Non-albicans Candida species are emerging in the nosocomial environment, with the multidrug-resistant species Candida auris being the most notorious example. Consequently, rapid and accurate species identification has become essential. The objective of this study was to evaluate five commercially available chromogenic media for the presumptive identification of C. auris. Two novel chromogenic formulations, CHROMagarTM Candida Plus (Chromagar) and HiCromeTM C. auris MDR Selective Agar (HiMedia), and three reference media, CandiSelectTM (Bio-Rad), CHROMagarTM Candida (Chromagar), and ChromaticTM Candida (Liofilchem) were inoculated with a collection of 9 genetically diverse C. auris strains and 35 strains from closely related comparator species. After 48h of incubation the media were evaluated for their ability to detect and identify C. auris. All media had the same limitations in the differentiation of the more common species Candida dubliniensis and Candida glabrata. Only on CHROMagarTM Candida Plus, C. auris colonies developed a species-specific coloration. Nevertheless, the closely related pathogenic species Candida pseudohaemulonii and Candida vulturna developed a similar appearance as C. auris on this medium. CHROMagarTM Candida Plus showed to be superior in the detection and identification of C. auris, with 100% inclusivity for C. auris compared to 0% and 33% for the reference media and HiCromeTM C. auris MDR Selective agar, respectively. Although C. vulturna and C. pseudohaemulonii can cause false positives, CHROMagarTM Candida Plus showed to be a valuable addition to the plethora of mostly molecular methods for C. auris detection and identification.

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.