BACKGROUND:Inborn Errors of Immunity (IEI) display increased susceptibility to infections among which cryptosporidiosis is an opportunistic infection poorly characterized in this population. We report cases of Cryptosporidium spp. infections in French patients with IEI based on data from the registry of the French National Reference Center for IEI (CEREDIH). METHODS:Patients diagnosed with an IEI between 1986 and 2025 and who experienced proven cryptosporidiosis were included. RESULTS:Of the 10,004 patients in the CEREDIH registry, 149 were identified with at least one episode of parasitic infection (≈1.4%). Forty-one patients (27.5%) had cryptosporidiosis (0.41% of the cohort) and had the following diagnoses: Combined immunodeficiency (CID, n=25 including 8 Hyper IgM (HIGM) syndromes, 9 other CID, 4 HLA class II deficiency), Hyper IgE syndrome (n=2), Diaphanous related formin 1 mutation (n=1), Signal transducer and activator of transcription 1 (STAT1) gain-of-function (GOF) (n=1), Activated PI3K-delta syndrome (n=6), Common variable immunodeficiency disorders (CVID, n=3) and 7 miscellaneous.. The male-to-female ratio was 1.92 and the mean age at onset of cryptosporidiosis was 16.6±17.5 years. Twenty (50%) patients had cholangitis and 23 (63%) had an indication for hematopoietic stem cell transplantation, which was performed in 15 (38%). Seventeen (41.5%) patients died. CONCLUSION:Cryptosporidiosis is a serious comorbidity in patients with IEI with a high mortality rate reaching more than one third of the patients. CID including HIGM syndrome and other CID were the most represented underlying condition in this study with the highest morbidity and mortality (cholangitis and its complications).

Drug-resistant fungal disease must be addressed in the 2026 update to the Global Action Plan on Antimicrobial Resistance

Molds are ubiquitous environmental microorganisms with major implications for human health, ranging from allergic reactions to invasive infections. Although the environmental seasonality of several fungal spores has long been recognized, its reflection in clinical isolates remains poorly explored. A total of 218 682 fungal spectra generated by 97 medical microbiology laboratories across France between 2020 and 2024 were analyzed, based on identifications performed using the MSI-2 Matrix Assisted Laser Desorption Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS) web platform. Seasonal patterns were assessed through additive decomposition, autocorrelation, and formal statistical testing. Distinct seasonal variation patterns were identified across taxa. Significant seasonality was detected for multiple taxa, including Alternaria, Cladosporium, Aspergillus sections Nigri and Flavi, Talaromyces, several taxa of Basidiomycota, and Rhizopus arrhizus. Positive or negative correlations between fungal identification counts and national mean temperature values were observed depending on the taxon. This study highlights the importance of considering seasonality in understanding the epidemiology of fungal diseases and demonstrates the value of multicenter MALDI-TOF MS data as a tool for epidemiological surveillance.

Invasive fungal diseases are life-threatening complications, particularly in immunocompromised patients, and require rapid and accurate diagnosis to improve clinical outcomes. Although major advances in fungal diagnostics that includes antigen detection, molecular assays, and Matrix-Assisted Laser Desorption/Ionization - Time Of Flight (MALDI-TOF) mass spectrometry, have transformed diagnostic strategies, access to these tools remains heterogeneous. In France, national data on diagnostic capacities for invasive fungal diseases have been lacking. Using the framework of the national prospective surveillance program for invasive fungal diseases (SINFONI network), we conducted a survey to assess laboratory diagnostic practices in France. A secured 116-item questionnaire was distributed to 58 participating laboratories, of which 48 responded (83%). Automated blood culture systems and MALDI-TOF mass spectrometry for yeast identification were universally available, with 40 (83%) of the 48 participating laboratories also using MALDI-TOF for mould identification. Antifungal susceptibility testing was performed on-site in 47 (98%) centres for yeasts and in 37 (77%) for moulds. Antigen-based biomarkers were widely available on-site, particularly cryptococcal antigen (n = 43, 90%) and Aspergillus galactomannan (n = 39, 81%), whereas β-D-glucan testing was available in only 26 (54%) of the centres. PCR-based diagnostics were implemented on-site in 43 (88%) centres, most commonly for Pneumocystis jirovecii, Aspergillus spp., and Mucorales. Systematic screening for Candidozyma auris colonization in at-risk patients was performed in 30 (63%) centres, predominantly using culture-based methods (n = 24). Overall, this survey provides the first national overview of diagnostic capacities for invasive fungal diseases in France, highlighting a strong laboratory mycology infrastructure while identifying remaining gaps in access to specific biomarkers, molecular assays, and mould antifungal susceptibility testing.

Penicillium, Talaromyces, and Purpureocillium species (so called Penicillium-like) are increasingly recognised as opportunistic fungal pathogens capable of causing a wide range of infections, from superficial to invasive. Although ocular infections caused by these environmental fungi have been reported in the literature, they remain relatively underrecognised. We conducted a multicentric retrospective study of Penicillium-like ocular cases reported in the RESeau de Surveillance des Infections Fongique (RESSIF) database of the French National Reference Center for Invasive Mycoses and Antifungals between 2012 and 2021. Among 55 cases of Penicillium-like invasive infections reported to the RESSIF network in France, a total of 24 cases (44%) were identified, which predominantly presented as keratitis (n = 22, 92%). Predisposing factors were as follows: contact lens wear (n = 11, 46%), topical corticosteroid use (n = 9, 37.5%), ocular trauma (n = 5, 21%), pre-existing corneal disease (n = 4, 17%), and previous ocular surgery (n = 2, 8%). Purpureocillium lilacinum was the predominant pathogen (n = 19, 79%), followed by four Penicillium species and one Talaromyces species. Direct examination of ocular samples was positive in 13 cases (54%). Antifungal susceptibility testing (European Committee on Antimicrobial Susceptibility Testing) revealed that all species exhibited high minimal inhibitory concentrations to amphotericin B (> 1 mg/l). Most patients were treated with a combination of topical voriconazole and amphotericin B (n = 15, 62.5%), which was administered alongside oral voriconazole in nine cases (37.5%). Surgical intervention was required in six cases (25%) and included keratoplasty (n = 4) and enucleation (n = 2). This study provides a valuable overview of Penicillium-like fungal ocular infections and highlights the importance of systematically surveilling filamentous fungal keratitis.

Schizophyllum commune is a cosmopolitan, saprophytic basidiomycete known to cause respiratory tract infections following spore inhalation. Management of such infections remained poorly defined, and antifungal susceptibility testing may provide valuable guidance for therapeutic decisions. However, existing data are limited, and protocols are not optimized for non-sporulating molds such as S. commune, requiring methodological adaptations. This study aimed to (i) perform molecular characterization of isolates and (ii) determine antifungal susceptibility profiles of a collection of S. commune isolates using both Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference methods. A total of 113 fungal isolates were included, comprising environmental (n = 31), clinical French isolates (n = 74), and strains from fungal international collections (n = 8). Species identification was confirmed via the large subunit (LSU) region of the ribosomal DNA sequencing and by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Phylogenetic analysis was conducted on a subset of 20 isolates using partial sequences of three genes: LSU, EF-1α, and RPB2. Modifications to the CLSI and EUCAST broth microdilution methods included: inoculum preparation using standardized culture slices fragmented by bead-beating, incubation at 35°C for 96 h and endpoints reading at 100% of inhibition. Phylogenetic analysis confirmed that all tested isolates were S. commune and not S. radiatum. Amphotericin B (AMB) and voriconazole (VOR) demonstrated low geometrical mean minimal inhibitory concentrations (MICs) across both methods (EUCAST: AMB = 0.39 µg/mL, VOR = 0.24 µg/mL; CLSI: AMB = 0.1 µg/mL, VOR = 0.2 µg/mL). In contrast, terbinafine exhibited high MIC values (>8 µg/mL) in both protocols. Notable discrepancies were observed for posaconazole (POS), isavuconazole (ISA), and itraconazole (ITR), with MICs approximately two dilution steps higher in EUCAST compared to CLSI (POS: 4.22 µg/mL vs 0.9 µg/mL, ISA: 3.64 µg/mL vs 0.74 µg/mL, and ITR: 3.9 µg/mL vs 0.81 µg/mL, respectively). After standardization of both methods for this non-sporulating mold, VOR and AMB have the lowest MIC values.IMPORTANCESchizophyllum commune is a fungal pathogen increasingly associated with respiratory infections, yet therapeutic guidance remains unclear. This study provides the largest collection to date of clinical and environmental isolates (113 total) and applies standardized antifungal susceptibility testing using adapted EUCAST and CLSI protocols for this non-sporulating species. The results show that amphotericin B and voriconazole are the most active agents in vitro, while terbinafine is ineffective. These findings are critical for informing treatment decisions and interpreting susceptibility tests, especially in the absence of established guidelines. By introducing a reproducible methodology and delivering clinically relevant data, this work addresses a gap in medical mycology and supports improved management of rare fungal infections.

BACKGROUND:The management of COVID-19-associated invasive aspergillosis (CAPA) is still debated while cases continue to occur, and more and more frequently in vulnerable populations, stressing the importance of obtaining data on the treatment of this disease. Only small cohort studies and case reports have yet discussed this essential issue, and the data obtained are insufficient to make conclusions with confidence. RESEARCH QUESTION:Is antifungal treatment associated with lower 60-day mortality in patients with probable or proven CAPA? STUDY DESIGN AND METHODS:This study assessed the association of antifungal treatment with 60-day mortality for probable/proven CAPA cases from a French multicenter study and all consecutive CAPA cases (after 2020) from ICUs of 5 major European centers. Patients were compared according to antifungal treatment. Survival analysis was conducted by using Cox regression analysis and inverse probability of treatment weighting based on a propensity score. RESULTS:In total, 259 patients with CAPA were included, 237 (91.5%) receiving antifungals for CAPA (215 [90.7%] of whom received azole antifungal drugs). Baseline characteristics were similar between patients who received antifungals and those who did not. Age (hazard ratio [HR], 1.02; 95% CI, 1.00-1.04; P = .048), immunosuppressive treatment (HR, 2.08; 95% CI, 1.12-3.41; P < .001), and remdesivir administration (HR, 1.96; 95% CI, 1.12-3.41; P = .018) were independently associated with increased 60-day mortality according to Cox regression analysis in the raw population. Male sex (HR, 0.61; 95% CI, 0.40-0.95; P = .024) and antifungal treatment (HR, 0.31; 95% CI, 0.17-0.59; P < .001) were associated with lower 60-day mortality. Cox-weighted regression showed lower 60-day mortality for patients receiving antifungals (weighted HR, 0.28; 95% CI, 0.13-0.58; P < .001. INTERPRETATION:Our results show that antifungal treatment was associated with lower 60-day mortality in patients with CAPA. The high mortality rate observed in CAPA in immunocompromised patients and improved outcome for treated patients should encourage clinicians to actively screen for CAPA to enable rapid diagnosis and targeted treatment.

Candidemia is associated with high morbidity and mortality. Delayed initiation of effective and appropriate antifungal therapy correlates with increased patient mortality, emphasizing the importance of rapid antifungal susceptibility testing (AFST). Usual commercial methods, such as the standard E-test, are time-consuming, often requiring a minimum of 48 h. This study aimed to evaluate the performance of direct E-test (ET-dir) directly from positive blood culture bottles, with the goal of reducing turnaround time and improving clinical decision-making. A total of 160 yeast positive blood cultures were included over a 4-year period, comprising 85 Candida albicans. The minimum inhibitory concentrations (MICs) of fluconazole, voriconazole, amphotericin B, and anidulafungin were determined using ET-dir and compared to ET method (ET-sd). Essential agreement, categorical agreement, error rates, and bias were analyzed for all species and specifically for C. albicans. The essential agreement between ET-dir and ET-sd exceeded 87% for all antifungal agents and reached ≥90% for fluconazole. The categorical agreement was above 90% for all agents, and error rates remained within acceptable limits except for anidulafungin. For C. albicans, 23 of 24 performance data met acceptability criteria, with essential agreement ≥90% for all agents except fluconazole. ET-dir results were interpretable within 24 h for 93.7% of strains, providing at least a 24-h time gain over ET-sd. ET-dir is a reliable and rapid AFST method for candidemia, meeting most performance criteria compared to ET-sd while significantly reducing turnaround time. Its routine implementation could enable faster adaptation of antifungal therapy, ensuring that treatments are optimized based on susceptibility results.

Scedosporium/Lomentospora species are ubiquitous moulds that can cause deep-seated infections and allergic bronchopulmonary mycoses (ABPM). Serodiagnosis is currently performed by immunoprecipitation (IP) techniques, which are time-consuming and lack reproducibility. In addition, as antigenic extracts for these fungi are not commercially available, many centers stopped performing this analysis. Therefore, there is a need for automated quantitative alternatives, such as Enzyme linked Immunosorbent Assay (ELISA) . The aim of this study was to develop an ELISA for serodiagnosis of Scedosporium/Lomentospora infections. All sera received for Scedosporium/Lomentospora serodiagnosis expertise from April 2022 to February 2024 were tested in parallel using IP and an in-house ELISA with antigenic extracts from both Scedosporium apiospermum and Lomentospora prolificans. Clinical and biological data such as positive culture, total IgE level, and final diagnosis retained were also collected prospectively. The concordance between techniques was calculated, with χ² tests performed to investigate the correlation between ELISA and culture results or final diagnosis. We tested 58 serum samples from 41 different patients. The concordance between IP and ELISA was 64% for S. apiospermum and 62% for L. prolificans. ELISA results obtained with S. apiospermum antigen extract were significantly correlated with culture results (P < .001, χ² test). ELISA was also more effective than IP to diagnose ABPM. The Scedosporium/Lomentospora ELISA gave satisfactory results, particularly for S. apiospermum. Further validation on a larger cohort is required to implement this ELISA for routine practice instead of IP. In addition, studies should be conducted on purified native proteins or in combination with recombinant antigens to improve standardization.

BACKGROUND AND OBJECTIVES:The emergence of azole resistance among Aspergillus fumigatus isolates has driven the development of novel antifungal compounds, which may potentially be used in combination with existing antifungal drugs. In this study, we evaluated the in vitro interaction between olorofim, a novel orotomide antifungal, and voriconazole, a triazole agent, against A. fumigatus using two complementary approaches. METHODS:A liquid microdilution checkerboard assay was performed in duplicate on 32 clinical isolates, including 27 voriconazole-susceptible and 5 voriconazole-resistant isolates, to determine the MICs of both drugs alone and in combination. Interactions were quantified using the FIC index and through response surface modelling based on the Bliss independence model. Furthermore, an agar-based method was conducted on a subset of 11 isolates. Media were supplemented with either voriconazole or olorofim, on which discs containing the reciprocal drug were applied. Additionally, interaction was assessed by using Etest® strips of voriconazole on olorofim-containing agar. RESULTS:Antagonism was observed for 56% of isolates based on the checkerboard technique and for 75% of the isolates based on response surface analysis. Antagonistic interaction was observed for all the voriconazole-resistant isolates. Across all tested isolates and agar configurations, antagonistic interactions were consistently observed, including reduced inhibition zones around olorofim discs in the presence of voriconazole and paradoxical fungal growth surrounding voriconazole discs or strips on olorofim-containing plates. CONCLUSIONS:These findings demonstrate the in vitro antagonism between olorofim and voriconazole and underscore the need for further investigation before considering their combined clinical use.

Background While invasive fusariosis and lomentosporiosis are known to be associated with fungemia, overall data on mold-related fungemia are limited, hampering early management. This study aimed to describe the epidemiology of mold-positive blood cultures.Methods Epidemiological and clinical data on mold-positive blood cultures from 2012 to 2022 were obtained from the RESSIF database. Pseudofungemia was excluded using modified Duthie and Denning criteria. Univariable and multivariable Firth logistical regression was used to study factors associated with 90-day mortality.Results Fusarium spp accounted for 67.5% of the 80 events, involving predominantly Fusarium fujikuroi spp complex (FFSC), Neocosmospora spp, and Fusarium oxysporum spp complex (FOSC). Lomentospora prolificans was the second most frequent (10%), followed by Trichoderma spp, Aspergillus spp, and Mucorales (5% each). Most patients had a history of hematological malignancy (HM) (70%). Forty-three percent had undergone allogeneic hematopoietic stem cell transplantation. Cutaneous and pulmonary lesions were common (43% each). Median time to blood culture positivity was 72 hours. HM and neutropenia were commonly reported in patients with FFSC, Neocosmospora spp, and L. prolificans fungemia. Pulmonary lesions were frequent in cases of L. prolificans fungemia. Patients with gastrointestinal conditions were frequently diagnosed with FOSC molds. HM (75%), particularly acute myeloblastic leukemia, was frequent in patients with Aspergillus spp fungemia. All patients with Trichoderma spp fungemia were exposed to corticosteroids. Day 90 mortality was 53%. Independent predictive factors of day 90 mortality included L. prolificans (odds ratio [OR], 33.3), Aspergillus spp fungemia (OR, 14.2), and corticosteroid exposure (OR, 7.85).Results Fusarium spp accounted for 67.5% of the 80 events, involving predominantly Fusarium fujikuroi spp complex (FFSC), Neocosmospora spp, and Fusarium oxysporum spp complex (FOSC). Lomentospora prolificans was the second most frequent (10%), followed by Trichoderma spp, Aspergillus spp, and Mucorales (5% each). Most patients had a history of hematological malignancy (HM) (70%). Forty-three percent had undergone allogeneic hematopoietic stem cell transplantation. Cutaneous and pulmonary lesions were common (43% each). Median time to blood culture positivity was 72 hours. HM and neutropenia were commonly reported in patients with FFSC, Neocosmospora spp, and L. prolificans fungemia. Pulmonary lesions were frequent in cases of L. prolificans fungemia. Patients with gastrointestinal conditions were frequently diagnosed with FOSC molds. HM (75%), particularly acute myeloblastic leukemia, was frequent in patients with Aspergillus spp fungemia. All patients with Trichoderma spp fungemia were exposed to corticosteroids. Day 90 mortality was 53%. Independent predictive factors of day 90 mortality included L. prolificans (odds ratio [OR], 33.3), Aspergillus spp fungemia (OR, 14.2), and corticosteroid exposure (OR, 7.85).Results Fusarium spp accounted for 67.5% of the 80 events, involving predominantly Fusarium fujikuroi spp complex (FFSC), Neocosmospora spp, and Fusarium oxysporum spp complex (FOSC). Lomentospora prolificans was the second most frequent (10%), followed by Trichoderma spp, Aspergillus spp, and Mucorales (5% each). Most patients had a history of hematological malignancy (HM) (70%). Forty-three percent had undergone allogeneic hematopoietic stem cell transplantation. Cutaneous and pulmonary lesions were common (43% each). Median time to blood culture positivity was 72 hours. HM and neutropenia were commonly reported in patients with FFSC, Neocosmospora spp, and L. prolificans fungemia. Pulmonary lesions were frequent in cases of L. prolificans fungemia. Patients with gastrointestinal conditions were frequently diagnosed with FOSC molds. HM (75%), particularly acute myeloblastic leukemia, was frequent in patients with Aspergillus spp fungemia. All patients with Trichoderma spp fungemia were exposed to corticosteroids. Day 90 mortality was 53%. Independent predictive factors of day 90 mortality included L. prolificans (odds ratio [OR], 33.3), Aspergillus spp fungemia (OR, 14.2), and corticosteroid exposure (OR, 7.85).Results Fusarium spp accounted for 67.5% of the 80 events, involving predominantly Fusarium fujikuroi spp complex (FFSC), Neocosmospora spp, and Fusarium oxysporum spp complex (FOSC). Lomentospora prolificans was the second most frequent (10%), followed by Trichoderma spp, Aspergillus spp, and Mucorales (5% each). Most patients had a history of hematological malignancy (HM) (70%). Forty-three percent had undergone allogeneic hematopoietic stem cell transplantation. Cutaneous and pulmonary lesions were common (43% each). Median time to blood culture positivity was 72 hours. HM and neutropenia were commonly reported in patients with FFSC, Neocosmospora spp, and L. prolificans fungemia. Pulmonary lesions were frequent in cases of L. prolificans fungemia. Patients with gastrointestinal conditions were frequently diagnosed with FOSC molds. HM (75%), particularly acute myeloblastic leukemia, was frequent in patients with Aspergillus spp fungemia. All patients with Trichoderma spp fungemia were exposed to corticosteroids. Day 90 mortality was 53%. Independent predictive factors of day 90 mortality included L. prolificans (odds ratio [OR], 33.3), Aspergillus spp fungemia (OR, 14.2), and corticosteroid exposure (OR, 7.85).Conclusions Underlying conditions and clinical presentation vary between genera and could be considered to guide early management. Fusarium species were the most common cause of mold-related fungemia. Patients' underlying conditions and clinical presentation differed between genera. Pulmonary and cutaneous lesions were common. Day 90 mortality was high and associated with corticosteroid exposure, Aspergillus spp, and Lomentospora prolificans infection.

BACKGROUND:Candida auris (Candidozyma auris) has emerged as an important pathogen across all continents, with clonal outbreaks and hospital transmissions. Most isolates are fluconazole resistant, and variable resistance rates are reported for amphotericin B and echinocandins. OBJECTIVES:This study aimed to present an overview of the newly established epidemiological cut-off values (ECOFFs) and antifungal breakpoints against C auris and the supporting evidence. SOURCES:This document is based on the recently updated European Committee for Antimicrobial Susceptibility Testing (EUCAST) rationale documents, clinical breakpoint, and ECOFF documents. CONTENT:An alternative approach was adopted for ECOFF setting of C. auris to avoid MIC distributions dominated by isogenic outbreak strains. A carefully selected strain collection of 30 isolates from 11 countries, representing five clades and 21 unique genotypes, was shared among five individual laboratories. MICs were determined with the EUCAST E.Def 7.4 methodology, providing five non-clonal datasets well above the required ≥100 total MICs per drug. Available PK-PD and clinical data were reviewed. IMPLICATIONS:The following ECOFFs and breakpoints were established for C auris: amphotericin B: ECOFF: 2 mg/L, S: ≤0.001 mg/L, R: >2 mg/L; implying that the entire wild-type distribution is susceptible, increased exposure (I) (increased dose: 5 mg/kg liposomal amphotericin B daily); anidulafungin and micafungin: ECOFFs: 0.25 mg/L, S: ≤0.25; R: >0.25; rezafungin: ECOFF: 0.125 mg/L; and flucytosine: ECOFF: 0.5 mg/L. Importantly, notable MIC variations have been reported for C auris and some agents across commercial tests. Consequently, important detailed guidance is provided on how to validate your MIC test in-house before adopting the EUCAST breakpoints for MIC interpretation.

This review provides an in-depth exploration of antifungal resistance in non-fumigatus Aspergillus species, mainly focusing on acquired resistance. The available data have been compiled and sometimes re-analysed. It highlights the increasing prevalence of resistance in non-fumigatus species belonging to Flavi, Terrei, Nigri, and Nidulantes Aspergillus sections, offering a detailed analysis of resistance detection methods and the global distribution of resistant strains. The review also thoroughly examines the molecular mechanisms behind resistance and raises key unresolved issues, such as the factors contributing to resistance selection and the clinical implications of in vitro resistance. Additionally, it addresses the challenges of treating infections caused by resistant Aspergillus species and cryptic species and discusses current and future strategies relying on combination therapy and newly developed antifungals. The conclusion emphasises the need for further research into resistance mechanisms and alternative treatments to address the rising threat of antifungal resistance in Aspergillus species.

Among 1107 cryptococcosis cases from the French surveillance network (2005-2020), the proportion of HIV-seronegative individuals has recently surpassed that of HIV-seropositive individuals. We observed marked differences in patient characteristics, disease presentations, cryptococcal antigen results, infecting species, and mortality according to HIV serostatus. [GRAPHICS] .

BACKGROUND:The resistance of Aspergillus flavus to the azole antifungal drugs is an emerging problem. Mutations in the molecular targets of the azole antifungals - CYP 51 A, B and C - are possible mechanisms of resistance, but data to confirm this hypothesis are scarce. In addition, the behaviour of resistant strains in vitro and in vivo is not yet understood. OBJECTIVES:This study had 3 objectives. The first was to compare the sequences of CYP51 A, B and C in resistant and susceptible strains of A. flavus. The second was to look for the existence of a fitness cost associated with resistance. The third was to evaluate the activity of voriconazole and posaconazole on resistant strains in the Galleria mellonella model. METHODS:The CYP51 A, B and C sequences of seven resistant strains with those of four susceptible strains are compared. Fitness costs were assessed by growing the strains in RPMI medium and testing their virulence in G. mellonella larvae. In addition, G. mellonella larvae infected with strains of A. flavus were treated with voriconazole and posaconazole. RESULTS:In the CYP51A sequences, we found the A91T, C708T and A1296T nucleotide substitutions only in the resistant strains. The resistant strains showed a fitness cost with reduced in vitro growth and reduced virulence in G. mellonella. In vivo resistance to posaconazole is confirmed in a strain with the highest MIC for this antifungal agent. CONCLUSIONS:These results allow to conclude that some substitutions in CYP51 genes, in particular CYP51A, contribute to resistance to azole drugs in A. flavus. The study of the relationship between drug dosage and treatment duration with resistance and the reduction of fitness costs in resistant strains is a major perspective of this study. This work could help to establish recommendations for the treatment of infections with resistant strains of A. flavus.