The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Beijing Hospital, National Center of Gerontology, National Health Commission; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, China.
National Tuberculosis Reference Laboratory, Chinese Center for Disease Control and Prevention, Beijing, China.
J Glob Antimicrob Resist. 2022 Dec;31:90-97. doi: 10.1016/j.jgar.2022.05.027. Epub 2022 Jun 2.
The Mycobacterium avium complex (MAC), comprising a series of subspecies, has a worldwide distribution, with differences in drug susceptibility among subspecies. This study aimed to assess the composition of MAC and susceptibility differences among subspecies in mainland China.
A total of 287 MAC clinical strains were included in the study. Multitarget sequences were applied to accurately identify subspecies, and a microdilution method was used to evaluate minimum inhibitory concentrations (MICs) among subspecies using Sensititre SLOMYCO plates.
Mycobacterium intracellular (N = 169), Mycobacterium avium (N = 52), Mycobacterium chimaera (N = 22), Mycobacterium marseillense (N = 25), Mycobacterium colombiense (N = 14), Mycobacterium yongonense (N = 4), Mycobacterium vulneris (N = 3) and Mycobacterium timonense (N = 2) were isolated from MAC. Clarithromycin, amikacin and rifabutin showed lower MIC and MIC values than other drugs, and the resistance rates of clarithromycin, amikacin, linezolid and moxifloxacin were 6.3%, 10.5%, 51.9% and 46.3%, respectively. The resistance rates of clarithromycin and moxifloxacin in the initial treatment group were significantly lower than those in the retreatment group (4.09% vs. 12.94%; 30.41% vs. 75.29%; P < 0.05). Drug susceptibility differences were observed in clarithromycin and moxifloxacin among the five major subspecies (P < 0.05); however, those statistically significant differences disappeared when MACs were divided into two groups according to previous anti-tuberculosis (anti-TB) treatment history.
This study revealed that MAC, primarily comprising M. intracellulare, was susceptible to clarithromycin, amikacin and rifabutin. Drug susceptibility among subspecies did not exhibit intrinsic differences in our study. Previous anti-TB treatment patients are more resistant to drugs; thus, attention should be given to those patients in the clinic.
包含一系列亚种的鸟分枝杆菌复合体（MAC）在世界范围内分布，亚种间药物敏感性存在差异。本研究旨在评估中国大陆 MAC 的组成以及亚种间的药敏差异。
共纳入 287 株 MAC 临床株。采用多重靶序列准确鉴定亚种，采用 Sensititre SLOMYCO 平板微量稀释法评估亚种间最小抑菌浓度（MIC）。
从 MAC 中分离出胞内分枝杆菌（N=169）、鸟分枝杆菌（N=52）、蕈形分枝杆菌（N=22）、马赛分枝杆菌（N=25）、哥伦比亚分枝杆菌（N=14）、永福分枝杆菌（N=4）、脆弱分枝杆菌（N=3）和蒂姆诺分枝杆菌（N=2）。克拉霉素、阿米卡星和利福布汀的 MIC 和 MIC 值均低于其他药物，克拉霉素、阿米卡星、利奈唑胺和莫西沙星的耐药率分别为 6.3%、10.5%、51.9%和 46.3%。初始治疗组克拉霉素和莫西沙星的耐药率明显低于复治组（4.09%比 12.94%；30.41%比 75.29%；P<0.05）。五种主要亚种之间克拉霉素和莫西沙星的药敏差异有统计学意义（P<0.05）；然而，根据既往抗结核（抗-TB）治疗史将 MAC 分为两组后，这些差异消失。
本研究表明，MAC 主要由胞内分枝杆菌组成，对克拉霉素、阿米卡星和利福布汀敏感。在本研究中，亚种间药物敏感性没有内在差异。既往抗 TB 治疗患者对药物的耐药性更高；因此，临床应注意这些患者。
