P088 Molecular identification and antifungal susceptibility of pathogenic yeasts from the China Antifungal Resistance Surveillance Trial (CARST-fungi) Study
Authors: Wang Qiqi , Li Yun , Li Ruoyu , Zheng Bo , Wan Zhe , Liu Wei 
Published: September 2022

Abstract

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

Objectives
Invasive fungal diseases (IFDs) caused by yeast species have considerable morbidity and mortality, especially in immunocompromised hosts, and those with antifungal resistance represent a major clinical challenge. In order to have a comprehensive understanding of the characteristics of epidemiology and antifungal susceptibilities in clinical yeasts, the China Antifungal Resistance Surveillance Trial (CARST-fungi) study, a prospective national surveillance program for IFDs in mainland China, was conducted.

Methods
The CARST-fungi study encompassed nine ‘rank-A tertiary’ hospitals distributed throughout different cities in China in the year 2019-2020. All yeast isolates recovered from various clinical samples were subcultured and identified by sequencing of the internal transcribed spacer (ITS), 28S ribosomal subunit (D1/D2), and the intergenic spacer (IGS, for Trichosporon spp. and Cryptococcus spp.). Antifungal susceptibilities of fluconazole (FLC), itraconazole (ITC), voriconazole (VRC), posaconazole (POS), caspofungin (CAS), anidulafungin (ANF), micafungin (MCF), and amphotericin B (AMB) against the yeast isolates were performed according to the Clinical and Laboratory Standards Institute (CLSI) M27-A4 broth microdilution method.

Results
A total of 269 nonduplicate yeast isolates from 261 patients were collected. About half of the yeast isolates (127, 47.9%) were recovered from blood, followed by ascetic fluid (46, 17.4%). C. albicans remained the most prevalent (120, 44.6%), followed by C. parapsilosis complex (50, 18.5%), C. tropicalis (40, 14.9%), and C. glabrata (36, 13.4%). Among C. albicans, 5 (4.2%), 11 (9.2%), 6 (5%), 10 (8.4%) isolates were resistant/non-wide-type (NWT) to FLC, ITC, VRC, and POS, respectively, and 9 (7.5%) isolates were cross-resistant to triazoles. As for C. parapsilosis complex, only 1 (2.4%) isolate of C. parapsilosis sensu stricto was cross-resistant to FLC and POS, while all the 9 C. metapsilosis isolates were wide-type (WT) to triazoles. However, only 45% (18/40) C. tropicalis were susceptible/WT to triazoles, and 12 (30%), 3 (7.5%), 8 (20%), 19 (47.5%) isolates were resistant/NWT to FLC, ITC, VRC, and POS, respectively, and 8 (20%) isolates were cross-resistant to triazoles. Among C. glabrata, 2 (5.6%) isolates were resistant to FLC and the remaining 34 isolates were susceptible-dose dependent (SDD), 20 (55.6%), and 8 (22.2%) isolates were resistant/NWT to VRC and POS, respectively, and 4 (10.3%) isolates were cross-resistant to triazoles. One isolate of Meyerozyma guilliermondii was NWT to POS. Except for 3 isolates of C. tropicalis exhibiting intermediate to CAS and ANF, and 2 isolates of C. glabrata were cross-resistant to CAS, MCF, ANF, which were also NWT to POS and defined as multidrug-resistant, other isolates of common Candida species were all susceptible to echinocandins. All yeast isolates tested in this study were WT to AMB (MICs ≤ 2 μg/ml). For less common species, 1 isolate of Rhodotorula mucilaginosa exhibited high MICs to echinocandins and FLC, and 1 isolate of Trichosporon asahii showed high MICs to all the antifungals tested except AMB.

Conclusion
Among 269 yeast isolates from the CARST-fungi study, C. albicans remain the most predominant, followed by C. parapsilosis complex, C. tropicalis, and C. glabrata. Triazole-resistance is notable among C. tropicalis and C. glabrata. Multidrug-resistant isolates of C. glabrata and less common yeast have been emerging.