AUTHOR=Chen Xin-Fei , Zhang Wei , Fan Xin , Hou Xin , Liu Xiao-Yu , Huang Jing-Jing , Kang Wei , Zhang Ge , Zhang Han , Yang Wen-Hang , Li Ying-Xing , Wang Jin-Wen , Guo Da-Wen , Sun Zi-Yong , Chen Zhong-Ju , Zou Ling-Gui , Du Xue-Fei , Pan Yu-Hong , Li Bin , He Hong , Xu Ying-Chun 

TITLE=Antifungal Susceptibility Profiles and Resistance Mechanisms of Clinical Diutina catenulata Isolates With High MIC Values

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.739496

DOI=10.3389/fcimb.2021.739496

ISSN=2235-2988

ABSTRACT=<p><italic>Diutina catenulata</italic> (<italic>Candida catenulata</italic>) is an ascomycete yeast species widely used in environmental and industrial research and capable of causing infections in humans and animals. At present, there are only a few studies on <italic>D. catenulata</italic>, and further research is required for its more in-depth characterization and analysis. Eleven strains of <italic>D. catenulata</italic> collected from China Hospital Invasive Fungal Surveillance Net (CHIF-NET) and the CHIF-NET North China Program were identified using matrix-assisted laser desorption ionization–time of flight mass spectrometry and internal transcribed spacer sequencing. The antifungal susceptibility of the <italic>Diutina catenulata</italic> strains was tested using the Clinical and Laboratory Standards Institute broth microdilution method and Sensititre YeastOne™. Furthermore, ERG11 and FKS1 were sequenced to determine any mutations related to azole and echinocandin resistance in <italic>D. catenulata</italic>. All isolates exhibited low minimum inhibitory concentration (MIC) values for itraconazole (0.06–0.12 μg/ml), posaconazole (0.06–0.12 μg/ml), amphotericin B (0.25–1 μg/ml), and 5-flucytosine (range, &lt;0.06–0.12 μg/ml), whereas four isolates showed high MICs (≥4 μg/ml) for echinocandins. Strains with high MIC values for azoles showed common <italic>ERG11</italic> mutations, namely, F126L/K143R. In addition, L139R mutations may be linked to high MICs of fluconazole. Two amino acid alterations reported to correspond to high MIC values of echinocandin, namely, F621I (F641) and S625L (S645), were found in the hot spot 1 region of <italic>FKS1</italic>. In addition, one new amino acid alteration, I1348S (I1368), was found outside of the <italic>FKS1</italic> hot spot 2 region, and its contribution to echinocandin resistance requires future investigation. <italic>Diutina catenulata</italic> mainly infects patients with a weak immune system, and the high MIC values for various antifungals exhibited by these isolates may represent a challenge to clinical treatment.</p>