Department of Microbiology, Meiji Pharmaceutical University, Tokyo, Japan.
Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases, Tokyo, Japan.
Drug Discov Ther. 2024 Sep 19;18(4):249-254. doi: 10.5582/ddt.2024.01043. Epub 2024 Aug 25.
Non-tuberculous mycobacteria (NTM) cause skin infections, respiratory diseases, and disseminated infections. Mycobacterium avium and Mycobacterium intracellulare, which are slow grown Mycobacterium, are main agents of those NTM diseases. A silkworm infection model with Mycobacterium abscessus, a rapidly growing Mycobacterium species, was established to quantitatively evaluate its virulence within a short period. However, a silkworm infection model to quantitatively evaluate the virulence of M. intracellulare has not yet been developed. In this study, we determined the virulence of M. intracellulare subspecies within 4 days using a silkworm infection model. The subspecies of M. intracellulare strains used in this study were estimated by phylogenetic tree analysis using core gene data. The median lethal dose (LD) values, which are the dose of a pathogen required to kill half of the silkworms in a group, were determined 4 days after infection. The LD value of M. intracellulare subsp. chimaera DSM44623 was higher than that of M. intracellulare subsp. intracellulare ATCC13950. These results suggest that the virulence of M. intracellulare subspecies can be compared using a silkworm model within 4 days.
非结核分枝杆菌（NTM）可引起皮肤感染、呼吸道疾病和播散性感染。生长缓慢的分枝杆菌，如鸟分枝杆菌和胞内分枝杆菌，是这些 NTM 疾病的主要病原体。我们建立了一种感染脓肿分枝杆菌（一种快速生长的分枝杆菌）的家蚕感染模型，以在短时间内定量评估其毒力。然而，尚未建立用于定量评估胞内分枝杆菌毒力的家蚕感染模型。在本研究中，我们使用家蚕感染模型在 4 天内确定了胞内分枝杆菌亚种的毒力。本研究中使用的胞内分枝杆菌菌株的亚种是通过使用核心基因数据的系统发育树分析来估计的。感染后 4 天，确定了半数蚕群死亡所需的病原体剂量（LD 值），即致死剂量。M. intracellulare subsp. chimaera DSM44623 的 LD 值高于 M. intracellulare subsp. intracellulare ATCC13950。这些结果表明，在 4 天内，可以使用家蚕模型比较胞内分枝杆菌亚种的毒力。
