Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany.
J Antimicrob Chemother. 2022 May 29;77(6):1645-1654. doi: 10.1093/jac/dkac062.
Interest in aspergillosis has increased over the past decades. An increase in the incidence of azole-resistant Aspergillus fumigatus strains has been reported; therefore, the need for novel therapeutic approaches is urgent. The formation of biofilms contributes to pathogen resistance. We investigated the biofilm formation capabilities of azole-resistant A. fumigatus and analysed the susceptibility of biofilms at various developmental stages to three antifungal agents.
Biofilm formation of 19 clinical A. fumigatus strains (3 azole-susceptible and 16 azole-resistant strains) was determined by crystal violet staining and by an XTT assay over a period of 48 h. We measured antibiofilm activity of voriconazole, amphotericin B and olorofim. These agents were added before adhesion, after adhesion, after germination and to mature fungal biofilm. Antibiofilm activity was assessed in an XTT assay and in confocal laser scan microscopy. Additionally, a growth-kinetic assay with planktonic A. fumigatus was performed.
Each of the antifungal agents inhibited the metabolic activity of A. fumigatus biofilms when applied at early stages of biofilm formation. The mature biofilms were more resistant. Olorofim and voriconazole showed promising effects against A. fumigatus adhesion and germination, whereas the mature biofilm was not affected by treatment. In contrast, the biofilm of A. fumigatus showed amphotericin B susceptibility throughout the entire developmental process. The planktonic cells were susceptible to all three antifungal drug classes with an inhibition peak at 12 h after incubation.
This is the first known study to demonstrate the antibiofilm activity of olorofim, voriconazole and amphotericin B against azole-resistant A. fumigatus.
过去几十年来，人们对曲霉菌病的兴趣日益增加。据报道，耐唑类烟曲霉菌株的发病率有所增加；因此，迫切需要新的治疗方法。生物膜的形成有助于病原体产生耐药性。我们研究了耐唑类烟曲霉的生物膜形成能力，并分析了不同发育阶段生物膜对三种抗真菌药物的敏感性。
通过结晶紫染色和 XTT 测定法，在 48 小时内测定了 19 株临床烟曲霉（3 株唑类敏感株和 16 株唑类耐药株）的生物膜形成能力。我们测量了伏立康唑、两性霉素 B 和奥洛氟米的抗生物膜活性。这些药物在粘附前、粘附后、发芽后和成熟真菌生物膜中添加。在 XTT 测定法和共聚焦激光扫描显微镜下评估抗生物膜活性。此外，还进行了浮游烟曲霉菌的生长动力学测定。
在生物膜形成的早期阶段应用时，每种抗真菌药物都抑制了烟曲霉生物膜的代谢活性。成熟的生物膜具有更强的耐药性。奥洛氟米和伏立康唑对烟曲霉的粘附和发芽显示出有希望的效果，而成熟的生物膜不受治疗影响。相比之下，生物膜的烟曲霉在整个发育过程中对两性霉素 B 敏感。浮游细胞对所有三种抗真菌药物都敏感，在孵育 12 小时后达到抑制峰值。
这是首次已知的研究表明奥洛氟米、伏立康唑和两性霉素 B 对耐唑类烟曲霉具有抗生物膜活性。
