Department of Medical Microbiology, Faculty of Medicine, Erciyes University, Kayseri 38030, Turkey.
Department of Infection Diseases, Faculty of Medicine, Erciyes University, Kayseri, Turkey.
J Mycol Med. 2023 Nov;33(4):101429. doi: 10.1016/j.mycmed.2023.101429. Epub 2023 Aug 28.
Cyberlindnera fabianii is an opportunistic pathogen isolated from clinical specimens. It can be incorrectly identified as Candida utulis by phenotypic methods. This study aimed to accurately identify Cy.fabianii strains isolated from the urinary tract, and to determine their molecular characterization and antifungal susceptibilities as well.
Twenty-nine yeast strains isolated from urinary tract samples were studied. Strains were identified by phenotypically, sequence analysis and MALDI-TOF MS. Sequence analysis using different gene regions (ITS1-2,D1/D2,EF-1-alpha) in ribosomal DNA was performed for the molecular analysis. Phylogenetic analysis was done by the neighbor-joining method. Antifungal susceptibilities of strains were determined for nine antifungals by reference broth microdilution and the Sensititre YeastOne broth microdilution method (SensititreYeastOneAST Plate, Thermo Fisher Scientific™,USA) according to CLSI M60-Ed2 recommendations.
All strains were identified as C.utulis phenotypically by conventional methods, however all strains were identified as Cy.fabianii by sequence analysis and MALDI-TOF MS. It was observed that the gene regions examined in terms of determining evolutionary relatedness did not show intraspecies nucleotide variations. In all strains, the MIC50/MIC90 values for fluconazole were higher than the other antifungals tested.
Cy.fabianii should be considered in fluconazole-resistant urinary tract yeast infections. Although conventional phenotypical methods were insufficient to identify Cy.fabianii, it could be correctly identified with sequence analysis using different gene regions (ITS1-2,D1/D2,EF-1-alpha) in ribosomal DNA and MALDI-TOF MS.
Cyberlindnera fabianii 是一种从临床标本中分离出来的机会性病原体。它可能会被表型方法错误地鉴定为 Candida utulis。本研究旨在准确鉴定从尿样中分离出的 Cy.fabianii 菌株，并确定其分子特征和抗真菌药敏性。
研究了 29 株从尿样中分离出的酵母菌株。菌株通过表型、序列分析和 MALDI-TOF MS 进行鉴定。使用核糖体 DNA 中的不同基因区域（ITS1-2、D1/D2、EF-1-α）进行序列分析，进行分子分析。通过邻接法进行系统发育分析。根据 CLSI M60-Ed2 建议，采用参考肉汤微量稀释法和 Sensititre YeastOne 肉汤微量稀释法（SensititreYeastOneAST 板，Thermo Fisher Scientific™，美国）对 9 种抗真菌药物的菌株进行药敏试验。
所有菌株在常规方法上均被鉴定为 C.utulis 表型，但所有菌株在序列分析和 MALDI-TOF MS 中均被鉴定为 Cy.fabianii。观察到，在确定进化相关性方面检查的基因区域没有显示种内核苷酸变异。在所有菌株中，氟康唑的 MIC50/MIC90 值均高于其他测试的抗真菌药物。
在氟康唑耐药的尿路感染酵母感染中应考虑 Cy.fabianii。尽管传统的表型方法不足以鉴定 Cy.fabianii，但使用核糖体 DNA 中的不同基因区域（ITS1-2、D1/D2、EF-1-α）进行序列分析和 MALDI-TOF MS 可以正确鉴定。
