Du Jun, Ma Wenshuang, Fan Jiaqi, Liu Xiaoming, Wang Yujiong, Zhou Xuezhang
Key Laboratory of the Ministry of Education for the Conservation and Utilization of Special Biological Resources of Western China, Ningxia University, Yinchuan, China.
College of Life Science, Ningxia University, Yinchuan, China.
Front Vet Sci. 2021 Aug 11;8:634286. doi: 10.3389/fvets.2021.634286. eCollection 2021.
() has been recently recognized as an important pathogen involved in mycotic mastitis of cows. The phenotypic and molecular characteristics of 15 clinical isolates collected from cows with clinical mastitis in three herds of Yinchuan, Ningxia, were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. In addition to sequencing analysis, the gene that encodes 14α-demethylases, the expression of the gene, and efflux transporters and in itraconazole-susceptible (S), itraconazole-susceptible dose dependent (SDD), and itraconazole-resistant (R) isolates was also quantified by a quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) assay. Sequencing analysis revealed three synonymous codon substitutions of the gene including T939C, A756T, and T642C in these clinical isolates. Among them, T642C and T939C mutations were detected in itraconazole-resistant and -susceptible isolates, but the A756T substitution was found only in itraconazole-resistant isolates. Importantly, the expression of the gene in itraconazole-resistant isolates was significantly higher compared with itraconazole-SDD and itraconazole-susceptible isolates ( = 0.052 and = 0.012, respectively), as determined by the qRT-PCR assay. Interestingly, the expression of the gene was also significantly higher in itraconazole-resistant isolates relative to the itraconazole-SDD and itraconazole-susceptible strains. Notably, the expression of was positively associated with resistance to itraconazole ( = 0.4177 in SDD compared with S, = 0.0107 in SDD with R, and = 0.0035 in S with R, respectively). These data demonstrated that mutations of the gene were involved in drug resistance in . The A756T synonymous codon substitution of the gene was correlated with an increased expression of drug-resistant genes including and in itraconazole-resistant isolates examined in this study.
（）最近被认为是奶牛霉菌性乳腺炎的一种重要病原体。通过基质辅助激光解吸电离飞行时间质谱法鉴定了从宁夏银川三个牛群的临床乳腺炎奶牛中收集的15株临床分离株的表型和分子特征。除了测序分析外，还通过定量实时逆转录聚合酶链反应（qRT-PCR）测定法对编码14α-脱甲基酶的基因、该基因的表达以及伊曲康唑敏感（S）、伊曲康唑敏感剂量依赖性（SDD）和伊曲康唑耐药（R）分离株中的外排转运蛋白和进行了定量。测序分析显示，这些临床分离株中该基因存在三个同义密码子替换，包括T939C、A756T和T642C。其中，T642C和T939C突变在伊曲康唑耐药和敏感分离株中均有检测到，但A756T替换仅在伊曲康唑耐药分离株中发现。重要的是，通过qRT-PCR测定法确定，与伊曲康唑-SDD和伊曲康唑敏感分离株相比，伊曲康唑耐药分离株中该基因的表达显著更高（分别为 = 0.052和 = 0.012）。有趣的是，相对于伊曲康唑-SDD和伊曲康唑敏感菌株，伊曲康唑耐药分离株中该基因的表达也显著更高。值得注意的是，的表达与对伊曲康唑的耐药性呈正相关（SDD与S相比 = 0.4177，SDD与R相比 = 0.0107，S与R相比 = 0.0035）。这些数据表明该基因的突变与的耐药性有关。本研究中检测的伊曲康唑耐药分离株中，该基因的A756T同义密码子替换与包括和在内的耐药基因表达增加相关。
