Mycobacterium abscessus is an emerging health risk to immunocompromised individuals and to people with pre-existing pulmonary conditions. As M. abscessus possesses multiple mechanisms of drug resistance, treatments of M. abscessus are of poor efficacy. Therefore, there is an urgent need for new therapeutic strategies targeting M. abscessus. We describe an experimental system for screening of compounds for their antimicrobial activity against intracellular M. abscessus using flow cytometry and imaging flow cytometry. The assay allows simultaneous analysis of multiple parameters, such as proportion of infected host cells, bacterial load per host cell from the infected population, and host cell viability. We verified the suitability of this method using two antibiotics with known activity against M. abscessus: clarithromycin and amikacin. Our analysis revealed a high degree of infection heterogeneity, which correlated with host cell size. A higher proportion of the larger host cells is infected with M. abscessus as compared to smaller host cells, and infected larger cells have higher intracellular bacterial burden than infected smaller cells. Clarithromycin treatment has a more pronounced effect on smaller host cells than on bigger host cells, suggesting that heterogeneity within the host cell population has an effect on antibiotic susceptibility of intracellular bacteria.

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巨噬细胞感染期间脓肿分枝杆菌药物敏感性的单细胞分析

脓肿分枝杆菌对免疫功能低下的个体和已有肺部疾病的人来说是一种新出现的健康风险。由于脓肿分枝杆菌具有多种耐药机制，治疗脓肿分枝杆菌疗效不佳。因此，迫切需要针对脓肿分枝杆菌的新治疗策略。我们描述了一种用于筛选化合物对细胞内脓肿分枝杆菌的抗菌活性的实验系统使用流式细胞仪和成像流式细胞仪。该测定允许同时分析多个参数，例如感染宿主细胞的比例、感染群体中每个宿主细胞的细菌载量和宿主细胞活力。我们使用两种对脓肿分枝杆菌具有已知活性的抗生素验证了该方法的适用性：克拉霉素和阿米卡星。我们的分析揭示了高度的感染异质性，这与宿主细胞大小相关。较大比例的较大宿主细胞感染了脓肿分枝杆菌与较小的宿主细胞相比，受感染的较大细胞比受感染的较小细胞具有更高的细胞内细菌负荷。克拉霉素处理对较小宿主细胞的影响比对较大宿主细胞的影响更显着，这表明宿主细胞群内的异质性对细胞内细菌的抗生素敏感性有影响。