| Summary: | Nagasaki University (長崎大学) 博士(医学) Echinocandins, including caspofungin, micafungin, and anidulafungin, are first-line antifungal agents for the treatment of invasive candidiasis. They exhibit fungicidal activity by inhibiting the synthesis of β-1,3-d-glucan, an essential component of the fungal cell wall. However, they are active only against proliferating fungal cells and unable to completely eradicate fungal cells even after a 24 h drug exposure in standard time-kill assays. Surprisingly, we found that caspofungin, when dissolved in low ionic solutions, had rapid and potent antimicrobial activities against multidrug-resistant (MDR) Candida and bacteria cells even in non-growth conditions. This effect was not observed in 0.9% NaCl or other ion-containing solutions and was not exerted by other echinocandins. Furthermore, caspofungin dissolved in low ionic solutions drastically reduced mature biofilm cells of MDR Candida auris in only 5 min, as well as Candida-bacterial polymicrobial biofilms in a catheter-lock therapy model. Caspofungin displayed ion concentration-dependent conformational changes and intracellular accumulation with increased reactive oxygen species production, indicating a novel mechanism of action in low ionic conditions. Importantly, caspofungin dissolved in 5% glucose water did not exhibit increased toxicity to human cells. This study facilitates the development of new therapeutic strategies in the management of catheter-related biofilm infections. 長崎大学学位論文 学位記番号:博(医歯薬)甲第1326号 学位授与年月日:令和3年3月22日 Makoto Sumiyoshi, Taiga Miyazaki, Juliann Nzembi Makau, Satoshi Mizuta, Yoshimasa Tanaka, Takeshi Ishikawa, Koichi Makimura, Tatsuro Hirayama, Takahiro Takazono, Tomomi Saijo, Hiroyuki Yamaguchi, Shintaro Shimamura, Kazuko Yamamoto, Yoshifumi Imamura, Noriho Sakamoto, Yasushi Obase, Koichi Izumikawa, Katsunori Yanagihara, Shigeru Kohno & Hiroshi Mukae Scientific Reports, 10, 17745; 2020 Nagasaki University (長崎大学), 博士(医学) (2021-03-22) doctoral thesis
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