Laboratory of Pharmaceutical Microbiology, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium.
J Antimicrob Chemother. 2010 Apr;65(4):694-700. doi: 10.1093/jac/dkq019. Epub 2010 Feb 3.
Although azole antifungals are considered to be fungistatic, miconazole has fungicidal activity against planktonic Candida albicans cells, presumably associated with the induction of reactive oxygen species (ROS) production. Only few data are available concerning the effect of miconazole against sessile C. albicans cells. In the present study, the fungicidal activity of miconazole against in vitro-grown mature Candida biofilms, and its relationship with the induction of ROS and ROS-dependent apoptosis were examined.
The effect of miconazole on mature biofilms formed by 10 C. albicans strains and 5 strains from other Candida species was evaluated by plate counting and measuring the level of ROS induction. MIC tests were performed in the absence and presence of ascorbic acid, a quencher of ROS. The apoptotic population in C. albicans cells was determined using annexin-Cy3.
Miconazole showed a significant fungicidal effect against all mature Candida biofilms tested and caused elevated ROS levels, both in planktonic and sessile cells. Addition of ascorbic acid drastically reduced these levels. While ROS quenching decreased the susceptibility to miconazole of planktonic cells of most Candida strains, no reduced fungicidal activity of miconazole against biofilms was observed. Miconazole did not cause a significant increase in apoptosis.
ROS levels increased in all Candida biofilms upon addition of miconazole. However, ROS induction was not the only factor that underlies its fungicidal activity, as quenching of ROS did not lead to an enhanced survival of biofilm cells. ROS-induced apoptosis was not observed in C. albicans cells after miconazole treatment.
尽管唑类抗真菌药物被认为具有抑菌作用，但咪康唑对浮游态白色念珠菌细胞具有杀菌活性，这可能与活性氧（ROS）产生的诱导有关。关于咪康唑对定殖白色念珠菌细胞的作用，仅有少量数据。本研究检测了咪康唑对体外生长的成熟白色念珠菌生物膜的杀菌活性及其与 ROS 诱导和 ROS 依赖性细胞凋亡的关系。
通过平板计数和测量 ROS 诱导水平评估咪康唑对 10 株白色念珠菌菌株和 5 株其他念珠菌属菌株形成的成熟生物膜的影响。在无和有抗坏血酸（ROS 淬灭剂）的情况下进行 MIC 测试。使用 Annexin-Cy3 测定白色念珠菌细胞中的凋亡群体。
咪康唑对所有测试的成熟白色念珠菌生物膜均表现出显著的杀菌作用，并导致浮游态和定殖态细胞中 ROS 水平升高。添加抗坏血酸可大大降低这些水平。虽然 ROS 淬灭降低了大多数念珠菌菌株浮游细胞对咪康唑的敏感性，但未观察到咪康唑对生物膜的杀菌活性降低。咪康唑未导致明显的细胞凋亡增加。
加入咪康唑后，所有白色念珠菌生物膜中的 ROS 水平均增加。然而，ROS 诱导并不是其杀菌活性的唯一因素，因为 ROS 淬灭并未导致生物膜细胞存活率增加。咪康唑处理后，白色念珠菌细胞中未观察到 ROS 诱导的细胞凋亡。
