Prevalence and characterization of azole-resistant Aspergillus fumigatus in patients with cystic fibrosis: a prospective multicentre study in Germany

Aspergillus fumigatus-a systematic review to inform the World Health Organization priority list of fungal pathogens

Recognizing the growing global burden of fungal infections, the World Health Organization established a process to develop a priority list of fungal pathogens (FPPL). In this systematic review, we aimed to evaluate the epidemiology and impact of invasive infections caused by Aspergillus fumigatus to inform the first FPPL. The pre-specified criteria of mortality, inpatient care, complications and sequelae, antifungal susceptibility, risk factors, preventability, annual incidence, global distribution, and emergence were used to search for relevant articles between 1 January 2016 and 10 June 2021. Overall, 49 studies were eligible for inclusion. Azole antifungal susceptibility varied according to geographical regions. Voriconazole susceptibility rates of 22.2% were reported from the Netherlands, whereas in Brazil, Korea, India, China, and the UK, voriconazole susceptibility rates were 76%, 94.7%, 96.9%, 98.6%, and 99.7%, respectively. Cross-resistance was common with 85%, 92.8%, and 100% of voriconazole-resistant A. fumigatus isolates also resistant to itraconazole, posaconazole, and isavuconazole, respectively. The incidence of invasive aspergillosis (IA) in patients with acute leukemia was estimated at 5.84/100 patients. Six-week mortality rates in IA cases ranged from 31% to 36%. Azole resistance and hematological malignancy were poor prognostic factors. Twelve-week mortality rates were significantly higher in voriconazole-resistant than in voriconazole-susceptible IA cases (12/22 [54.5%] vs. 27/88 [30.7%]; P = .035), and hematology patients with IA had significantly higher mortality rates compared with solid-malignancy cases who had IA (65/217 [30%] vs. 14/78 [18%]; P = .04). Carefully designed surveillance studies linking laboratory and clinical data are required to better inform future FPPL.

Antifungal Resistance in Pulmonary Aspergillosis

Aspergilli may cause various pulmonary diseases in humans, including allergic bronchopulmonary aspergillosis (ABPA), chronic pulmonary aspergillosis (CPA), and acute invasive pulmonary aspergillosis (IPA). In addition, chronic colonization may occur in cystic fibrosis (CF). Aspergillus fumigatus represents the main pathogen, which may employ different morphotypes, for example, conidia, hyphal growth, and asexual sporulation, in the various Aspergillus diseases. These morphotypes determine the ease by which A. fumigatus can adapt to stress by antifungal drug exposure, usually resulting in one or more resistance mutations. Key factors that enable the emergence of resistance include genetic variation and selection. The ability to create genetic variation depends on the reproduction mode, including, sexual, parasexual, and asexual, and the population size. These reproduction cycles may take place in the host and/or in the environment, usually when specific conditions are present. Environmental resistance is commonly characterized by tandem repeat (TR)-mediated mutations, while in-host resistance selection results in single-resistance mutations. Reported cases from the literature indicate that environmental resistance mutations are almost exclusively present in patients with IA indicating that the risk for in-host resistance selection is very low. In aspergilloma, single-point mutations are the dominant resistance genotype, while in other chronic Aspergillus diseases, for example, ABPA, CPA, and CF, both TR-mediated and single-resistance mutations are reported. Insights into the pathogenesis of resistance selection in various Aspergillus diseases may help to improve diagnostic and therapeutic strategies.

Drug-Resistant Aspergillus spp.: A Literature Review of Its Resistance Mechanisms and Its Prevalence in Europe

Infections due to the Aspergillus species constitute an important challenge for human health. Invasive aspergillosis represents a life-threatening disease, mostly in patients with immune defects. Drugs used for fungal infections comprise amphotericin B, triazoles, and echinocandins. However, in the last decade, an increased emergence of azole-resistant Aspergillus strains has been reported, principally belonging to Aspergillus fumigatus species. Therefore, both the early diagnosis of aspergillosis and its epidemiological surveillance are very important to establish the correct antifungal therapy and to ensure a successful patient outcome. In this paper, a literature review is performed to analyze the prevalence of Aspergillus antifungal resistance in European countries. Amphotericin B resistance is observed in 2.6% and 10.8% of Aspergillus fumigatus isolates in Denmark and Greece, respectively. A prevalence of 84% of amphotericin B-resistant Aspergillus flavus isolates is reported in France, followed by 49.4%, 35.1%, 21.7%, and 20% in Spain, Portugal, Greece, and amphotericin B resistance of Aspergillus niger isolates is observed in Greece and Belgium with a prevalence of 75% and 12.8%, respectively. The prevalence of triazole resistance of Aspergillus fumigatus isolates, the most studied mold obtained from the included studies, is 0.3% in Austria, 1% in Greece, 1.2% in Switzerland, 2.1% in France, 3.9% in Portugal, 4.9% in Italy, 5.3% in Germany, 6.1% in Denmark, 7.4% in Spain, 8.3% in Belgium, 11% in the Netherlands, and 13.2% in the United Kingdom. The mechanism of resistance is mainly driven by the TR34/L98H mutation. In Europe, no in vivo resistance is reported for echinocandins. Future studies are needed to implement the knowledge on the spread of drug-resistant Aspergillus spp. with the aim of defining optimal treatment strategies.

Synthesis, Antifungal Ergosterol Inhibition, Antibiofilm Activities, and Molecular Docking on β-Tubulin and Sterol 14-Alpha Demethylase along with DFT-Based Quantum Mechanical Calculation of Pyrazole Containing Fused Pyridine-Pyrimidine Derivatives

Multidrug-resistant fungal infections have become much more common in recent years, especially in immune-compromised patients. Therefore, researchers and pharmaceutical professionals have focused on the development of novel antifungal agents that can tackle the problem of resistance. In continuation to this, a novel series of pyrazole-bearing pyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione derivatives (4a-4o) have been developed. These compounds have been screened against Candida albicans, Aspergillus niger, and Aspergillus clavatus. The synthesized compounds were characterized by well-known spectroscopic techniques, i.e., IR, 1H NMR, 13C NMR, and mass spectrometry. In vitro antifungal results revealed that compound 4n showed activity against C. albicans having MIC value of 200 μg/mL. To know the plausible mode of action, the active derivatives were screened for anti-biofilm and ergosterol biosynthesis inhibition activities. The compounds 4h, 4j, 4k, and 4n showed greater ergosterol biosynthesis inhibition than the control DMSO. To comprehend how molecules interact with the receptor, studies of molecular docking of 4k and 4n have been performed on the homology-modeled protein of β-tubulin. The molecular docking revealed that the active compounds 4h, 4j, 4k, 4l, and 4n interacting with the active site amino acid of sterol 14-alpha demethylase (PDB ID: 5v5z) indicate one of the possible modes of action of ergosterol inhibition activity. The synthesized compounds 4c, 4e, 4h, 4i, 4j, 4k, 4l, and 4n inhibited biofilm formation and possessed the potential for anti-biofilm activity. DFT-based quantum mechanical calculations were carried out to optimize, predict, and compare the vibration modes of the molecule 4a.

Invasive Aspergillosis and the Impact of Azole-resistance

Purpose of Review

IA (invasive aspergillosis) caused by azole-resistant strains has been associated with higher clinical burden and mortality rates. We review the current epidemiology, diagnostic, and therapeutic strategies of this clinical entity, with a special focus on patients with hematologic malignancies.

Recent Findings

There is an increase of azole resistance in Aspergillus spp. worldwide, probably due to environmental pressure and the increase of long-term azole prophylaxis and treatment in immunocompromised patients (e.g., in hematopoietic stem cell transplant recipients). The therapeutic approaches are challenging, due to multidrug-resistant strains, drug interactions, side effects, and patient-related conditions.

Summary

Rapid recognition of resistant Aspergillus spp. strains is fundamental to initiate an appropriate antifungal regimen, above all for allogeneic hematopoietic cell transplantation recipients. Clearly, more studies are needed in order to better understand the resistance mechanisms and optimize the diagnostic methods to identify Aspergillus spp. resistance to the existing antifungal agents/classes. More data on the susceptibility profile of Aspergillus spp. against the new classes of antifungal agents may allow for better treatment options and improved clinical outcomes in the coming years. In the meantime, continuous surveillance studies to monitor the prevalence of environmental and patient prevalence of azole resistance among Aspergillus spp. is absolutely crucial.

In Vitro and In Vivo Activity of Luliconazole (NND-502) against Planktonic Cells and Biofilms of Azole Resistant Aspergillus fumigatus

Aspergillus fumigatus has become a significant threat in clinical settings. Cases of invasive infections with azole-resistant A. fumigatus isolates (ARAF) increased recently. Developing strategies for dealing with ARAF has become crucial. We here investigated the in-vitro and in-vivo activity of the imidazole luliconazole (LLCZ) against clinical ARAF. In total, the LLCZ minimum inhibitory concentrations (MICs) were tested for 101 A. fumigatus isolates (84 ARAF and 17 azole-susceptible A. fumigatus as wild-type controls) according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Additionally, antifungal activity was assessed in vitro, including an XTT planktonic growth kinetics assay and biofilm assays (crystal violet and XTT assay). Further, a single-dose LLCZ treatment (152 mg/L) was tested for seven days in vivo in a Galleria mellonella infection model. LLCZ showed an MIC₅₀ of 0.002 mg/L and no significant difference was found between triazole-resistant and wild-type isolates. Growth inhibition took place between 6 and 12 h after the start of incubation. LLCZ inhibited biofilm formation when added in the pre-adhesion stages. In vivo, single-dose LLCZ-treated larvae show a significantly higher survival percentage than the control group (20%). In conclusion, LLCZ has activity against planktonic cells and early biofilms of ARAF.

COVID-19-associated pulmonary aspergillosis in ICU patients in a German reference centre: phenotypic and molecular characterization of Aspergillus fumigatus isolates

Background

COVID‐19‐associated invasive pulmonary aspergillosis (CAPA) is associated with increased mortality. Cases of CAPA caused by azole‐resistant Aspergillus fumigatus strains have been reported.

Objectives

To analyse the twelve‐month CAPA prevalence in a German tertiary care hospital and to characterise clinical A. fumigatus isolates from two German hospitals by antifungal susceptibility testing and microsatellite genotyping.

Patients/Methods.

Retrospective observational study in critically ill adults from intensive care units with COVID‐19 from 17 February 2020 until 16 February 2021 and collection of A. fumigatus isolates from two German centres. EUCAST broth microdilution for four azole compounds and microsatellite PCR with nine markers were performed for each collected isolate (N = 27) and additional for three non‐COVID A. fumigatus isolates.

Results

welve‐month CAPA prevalence was 7.2% (30/414), and the rate of azole‐resistant A. fumigatus isolates from patients with CAPA was 3.7% with detection of one TR34/L98H mutation. The microsatellite analysis revealed no major clustering of the isolates. Sequential isolates mainly showed the same genotype over time.

Conclusions

Our findings demonstrate similar CAPA prevalence to other reports and a low azole‐resistance rate. Genotyping of A. fumigatus showed polyclonal distribution except for sequential isolates.

Molecular Epidemiology of Azole-Resistant Aspergillus fumigatus in France Shows Patient and Healthcare Links to Environmentally Occurring Genotypes

Resistance of the human pathogenic fungus Aspergillus fumigatus to antifungal agents is on the rise. However, links between patient infections, their potential acquisition from local environmental sources, and links to global diversity remain cryptic. Here, we used genotyping analyses using nine microsatellites in A. fumigatus, in order to study patterns of diversity in France. In this study, we genotyped 225 local A. fumigatus isolates, 112 azole susceptible and 113 azole resistant, collected from the Bourgogne-Franche-Comté region (Eastern France) and sampled from both clinical (n = 34) and environmental (n = 191) sources. Azole-resistant clinical isolates (n = 29) were recovered mainly from cystic fibrosis patients and environmental isolates (n = 84) from market gardens and sawmills. In common with previous studies, the TR₃₄/L98H allele predominated and comprised 80% of resistant isolates. The genotypes obtained for these local TR₃₄/L98H isolates were integrated into a broader analysis including all genotypes for which data are available worldwide. We found that dominant local TR₃₄/L98H genotypes were isolated in different sample types at different dates (different patients and types of environments) with hospital air and patient's isolates linked. Therefore, we are not able to rule out the possibility of some nosocomial transmission. We also found genotypes in these same environments to be highly diverse, emphasizing the highly mixed nature of A. fumigatus populations. Identical clonal genotypes were found to occur both in the French Eastern region and in the rest of the world (notably Australia), while others have not yet been observed and could be specific to our region. Our study demonstrates the need to integrate patient, healthcare, and environmental sampling with global databases in order to contextualize the local-scale epidemiology of antifungal resistant aspergillosis.

Genetic Analyses of Amphotericin B Susceptibility in Aspergillus fumigatus

Aspergillus fumigatus is a ubiquitous saprophytic mold that can cause a range of clinical syndromes, from allergic reactions to invasive infections. Amphotericin B (AMB) is a polyene antifungal drug that has been used to treat a broad range of systemic mycoses since 1958, including as a primary treatment option against invasive aspergillosis in regions with high rates (≥10%) of environmental triazole resistance. However, cases of AMB-resistant A. fumigatus strains have been increasingly documented over the years, and high resistance rates were recently reported in Brazil and Canada. The objective of this study is to identify candidate mutations associated with AMB susceptibility using a genome-wide association analysis of natural strains, and to further investigate a subset of the mutations in their putative associations with differences in AMB minimum inhibitory concentration (MIC) and in growths at different AMB concentrations through the analysis of progeny from a laboratory genetic cross. Together, our results identified a total of 34 candidate single-nucleotide polymorphisms (SNPs) associated with AMB MIC differences-comprising 18 intergenic variants, 14 missense variants, one synonymous variant, and one non-coding transcript variant. Importantly, progeny from the genetic cross allowed us to identify putative SNP-SNP interactions impacting progeny growth at different AMB concentrations.

Aspergillus fumigatus and aspergillosis: From basics to clinics

The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.

Aspergillus fumigatus In-Host HOG Pathway Mutation for Cystic Fibrosis Lung Microenvironment Persistence

The prevalence of Aspergillus fumigatus colonization in individuals with cystic fibrosis (CF) and subsequent fungal persistence in the lung is increasingly recognized. However, there is no consensus for clinical management of A. fumigatus in CF individuals, due largely to uncertainty surrounding A. fumigatus CF pathogenesis and virulence mechanisms. To address this gap in knowledge, a longitudinal series of A. fumigatus isolates from an individual with CF were collected over 4.5 years. Isolate genotypes were defined with whole-genome sequencing that revealed both transitory and persistent A. fumigatus in the lung. Persistent lineage isolates grew most readily in a low-oxygen culture environment, and conidia were more sensitive to oxidative stress-inducing conditions than those from nonpersistent isolates. Closely related persistent isolates harbored a unique allele of the high-osmolarity glycerol (HOG) pathway mitogen-activated protein kinase kinase, Pbs2 (pbs2C2). Data suggest this novel pbs2C2 allele arose in vivo and is necessary for the fungal response to osmotic stress in a low-oxygen environment through hyperactivation of the HOG (SakA) signaling pathway. Hyperactivation of the HOG pathway through pbs2C2 comes at the cost of decreased conidial stress resistance in the presence of atmospheric oxygen levels. These novel findings shed light on pathoadaptive mechanisms of A. fumigatus in CF, lay the foundation for identifying persistent A. fumigatus isolates that may require antifungal therapy, and highlight considerations for successful culture of persistent Aspergillus CF isolates. IMPORTANCE Aspergillus fumigatus infection causes a spectrum of clinical manifestations. For individuals with cystic fibrosis (CF), allergic bronchopulmonary aspergillosis (ABPA) is an established complication, but there is a growing appreciation for A. fumigatus airway persistence in CF disease progression. There currently is little consensus for clinical management of A. fumigatus long-term culture positivity in CF. A better understanding of A. fumigatus pathogenesis mechanisms in CF is expected to yield insights into when antifungal therapies are warranted. Here, a 4.5-year longitudinal collection of A. fumigatus isolates from a patient with CF identified a persistent lineage that harbors a unique allele of the Pbs2 mitogen-activated protein kinase kinase (MAPKK) necessary for unique CF-relevant stress phenotypes. Importantly for A. fumigatus CF patient diagnostics, this allele provides increased fitness under CF lung-like conditions at a cost of reduced in vitro growth under standard laboratory conditions. These data illustrate a molecular mechanism for A. fumigatus CF lung persistence with implications for diagnostics and antifungal therapy.

Emerging Fungal Threats in Cystic Fibrosis

In the past three decades, fungal respiratory colonization and fungal respiratory infections increasingly raised concern in cystic fibrosis (CF). Reasons for this are a better knowledge of the pathogenicity of fungi, whereby detection is sought in more and more CF centers, but also improvement of detection methods. However, differences in fungal detection rates within and between geographical regions exist and indicate the need for standardization of mycological examination of respiratory secretions. The still existing lack of standardization also complicates the assessment of fungal pathogenicity, relevance of fungal detection and risk factors for fungal infections. Nevertheless, numerous studies have now been conducted on differences in detection methods, epidemiology, risk factors, pathogenicity and therapy of fungal diseases in CF. Meanwhile, some research groups now have classified fungal disease entities in CF and developed diagnostic criteria as well as therapeutic guidelines.The following review presents an overview on fungal species relevant in CF. Cultural detection methods with their respective success rates as well as susceptibility testing will be presented, and the problem of increasing azole resistance in Aspergillus fumigatus will be highlighted. Next, current data and conflicting evidence on the epidemiology and risk factors for fungal diseases in patients with CF will be discussed. Finally, an overview of fungal disease entities in CF with their current definitions, diagnostic criteria and therapeutic options will be presented.

Future challenges and chances in the diagnosis and management of invasive mould infections in cancer patients

Diagnosis, treatment, and management of invasive mould infections (IMI) are challenged by several risk factors, including local epidemiological characteristics, the emergence of fungal resistance and the innate resistance of emerging pathogens, the use of new immunosuppressants, as well as off-target effects of new oncological drugs. The presence of specific host genetic variants and the patient's immune system status may also influence the establishment of an IMI and the outcome of its therapy. Immunological components can thus be expected to play a pivotal role not only in the risk assessment and diagnosis, but also in the treatment of IMI. Cytokines could improve the reliability of an invasive aspergillosis diagnosis by serving as biomarkers as do serological and molecular assays, since they can be easily measured, and the turnaround time is short. The use of immunological markers in the assessment of treatment response could be helpful to reduce overtreatment in high risk patients and allow prompt escalation of antifungal treatment. Mould-active prophylaxis could be better targeted to individual host needs, leading to a targeted prophylaxis in patients with known immunological profiles associated with high susceptibility for IMI, in particular invasive aspergillosis. The alteration of cellular antifungal immune response through oncological drugs and immunosuppressants heavily influences the outcome and may be even more important than the choice of the antifungal treatment. There is a need for the development of new antifungal strategies, including individualized approaches for prevention and treatment of IMI that consider genetic traits of the patients.

Lay Abstract

Anticancer and immunosuppressive drugs may alter the ability of the immune system to fight invasive mould infections and may be more important than the choice of the antifungal treatment. Individualized approaches for prevention and treatment of invasive mold infections are needed.

Azole resistance in Aspergillus species: promising therapeutic options

INTRODUCTION

Azoles are the first-line antifungal agents used for the treatment of Aspergillus infection. There is an increasing concern for azole resistance all over the world mainly from agricultural fungicide use. Choosing safe and effective antifungal regimens has become a challenge.

AREAS COVERED

Here, the authors review the epidemiology, mechanisms, and detection of azole resistance along with management options for azole-resistant Aspergillus infection, including new antifungal agents under development.

EXPERT OPINION

Routine global epidemiological surveillance is required to understand azole resistance prevalence. Azole-resistant Aspergillus infections are associated with high mortality. No good therapeutic options are currently available. High index of suspicion of resistance is required if a patient is not responding to 4-7 days of azole therapy, particularly in the areas of resistance. Susceptibility testing for Aspergillus is not routinely available in many parts of the world, which makes it difficult to diagnose azole resistance in Aspergillus infection. There are several new antifungal classes with novel mechanisms of action; clinical trials are ongoing.

Genome-Wide Association Analysis for Triazole Resistance in Aspergillus fumigatus

Aspergillus fumigatus is a ubiquitous fungus and the main agent of aspergillosis, a common fungal infection in the immunocompromised population. Triazoles such as itraconazole and voriconazole are the common first-line drugs for treating aspergillosis. However, triazole resistance in A. fumigatus has been reported in an increasing number of countries. While most studies of triazole resistance have focused on mutations in the triazole target gene cyp51A, >70% of triazole-resistant strains in certain populations showed no mutations in cyp51A. To identify potential non-cyp51A mutations associated with triazole resistance in A. fumigatus, we analyzed the whole genome sequences and triazole susceptibilities of 195 strains from 12 countries. These strains belonged to three distinct clades. Our genome-wide association study (GWAS) identified a total of six missense mutations significantly associated with itraconazole resistance and 18 missense mutations with voriconazole resistance. In addition, to investigate itraconazole and pan-azole resistance, Fisher's exact tests revealed 26 additional missense variants tightly linked to the top 20 SNPs obtained by GWAS, of which two were consistently associated with triazole resistance. The large number of novel mutations related to triazole resistance should help further investigations into their molecular mechanisms, their clinical importance, and the development of a comprehensive molecular diagnosis toolbox for triazole resistance in A. fumigatus.

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.

Azole Resistance in Aspergillus fumigatus: A Five-Year Follow Up Experience in a Tertiary Hospital With a Special Focus on Cystic Fibrosis

Azole-resistant Aspergillus fumigatus (ARAf) has emerged worldwide during the last decades. Drug pressure after long term treatments of chronically infected patients and the propagation of environmental clones selected under the pressure of imidazoles fungicides used in agriculture and farming both account for this emergence. The objectives of this study were to determine the rate of azole resistance in Aspergillus fumigatus during a 5-year period, taking into account (i) differences between underlying diseases of the patients treated, (ii) cross-resistance between azoles, and (iii) focusing on the 5-year evolution of our center’s cystic fibrosis cohort. Overall, the rates of voriconazole (VRC)-resistant and itraconazole (ITC)-resistant A. fumigatus isolates were 4.1% (38/927) and 14.5% (95/656), respectively, corresponding to 21/426 (4.9%) and 44/308 (14.3%) patients, respectively. Regarding cross-resistance, among VRC-R isolates tested for ITC, nearly all were R (20/21;95%), compared to only 27% (20/74) of VRC-R among ITC-R isolates. The level of azole resistance remained somewhat stable over years but greatly varied according to the azole drug, patient origin, and clinical setting. Whereas azole resistance during invasive aspergillosis was very scarce, patients with cystic fibrosis were infected with multiple strains and presented the highest rate of resistance: 5% (27/539) isolates were VRC-R and 17.9% (78/436) were ITC-R. These results underline that the interpretation of the azole resistance level in Aspergilllus fumigatus in a routine setting may consider the huge variability depending on the azole drug, the clinical setting, the patient background and the type of infection.

Orbital aspergillosis: a case report and review of the literature

Background

Orbital aspergillosis is a rare sight- and life-threatening fungal infection affecting immunocompromised or otherwise healthy patients. It is often misdiagnosed due to its unspecific clinical and radiologic appearance. Therapeutic delay can have dramatic consequences. However, progress in microbiological diagnostic techniques and therapeutic experience from case series help improve the management of this disease.

Case presentation

A 78-year-old immunocompetent woman presented at an eye clinic for subacute swelling, reddening, and ptosis of her left upper eyelid. Based on radiologic and histologic considerations, she was treated for idiopathic orbital inflammation, but her condition worsened. After a second biopsy of the orbital mass, aspergillosis was diagnosed. Her condition improved promptly after initiation of an oral voriconazole treatment. Additionally, using a polymerase chain reaction (PCR) assay, A. fumigatus was identified on tissue of both biopsies and its azole susceptibility was examined simultaneously.

Conclusions

In the case described here, oral antifungal treatment was sufficient for the therapy of invasive orbital aspergillosis. Performing fungal PCR on orbital tissue can accelerate the diagnostic process and should be performed in ambiguous cases of slowly growing orbital mass. Finally, interdisciplinary management is the key to optimal treatment of orbital tumours and infections.

Performance of the AsperGenius® PCR assay for detecting azole resistant Aspergillus fumigatus in BAL fluids from allogeneic HSCT recipients: A prospective cohort study from Essen, West Germany

In this study a commercially available multiplex real-time PCR (AsperGenius®) was evaluated for its efficacy in detecting Aspergillus fumigatus and azole resistance markers in comparison with conventional culture methods and galactomannan (GM) testing from BAL fluids in allogeneic HSCT recipients. Between January 2015 and May 2017 100 allogeneic HSCT recipients with pulmonary infiltrates and suspicion of invasive fungal infection were recruited to the study from a tertiary care center in Germany. BAL fluid was routinely assessed using the following diagnostic tests: AsperGenius® PCR assay, GM testing (cut-off: 1.0) and conventional culture. Susceptibility testing of azoles was performed by using Etest and, in case presenting elevated MICs, PCR for mutations in the cyp51A gene was carried out. Criteria of EORTC/MSG were used to classify the patients for invasive fungal disease. According to the EORTC/MSG criteria 23 patients presented with probable invasive aspergillosis (IA). Aspergillus PCR showed a sensitivity of 65% for probable IA cases. A combination of PCR and GM results in BAL displayed a sensitivity of 96% (22/23) and 100% specificity. Mutations in the cyp51A gene were detected by PCR in three cases (3/23; 13%) which were also found resistant with the culture method. In one case a Y121F/T289A mutation and in two cases a L98H were found. The combination of a commercial Aspergillus PCR assay and GM testing from BAL demonstrated a high sensitivity and specificity for diagnosing IA in allogeneic HSCT recipients. The Aspergillus PCR assay was not superior in detecting azole resistant A. fumigatus compared to culture.

Azole-Resistant Aspergillus fumigatus Among Danish Cystic Fibrosis Patients: Increasing Prevalence and Dominance of TR34/L98H

Azole-resistant (azole-R) Aspergillus is an increasing challenge worldwide. Patients with cystic fibrosis (CF) are at risk of Aspergillus colonization and disease due to a favorable lung environment for microorganisms. We performed a nationwide study in 2018 of azole-non-susceptible Aspergillus in CF patients and compared with data from two prior studies. All airway samples with mold isolates from patients monitored at the two CF centers in Denmark (RH, Jan-Sept and AUH, Jan-Jun) were included. Classical species identification (morphology and thermo-tolerance) was performed and MALDI-TOF/β-tubulin sequencing was performed if needed. Susceptibility was determined using EUCAST E.Def 10.1, and E.Def 9.3.2. cyp51A sequencing and STRAf genotyping were performed for azole-non-susceptible isolates and relevant sequential isolates. In total, 340 mold isolates from 159 CF patients were obtained. The most frequent species were Aspergillus fumigatus (266/340, 78.2%) and Aspergillus terreus (26/340, 7.6%). Azole-R A. fumigatus was cultured from 7.3% (10/137) of patients, including 9.5% (9/95) of patients at RH and 2.4% at AUH (1/42), respectively. In a 10-year perspective, azole-non-susceptibility increased numerically among patients at RH (10.5% in 2018 vs 4.5% in 2007-2009). Cyp51A resistance mechanisms were found in nine azole-R A. fumigatus from eight CF patients. Five were of environmental origin (TR₃₄/L98H), three were human medicine-driven (two M220K and one M220R), and one was novel (TR₃₄ ³/L98H) and found in a patient who also harbored a TR₃₄/L98H isolate. STRAf genotyping identified 27 unique genotypes among 45 isolates and ≥2 genotypes in 8 of 12 patients. This included one patient carrying two unique TR₃₄/L98H isolates, a rare phenomenon. Genotyping of sequential TR₃₄ ³/L98H and TR₃₄/L98H isolates from the same patient showed only minor differences in 1/9 markers. Finally, azole-R A. terreus was found in three patients including two with Cyp51A alterations (M217I and G51A, respectively). Azole-R A. fumigatus is increasing among CF patients in Denmark with the environmentally associated resistance TR₃₄/L98H mechanism being dominant. Mixed infections (wildtype/non-wildtype and several non-wildtypes) and a case of potential additional tandem repeat acquisition in vivo were found. However, similar genotypes were identified from another patient (and outside this study), potentially suggesting a predominant TR₃₄/L98H clone in DK. These findings suggest an increasing prevalence and complexity of azole resistance in A. fumigatus.

One year prospective survey of azole resistance in Aspergillus fumigatus at a French cystic fibrosis reference centre: prevalence and mechanisms of resistance

BACKGROUND

Studies on Aspergillus fumigatus azole resistance in cystic fibrosis patients are scarce despite the fact that it is the most frequently isolated fungus from respiratory samples from these individuals.

OBJECTIVES

To evaluate resistance prevalence, investigate mechanisms of resistance and explore the relationship between resistant isolates by genotyping.

METHODS

We conducted a prospective 1 year study (from 1 January to 31 December 2015), based on the investigation of up to five colonies per sample from cystic fibrosis patients.

RESULTS

Twenty-three (6.5%) isolates among the 355 tested were resistant to at least one triazole drug, using the EUCAST reference method, leading to a prevalence of 6.8% (6/88 patients). Analysis of resistance mechanisms highlighted TR34/L98H (n = 10), TR46/Y121F/T289A (n = 1), WT cyp51A (n = 11) and F46Y/M172V/N248T/D255E/E427K (n = 1). No genotype was shared between patients.

CONCLUSIONS

This study showed a relatively stable resistance prevalence in comparison with the previous study conducted in 2010-11 (8%), although resistance mechanisms varied between the two studies.

In vitro activity of olorofim (F901318) against fungi of the genus, Scedosporium and Rasamsonia as well as against Lomentospora prolificans, Exophiala dermatitidis and azole-resistant Aspergillus fumigatus

In recent decades, invasive infections caused by fungal pathogens have been reported with increasing frequency. Concurrently, the rates of detected resistance mechanisms against commonly used antifungal agents in fungi are increasing. The need for novel antifungal drugs is thus imminent. In this study, the novel drug olorofim (F901318) was tested for its antifungal activity against the human fungal pathogens Lomentospora prolificans (n = 20), Scedosporium aurantiacum (n = 2), Scedosporium apiospermum (n = 6), Rasamsonia argillacea species complex (n = 23), Exophiala dermatitidis (n = 10) and azole-resistant Aspergillus fumigatus (ARAF) (n = 25) in an in vitro broth microdilution assay according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommendations. Whilst olorofim was ascertained to be effective against R. argillacea species complex [minimum inhibitory concentrations (MICs) of ≤0.008 mg/L], Scedosporium spp. (MICs of 0.032-0.5 mg/L), L. prolificans (MICs of 0.032-0.5 mg/L) and ARAF (MICs of ≤0.008-0.032 mg/L), the drug had an MIC of >4 mg/L against E. dermatitidis. These data demonstrate the antifungal activity of olorofim against a broad range of filamentous fungal pathogens.

A Novel Combination of CYP51A Mutations Confers Pan-Azole Resistance in Aspergillus fumigatus

The treatment of invasive and chronic aspergillosis involves triazole drugs. Its intensive use has resulted in the selection of resistant isolates, and at present, azole resistance in Aspergillus fumigatus is considered an emerging threat to public health worldwide. The aim of this work is to uncover the molecular mechanism implicated in the azole resistance phenotype of three Aspergillus fumigatus clinical strains isolated from an Argentinian cystic fibrosis patient under long-term triazole treatment. Strain susceptibilities were assessed, and CYP51A gene sequences were analyzed. Two of the studied Aspergillus fumigatus strains harbored the TR34-L98H allele. These strains showed high MIC values for all tested triazoles (>16.00 μg/ml, 1.00 μg/ml, 1.00 μg/ml, and 2.00 μg/ml for itraconazole, isavuconazole, posaconazole, and voriconazole, respectively). The third strain had a novel amino acid change (R65K) combined with the TR34-L98H mutations. This new mutation combination induces a pan-azole MIC augment compared with TR34-L98H mutants (>16 μg/ml, 4.00 μg/ml, 4.00 μg/ml, and 8.00 μg/ml for itraconazole, isavuconazole, posaconazole, and voriconazole, respectively). The strain harboring the TR34-R65K-L98H allele showed no inhibition halo when voriconazole susceptibility was evaluated by disk diffusion. The effect of these mutations in the azole-resistant phenotype was confirmed by gene replacement experiments. Transformants harboring the TR34-L98H and TR34-R65K-L98H alleles mimicked the azole-resistant phenotype of the clinical isolates, while the incorporation of the TR34-R65K and R65K alleles did not significantly increase azole MIC values. This is the first report of the TR34-L98H allele in Argentina. Moreover, a novel CYP51A allele (TR34-R65K-L98H) that induces a pan-azole MIC augment is described.

Azole resistance among clinical isolates of Aspergillus fumigatus in Lima-Peru

Azole resistance among Aspergillus fumigatus isolates, which is mainly related to mutations in the cyp51A gene, is a concern because it is rising, worldwide disseminated, and associated with treatment failure and death. Data on azole resistance of aspergillus from Latin American countries is very scarce and do not exist for Peru. Two hundred and seven Aspergillus clinical isolates collected prospectively underwent mycology and molecular testing for specie identification, and 143 isolates were confirmed as A. fumigatus sensu stricto (AFSS). All AFSS were tested for in vitro azole susceptibility, and resistant isolates underwent PCR amplification and sequencing of the whole cyp51A gene and its promoter. The in vitro susceptibility showed a minimal inhibitory concentration (MIC) range, MIC50 and MIC90 of 0.125 to >16, 0.25, and 0.5 μg/ml for itraconazole; 0.25 to 2, 0.5, and 0.5 μg/ml for voriconazole; and 0.003 to 1, 0.06, and 0.125 μg/ml for posaconazole. Three isolates (2%) showed resistance to itraconazole and exhibited different mutations of the cyp51A gene. One isolate harbored the mutation M220K, while a second one exhibited the G54 mutation plus a modification in the cyp51A gene promoter. The third isolate, from an azole naive patient, presented an integration of a 34-bp tandem repeat (TR34) in the promoter region of the gene and a substitution of leucine 98 by histidine (L98H). The three source patients had a diagnosis or suspicion of chronic pulmonary aspergillosis.

First azole-resistant Aspergillus fumigatus isolates with the environmental TR46 /Y121F/T289A mutation in Iran

Background

Azole resistance in Aspergillus fumigatus is an emerging problem and reported from all continents. As triazole antifungals are the mainstay of therapy in the management of invasive aspergillosis, azole‐resistant A fumigatus has become a major medical concern and with complicated clinical management.

Objective

Screening of environmental presence of azole‐resistant A fumigatus in Iran.

Methods

Compost from Northern Iran, collected between 2017 and 2018, was screened for the presence of azole‐resistant A fumigatus with azole‐containing agar. Phenotypic MICs were obtained from selected, molecularly confirmed isolates. cyp51A gene sequencing and genotyping of azole‐resistant isolates were done.

Results

Among 300 compost samples, three A fumigatus isolates had high voriconazole MICs (≥16 mg/L) and harboured the TR₄₆/Y121F/T289A mutation in the cyp51A gene. Microsatellite typing of these isolates showed that two strains had the same allele across all nine examined microsatellite loci and were genotypically related to Indian azole‐resistant strains. The other isolate had a different genotype.

Conclusion

This is the first report of A fumigatus with TR₄₆/Y121F/T289A mutation from the region. Monitoring and surveillance of antifungal susceptibility of clinical A fumigatus is warranted in Iran and elsewhere in the region.

Antifungal susceptibility testing in Candida, Aspergillus and Cryptococcus infections: are the MICs useful for clinicians?

BACKGROUND

Invasive fungal infections (IFIs) represent a global issue and affect various patient populations. In recent years, resistant fungal isolates showing increased azole or echinocandin MICs have been reported, and their potential clinical impact has been investigated.

AIMS

To provide an update on the epidemiology of resistance among fungi (e.g., Candida spp., Aspergillus spp., and Cryptococcus spp.) and to offer a critical appraisal of the relevant literature regarding the impact of MICs on clinical outcome in patients with IFI.

SOURCES

PubMed search with relevant keywords along with a personal collection of relevant publications.

CONTENT

Although antifungal resistance has been associated with a poorer response to antifungal therapy in various studies, other factors such as comorbidities, septic shock and source of infection appear to be key determinants affecting the clinical outcome of patients with IFI.

IMPLICATIONS

Future international collaborative studies are required to tease out the relative contribution of in vitro antifungal resistance on patient outcomes, thus enabling the optimization of IFI management.

The prevalence of Aspergillus fumigatus in early cystic fibrosis disease is underestimated by culture-based diagnostic methods

Aspergillus fumigatus is the most common fungus infecting/colonising people with cystic fibrosis (CF) and can negatively impact clinical status. Diagnostic laboratories rely on culture to detect A. fumigatus which is known to be less sensitive than molecular approaches. Therefore, A. fumigatus colonisation in the CF population may be underestimated. Sputum (n = 60) from 25 children with CF were collected and A. fumigatus was detected using routine culture (CM1), enhanced culture (CM2) and ITS1 qPCR. The prevalence of A. fumigatus in this young CF population was 68% by qPCR and only 16% by CM1. CM1, CM2 and qPCR detected A. fumigatus in 8%, 22% and 53% of samples, respectively. qPCR had a 94.2% and 77.4% increased odds of detecting A. fumigatus over CM1 and CM2, respectively. Molecular methods proved superior for detecting A. fumigatus in CF sputum. A. fumigatus is likely more prevalent in early CF disease than is currently reported.

Emerging Fungal Infections: New Patients, New Patterns, and New Pathogens

The landscape of clinical mycology is constantly changing. New therapies for malignant and autoimmune diseases have led to new risk factors for unusual mycoses. Invasive candidiasis is increasingly caused by non-albicans Candida spp., including C. auris, a multidrug-resistant yeast with the potential for nosocomial transmission that has rapidly spread globally. The use of mould-active antifungal prophylaxis in patients with cancer or transplantation has decreased the incidence of invasive fungal disease, but shifted the balance of mould disease in these patients to those from non-fumigatus Aspergillus species, Mucorales, and Scedosporium/Lomentospora spp. The agricultural application of triazole pesticides has driven an emergence of azole-resistant A. fumigatus in environmental and clinical isolates. The widespread use of topical antifungals with corticosteroids in India has resulted in Trichophyton mentagrophytes causing recalcitrant dermatophytosis. New dimorphic fungal pathogens have emerged, including Emergomyces, which cause disseminated mycoses globally, primarily in HIV infected patients, and Blastomyceshelicus and B. percursus, causes of atypical blastomycosis in western parts of North America and in Africa, respectively. In North America, regions of geographic risk for coccidioidomycosis, histoplasmosis, and blastomycosis have expanded, possibly related to climate change. In Brazil, zoonotic sporotrichosis caused by Sporothrix brasiliensis has emerged as an important disease of felines and people.

Contemporary Gene Flow is a Major Force Shaping the Aspergillus fumigatus Population in Auckland, New Zealand

Aspergillus fumigatus is a globally distributed opportunistic fungal pathogen capable of causing highly lethal invasive aspergillosis in immunocompromised individuals. Recent studies have indicated that the global population consists of multiple, divergent genetic clusters that are geographically broadly distributed. However, most of the analyzed samples have come from continental Eurasia and the Americas where the effects of ancient versus recent factors are difficult to distinguish. Here, we investigated environmental A. fumigatus isolates from Auckland, New Zealand, a geographically isolated population, and compared them with those from other parts of the world to determine the relative roles of historical differentiation and recent gene flow in shaping A. fumigatus populations. Our data suggest that the Auckland A. fumigatus population contains both unique indigenous genetic elements as well as genetic elements that are similar to those from other regions such as Europe, Africa, and North America. Though the hypothesis of random recombination was rejected, we found abundant evidence for phylogenetic incompatibility and recombination within the Auckland A. fumigatus population. Additionally, susceptibility testing identified two triazole-resistant strains, one of which contained the globally distributed mutation TR₃₄/L98H in the cyp51A gene. Our results suggest that contemporary gene flow, likely due to anthropogenic factors, is a major force shaping the New Zealand A. fumigatus population.

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.

Anti-infective Properties of the Golden Spice Curcumin

The search for novel anti-infectives is one of the most important challenges in natural product research, as diseases caused by bacteria, viruses, and fungi are influencing the human society all over the world. Natural compounds are a continuing source of novel anti-infectives. Accordingly, curcumin, has been used for centuries in Asian traditional medicine to treat various disorders. Numerous studies have shown that curcumin possesses a wide spectrum of biological and pharmacological properties, acting, for example, as anti-inflammatory, anti-angiogenic and anti-neoplastic, while no toxicity is associated with the compound. Recently, curcumin’s antiviral and antibacterial activity was investigated, and it was shown to act against various important human pathogens like the influenza virus, hepatitis C virus, HIV and strains of Staphylococcus, Streptococcus, and Pseudomonas. Despite the potency, curcumin has not yet been approved as a therapeutic antiviral agent. This review summarizes the current knowledge and future perspectives of the antiviral, antibacterial, and antifungal effects of curcumin.

Cornely O, Kurzai O. Invasive Fungal Infection

BACKGROUND

The incidence of invasive fungal infection is approximately 6 cases per 100 000 persons per year. It is estimated that only half of such infections are detected during the patient's lifetime, making this one of the more common overlooked causes of death in intensive-care patients. The low detection rate is due in part to the complexity of the diagnostic work-up, in which the clinical, radiological, and microbiological findings must be considered. Fungi with resistance to antimycotic drugs have been found to be on the rise around the world.

METHODS

This review is based on pertinent publications retrieved from a selective search in PubMed, with special attention to guidelines on the diagnosis and treatment of invasive fungal infections caused by Candida spp., Aspergillus spp., Mucorales, and Fusarium spp.

RESULTS

The clinical risk factors for invasive fungal infection include, among others, congenital immune deficiency, protracted (>10 days) marked granulocytopenia (<0.5 x 109/L), allogeneic stem-cell transplantation, and treatment with immunosuppressive drugs or corticosteroids. High-risk groups include patients in intensive care and those with structural pulmonary disease and/or compli- cated influenza. The first line of treatment, supported by the findings of randomized clinical trials, consists of echinocandins for in- fections with Candida spp. (candidemia response rates: 75.6% for anidulafungin vs. 60.2% for fluconazole) and azole antimycotic drugs for infections with Aspergillus spp. (response rates: 52.8% for voriconazole vs. 31.6% for conventional amphotericin B). The recommended first-line treatment also depends on the local epidemiology. This challenge should be met by interdisciplinary collaboration. Therapeutic decision-making should also take account of the often severe undesired effects of antimycotic drugs (including impairment of hepatic and/or renal function) and the numerous interactions that some of them have with other drugs.

CONCLUSION

Invasive fungal infections are often overlooked in routine hospital care. They should be incorporated into antimicro- bial stewardship programs as an essential component. There is also a pressing need for the development of new classes of antimycotic drug.

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.

Prevalence and diversity of filamentous fungi in the airways of cystic fibrosis patients - A Dutch, multicentre study

BACKGROUND

Progressive lung injury in Cystic Fibrosis (CF) patients can lead to chronic colonization with bacteria and fungi. Fungal colonization is obtained from the environment which necessitates locally performed epidemiology studies. We prospectively analyzed respiratory samples of CF patients during a 3-year period, using a uniform fungal culture protocol, focusing on filamentous fungi and azole resistance in Aspergillus fumigatus.

METHODS

Over a 3-year period, all respiratory specimens collected from CF patients in 5 Dutch CF centers, were analyzed. Samples were inoculated onto the fungal culture media Sabouraud dextrose agar (SDA) and Medium B+. All fungal isolates were collected and identified in one centre, using Amplified Fragment Length Polymorphism (AFLP) fingerprinting, rDNA PCR and ITS, calmodulin and β-tubulin sequencing. Azole resistance was assessed for all A. fumigatus using a qPCR assay followed by phenotypic confirmation.

RESULTS

Filamentous fungi were recovered from 699 patients from at least one respiratory sample, corresponding with 3787 cultured fungal species. A. fumigatus was cultured most often with a mean prevalence of 31.7%, followed by Penicillium species (12.6%), non-fumigatus Aspergillus species (5.6%), Scedosporium species (4.5%) and Exophiala dermatitidis and Cladosporium species (1.1% each). In total 107 different fungal species were identified, with 39 Penicillium species and 15 Aspergillus species. Azole resistance frequency in A. fumigatus was 7.1%, with TR₃₄/L98H being the dominant resistance mechanism.

CONCLUSION

A vast diversity of filamentous fungi was demonstrated, dominated by Aspergillus and Penicillium species. We observed a mean azole resistance prevalence of 7.1% of A. fumigatus culture positive patients.

Determination of Azole Resistance and TR34/L98H Mutations in Isolates of Aspergillus Section Fumigati from Turkish Cystic Fibrosis Patients

BACKGROUND

Aspergillus fumigatus is the species section Fumigati most frequently isolated from the respiratory tract of cystic fibrosis (CF) patients. Recent studies suggest that mutations in the Cyp51 gene, particularly TR₃₄/L98H, are responsible for azole resistance.

OBJECTIVES AND METHODS

The focus of this study was on section Fumigati isolates isolated from the respiratory tract samples of CF patients. More specifically, the goal was to detect A. fumigatus isolates, test their antifungal susceptibility to itraconazole, voriconazole and posaconazole, and finally determine the presence of TR₃₄/L98H and other mutations in the isolates Cyp51A gene.

RESULTS AND CONCLUSIONS

A set of 31 isolates of Aspergillus section Fumigati were obtained from the sputum samples of 6 CF patients and subsequently identified to species level by microsatellite genotyping. All isolates were determined as A. fumigatus and involved 14 different genotypes. The minimal inhibitory concentrations to the three azoles were determined by the E-test method, and the Cyp51A gene was sequenced. One of the genotypes was found to be resistant to all azoles but no mutations were detected in the Cyp51A gene, especially the TR₃₄/L98H mutation. Therefore, mutations in genes other than Cyp51A or other distinct mechanisms may be responsible for this reported multiazole resistance found in a Turkish CF patient.