{"doi":"10.1093/jac/dkaa102","title":"A multicentre study to optimize echinocandin susceptibility testing of Aspergillus species with the EUCAST methodology and a broth microdilution colorimetric method","abstract":"BACKGROUND: The determination of the minimal effective concentration (MEC) of echinocandins against Aspergillus species is subjective, time consuming and has been associated with very major errors. METHODS: The MECs/MICs of 40 WT [10 each of Aspergillus fumigatus species complex (SC), Aspergillus flavus SC, Aspergillus terreus SC and Aspergillus niger SC] and 4 non-WT A. fumigatus isolates were determined with EUCAST E.Def 9.3.1 read microscopically, macroscopically, spectrophotometrically and colorimetrically in three centres. The optimal conditions for spectrophotometric (single- versus multi-point readings) and colorimetric (XTT/menadione concentration and stability, incubation time) methods were evaluated in preliminary studies using different cut-offs for the determination of macroscopic, spectrophotometric and colorimetric MIC endpoints compared with the microscopically determined MEC. Inter-centre and inter-method essential (within one 2-fold dilution) agreement (EA) and categorical agreement (CA) were determined. RESULTS: Both macroscopic and spectrophotometric endpoint readings showed poor inter-centre EA (53%-66%) and low CA (41%-88%) in distinguishing WT from non-WT A. fumigatus SC isolates, while significant differences compared with the microscopic MECs were observed for all echinocandins (EA 6%-54%). For the colorimetric method, the optimal conditions were 400 mg/L XTT/6.25 μΜ menadione, incubation for 1-2 h until the drug-free control reached an absorbance at 450/630 nm of >0.8 and use of 50% inhibition of XTT conversion as a cut-off for all species and echinocandins. All non-WT isolates had high XTT MICs >1 mg/L, whereas the overall inter-centre EA and CA were 72%-89% and 100%, respectively. CONCLUSIONS: The XTT colorimetric assay improved the antifungal susceptibility testing of echinocandins against Aspergillus spp., reliably detecting non-WT isolates.","journal":"Journal of Antimicrobial Chemotherapy","year":2020,"id":71508,"datarank":0.9277993726080971,"base_score":2.8903717578961645,"endowment":2.8903717578961645,"self_citation_contribution":0.4335557636844247,"citation_network_contribution":0.4942436089236723,"self_endowment_contribution":0.4335557636844247,"citer_contribution":0.4942436089236723,"corpus_percentile":null,"corpus_rank":null,"citation_count":17,"citer_count":10,"citers_with_citation_signal":9,"citers_with_endowment":9,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.8836,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":119975,"name":"Maria Siopi","orcid":"0000-0002-5924-1007","position":1,"is_corresponding":false},{"id":379608,"name":"Lamprini Kanioura","orcid":null,"position":2,"is_corresponding":false},{"id":379609,"name":"Karin Meinike Jørgensen","orcid":null,"position":3,"is_corresponding":false},{"id":235823,"name":"David S. Perlin","orcid":"0000-0002-9503-3184","position":4,"is_corresponding":false},{"id":378125,"name":"Johan W. Mouton","orcid":"0000-0001-6736-4149","position":5,"is_corresponding":false},{"id":119981,"name":"Maiken Cavling Arendrup","orcid":"0000-0002-4747-0144","position":6,"is_corresponding":false},{"id":119988,"name":"Joseph Meletiadis","orcid":"0000-0002-8869-1509","position":0,"is_corresponding":true}],"reference_count":22,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-18T21:44:25.469842Z","pmid":"32330938","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}