Evolutionary trends in antifungal resistance: a meta-analysis

The present paper includes a meta-analysis of literature data on 318 species of fungi belonging to 34 orders in their response to 8 antifungal agents (amphotericin B, caspofungin, fluconazole, itraconazole, ketoconazole, posaconazole, terbinafine, and voriconazole). Main trends of MIC results at the ordinal level were visualized. European Committee on Antimicrobial Susceptibility Testing and Clinical & Laboratory Standards Institute (CLSI) clinical breakpoints were used as the staff gauge to evaluate MIC values ranging from resistance to susceptibility, which were subsequently compared with a phylogenetic tree of the fungal kingdom. Several orders (Hypocreales, Microascales, and Mucorales) invariably showed resistance. Also the basidiomycetous orders Agaricales, Polyporales, Sporidiales, Tremellales, and Trichosporonales showed relatively high degrees of azole multi-resistance, while elsewhere in the fungal kingdom, including orders with numerous pathogenic and opportunistic species, that is, Onygenales, Chaetothyiales, Sordariales, and Malasseziales, in general were susceptible to azoles. In most cases, resistance vs susceptibility was consistently associated with phylogenetic distance, members of the same order showing similar behavior.

IMPORTANCE

A kingdom-wide the largest set of published wild-type antifungal data comparison were analyzed. Trends in resistance in taxonomic groups (monophyletic clades) can be compared with the phylogeny of the fungal kingdom, eventual relationships between fungus-drug interaction and evolution can be described.

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.

Aspergillus Outbreak in an Intensive Care Unit: Source Analysis with Whole Genome Sequencing and Short Tandem Repeats

Whole genome sequencing (WGS) is widely used for outbreak analysis of bacteriology and virology but is scarcely used in mycology. Here, we used WGS for genotyping Aspergillus fumigatus isolates from a potential Aspergillus outbreak in an intensive care unit (ICU) during construction work. After detecting the outbreak, fungal cultures were performed on all surveillance and/or patient respiratory samples. Environmental samples were obtained throughout the ICU. WGS was performed on 30 isolates, of which six patient samples and four environmental samples were related to the outbreak, and twenty samples were unrelated, using the Illumina NextSeq 550. A SNP-based phylogenetic tree was created from outbreak samples and unrelated samples. Comparative analysis (WGS and short tandem repeats (STRs), microsatellite loci analysis) showed that none of the strains were related to each other. The lack of genetic similarity suggests the accumulation of Aspergillus spores in the hospital environment, rather than a single source that supported growth and reproduction of Aspergillus fumigatus. This supports the hypothesis that the Aspergillus outbreak was likely caused by release of Aspergillus fumigatus spores during construction work. Indeed, no new Aspergillus cases were observed in the ICU after cessation of construction. This study demonstrates that WGS is a suitable technique for examining inter-strain relatedness of Aspergillus fumigatus in the setting of an outbreak investigation.

Absence of COVID-19 associated mucormycosis in a tertiary intensive care unit in the Netherlands

Mucormycosis is a severe complication in critically ill COVID-19 patients. Throughout the pandemic, a notable prevalence of mucormycosis has been observed in the Indian population, whereas lower occurrences have been reported in Europe. However, limited data exist regarding its prevalence in Europe, which is potentially underestimated due to the low sensitivity of bronchoalveolar lavage (BAL) cultures. We aimed to evaluate the prevalence of mucormycosis in a high-risk critically ill COVID-19 population in the Netherlands, and to evaluate the potential benefit of adding Mucor PCR to BAL as part of routine follow-up. In this study, we included 1035 critically ill COVID-19 patients admitted to either one of the two ICUs at AmsterdamUMC between March 2020 and May 2022; of these, 374 had undergone at least one bronchoscopy. Following the AmsterdamUMC protocols, bronchoscopies were conducted weekly until clinical improvement was achieved. We cultured BAL fluid for fungi and used PCR and galactomannan testing to detect Aspergillus spp. Additionally, we retrospectively performed qPCR targeting Mucorales DNA in the BAL of 89 deceased patients. All cultures were negative for Mucorales, whereas 42 (11%) cultures were positive for Aspergillus. Furthermore, qPCR targeting Mucorales was negative in all 89 deceased patients. This study showed that pulmonary mucormycosis was not present in critically ill COVID-19 patients in two tertiary care ICUs. These results indicate routine Mucorales qPCR screening is not clinically necessary in a high-standard-of-care tertiary ICU in a low-endemic area.

Population Pharmacokinetics of Total and Unbound Isavuconazole in Critically Ill Patients: Implications for Adaptive Dosing Strategies

BACKGROUND AND OBJECTIVES

Isavuconazole is a broad-spectrum antifungal agent for the management of invasive fungal disease. Optimised drug exposure is critical for patient outcomes, specifically in the critically ill population. Solid information on isavuconazole pharmacokinetics including protein binding in patients in the intensive care unit is scarce. We aimed to describe the total and unbound isavuconazole pharmacokinetics and subsequently propose a dosage optimisation strategy.

METHODS

A prospective multi-centre study in adult intensive care unit patients receiving isavuconazole was performed. Blood samples were collected on eight timepoints over one dosing interval between days 3-7 of treatment and optionally on one timepoint after discontinuation. Total and unbound isavuconazole pharmacokinetics were analysed by means of population pharmacokinetic modelling using NONMEM. The final model was used to perform simulations to assess exposure described by the area under the concentration-time curve and propose an adaptive dosing approach.

RESULTS

Population pharmacokinetics of total and unbound isavuconazole were best described by an allometrically scaled two-compartment model with a saturable protein-binding model and interindividual variability on clearance and the maximum binding capacity. The median (range) isavuconazole unbound fraction was 1.65% (0.83-3.25%). After standard dosing, only 35.8% of simulated patients reached a total isavuconazole area under the concentration-time curve > 60 mg·h/L at day 14. The proposed adaptive dosing strategy resulted in an increase to 62.3% of patients at adequate steady-state exposure.

CONCLUSIONS

In critically ill patients, total isavuconazole exposure is reduced and protein binding is highly variable. We proposed an adaptive dosing approach to enhance early treatment optimisation in this high-risk population.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04777058.

High Variability in Isavuconazole Unbound Fraction in Clinical Practice: A Call to Reconsider Pharmacokinetic/Pharmacodynamic Targets and Breakpoints

Isavuconazole exposure-response relationships have been studied with a focus on total rather than unbound exposure, assuming a constant unbound fraction of 1%. We observed a median (range) unbound fraction of 1.59% (0.42-5.30%) in patients. This highly variable protein binding asks for re-evaluation of current pharmacokinetic and pharmacodynamic targets for isavuconazole.

Genomic Epidemiology Identifies Azole Resistance Due to TR34/L98H in European Aspergillus fumigatus Causing COVID-19-Associated Pulmonary Aspergillosis

Aspergillus fumigatus has been found to coinfect patients with severe SARS-CoV-2 virus infection, leading to COVID-19-associated pulmonary aspergillosis (CAPA). The CAPA all-cause mortality rate is approximately 50% and may be complicated by azole resistance. Genomic epidemiology can help shed light on the genetics of A. fumigatus causing CAPA, including the prevalence of resistance-associated alleles. We present a population genomic analysis of 21 CAPA isolates from four European countries with these isolates compared against 240 non-CAPA A. fumigatus isolates from a wider population. Bioinformatic analysis and antifungal susceptibility testing were performed to quantify resistance and identify possible genetically encoded azole-resistant mechanisms. The phylogenetic analysis of the 21 CAPA isolates showed that they were representative of the wider A. fumigatus population with no obvious clustering. The prevalence of phenotypic azole resistance in CAPA was 14.3% (n = 3/21); all three CAPA isolates contained a known resistance-associated cyp51A polymorphism. The relatively high prevalence of azole resistance alleles that we document poses a probable threat to treatment success rates, warranting the enhanced surveillance of A. fumigatus genotypes in these patients. Furthermore, potential changes to antifungal first-line treatment guidelines may be needed to improve patient outcomes when CAPA is suspected.

Fungi involved in rhinosinusitis in arid regions: insights from molecular identification and antifungal susceptibility

Fungal rhinosinusitis (FRS) is a common problem worldwide, with an increasing burden in arid climate regions. Aspergillus species are the most common causative agents involved. In the present study, we investigated the prevalence, molecular characterization, and antifungal susceptibility of opportunists causing FRS in Sudan on the basis of strains collected over a period of 5 years. β-Tubulin and calmodulin sequencing were used for species identification, and antifungal susceptibility profiles were evaluated by the protocol of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Predominant species belonged to the Aspergillus flavus complex (n = 244), A. terreus complex (n = 16), A. fumigatus complex (n = 7), and other fungi (n = 17). Molecular identification of 94 strains of Aspergillus revealed the following species: A. flavus (n = 88), A. terreus (n = 1), A. citrinoterreus (n = 2), A. fumigatus (n = 1), A. caespitosus (n = 1), and A. sydowii (n = 1). Several A. flavus and an A. fumigatus isolates showed reduced susceptibility to azoles (minimum inhibitory concentrations above the clinical breakpoints or epidemiological cutoff values). Despite several mutations revealed in cyp51A of these isolates, none could be directly linked to azole resistance. Molecular identification of fungi causing FRS is useful to identify cryptic species and for epidemiologic studies. IMPORTANCE Fungal rhinosinusitis (FRS) is a significant clinical problem in arid regions. This study provides new insights into the prevalence, etiology, and antifungal susceptibility of FRS pathogens in Sudan, where the disease burden is high. Aspergillus species, particularly the A. flavus complex, were identified as the primary FRS pathogens in the region, with some evidence of antifungal resistance. The molecular identification of fungal species causing FRS is useful for detecting antifungal resistance, identifying cryptic species, and characterizing the epidemiology of the disease. The emergence of Azole resistance Aspergilli in Sudan highlights the need for continued surveillance and appropriate use of antifungal agents. These findings have important implications for clinical management, public health policy, and future research on FRS. Publishing this study in Microbiology Spectrum would enable other researchers and clinicians to build on these findings, ultimately improving the diagnosis, treatment, and prevention of FRS.

The C2H2 transcription factor SltA is required for germination and hyphal development in Aspergillus fumigatus

Germination of inhaled Aspergillus fumigatus conidia is a necessary sequitur for infection. Germination of conidia starts with the breaking of dormancy, which is initiated by an increase of the cellular perimeter in a process termed isotropic growth. This swelling phase is followed by polarized growth, resulting in the formation of a germ tube. The multinucleate tubular cells exhibit tip growth from the hyphae, after which lateral branches emerge to form the mycelial network. The regulatory mechanisms governing conidial germination are not well defined. In this study, we identified a novel role for the transcription factor SltA in the orchestration of germination and hyphal development. Conidia lacking sltA fail to appropriately regulate isotropic growth and begin to swell earlier and subsequently switch to polarized growth faster. Additionally, hyphal development is distorted in a ∆sltA isolate as hyphae are hyper-branching and wider, and show branching at the apical tip. ∆sltA conidia are more tolerant to cell wall stressors on minimal medium compared to the wild-type (WT) strain. A transcriptome analysis of different stages of early growth was carried out to assess the regulatory role of SltA. Null mutants generated for three of the most dysregulated genes showed rapid germ tube emergence. Distinct from the phenotype observed for ∆sltA, conidia from these strains lacked defects in isotropic growth, but switched to polarized growth faster. Here, we characterize and describe several genes in the regulon of SltA, highlighting the complex nature of germination.IMPORTANCEAspergillus fumigatus is the main human fungal pathogen causing aspergillosis. For this fungus, azoles are the most commonly used antifungal drugs for treatment of aspergillosis. However, the prevalence of azole resistance is alarmingly increasing and linked with elevated mortality. Germination of conidia is crucial within its asexual life cycle and plays a critical role during the infection in the human host. Precluding germination could be a promising strategy considering the role of germination in Aspergillus spp. pathogenicity. Here, we identify a novel role for SltA in appropriate maintenance of dormancy, germination, and hyphal development. Three genes in the regulon of SltA were also essential for appropriate germination of conidia. With an expanding knowledge of germination and its different morphotypes, more advances can be made toward potential anti-germination targets for therapy.

The in vitro Activity of Echinocandins Against Clinical Trichophyton rubrum Isolates and Review of the Susceptibility of T. rubrum to Echinocandins Worldwide

Introduction

The emergence of resistance in Trichophyton rubrum to azoles and terbinafine has become increasingly evident in recent years, necessitating the development of novel antifungal drugs and the exploration of new indications for existing agents.

Methods

In this study, we retrospectively evaluated the in vitro antifungal activity of 3 echinocandins (anidulafungin, caspofungin, and micafungin) against 73 clinical isolates of T. rubrum collected from a teaching hospital in Shanghai, China, using EUCAST E.DEF 9.3.1 with minor modification. We also reviewed the susceptibility of T. rubrum to echinocandins globally by literature searching.

Results

Our findings revealed that micafungin exhibited the lowest modal minimum effective concentration (MEC) value (0.08 mg/L, n = 28) and the lowest geometric mean (GM) MEC value (0.014 mg/L) among the 73 isolates of T. rubrum tested, followed by anidulafungin with a modal MEC value of 0.016 mg/L (n = 67) and a GM of 0.018 mg/L. Caspofungin displayed a higher modal MEC value of 0.5 mg/L (n = 35) and a GM of 0.308 mg/L. Despite variations in methodologies, similar results were obtained from the review of five relevant studies included in our analysis.

Discussion

Echinocandins exhibited excellent in vitro activity against T. rubrum isolates, with micafungin and anidulafungin demonstrating greater potency than caspofungin. These findings suggest that echinocandins could be considered as potential treatment options for managing recalcitrant dermatophytoses resulting from the emergence of resistance. However, it is important to note that the clinical efficacy of these in vitro findings has yet to be established and warrants further investigation.

The Transcriptome Response to Azole Compounds in Aspergillus fumigatus Shows Differential Gene Expression across Pathways Essential for Azole Resistance and Cell Survival

The opportunistic pathogen Aspergillus fumigatus is found on all continents and thrives in soil and agricultural environments. Its ability to readily adapt to novel environments and to produce billions of spores led to the spread of azole-resistant A. fumigatus across the globe, posing a threat to many immunocompromised patients, including critically ill patients with severe influenza or COVID-19. In our study, we sought to compare the adaptational response to azoles from A. fumigatus isolates that differ in azole susceptibility and genetic background. To gain more insight into how short-term adaptation to stressful azole compounds is managed through gene expression, we conducted an RNA-sequencing study on the response of A. fumigatus to itraconazole and the newest clinically approved azole, isavuconazole. We observed many similarities in ergosterol biosynthesis up-regulation across isolates, with the exception of the pan-azole-resistant isolate, which showed very little differential regulation in comparison to other isolates. Additionally, we found differential regulation of membrane efflux transporters, secondary metabolites, iron metabolism, and various stress response and cell signaling mechanisms.

Performance of the beta-glucan test for the diagnosis of invasive fusariosis and scedosporiosis: a meta-analysis

The (1→3)-β-D-glucan (BDG) is a component of the fungal cell wall that can be detected in serum and used as an adjunctive tool for the diagnosis of invasive mold infections (IMI) in patients with hematologic cancer or other immunosuppressive conditions. However, its use is limited by modest sensitivity/specificity, inability to differentiate between fungal pathogens, and lack of detection of mucormycosis. Data about BDG performance for other relevant IMI, such as invasive fusariosis (IF) and invasive scedosporiosis/lomentosporiosis (IS) are scarce. The objective of this study was to assess the sensitivity of BDG for the diagnosis of IF and IS through systematic literature review and meta-analysis. Immunosuppressed patients diagnosed with proven or probable IF and IS, with interpretable BDG data were eligible. A total of 73 IF and 27 IS cases were included. The sensitivity of BDG for IF and IS diagnosis was 76.7% and 81.5%, respectively. In comparison, the sensitivity of serum galactomannan for IF was 27%. Importantly, BDG positivity preceded the diagnosis by conventional methods (culture or histopathology) in 73% and 94% of IF and IS cases, respectively. Specificity was not assessed because of lacking data. In conclusion, BDG testing may be useful in patients with suspected IF or IS. Combining BDG and galactomannan testing may also help differentiating between the different types of IMI.

Clinical Impact of Polymerase Chain Reaction-Based Aspergillus and Azole Resistance Detection in Invasive Aspergillosis: A Prospective Multicenter Study

BACKGROUND

Invasive aspergillosis (IA) by a triazole-resistant Aspergillus fumigatus is associated with high mortality. Real-time resistance detection will result in earlier initiation of appropriate therapy.

METHODS

In a prospective study, we evaluated the clinical value of the AsperGenius polymerase chain reaction (PCR) assay in hematology patients from 12 centers. This PCR assay detects the most frequent cyp51A mutations in A. fumigatus conferring azole resistance. Patients were included when a computed tomography scan showed a pulmonary infiltrate and bronchoalveolar fluid (BALf) sampling was performed. The primary end point was antifungal treatment failure in patients with azole-resistant IA.

RESULTS

Of 323 patients enrolled, complete mycological and radiological information was available for 276 (94%), and probable IA was diagnosed in 99/276 (36%). Sufficient BALf for PCR testing was available for 293/323 (91%). Aspergillus DNA was detected in 116/293 (40%) and A. fumigatus DNA in 89/293 (30%). The resistance PCR was conclusive in 58/89 (65%) and resistance detected in 8/58 (14%). Two had a mixed azole-susceptible/azole-resistant infection. In the 6 remaining patients, treatment failure was observed in 1. Galactomannan positivity was associated with mortality (P = .004) while an isolated positive Aspergillus PCR was not (P = .83).

CONCLUSIONS

Real-time PCR-based resistance testing may help to limit the clinical impact of triazole resistance. In contrast, the clinical impact of an isolated positive Aspergillus PCR on BALf seems limited. The interpretation of the EORTC/MSGERC PCR criterion for BALf may need further specification (eg, minimum cycle threshold value and/or PCR positive on >1 BALf sample).

Invasive candidiasis: current clinical challenges and unmet needs in adult populations

Invasive candidiasis (IC) is a serious infection caused by several Candida species, and the most common fungal disease in hospitals in high-income countries. Despite overall improvements in health systems and ICU care in the last few decades, as well as the development of different antifungals and microbiological techniques, mortality rates in IC have not substantially improved. The aim of this review is to summarize the main issues underlying the management of adults affected by IC, focusing on specific forms of the infection: IC developed by ICU patients, IC observed in haematological patients, breakthrough candidaemia, sanctuary site candidiasis, intra-abdominal infections and other challenging infections. Several key challenges need to be tackled to improve the clinical management and outcomes of IC patients. These include the lack of global epidemiological data for IC, the limitations of the diagnostic tests and risk scoring tools currently available, the absence of standardized effectiveness outcomes and long-term data for IC, the timing for the initiation of antifungal therapy and the limited recommendations on the optimal step-down therapy from echinocandins to azoles or the total duration of therapy. The availability of new compounds may overcome some of the challenges identified and increase the existing options for management of chronic Candida infections and ambulant patient treatments. However, early identification of patients that require antifungal therapy and treatment of sanctuary site infections remain a challenge and will require further innovations.

Retrospective Multicenter Evaluation of the VirClia Galactomannan Antigen Assay for the Diagnosis of Pulmonary Aspergillosis with Bronchoalveolar Lavage Fluid Samples from Patients with Hematological Disease

Galactomannan (GM) testing of bronchoalveolar lavage (BAL) fluid samples has become an essential tool to diagnose invasive pulmonary aspergillosis (IPA) and is part of diagnostic guidelines. Enzyme-linked immunosorbent assays (ELISAs) (enzyme immunoassays [EIAs]) are commonly used, but they have a long turnaround time. In this study, we evaluated the performance of an automated chemiluminescence immunoassay (CLIA) with BAL fluid samples. This was a multicenter retrospective study in the Netherlands and Belgium. BAL fluid samples were collected from patients with underlying hematological diseases with a suspected invasive fungal infection. Diagnosis of IPA was based on the 2020 European Organisation for Research and Treatment of Cancer (EORTC)/Mycoses Study Group Education and Research Consortium (MSGERC) consensus definitions. GM results were reported as optical density index (ODI) values. ODI cutoff values for positive results that were evaluated were 0.5, 0.8, and 1.0 for the EIA and 0.16, 0.18, and 0.20 for the CLIA. Probable IPA cases were compared with two control groups, one with no evidence of IPA and another with no IPA or possible IPA. Qualitative agreement was analyzed using Cohen's κ, and quantitative agreement was analyzed by Spearman's correlation. We analyzed 141 BAL fluid samples from 141 patients; 66 patients (47%) had probable IPA, and 56 cases remained probable IPA when the EIA GM result was excluded as a criterion, because they also had positive culture and/or duplicate positive PCR results. Sixty-three patients (45%) had possible IPA and 12 (8%) had no IPA. The sensitivity and specificity of the two tests were quite comparable, and the overall qualitative agreement between EIA and CLIA results was 81 to 89%. The correlation of the actual CLIA and EIA values was strong at 0.72 (95% confidence interval, 0.63 to 0.80). CLIA has similar performance, compared to the gold-standard EIA, with the benefits of faster turnaround because batching is not required. Therefore, CLIA can be used as an alternative GM assay for BAL fluid samples.

The battle against fungi- lessons in antifungal stewardship from COVID-19 times: a consensus statement on behalf of the International Society of Antimicrobial Chemotherapy, Alliance for the Prudent Use of Antibiotics, European Society of Clinical Microbiology and Infectious Diseases Study Group for Antimicrobial Stewardship, and European Society of Clinical Microbiology and Infectious Diseases Fungal Infection Study Group

The COVID-19 pandemic has undoubtedly highlighted the detrimental effect of secondary pathogens in patients with a primary viral insult. In addition to superinfections with bacterial pathogens, invasive fungal infections were increasingly reported. While the diagnosis of pulmonary fungal infections has always been challenging, it became even more problematic in the setting of COVID-19 especially when it comes to the interpretation of the radiological findings and mycology test results in these patients. Moreover, the long duration of hospitalization in intensive care units coupled with underlying host factors such as multiple comorbidities including preexisting immunosuppression, the use of immunomodulatory agents and pulmonary compromise caused additional vulnerability to fungal infections in this patient population. In addition, the heavy workload during the COVID-19 outbreak, the redeployment of untrained staff, and sometimes the lack of gloves, gown and masks has made it more difficult for many healthcare workers to strictly adhere to infection control preventive measures. Taken together, these factors favored patient to patient spread of fungal infections such as those caused by Candida auris or environment to patient transmission such as nosocomial aspergillosis. Because fungal infections were associated with increased morbidity and mortality, empiric treatment was overly used and abused in COVID-19 infected patients, potentially contributing to increased resistance in fungal pathogens. In this paper, we aim to focus on essential elements of antifungal stewardship in COVID-19 for three fungal infections, namely COVID-19 associated candidemia (CAC), pulmonary aspergillosis (CAPA) and mucormycosis (CAM).

Tackling Histoplasmosis Infection in People Living with HIV from Latin America: From Diagnostic Strategy to Public Health Solutions

Histoplasmosis, caused by the thermally dimorphic fungus Histoplasma spp., is a disease with a broad clinical spectrum, presenting from asymptomatic/flu-like symptoms to progressive disseminated disease in people with immunosuppression. In recent years, the concept of histoplasmosis as a disease restricted to the American continent has changed, as now histoplasmosis is reported in many regions around the world. In Latin America, histoplasmosis represents a threat, especially in people with advanced HIV disease (AHD). Diagnosis of histoplasmosis in people living with HIV (PLHIV) is challenging due to the low index of suspicion of the disease, non-specificity of signs and symptoms, and limited access to specific laboratory testing, while the diagnostic delay is significantly associated with mortality. In the last decade, novel diagnostic tests have been developed for the rapid detection of histoplasmosis, such as commercial kits for antigen detection. Furthermore, advocacy groups were created that presented histoplasmosis as a public health problem, with emphasis on patients at risk of progressive disseminated disease. This review aims to discuss the impact of histoplasmosis associated with AHD in Latin America and the strategies employed to tackle histoplasmosis, from the implementation of laboratory testing to disease advocacy and public health interventions.

Incidence, risk factors and pre-emptive screening for COVID-19 associated pulmonary aspergillosis in an era of immunomodulant therapy

PURPOSE

COVID-19 associated pulmonary aspergillosis (CAPA) is associated with increased morbidity and mortality in ICU patients. We investigated the incidence of, risk factors for and potential benefit of a pre-emptive screening strategy for CAPA in ICUs in the Netherlands/Belgium during immunosuppressive COVID-19 treatment.

MATERIALS AND METHODS

A retrospective, observational, multicentre study was performed from September 2020-April 2021 including patients admitted to the ICU who had undergone diagnostics for CAPA. Patients were classified based on 2020 ECMM/ISHAM consensus criteria.

RESULTS

CAPA was diagnosed in 295/1977 (14.9%) patients. Corticosteroids were administered to 97.1% of patients and interleukin-6 inhibitors (anti-IL-6) to 23.5%. EORTC/MSGERC host factors or treatment with anti-IL-6 with or without corticosteroids were not risk factors for CAPA. Ninety-day mortality was 65.3% (145/222) in patients with CAPA compared to 53.7% (176/328) without CAPA (p = 0.008). Median time from ICU admission to CAPA diagnosis was 12 days. Pre-emptive screening for CAPA was not associated with earlier diagnosis or reduced mortality compared to a reactive diagnostic strategy.

CONCLUSIONS

CAPA is an indicator of a protracted course of a COVID-19 infection. No benefit of pre-emptive screening was observed, but prospective studies comparing pre-defined strategies would be required to confirm this observation.

Therapeutic drug monitoring-guided treatment versus standard dosing of voriconazole for invasive aspergillosis in haematological patients: a multicentre, prospective, cluster randomised, crossover clinical trial

OBJECTIVES

Voriconazole therapeutic drug monitoring (TDM) is recommended based on retrospective data and limited prospective studies. This study aimed to investigate whether TDM-guided voriconazole treatment is superior to standard treatment for invasive aspergillosis.

METHODS

A multicentre (n = 10), prospective, cluster randomised, crossover clinical trial was performed in haematological patients aged ≥18 years treated with voriconazole. All patients received standard voriconazole dose at the start of treatment. Blood/serum/plasma was periodically collected after treatment initiation of voriconazole and repeated during treatment in both groups. The TDM group had measured voriconazole concentrations reported back, with dose adjustments made as appropriate, while the non-TDM group had voriconazole concentrations measured only after study completion. The composite primary endpoint included response to treatment and voriconazole treatment discontinuation due to an adverse drug reaction related to voriconazole within 28 days after treatment initiation.

RESULTS

In total, 189 patients were enrolled in the study. For the composite primary endpoint, 74 patients were included in the non-TDM group and 68 patients in the TDM group. Here, no significant difference was found between both groups (P = 0.678). However, more trough concentrations were found within the generally accepted range of 1-6 mg/L for the TDM group (74.0%) compared with the non-TDM group (64.0%) (P < 0.001).

CONCLUSIONS

In this trial, TDM-guided dosing of voriconazole did not show improved treatment outcome compared with standard dosing. We believe that these findings should open up the discussion for an approach to voriconazole TDM that includes drug exposure, pathogen susceptibility and host defence.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov registration no. NCT00893555.

Fungal keratitis in Iran: Risk factors, clinical features, and mycological profile

Introduction

This study was intended to investigate the clinical features and predisposing factors of fungal keratitis (FK), as well as molecular identification and antifungal susceptibility of causative agents in Tehran, Iran.

Methods

This cross-sectional study was carried out from April 2019 to May 2021. All fungi isolates were identified using conventional methods and were confirmed by DNA-PCR-based molecular assays. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) was used to identify yeast species. Minimum inhibitory concentrations (MIC) of eight antifungal agents were assessed according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) microbroth dilution reference method.

Results

Fungal etiology was confirmed in 86 (7.23%) of 1189 corneal ulcers. A significant predisposing factor for FK was ocular trauma caused by plant materials. Therapeutic penetrating keratoplasty (PKP) was required in 60.4% of cases. The predominant fungal species isolated was Fusarium spp. (39.5%) followed by Aspergillus spp. (32.5%) and Candida spp. (16.2%).

Discussion

The MIC results indicate that amphotericin B may be appropriate for treating FK caused by Fusarium species. FK caused by Candida spp. can be treated with flucytosine, voriconazole, posaconazole, miconazole, and caspofungin. In developing countries such as Iran, corneal infection due to filamentous fungi is a common cause of corneal damage. In this region, fungal keratitis is observed primarily within the context of agricultural activity and subsequent ocular trauma. Fungal keratitis can be managed better with understanding the "local" etiologies and antifungal susceptibility patterns.

870. Olorofim for the treatment of invasive mould infections in patients with limited or no treatment options: Comparison of interim results from a Phase 2B open-label study with outcomes in historical control populations (NCT03583164, FORMULA-OLS, Study 32)

Background

Olorofim is a novel antifungal agent active against Aspergillus spp (including azole-resistant strains), rare, resistant moulds (e.g., Lomentospora prolificans) and dimorphic moulds.

Serial images of Lomentospora prolificans infection following breast enhancement surgery: progression of healing pre- and post-olorofim therapy.

Post-surgical bone/ soft tissue Lomentospora prolificans infection of the chest wall in a healthy woman was uncontrolled with available agents (D -9 visible mould in wound base). At D42/84 overall response on olorofim monotherapy was stable; wound closure with complete resolution of IFI was achieved at D322 (case previously reported, ECCMID 2020 abstract #2585).

Methods

Patients with limited/no treatment options for proven invasive fungal infection (IFI) or probable pulmonary invasive aspergillosis (IA) using EORTC-MSGERC criteria¹ received oral olorofim (150mg BID x1d loading dose then 90mg BID). Outcomes in the first 100 patients are compared with historical controls (HCs) as well as with expected outcomes in patients with baseline highly active, uncontrolled IFI (HAU-IFI).

Results

All-cause mortality in IA at month 3 (includes data to Day 100, the best-fit time point for IA HC data) was 17/53 (32%, 95 CI 20–46%) for olorofim vs. 40/46 (87%, 74–95%) in HCs given either no therapy or azole monotherapy for azole-resistant IA. Successful EORTC-MSGERC overall response² (OR, complete or partial based on clinical + radiologic + mycologic improvement) was 47%/42% in IA (Day 42/D84, n = 53), 53%/53% (L. prolificans, n=17), 55%/36% (Scedosporium, n=11), and 50%/50% (other moulds, n=8). Stable response at D42/D84 predicted extended therapy responses, especially in HAU-IFI of brain and bone (Figure). For Coccidioides (n=11) OR was limited to stable due to very slow clearance of fungal serology but clinical response was rapid. Symptoms resolved completely in 18% (2/11) by D84 vs 3% (1/29) by D1523 in comparable HCs with poorly controlled extrapulmonary Coccidioides infection; similar trends were seen for other response measures.

Conclusion

Olorofim is a novel oral antifungal with activity against a wide range of mould infections which are difficult to treat. Compared with relevant HCs or expected outcomes for HAU-IFI, olorofim has a positive benefit-risk profile in a well-defined population of patients with limited/no treatment options. As noted previously³, considering stable in overall success if often appropriate when assessing responses in non-IA mould IFI.

References:

1. Donnelly CID 2020; 71:1367–76

2. Segal CID 2008; 47:674–83

3. Perfect Mycoses 2018: 61:420

Disclosures

Johan A. Maertens, MD PhD, F2G Ltd: Advisor/Consultant|Gilead Sciences Ltd: Advisor/Consultant|Mundipharma: Advisor/Consultant|Pfizer Inc: Advisor/Consultant Paul E. Verweij, PhD, Gilead: Grant/Research Support Emma L. Harvey, MBBS, F2G Ltd: Stocks/Bonds Aaron Dane, MSc, Amplyx: Advisor/Consultant|AN2 therapeutics: Advisor/Consultant|Artizan: Advisor/Consultant|Cidara: Advisor/Consultant|ContraFect: Advisor/Consultant|Correvio: Advisor/Consultant|Davolterra: Advisor/Consultant|Destiny Pharma: Advisor/Consultant|Entasis: Advisor/Consultant|F2G Limited: Advisor/Consultant|GSK: Advisor/Consultant|Humanigen: Advisor/Consultant|Kymab: Advisor/Consultant|Modis: Advisor/Consultant|Orca: Advisor/Consultant|Pfizer: Advisor/Consultant|Phico: Advisor/Consultant|Pled Pharma: Advisor/Consultant|Rare Thyroid: Advisor/Consultant|Roche: Advisor/Consultant|Scynexis: Advisor/Consultant|Sinovent: Advisor/Consultant|Spero Therapeutics: Advisor/Consultant|Transcrip: Advisor/Consultant|Venatorx: Advisor/Consultant Daniela Zinzi, Infectious Diseases Specialist, F2G: F2G employee|F2G: Stocks/Bonds John H. Rex, MD, Advent Life Sciences: Operating Partner|Advent Life Sciences: Ownership Interest|AMR Action Fund: Advisor/Consultant|AstraZeneca: Stocks/Bonds|Basilea Pharmaceutica: Advisor/Consultant|Bugworks Research, Inc.: Advisor/Consultant|F2G, Limited: Employee|F2G, Limited: Stocks/Bonds|Forge Therapeutics: Advisor/Consultant|GlaxoSmithKline: Advisor/Consultant|Pfizer Pharmaceuticals: Honoraria|Sumitovant: Advisor/Consultant Sharon C. Chen, PhD MBBS, F2G PTy Ltd: Grant/Research Support|MSD Australia: Grant/Research Support.

353. Evaluation of the in vitro activity of amphotericin B used in the liposomal formulation AmBisome against contemporary human fungal pathogens

Background

Amphotericin B is an antifungal drug whose main limitation is toxicity. To reduce these side effects, liposomal formulations have been developed, being AmBisome (L-AmB, Gilead Science Inc) the most commonly used. We describe the in vitro antifungal activity of L-AmB component used in the AmBisome formulation

Methods

We performed a multicenter study to determine the susceptibility to L-AmB using CLSI and EUCAST reference methods. Contemporary human fungal pathogenic species (14 yeast spp and 23 mould spp from different geographical regions were included. Other antifungals (triazoles and echinocandins) were also evaluated.

Results

L-AmB showed activity against yeast species using both EUCAST and CLSI protocols. The strongest activity was shown against Candida albicans (GM-EUCAST 0.24 mg/L (n=85), CLSI 0.23 mg/L (n=111)), C. parapsilosis (GM-EUCAST 0.32 mg/L (n=82), CLSI 0.32 mg/L (n=124)), C. glabrata (GM-EUCAST 0.32 mg/L (n=84), CLSI 0.38 mg/L (n=145)), C. auris (GM-EUCAST 0.46 mg/L (n=20), CLSI 0.31 mg/L (n=22)). In filamentous fungi, lowest MICs were found for Aspergillus fumigatus (GM-EUCAST 0.62 mg/L (n=77), CLSI 0.65 mg/L (n=124)), and A. niger (GM-EUCAST 0.25 mg/L (n=72) , CLSI 0.32 mg/L (n=85)), while for other Aspergillus species, there was a higher variability in the MICs (A. flavus, GM-EUCAST 1.2 mg/L (n=71), CLSI 1.75 mg/L (n=76); A. terreus GM-EUCAST 1.7 mg/L (n=65), CLSI 1.04 mg/L (n=71); A. nidulans GM-EUCAST 1.38 mg/L (n=39), CLSI 0.73 mg/L (n=39)). For other genera from filamentous fungi, L-AmB had a strong activity (GM around 0.2-0.5 mg/L for both methods, including Talaromyces marneffei, Rhizopus arrhizus and R. microscoporus, Lichtheimia corymbifera, Mucor circinelloides). The less susceptible species corresponded to multi-resistant (MDR) species, such as Lomentospora prolificans and Cunninghamella bertholletiae.

Conclusion

The L-AmB component of AmBisome showed activity against most contemporary human fungal pathogens and only showed limited activity against some MDR mould species.

Disclosures

Oscar Zaragoza, Principal Investigator, Gilead: Grant/Research Support Teresa Merino-Amador, n/a, Gilead: Grant/Research Support Cristina de Armentia, n/a, Gilead: Grant/Research Support Cornelia Lass-Flörl, PhD, Gilead: Grant/Research Support Jochem B. Buil, PhD, Gilead: Grant/Research Support Paul E. Verweij, PhD, Gilead: Grant/Research Support Patrick C. Y. Woo, PhD, Gilead: Grant/Research Support Chi-Ching Tsang, PhD, Gilead: Grant/Research Support P. Lewis White, PhD, Associates of Cape Cod: Honoraria|F2G: Advisor/Consultant|Gilead: Grant/Research Support|IMMY: Honoraria|Pfizer: Advisor/Consultant|Pfizer: Honoraria Jessica Price, PhD, Gilead: Grant/Research Support Carolyn Grimes, PhD, Gilead: Grant/Research Support Alessandro C. Pasqualotto, PhD, Gilead: Grant/Research Support Manuel Cuenca-Estrella, PhD, Gilead: Grant/Research Support.

Dual use of antifungals in medicine and agriculture: How do we help prevent resistance developing in human pathogens?

Azole resistance in Aspergillus fumigatus is a One Health resistance threat, where azole fungicide exposure compromises the efficacy of medical azoles. The use of the recently authorized fungicide ipflufenoquin, which shares its mode-of-action with a new antifungal olorofim, underscores the need for risk assessment for dual use of antifungals.

Triazole-resistant Aspergillus luchuensis, an industrially important black Aspergillus spp. used in fermentation in East Asia, isolated from the patient with invasive pulmonary aspergillosis in China

Aspergillus luchuensis, an industrially important member of Aspergillus species belonging to section Nigri used in fermentation in East Asia, was isolated from an immunocompromised patient with probable invasive pulmonary aspergillosis who failed voriconazole therapy in China. This isolate showed non-wild-type susceptibility to itraconazole, voriconazole, isavuconazole, and posaconazole. A G1378A mutation in cyp51A, resulting in the G441S amino acid substitution, which is the homolog to G448S conferring triazole-resistance in A. fumigatus, was detected in the A. luchuensis isolate.

Liposomal amphotericin B—the future

Advances in medicine have led to a growing number of people with compromised or suppressed immune systems who are susceptible to invasive fungal infections. In particular, severe fungal infections are becoming increasingly common in ICUs, affecting people within and outside of traditional risk groups alike. This is exemplified by the emergence of severe viral pneumonia as a significant risk factor for invasive pulmonary aspergillosis, and the recognition of influenza-associated pulmonary aspergillosis and, more recently, COVID-19-associated pulmonary aspergillosis.

The treatment landscape for haematological malignancies has changed considerably in recent years, and some recently introduced targeted agents, such as ibrutinib, are increasing the risk of invasive fungal infections. Consideration must also be given to the risk of drug–drug interactions between mould-active azoles and small-molecule kinase inhibitors.

At the same time, infections caused by rare moulds and yeasts are increasing, and diagnosis continues to be challenging. There is growing concern about azole resistance among both moulds and yeasts, mandating continuous surveillance and personalized treatment strategies.

It is anticipated that the epidemiology of fungal infections will continue to change and that new populations will be at risk. Early diagnosis and appropriate treatment remain the most important predictors of survival, and broad-spectrum antifungal agents will become increasingly important. Liposomal amphotericin B will remain an essential therapeutic agent in the armamentarium needed to manage future challenges, given its broad antifungal spectrum, low level of acquired resistance and limited potential for drug–drug interactions.

P219 Fungal keratitis caused by Pseudallescheria boydii: Clinical and mycological characteristics

 

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM

Objectives

Pseudallescheria boydii keratitis is rare but important type of fungal keratitis because of the inherently resistance of the organism to many existing antifungal agents. We present the clinical characteristics, risk factors, treatment, and prognosis of patients with P. boydii keratitis, and also present the antifungal sensitivities of the isolated strain.

Methods

Slit-lamp and confocal microscopy were used for clinical examinations. Fungal isolates were identified based on morphological characteristics and DNA sequence of the internal transcribed spacer region (ITS). In vitro antifungal susceptibility testing for fungal isolates was performed according to the Clinical and Laboratory Standards Institute (CLSI).

Results

Pseudallescheria boydii was identified in four patients. All patients had a history of ocular trauma. In clinical examination hypopyon was seen in three patients. The main antifungal medications were oral and topical voriconazole. After treatment the visual activity of all patients improved in 2-3 weeks.

Conclusion

These patients bold the importance of determining causative organism of fungal keratitis and their antibiotic susceptibility. Culture findings are limited in identifying organisms. Sequencing of polymerase chain reaction-amplified DNA is good for accurate and rapid identification of species that can be helpful for optimizing treatment.

P001 Characteristics and dynamics of azole-resistant Aspergillus fumigatus variants emerging over a 28-year period in the Netherlands

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM

 

Background

Aspergillus fumigatus, a globally distributed opportunistic pathogen, is the main cause of invasive aspergillosis, especially in immunocompromised patients with high mortality. The emergence of azole-resistant A. fumigatus isolates has been a significant concern worldwide and an important clinical problem.

Objectives

We aim to determine the presence of variants in a large collection of clinical A. fumigatus isolates from the Netherlands, if the number of variants increased over time and if the presence of additional short nucleotide polymorphisms (SNPs) or tandem repeats (TR) variations impacted on the triazole phenotype.

Methods

The Radboud University Medical Center has collected 11 813 clinical A. fumigatus isolates since 1994. The collection includes isolates cultured from patients admitted to our own center, isolates sent from other hospitals for identification and in vitro susceptibility testing, and isolates sent from five university medical centers and five teaching hospitals that contribute to the national Aspergillus resistance surveillance. The genotypes were detected by Cyp51A Sanger sequencing. All isolates were subjected to in vitro susceptibility testing using the EUCAST microdilution reference method. Minimal inhibitory concentrations (MICs) were determined for itraconazole, voriconazole, posaconazole, in all isolates and for isavuconazole in isolates cultured in 2015 and thereafter.

Results

In total, 1826 A. fumigatus isolates harbored azole-resistant mutations in the Cyp51A-gene with 92 genotypes. Tandem Repeat-associated resistance genotypes accounted for 55.43% of the variants and were involved in 1728 isolates (94.63%). TR34/L98H and TR46/Y121F/T289A resistance mutations remained dominant, and increasingly additional SNPs in the Cyp51A-gene or changes to the gene promoter were observed. The G448S mutation was relatively common and present in various genetic backgrounds. This SNP was most often found in isolates harboring the TR46 resistance mechanism (8 variants) and was also observed in two variants in the TR34 genetic background. TR34 and TR46 resistance mutations are associated with 1170 (64.07%) isolates that exhibited a pan-azole resistance phenotype, 547 (29.96%) a multi-azole resistance phenotype, and 75 (4.11%) resistance to a single azole. TR34/L98H confers high itraconazole resistance, while T289A confers high voriconazole resistance in the TR46 background. Isolates with a G448S point mutation show high MICs for both voriconazole and itraconazole. The TR34/L98H/T289A/G448S isolate showed low itraconazole MICs but high voriconazole resistance, and mutations in the promoter region, TR34/C-86 G/L98H, and (T-66 G)/TR34/L98H variants, showed increased voriconazole and isavuconazole MIC compared with the parent phenotype. TR46/Y121F/M172I/T289A/G448S variant was observed with an increased itraconazole (GM MIC 16 mg/L, 1→16 mg/l) and decreased voriconazole (GM MIC 18.664 mg/l, 4→16 mg/l) compared with the parent MIC of TR46/Y121F/T289A, while TR92/Y121F/M172I/T289A/G448S and TR46/Y121F/ T289A/G448S variants showed the consistent MIC distribution with parent genotype. The variants with more combination mutations showed pan-azole resistance with increased MIC distribution.

Conclusion

Our survey showed a significant increase in resistance genotypes in clinical A. fumigatus over a period of 28 years. Azoles resistance phenotypes vary from resistant variants in clinical isolates; it is an implication for clinical A. fumigatus infection treatment options and antifungal stewardship.

Tackling the emerging threat of antifungal resistance to human health

Invasive fungal infections pose an important threat to public health and are an under-recognized component of antimicrobial resistance, an emerging crisis worldwide. Across a period of profound global environmental change and expanding at-risk populations, human-infecting pathogenic fungi are evolving resistance to all licensed systemic antifungal drugs. In this Review, we highlight the main mechanisms of antifungal resistance and explore the similarities and differences between bacterial and fungal resistance to antimicrobial control. We discuss the research and innovation topics that are needed for risk reduction strategies aimed at minimizing the emergence of resistance in pathogenic fungi. These topics include links between the environment and One Health, surveillance, diagnostics, routes of transmission, novel therapeutics and methods to mitigate hotspots for fungal adaptation. We emphasize the global efforts required to steward our existing antifungal armamentarium, and to direct the research and development of future therapies and interventions.

Invasive Fungal Disease in Patients with Myeloid Malignancies: A Retrospective Cohort Study of a Diagnostic-Driven Care Pathway Withholding Mould-Active Prophylaxis

Objectives: Patients receiving remission induction therapy for acute myeloid leukaemia (AML) are at high risk of developing invasive fungal disease (IFD). Newer therapies with targeted antileukemic agents and the emergence of azole resistance pose a challenge to the strategy of primary antifungal prophylaxis. We report the experience of a diagnostic-driven care pathway (DCP) for the management of IFD in these patients, using only culture-directed mould inactive prophylaxis. Methods: Retrospectively, we used a single-centre study of consecutive patients receiving intensive chemotherapy for myeloid malignancies between 2014 and 2021. DCP consisted of serial cultures and serum galactomannan (sGM) screening, CT imaging, and bronchoscopy to direct targeted antifungal treatment. IFD was classified according to the 2020 EORTC/MSGERC criteria. Results: A total of 192 patients with myeloid malignancies received 300 courses of intensive chemotherapy. There were 14 cases of invasive yeast infections and 18 of probable/proven invasive mould disease (IMD). The incidence of probable/proven IMD during the first cycle of remission-induction chemotherapy was 4.6% (n = 9). sGM remained negative in all cases of invasive aspergillosis (IA), with positive mycology findings in bronchoalveolar lavage. All-cause mortality was 9.4% (n = 18) 100 days after starting chemotherapy and was comparable between patients with or without IFD. The fungal-related mortality was 1% (n = 2). Conclusion: Diagnostic-driven based management without universal mould active prophylaxis is a feasible strategy in the management of IFD and limits unnecessary antimould treatment during intensive chemotherapy. The poor performance of serial serum galactomannan screening in detecting IA warrants further investigation.

Total bodyweight and sex both drive pharmacokinetic variability of fluconazole in obese adults

BACKGROUND

Fluconazole is commonly used to treat or prevent fungal infections. It is typically used orally but in critical situations, IV administration is needed. Obesity may influence the pharmacokinetics and therapeutic efficacy of a drug. In this study, we aim to assess the impact of obesity on fluconazole pharmacokinetics given orally or IV to guide dose adjustments for the obese population.

METHODS

We performed a prospective pharmacokinetic study with intensive sampling in obese subjects undergoing bariatric surgery (n = 17, BMI ≥ 35 kg/m2) and non-obese healthy controls (n = 8, 18.5 ≤ BMI < 30.0 kg/m2). Participants received a semi-simultaneous oral dose of 400 mg fluconazole capsules, followed after 2 h by 400 mg IV. Population pharmacokinetic modelling and simulation were performed using NONMEM 7.3.

RESULTS

A total of 421 fluconazole concentrations in 25 participants (total bodyweight 61.0-174 kg) until 48 h after dosing were obtained. An estimated bioavailability of 87.5% was found for both obese and non-obese subjects, with a 95% distribution interval of 43.9%-98.4%. With increasing total bodyweight, both higher CL and Vd were found. Sex also significantly impacted Vd, being 27% larger in male compared with female participants.

CONCLUSIONS

In our population of obese but otherwise healthy individuals, obesity clearly alters the pharmacokinetics of fluconazole, which puts severely obese adults, particularly if male, at risk of suboptimal exposure, for which adjusted doses are proposed.

Exposure to intravenous posaconazole in critically ill patients with influenza: a pharmacokinetic analysis of the POSA-FLU study

BACKGROUND

Data on posaconazole in the critically ill are scarce. In the POSA-FLU study we examined the prevention of influenza-associated pulmonary aspergillosis with posaconazole in this population.

METHODS

In this observational sub-study, we performed a pharmacokinetic analysis, including protein binding and target attainment (TA). Blood samples were collected over a 24h-dosing interval on both an early (day 2 or 3) and a later (≥ day 4) treatment day.

RESULTS

TA was shown for AUC_0-24 and C_min prophylaxis but not for C_min treatment. Moreover, a saturable protein binding with a significant, positive relationship between albumin concentrations and the maximum binding capacity was observed.

CONCLUSIONS

Our analysis indicates that posaconazole may be a suitable drug to further investigate for prophylaxis, as TA for prophylaxis was reached. Exposure targets for treatment were insufficiently attained in this population.

Use of Bulk Segregant Analysis for Determining the Genetic Basis of Azole Resistance in the Opportunistic Pathogen Aspergillus fumigatus

A sexual cycle was described in 2009 for the opportunistic fungal pathogen Aspergillus fumigatus, opening up for the first time the possibility of using techniques reliant on sexual crossing for genetic analysis. The present study was undertaken to evaluate whether the technique 'bulk segregant analysis' (BSA), which involves detection of differences between pools of progeny varying in a particular trait, could be applied in conjunction with next-generation sequencing to investigate the underlying basis of monogenic traits in A. fumigatus. Resistance to the azole antifungal itraconazole was chosen as a model, with a dedicated bioinformatic pipeline developed to allow identification of SNPs that differed between the resistant progeny pool and resistant parent compared to the sensitive progeny pool and parent. A clinical isolate exhibiting monogenic resistance to itraconazole of unknown basis was crossed to a sensitive parent and F1 progeny used in BSA. In addition, the use of backcrossing and increasing the number in progeny pools was evaluated as ways to enhance the efficiency of BSA. Use of F1 pools of 40 progeny led to the identification of 123 candidate genes with SNPs distributed over several contigs when aligned to an A1163 reference genome. Successive rounds of backcrossing enhanced the ability to identify specific genes and a genomic region, with BSA of progeny (using 40 per pool) from a third backcross identifying 46 genes with SNPs, and BSA of progeny from a sixth backcross identifying 20 genes with SNPs in a single 292 kb region of the genome. The use of an increased number of 80 progeny per pool also increased the resolution of BSA, with 29 genes demonstrating SNPs between the different sensitive and resistant groupings detected using progeny from just the second backcross with the majority of variants located on the same 292 kb region. Further bioinformatic analysis of the 292 kb region identified the presence of a cyp51A gene variant resulting in a methionine to lysine (M220K) change in the CYP51A protein, which was concluded to be the causal basis of the observed resistance to itraconazole. The future use of BSA in genetic analysis of A. fumigatus is discussed.

[Diagnosis of suspected superficial fungal infections]

Most medical microbiology laboratories in the Netherlands have switched from direct potassium hydroxide microscopy and culture to polymerase chain reaction (PCR) testing when diagnosing dermato- and onychomycoses and Candida species in human dander, hair and nails. The predictive value of a PCR test is in most cases higher than the predictive value of KOH microscopy and culture in diagnosing or ruling out a fungal infection and should therefore replace traditional diagnostics in routine care. KOH microscopy and culture should be reserved in cases of therapy failure and suspected false negative PCR testing. An application for a PCR should be performed if there is any doubt about the clinical diagnosis. The application must be accompanied by sufficient clinical information from the patient to enable the microbiologist to determine whether the PCR test used is appropriate.

Spectrophotometric detection of azole-resistant Aspergillus fumigatus with the EUCAST broth microdilution method: is it time for automated MIC reading of EUCAST antifungal susceptibility testing of Aspergillus species?

OBJECTIVES

Current reference susceptibility testing methods of Aspergillus require visual reading, which is subjective and necessitates experienced staff. We compared spectrophotometric and visual MIC reading of EUCAST E.Def 9.3.2 susceptibility testing of Aspergillus fumigatus for a large collection of isolates with different azole resistance mechanisms.

METHODS

A. fumigatus (n = 200) were examined, including 62 WT and 138 non-WT with the following alterations: TR34/L98H (n = 57), TR46/Y121F/T289A (n = 54) or single point mutations (n = 27). EUCAST E.Def 9.3.2 susceptibility testing was performed for amphotericin B, itraconazole, voriconazole, posaconazole and isavuconazole. MICs were determined after 48 h of incubation visually and spectrophotometrically, as the lowest concentration corresponding to a 1%, 3%, 5%, 10% or 15% OD increase above the background OD. The best spectrophotometric endpoint (SPE) was identified based on the highest essential agreement (EA; ±1 two-fold dilution) and categorical agreement (CA) and fewer very major errors (VMEs) and major errors (MEs).

RESULTS

Τhe best SPEs were 5% and 10% for all drugs. The best agreement between visual and spectrophotometric MICs was found with the 10% growth endpoint, which resulted in identical median MICs with 90% of differences being ≤1 two-fold and higher EA (91%-100%) and CA (100%) and no VMEs and MEs compared with the 5% endpoint (77%-100%, 96%-98%, 0% and 0%-4%, respectively).

CONCLUSIONS

Spectrophotometric MIC reading can be used for A. fumigatus susceptibility testing and for detecting azole resistance. A visual inspection of the plate should be performed to confirm equal inoculation, absence of well contamination and proper growth, and to identify potential uncommon phenotypes or subpopulations.

Posaconazole bioavailability of the solid oral tablet is reduced during severe intestinal mucositis

OBJECTIVES

To describe the absolute oral bioavailability of the solid oral formulation of posaconazole and the impact of severe intestinal mucositis in haematology patients. Further, to describe posaconazole protein binding in haematology patients.

METHODS

A pharmacokinetic study was performed where patients receiving induction chemotherapy or a haematopoietic cell transplantation were randomized to receive 7 days of intravenous posaconazole therapy followed by 9 days of oral therapy or vice versa. Patients received posaconazole licensed dose until day 12, thereafter a reduced once daily dose of 200 mg was given. At days 7, 12, and 16 blood samples were obtained for pharmacokinetic curves, trough samples were collected on all other days. Total and unbound posaconazole pharmacokinetics were analysed by population pharmacokinetic modelling. The presence of severe intestinal mucositis was assessed by plasma citrulline levels and analysed as a binary covariate using 10 μmol/L as cut-off. Monte Carlo simulations were performed to simulate posaconazole exposure at steady state.

RESULTS

Twenty-three patients were included for analysis with 581 total posaconazole concentrations and 91 paired unbound concentrations. Absolute bioavailability in the final model was estimated at 51.4% (%relative standard error (RSE) 56.5) and 67.6% (%RSE 75.0) in patients with and without severe intestinal mucositis, respectively. Posaconazole unbound fraction was estimated at 2.7% (%RSE 3.9).

CONCLUSIONS

Posaconazole bioavailability is reduced in haematological patients with severe intestinal mucositis, requiring an increase in oral posaconazole dose to 400 mg twice daily on day 1 followed by 400 mg once daily or a switch to intravenous therapy.

Resistance profiling of Aspergillus fumigatus to olorofim indicates absence of intrinsic resistance and unveils the molecular mechanisms of acquired olorofim resistance

Olorofim (F901318) is a new antifungal currently under clinical development that shows both in vitro and in vivo activity against a number of filamentous fungi including Aspergillus fumigatus. In this study, we screened A. fumigatus isolates for intrinsic olorofim-resistant A. fumigatus and evaluated the ability of A. fumigatus to acquire an olorofim-resistant phenotype. No intrinsic resistance was found in 975 clinical A. fumigatus isolates. However, we found that isolates with increased olorofim MICs (> 8 mg/L) could be selected using a high number of conidia and olorofim exposure under laboratory conditions. Assessment of the frequency of acquired olorofim resistance development of A. fumigatus was shown to be higher than for voriconazole but lower than for itraconazole. Sequencing the PyrE gene of isogenic isolates with olorofim MICs of >8 mg/L identified various amino acid substitutions with a hotspot at locus G119. Olorofim was shown to have reduced affinity to mutated target protein dihydroorotate dehydrogenase (DHODH) and the effect of these mutations was proven by introducing the mutations directly in A. fumigatus. We then investigated whether G119 mutations were associated with a fitness cost in A. fumigatus. These experiments showed a small but significant reduction in growth rate for strains with a G119V substitution, while strains with a G119C substitution did not exhibit a reduction in growth rate. These in vitro findings were confirmed in an in vivo pathogenicity model.

ESCMID COVID-19 living guidelines: drug treatment and clinical management

SCOPE

In January 2021, the ESCMID Executive Committee decided to launch a new initiative to develop ESCMID guidelines on several COVID-19-related issues, including treatment of COVID-19.

METHODS

An ESCMID COVID-19 guidelines task force was established by the ESCMID Executive Committee. A small group was established, half appointed by the chair, and the remaining selected with an open call. Each panel met virtually once a week. For all decisions, a simple majority vote was used. A long list of clinical questions using the PICO (population, intervention, comparison, outcome) format was developed at the beginning of the process. For each PICO, two panel members performed a literature search with a third panellist involved in case of inconsistent results. Voting was based on the GRADE approach.

QUESTIONS ADDRESSED BY THE GUIDELINE AND RECOMMENDATIONS

A synthesis of the available evidence and recommendations is provided for each of the 15 PICOs, which cover use of hydroxychloroquine, bamlanivimab alone or in combination with etesevimab, casirivimab combined with imdevimab, ivermectin, azithromycin and empirical antibiotics, colchicine, corticosteroids, convalescent plasma, favipiravir, remdesivir, tocilizumab and interferon β-1a, as well as the utility of antifungal prophylaxis and enoxaparin. In general, the panel recommended against the use of hydroxychloroquine, ivermectin, azithromycin, colchicine and interferon β-1a. Conditional recommendations were given for the use of monoclonal antibodies in high-risk outpatients with mild-moderate COVID-19, and remdesivir. There was insufficient evidence to make a recommendation for use of favipiravir and antifungal prophylaxis, and it was recommended that antibiotics should not be routinely prescribed in patients with COVID-19 unless bacterial coinfection or secondary infection is suspected or confirmed. Tocilizumab and corticosteroids were recommended for treatment of severe COVID-19 but not in outpatients with non-severe COVID-19.

SCOPE

The aim of the present guidance is to provide evidence-based recommendations for management of adults with coronavirus disease 2019 (COVID-19). More specifically, the goal is to aid clinicians managing patients with COVID-19 at various levels of severity including outpatients, hospitalized patients, and those admitted to intensive care unit. Considering the composition of the panel, mostly clinical microbiologists or infectious disease specialists with no pulmonology or intensive care background, we focus only on pharmacological treatment and do not give recommendations on oxygen supplement/support. Similarly, as no paediatricians were included in the panel; the recommendations are only for adult patients with COVID-19. Considering the current literature, no guidance was given for special populations such as the immunocompromised.

Flower Bulb Waste Material Is a Natural Niche for the Sexual Cycle in Aspergillus fumigatus

With population genetic evidence of recombination ongoing in the natural Aspergillus fumigatus population and a sexual cycle demonstrated in the laboratory the question remained what the natural niche for A. fumigatus sex is. Composting plant-waste material is a known substrate of A. fumigatus to thrive and withstand temperatures even up to 70°C. Previous studies have shown indirect evidence for sexual reproduction in these heaps but never directly demonstrated the sexual structures due to technical limitations. Here, we show that flower bulb waste material from stockpiles undergoing composting can provide the conditions for sexual reproduction. Direct detection of ascospore structures was shown in agricultural flower bulb waste material by using a grid-based detection assay. Furthermore, we demonstrate that ascospores can germinate after exposure to 70°C for up to several days in contrast to asexual conidia that are unable to survive a two-hour heat shock. This indicates a sufficient time frame for ascospores to survive and escape composting stockpiles. Finally, sexual crosses with cleistothecium and viable ascospore formation could successfully be performed on flower bulb waste material. Recombination of A. fumigatus can now be explained by active sexual reproduction in nature as we show in this study that flower bulb waste material provides an environmental niche for sex.

Regional Impact of COVID-19-Associated Pulmonary Aspergillosis (CAPA) during the First Wave

Background: Critically ill COVID-19 patients have proven to be at risk for developing invasive fungal infections. However, the incidence and impact of possible/probable COVID-19-associated pulmonary aspergillosis (CAPA) in severe COVID-19 patients varies between cohorts. We aimed to assess the incidence, risk factors, and clinical outcome of invasive pulmonary aspergillosis in a regional cohort of COVID-19 intensive care patients. Methods: We performed a regional, multicentre, retrospective cohort study in the intensive care units (ICUs) in North Brabant, The Netherlands. We included adult patients with rt-PCR-confirmed SARS-CoV-2 infection (COVID-19), requiring mechanical ventilation for acute respiratory distress syndrome. Demographics, clinical course, biomarker value, and treatment outcomes were compared between the groups with possible/probable CAPA from the main study centre and the regional centres, and without signs of CAPA from the main study centre as controls. The primary aim was to assess the regional impact of possible/probable CAPA in COVID-19 ICU patients, measured as all-cause mortality at 30 days after ICU admission. Secondary outcomes were risk factors for developing CAPA, based on underlying host factors and to identify the value of the mycological arguments for the diagnosing of CAPA. Results: Between 1 March and 30 April 2020, we included 123 patients with severe COVID-19: 29 patients (30.9%) in the main ICU with possible/probable CAPA, and 65 (69.1%) with no signs of CAPA; 29 patients in the regional ICUs with signs of CAPA. Patients’ characteristics and risk factors did not differ for CAPA and non-CAPA patients. Patients with COPD and/or chronic steroid medication developed CAPA more frequently, although this was not statistically significant. CAPA patients were admitted to the ICU earlier, had lower PF-ratios, and more often required renal replacement therapy. All-cause 30-day mortality was significantly higher in mechanically ventilated COVID-19 patients with possible/probable CAPA 39.7% (23/58) compared to patients without evidence for CAPA 16.9% (11/65) (OR 3.2 [95% CI 1.4–7.4] p = 0.005). Conclusion: The high incidence of possible and probable CAPA in critically ill COVID-19 patients is alarming. The increase in 30-day mortality in CAPA highlights the need for active surveillance and management strategies in critically ill COVID-19 patients.

Meanderella rijsii, a new opportunist in the fungal order Pleosporales

Subcutaneous phaeohyphomycosis is an implantation disease caused by melanized fungi and affect both immunocompetent as well as immunocompromised individuals. Diagnosis and treatment require proper isolation and accurate identification of the causative pathogen. We isolated a novel fungus from a case of subcutaneous phaeohyphomycosis in an immunocompetent patient. The 56-year-old patient suffered from a slowly progressive swelling on the metatarsophalangeal join of the left food. The isolated fungus lacked sporulation and sequences of the ribosomal operon did not match with any known species. In a multi-locus phylogenetic analysis involving five markers, the fungus formed a unique lineage in the order Pleosporales, family Trematosphaeriaceae. A new genus, Meanderella and a new species, M. rijsii are here proposed to accommodate the clinical isolate. Whole genome analysis of M. rijsii revealed a number of genes that can be linked to pathogenicity and virulence. Further studies are however needed to understand the role of each gene in the pathogenic process and to determine the origin of pathogenicity in the family of Trematosphaeriaceae.

A 67-Year-Old Male Patient With COVID-19 With Worsening Respiratory Function and Acute Kidney Failure

CASE PRESENTATION

A 67-year-old obese man (BMI 38.0) with type 2 diabetes mellitus (DM), chronic atrial fibrillation, and chronic lymphocytic leukemia stage II, stable for 8 years after chemotherapy, and a history of smoking presented to the ED with progressive dyspnea and fever due to SARS-CoV-2 infection. He was admitted to a general ward and treated with dexamethasone (6 mg IV once daily) and oxygen. On day 3 of hospital admission, he became progressively hypoxemic and was admitted to the ICU for invasive mechanical ventilation. Dexamethasone treatment was continued, and a single dose of tocilizumab (800 mg) was administered. On day 9 of ICU admission, voriconazole treatment was initiated after tracheal white plaques at bronchoscopy, suggestive of invasive Aspergillus tracheobronchitis, were noticed. However, his medical situation dramatically deteriorated.

OUP accepted manuscript

The increasing incidence and changing epidemiology of invasive fungal infections continue to present many challenges to their effective management. The repertoire of antifungal drugs available for treatment is still limited although there are new antifungals on the horizon. Successful treatment of invasive mycoses is dependent on a mix of pathogen-, host- and antifungal drug-related factors. Laboratories need to be adept at detection of fungal pathogens in clinical samples in order to effectively guide treatment by identifying isolates with acquired drug resistance. While there are international guidelines on how to conduct in vitro antifungal susceptibility testing, these are not performed as widely as for bacterial pathogens. Furthermore, fungi generally are recovered in cultures more slowly than bacteria, and often cannot be cultured in the laboratory. Therefore, non-culture-based methods, including molecular tests, to detect fungi in clinical specimens are increasingly important in patient management and are becoming more reliable as technology improves. Molecular methods can also be used for detection of target gene mutations or other mechanisms that predict antifungal drug resistance. This review addresses acquired antifungal drug resistance in the principal human fungal pathogens and describes known resistance mechanisms and what in-house and commercial tools are available for their detection. It is emphasized that this approach should be complementary to culture-based susceptibility testing, given the range of mutations, resistance mechanisms and target genes that may be present in clinical isolates, but may not be included in current molecular assays.

Global guideline for the diagnosis and management of the endemic mycoses: an initiative of the European Confederation of Medical Mycology in cooperation with the International Society for Human and Animal Mycology

The global burden of the endemic mycoses (blastomycosis, coccidioidomycosis, emergomycosis, histoplasmosis, paracoccidioidomycosis, sporotrichosis, and talaromycosis) continues to rise yearly and these infectious diseases remain a leading cause of patient morbidity and mortality worldwide. Management of the associated pathogens requires a thorough understanding of the epidemiology, risk factors, diagnostic methods and performance characteristics in different patient populations, and treatment options unique to each infection. Guidance on the management of these infections has the potential to improve prognosis. The recommendations outlined in this Review are part of the "One World, One Guideline" initiative of the European Confederation of Medical Mycology. Experts from 23 countries contributed to the development of these guidelines. The aim of this Review is to provide an up-to-date consensus and practical guidance in clinical decision making, by engaging physicians and scientists involved in various aspects of clinical management.

[Terbinafine resistance explains treatment failure in a patient with tinea corporis]

BACKGROUND

Tinea corporis is a superficial fungal infection of the limbs, chest or back caused by dermatophytes. Local antifungal treatment is often sufficient to treat tinea corporis. Systemic treatment may be needed in more severe cases, in immunocompromised patients or when treatment failure is documented. Treatment failure is relative common and frequent causes are low compliance, low systemic antifungal drug concentrations, reduced penetration of topical agents or an immunocompromised status. Recently, antifungal resistance has been documented in dermatophytes.

CASE DESCRIPTION

We describe a patient with terbinafine treatment failure caused by antifungal drug resistance.

CONCLUSION

The frequency of terbinafine resistance in the Netherlands is unknown as no surveillance is performed. Recent reports from both India and European countries indicate that antifungal resistance should be considered in patients with terbinafine treatment failure.

Multinational Observational Cohort Study of COVID-19-Associated Pulmonary Aspergillosis1

We performed an observational study to investigate intensive care unit incidence, risk factors, and outcomes of coronavirus disease-associated pulmonary aspergillosis (CAPA). We found 10%-15% CAPA incidence among 823 patients in 2 cohorts. Several factors were independently associated with CAPA in 1 cohort and mortality rates were 43%-52%.

Molecular Mechanisms of 5-Fluorocytosine Resistance in Yeasts and Filamentous Fungi

Effective management and treatment of fungal diseases is hampered by poor diagnosis, limited options for antifungal therapy, and the emergence of antifungal drug resistance. An understanding of molecular mechanisms contributing to resistance is essential to optimize the efficacy of currently available antifungals. In this perspective, one of the oldest antifungals, 5-fluorocytosine (5-FC), has been the focus of recent studies applying advanced genomic and transcriptomic techniques to decipher the order of events at the molecular level that lead to resistance. These studies have highlighted the complexity of resistance and provided new insights that are reviewed in the present paper.