the present study, we have assessed the potential therapeutic efficacy of a CCR4 small molecule antagonist, SP50, discovered via an in silico-based approach, against a variety of pre-clinical settings of infection with the fungus Aspergillus fumigatus. We show that SP50 efficiently worked as prophylactic vaccine adjuvant in immunocompetent mice, protected against invasive aspergillosis in immunosuppressed mice. Further, the CCR4 antagonist prevented allergic bronchopulmonary aspergillosis in susceptible mice, and in a murine model of cystic fibrosis, a genetic disorder characterized by chronic pulmonary inflammation and recurrent infections. In conclusion, our results extend the potential applications of CCR4 antagonism and prompt for the development of novel compounds with the potential to progress to clinical trials.

Urban Life as Risk Factor for Aspergillosis

Aspergillus fumigatus (Af) frequently colonizes the airways of patients with cystic fibrosis (CF) and can cause severe diseases, such as allergic bronchopulmonary aspergillosis, Af bronchitis or even Af pneumonia. However, risk factors, including environmental factors, for acquiring Af in the respiratory tract of patients with CF are rarely studied and described. The aim of this study was to investigate whether urban or rural life could affect colonization with Af in the respiratory tract of patients with CF. Due to privacy policy, registry data are usually not linked to patients´ home addresses. It is therefore very difficult to analyze the influence of the patient´s residential environment. This prospective questionnaire survey was carried out in 31 German CF centers in 2018. Only completed surveys, including a clearly assigned type of residential area were included. Statistical analysis was performed by chi-squared test and logistic regression models. A total of 1016 questionnaires were analyzed (Patients` age: 23 ± 13; 0–88 years; female gender: n=492; 48%). The majority of patients with CF live in large cities (n =314; 30.9%) or urban districts (n=461; 45.4%). Prevalence of 30.2% was found for Af, within the 12 months of investigation period. Af colonization was significantly associated with urban life (p=0.004). Urban live should be considered as possible new risk factor for colonization with Af in the respiratory tract of patients with CF. These new results may raise the awareness of the influence of environmental factors on patient outcomes and should be included in patient guidance and preventive measures.

Risk factors for respiratory Aspergillus fumigatus in German Cystic Fibrosis patients and impact on lung function

Airway inflammation and chronic lung infections in cystic fibrosis (CF) patients are mostly caused by bacteria, e.g. Pseudomonas aeruginosa (PA). The role of fungi in the CF lung is still not well elucidated, but evidence for a harmful and complex role is getting stronger. The most common filamentous fungus in CF is Aspergillus fumigatus (AF). Age and continuous antibiotic treatment have been discussed as risk factors for AF colonisation but did not differentiate between transient and persistent AF colonisation. Also, the impact of co-colonisation of PA and AF on lung function is still under investigation. Data from patients with CF registered in the German Cystic Fibrosis Registry database in 2016 and 2017 were retrospectively analysed, involving descriptive and multivariate analysis to assess risk factors for transient or persistent AF colonisation. Age represented an independent risk factor for persistent AF colonisation. Prevalence was low in children less than ten years, highest in the middle age and getting lower in higher age (≥ 50 years). Continuous antibiotic lung treatment was significantly associated with AF prevalence in all age groups. CF patients with chronic PA infection had a lower lung function (FEV1%predicted), which was not influenced by an additional AF colonisation. AF colonisation without chronic PA infection, however, was significantly associated with a lower function, too. Older age up to 49 years and continuous antibiotic use were found to be the main risk factors for AF permanent colonisation. AF might be associated with decrease of lung function if not disguised by chronic PA infection.

Review of Potential Pseudomonas Weaponry, Relevant to the Pseudomonas-Aspergillus Interplay, for the Mycology Community

Pseudomonas aeruginosa is one of the most prominent opportunistic bacteria in airways of cystic fibrosis patients and in immunocompromised patients. These bacteria share the same polymicrobial niche with other microbes, such as the opportunistic fungus Aspergillus fumigatus. Their inter-kingdom interactions and diverse exchange of secreted metabolites are responsible for how they both fare in competition for ecological niches. The outcomes of their contests likely determine persistent damage and degeneration of lung function. With a myriad of virulence factors and metabolites of promising antifungal activity, P. aeruginosa products or their derivatives may prove useful in prophylaxis and therapy against A. fumigatus. Quorum sensing underlies the primary virulence strategy of P. aeruginosa, which serves as cell–cell communication and ultimately leads to the production of multiple virulence factors. Understanding the quorum-sensing-related pathogenic mechanisms of P. aeruginosa is a first step for understanding intermicrobial competition. In this review, we provide a basic overview of some of the central virulence factors of P. aeruginosa that are regulated by quorum-sensing response pathways and briefly discuss the hitherto known antifungal properties of these virulence factors. This review also addresses the role of the bacterial secretion machinery regarding virulence factor secretion and maintenance of cell–cell communication.

Oral prevalence and antifungal susceptibility of Candida species in cystic fibrosis patients

OBJECTIVE

This study aimed at assessing the oral prevalence ofCandida species in cystic fibrosis patients and the antifungal susceptibility of the isolates.

DESIGN

One hundred patients aged 3-20 years old were included in the study and were divided into three groups: G1 (low severity disease): 25 cystic fibrosis patients with Shwachman-Kulczycki score (SK) between 100 and 71; G2 (high severity disease): 25 cystic fibrosis patients with SK score under 40; and G3 (control): 50 healthy patients age- and gender-matched to cystic fibrosis patients. Stimulated saliva samples were collected and the oral fungal concentrations were assessed. Isolates were identified by phenotypic and genotypic tests. Antifungal susceptibilities to amphotericin B, flucytosine and fluconazole were determined by CLSI methodology. Fungal counts were compared by Kruskal Wallis and Dunn's test (5%).

RESULTS

A total of 68 % of Group 1, 80 % of Group 2, and 44 % of controls yielded positive Candida cultures. Oral concentrations of fungi were significantly higher in cystic fibrosis patients in relation to the control group (p < 0.0005). No significant difference was observed between low and high severity cystic fibrosis groups (p > 0.05). C. albicans was most frequently isolated species in all groups. Higher variability of Candida species was observed in the control group. C. dubliniensis and C. tropicalis were only detected among cystic fibrosis groups. All the isolates were susceptible to flucytosine and fluconazole.

CONCLUSIONS

Patients with cystic fibrosis were more frequently colonized by Candida species and showed higher oral fungal burden. No antifungal resistant isolates were detected.

Taking a look on fungi in cystic fibrosis: More questions than answers

Cystic fibrosis (CF) is one of the most frequent recessive inherited diseases in western countries. Advances in medical care have led to a substantial increase in the life expectancy of CF patients. Survival beyond adolescence has permitted to see fungi not only as late colonizers, but also as potential pathogens responsible of allergic reactions and chronic infections related to lung function deterioration. The role of fungi, nevertheless, has been overlooked until recently. As a result, a number of questions on their epidemiology, clinical significance, or diagnosis, among others, remain unanswered. Besides more in depth studies about the extent of the deleterious effect of fungi on the CF host, new technologies may provide the key to understand its pathogenic role, its interaction with other microbial components of the respiratory microbiota, and should pave the way to define subsets of patients at risk who would benefit from specific therapy. This review is intended to provide a quick overview on what we know about the presence of fungi in the CF airway and its repercussion in the host, and to point out some of the many knowledge gaps needed to understand and advance in the management of fungi in the airway of CF subjects.

Effect of Candida albicans bronchial colonization on hospital-acquired bacterial pneumonia in patients with systemic lupus erythematosus

Background

To investigate the effect of Candida albicans airway colonization on hospital-acquired bacterial pneumonia (HABP) in patients with systemic lupus erythematosus (SLE).

Methods

SLE patients with HAP were enrolled in this retrospective cohort study from January 2015 to December 2018. According to the culture results of respiratory tract secretions and antifungal treatment, patients were divided into non-C. albicans colonization group (NCG), C. albicans colonization with antifungal treatment group (CTG) and C. albicans colonization without antifungal treatment group (CNTG). Twenty-eight days of all-cause mortality after the onset of HABP of each group was assessed, total duration of antibiotic treatment, changes of inflammatory cytokines and markers of immune status were documented.

Results

A total of 269 SLE patients with HABP were finally included in the study. Among them, 69.1% (186/269) were found C. albicans airway colonization, and 36.1% (97/269) received antifungal treatment. No difference of 28 days of all-cause mortality after HABP onset was found among the three groups (10.8% vs. 13.4% vs. 15.7%, P>0.05). Duration of antibiotic treatment of HABP due to Acinetobacter baumannii was shorter in CTG (11.21±2.45 days) than that in CNTG (12.89±3.87 days) as well as HABP due to Pseudomonas aeruginosa (10.57±2.66 vs. 12.56±3.04 days) (P<0.05, respectively). Antifungal treatment could decrease the level of interleukin-1β, interleukin-6, tumor necrosis factor-α and interferon-γ in CTG than in CNTG (P<0.05, respectively). In addition, it could regulate immune function by decrease the concentration of interleukin-17 and elevate the counts of CD4+Th lymphocyte as well (P<0.05, respectively).

Conclusions

C. albicans airway colonization was not associated with HABP mortality in SLE patients. Antifungal therapy in these patients might shorten the duration of antibiotics in treating HABP due to A. baumannii and P. aeruginosa.

Pseudomonas aeruginosa eradication therapy and risk of acquiring Aspergillus in young children with cystic fibrosis

Background

While Aspergillus detection rates in adults, adolescents and older children with cystic fibrosis (CF) have increased, the risk of acquiring this fungal pathogen in young children is unknown.

Aim

To determine the risk and explanatory factors of acquiring Aspergillus in children with CF by age 5 years.

Methods

Cross-sectional analysis of clinical, bronchoalveolar lavage and treatment data from the Australasian Cystic Fibrosis Bronchoalveolar Lavage study was used to identify predictive factors for detecting Aspergillus at age 5 years. A parametric repeated time-to-event model quantitatively described the risk and factors associated with acquiring Aspergillus and Pseudomonas aeruginosa from birth until age 5 years.

Results

Cross-sectional analysis found that the number of P. aeruginosa eradication courses increased the odds of detecting Aspergillus at age 5 years (OR 1.61, 95% CI 1.23 to 2.12). The median (IQR) age for the first P. aeruginosa positive culture was 2.38 (1.32–3.79) years and 3.69 (1.68–4.74) years for the first Aspergillus positive culture. The risk of P. aeruginosa and Aspergillus events changes with time after the first year of study entry. It also decreases for P. aeruginosa after completing P. aeruginosa eradication (HR 0.15, 95% CI 0.00 to 0.79), but increases for Aspergillus events (HR 2.75, 95% CI 1.45 to 5.41). The risk of acquiring both types of events increases after having had a previous event.

Conclusion

In young children with CF, completing P. aeruginosa eradication therapy and previous Aspergillus events are associated with increased risk of acquiring Aspergillus.

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.

Coexistence of Candida species and bacteria in patients with cystic fibrosis

Cystic fibrosis (CF) patients become colonized by pathogenic bacteria as well as by Candida species. The interplay between different microorganisms may play a key role in the prognosis of CF. The aim of the study was to analyze the coexistence patterns of bacteria and Candida spp. in sputum samples of patients with CF and to compare these patterns with the results of patients with other respiratory disorders (ORD). Sputum samples from 130 patients with CF and 186 patients with ORD were cultured on six different agar plates promoting the growth of bacteria and yeasts. Bacterial and Candida species were identified with MALDI-TOF MS. Pathogenic bacteria were found in 69.2% of the sputum samples of the CF patients, and in 44.1% the patients with ORD. CF patients tended to have growth of Pseudomonas aeruginosa and Staphylococcus aureus in sputum more often than patients with ORD. Overall, there was no difference in the coexistence of pathogenic bacteria and Candida spp. in these patient groups. However, when analyzed at the species level, P. aeruginosa and S. aureus coexisted with Candida spp. more frequently in sputum samples of CF patients compared with patients with ORD. Also, when analyzed according to age, it was shown that the adult (≥ 18 years) CF patients had a higher rate of coexistence of any pathogenic bacteria and Candida spp. than the children with CF and the adult patients with ORD. The rate for colonization with Candida together with pathogenic bacteria is increased in adult patients with CF.

Fungal Diseases in the 21st Century: The Near and Far Horizons

Fungal diseases became a major medical problem in the second half of the 20th century when advances in modern medicine together with the HIV epidemic resulted in large numbers of individuals with impaired immunity. Fungal diseases are difficult to manage because they tend to be chronic, hard to diagnose, and difficult to eradicate with antifungal drugs. This essay considers the future of medical mycology in the 21st century, extrapolating from current trends. In the near horizon, the prevalence of fungal diseases is likely to increase, as there will be more hosts with impaired immunity and drug resistance will inevitably increase after selection by antifungal drug use. We can expect progress in the development of new drugs, diagnostics, vaccines, and immunotherapies. In the far horizon, humanity may face new fungal diseases in association with climate change. Some current associations between chronic diseases and fungal infections could lead to the establishment of fungi as causative agents, which will greatly enhance their medical importance. All trends suggest that the importance of fungal diseases will increase in the 21st century, and enhanced human preparedness for this scourge will require more research investment in this group of infectious diseases.

Risk factors for persistent Aspergillus respiratory isolation in cystic fibrosis

BACKGROUND

Aspergillus species are increasingly detected in the respiratory tracts of individuals with cystic fibrosis (CF), and chronic Aspergillus fumigatus is associated with more frequent hospitalizations for pulmonary exacerbations. However, patient and clinical factors that may contribute to the acquisition of persistent Aspergillus infection have yet to be identified. The objective of this study was to identify risk factors for development of Aspergillus respiratory isolation in CF.

METHODS

A retrospective cohort study of participants in the CF Foundation Patient Registry between 2006 and 2012 was conducted. Generalized estimating equation models were used to evaluate the association between the development of persistent Aspergillus respiratory isolation and individual level demographic and clinical characteristics.

RESULTS

Among 16,095 individuals with CF followed from 2006 to 2012, 1541 (9.6%) subjects developed persistent Aspergillus isolation. White race (Odds Ratio [OR] 1.74, 95% confidence interval 1.23, 2.48, p<0.001) and pancreatic insufficiency (OR 1.50, 95% CI 1.09, 2.06, p<0.001) were found to be risk factors for persistent Aspergillus isolation. Chronic therapies, including inhaled antibiotics (OR 1.33; 95% CI 1.21, 1.46), macrolides (OR 1.23, 95% CI 1.14, 1.32, p<0.001), and inhaled corticosteroids (OR 1.13, 95% CI 1.04, 1.20, p<0.001) were also independently associated with an increased risk for persistent Aspergillus isolation.

CONCLUSIONS

We identified macrolides and inhaled antibiotics, which individually have been shown to improve CF outcomes, and inhaled corticosteroids as risk factors for developing persistent Aspergillus isolation. Further work is needed to determine whether these associations are causal or due to confounding by other factors.