Department of Medical Technology, School of Health Sciences, Tokyo University of Technology, Tokyo, Japan.
Drug Discoveries by Silkworm Models, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan.
Drug Discov Ther. 2021 May 11;15(2):73-77. doi: 10.5582/ddt.2021.01035. Epub 2021 Apr 29.
Nocardia is a ubiquitous environmental microbe that causes nocardiosis against immunosuppressed and immunocompromised hosts. The assay system for the quantitative evaluation of virulence of Nocardia sp. or therapeutic effectiveness of antimicrobials for treatment of nocardiosis is not established so far. In this study, we established an infection model of Nocardia sp. using silkworm as an alternative animal model. We found that all tested Nocardia sp. such as Nocardia asiatica, Nocardia elegans, Nocardia exalbida, Nocardia farcinica, and Nocardia nova killed silkworm and their killing ability were different by species. N. farcinica showed higher pathogenicity among tested strain, similar to the mouse model as previously reported. In addition, we found that antimicrobials such as amikacin and minocycline showed therapeutic effectiveness in silkworms infected with N. farcinica, and we could determine effective doses 50 (ED₅₀) values. These results suggest that silkworm is a useful alternative animal to evaluate the pathogenicity of Nocardia pathogen and the therapeutic effects of antimicrobials against Nocardia sp. in a quantitative manner.
诺卡氏菌是一种无处不在的环境微生物，可引起免疫抑制和免疫功能低下宿主的诺卡氏菌病。目前尚未建立用于定量评估诺卡氏菌属的毒力或治疗诺卡氏菌病的抗菌药物治疗效果的检测系统。在这项研究中，我们建立了一种使用家蚕作为替代动物模型的诺卡氏菌感染模型。我们发现，所有测试的诺卡氏菌，如亚洲诺卡氏菌、美丽诺卡氏菌、白黄诺卡氏菌、星形诺卡氏菌和新星诺卡氏菌，均可杀死家蚕，且其杀伤能力因物种而异。在测试的菌株中，星形诺卡氏菌表现出更高的致病性，与之前报道的小鼠模型相似。此外，我们发现阿米卡星和米诺环素等抗菌药物在家蚕感染星形诺卡氏菌时具有治疗效果，并且我们可以确定有效剂量 50（ED₅₀）值。这些结果表明，家蚕是一种有用的替代动物，可以定量评估诺卡氏菌病原体的致病性和抗菌药物对诺卡氏菌属的治疗效果。
