AUTHOR=Chen Xin-Fei , Hou Xin , Zhang Han , Jia Xin-Miao , Ning Li-Ping , Cao Wei , Fan Xin , Huang Jing-Jing , Yang Wen-Hang , Zhang Ge , Zhang Jing-Jia , Kang Wei , Xiao Meng , Xu Ying-Chun 

TITLE=First two fungemia cases caused by Candida haemulonii var. vulnera in China with emerged antifungal resistance

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1036351

DOI=10.3389/fmicb.2022.1036351

ISSN=1664-302X

ABSTRACT=<p><italic>Candida haemulonii var. vulnera</italic> is a rare variant of <italic>C. haemulonii</italic>, which has been previously reported to cause human infections. Owing to the close kinship between <italic>C. haemulonii</italic> sensu stricto and <italic>C. haemulonii var. vulnera</italic>, accurate identification of <italic>C. haemulonii var. vulnera</italic> relied on DNA sequencing assay targeting, for example, rDNA internal transcribed spacer (ITS) region. In this work, two strains of <italic>C. haemulonii var. vulnera</italic> were collected from the China Hospital Invasive Fungal Surveillance Net (CHIF-NET). The identification capacity of three matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and VITEK 2 YST ID biochemical methods were evaluated against ITS sequencing. In addition, antifungal susceptibility testing was performed using Sensititre YeastOne. Moreover, we comprehensively screened drug-resistant related genes by whole-genome sequencing. The two strains were not correctly identified to species variant level using MALDI-TOF MS and YST ID cards. Both strains were resistant to amphotericin B (minimum inhibitory concentration [MIC] &gt; 2 μg/ml). Moreover, strain F4564 and F4584 exhibited high MIC to fluconazole (&gt;256 μg/ml) and 5-flucytosine (&gt;64 μg/ml), respectively, which were supposed to result from key amino acid substitutions Y132F and G307A in Erg11p and V58fs and G60K substitutions in Fur1p. The rare species <italic>C. haemulonii var. vulnera</italic> has emerged in China, and such drug-resistant fungal species that can cause invasive diseases require further close attention.</p>