Li Zhen, Zhu Bin, Chen Weiqin, Hu Jun, Xue Yingjun, Yin Hongmei, Hu Xiaobo, Liu Weiwei
Department of Laboratory Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, People's Republic of China.
Department of Rehabilitation, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200025, People's Republic of China.
Infect Drug Resist. 2023 Sep 7;16:5953-5964. doi: 10.2147/IDR.S419646. eCollection 2023.
The non (NAC) species have recently gained great importance worldwide due to the increasing proportion in causing bloodstream infections. This investigation aimed to explore the efficacy of Pseudolaric acid A (PAA, a diterpenoid derived from Pseudolarix kaempferi) and its synergistic effect with fluconazole (FLC) against NAC species, including , and .
The microdilution checkerboard assay and time-killing curves were performed to detect the antifungal efficiency. To examine the integrity of cell walls and membranes, calcofluor white stain and propidium iodide stain were used. The changes of intracellular ultrastructure in cells after treatment were observed using transmission electron microscopy. Changes in cell viability with the autophagy inhibitor 3-MA were assessed by the XTT method.
It was revealed that PAA alone is effective on , and (MIC 8-128 µg/mL). Strong synergism against FLC-resistant was observed (FICI 0.07-0.281), when PAA and FLC were combined. PAA had dose-dependently detrimental effects on cell membranes. Moreover, increased vacuoles and autophagosome formation were found in exposed to PAA. And the inhibitory effect of PAA against can be relieved by autophagy inhibitor 3-MA in a certain concentration range. Ultrastructural alterations of were more pronounced under the combination of PAA and FLC, including separation of the cell membrane from the cell wall, increased number of vacuoles, and degradation of organelles.
These observations indicated that PAA and its combination with FLC could be a promising therapeutic candidate for treating infections caused by NAC species.
非白色念珠菌（NAC）菌种由于在引起血流感染中所占比例不断增加，近来在全球范围内变得极为重要。本研究旨在探讨土槿甲酸A（PAA，一种从金钱松中提取的二萜类化合物）及其与氟康唑（FLC）对NAC菌种（包括光滑念珠菌、近平滑念珠菌和热带念珠菌）的协同作用。
采用微量稀释棋盘法和时间杀菌曲线检测抗真菌效果。使用荧光增白剂染色和碘化丙啶染色检查细胞壁和细胞膜的完整性。通过透射电子显微镜观察处理后光滑念珠菌细胞内超微结构的变化。用XTT法评估自噬抑制剂3-甲基腺嘌呤（3-MA）对细胞活力变化的影响。
结果显示，单独使用PAA对光滑念珠菌、近平滑念珠菌和热带念珠菌有效（最低抑菌浓度为8 - 128μg/mL）。当PAA与FLC联合使用时，观察到对氟康唑耐药的光滑念珠菌有很强的协同作用（联合抑菌系数为0.07 - 0.281）。PAA对光滑念珠菌细胞膜有剂量依赖性的损害作用。此外，在暴露于PAA的光滑念珠菌中发现液泡增多和自噬体形成。并且在一定浓度范围内，自噬抑制剂3-MA可减轻PAA对光滑念珠菌的抑制作用。在PAA和FLC联合作用下，光滑念珠菌的超微结构改变更为明显，包括细胞膜与细胞壁分离、液泡数量增加和细胞器降解。
这些观察结果表明，PAA及其与FLC的联合使用可能是治疗由NAC菌种引起的感染的有前景的治疗候选药物。
