In vitro activity of isavuconazole against clinically relevant Trichosporon species: a comparative evaluation of EUCAST broth microdilution and MIC Test Strip methods

Author(s)

Francisco, Elaine Cristina ; Dieleman, Chendo ; Hagen, Ferry ; Colombo, Arnaldo Lopes ; Trichosporon Brazilian Network

• Document type: Journal article
• Source: Journal of Antimicrobial Chemotherapy; v. N/A, p. 6-pg., 2023-01-26.

Abstract

Objectives To evaluate the in vitro activity of isavuconazole on 154 clinical and reference strains of Trichosporon asahii, Trichosporon asteroides, Trichosporon coremiiforme, Trichosporon faecale and Trichosporon inkin by using the EUCAST broth microdilution method (BMD) and Liofilchem MIC Test Strips (MTS). Methods Antifungal susceptibility testing for isavuconazole, fluconazole, voriconazole and posaconazole was assessed by EUCAST E.DEF 7.3.2. MIC values of isavuconazole obtained by BMD after 48 h of incubation were compared with MTS MICs after 24 and 48 h of incubation. Results T. asahii and T. asteroides showed the highest isavuconazole MIC90 values (0.5 mg/L). In clinical isolates, T. asahii exhibited the highest MIC90 values (0.5 mg/L) compared with non-T. asahii (0.06-0.25 mg/L). The five non-WT T. asahii isolates for fluconazole, voriconazole and posaconazole also exhibited high MICs of isavuconazole (>= 0.5 mg/L). A better correlation between MTS and BMD MICs was observed after 24 h incubation for all species tested. MTS measurements performed at 48 h increased by at least 122% the number of isolates with >2 dilutions compared with the standard method. Conclusions Isavuconazole exhibited variable in vitro activity among the Trichosporon species tested, showing higher or equal MICs than the other azoles. The five non-WT T. asahii clinical isolates tested also exhibited high isavuconazole MICs, suggesting the occurrence of triazole cross-resistance. Our MTS data indicate that there is no advantage in extended reading time for MTS from 24 to 48 h for Trichosporon yeasts. (AU)

• FAPESP's process: 20/14097-0 - International partnership for the assessment of the genetic heterogeneity of Trichosporon spp. clinical isolates and their impact on taxonomy, biology and species identification
• Grantee: Elaine Cristina Francisco Del Ciello
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 19/24960-0 - International partnership for the evaluation of genetic heterogeneity of Trichosporon sp. clinical isolates and impact on taxonomy, biology and species identification
• Grantee: Elaine Cristina Francisco Del Ciello
• Support Opportunities: Scholarships in Brazil - Post-Doctoral