摘要
      抗生素耐药性基因（ARGs）的空气传播已成为全球健康威胁，而其宿主的耐药性表型在很大程度上仍然未知。在这里，使用便携式大容量采样器（1000L/min）从北京的污染空气中采集了可培养的细菌气溶胶样本。进行了抗菌药物敏感性测试，以探索可培养细菌气溶胶对七种广泛使用的抗生素的敏感性。作为比较，还研究了ARG在两种人类呼吸道致病菌株（铜绿假单胞菌和耐甲氧西林金黄色葡萄球菌）和一种非致病菌株（荧光假单胞菌）中的分布和表达。通过高通量实时qPCR平台研究了流感嗜血杆菌等三种菌株中39种ARG亚型的相对丰度。令人惊讶的是，污染空气中24.66%的可培养细菌气溶胶对万古霉素（迄今为止最强效的抗生素）具有耐药性，而53.05%的空气中可培养细菌对氨苄青霉素（β-内酰胺）敏感。不同的细菌表现出非常不同的ARG分布模式，或多或少偏向于某一种ARG类型。另一方面，在流行性感冒和荧光假单胞菌中都检测到万古霉素抗性基因vanB，但这些细菌没有表现出抗万古霉素表型。此外，在铜绿假单胞菌和荧光假单胞菌中没有观察到对环丙沙星（喹诺酮类）的耐药性，尽管这些细菌携带丰富的喹诺酮类耐药性基因qepA。这项工作的实验数据表明，空气是多种ARG的重要活性库，一些细菌气溶胶虽然没有表达，但携带万古霉素抗性基因。人类呼吸道病原体的研究结果进一步证明了类似的发现。这项工作强调了ARBs在空气中传播的严重关切，包括那些在污染的环境中对万古霉素具有耐药性的ARBs，同时揭示了病原菌和非病原菌中各种ARBs的丰度和模式。
Abstract
Airborne transmission of antibiotic resistance genes (ARGs) has emerged as a global health threat, while their hosts’ resistance phenotype remains largely unknown. Here, culturable bacterial aerosol samples were collected from polluted air in Beijing using a portable high volume sampler (1000 L/min). Antimicrobial susceptibility testing was conducted to explore the antibiotic sensitivity of culturable bacterial aerosols to seven widely used antibiotics. As a comparison, ARG distribution and expression in two human respiratory pathogenic bacterial strains (Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus) and a non-pathogenic bacterial strain (Pseudomonas fluorescens) were also studied. Relative abundances of 39 ARG subtypes in three bacterial strains including Haemophilus influenzae were investigated by high throughput real-time qPCR platform. Surprisingly, 24.66% of the culturable bacterial aerosols in polluted air were resistant to vancomycin-the most powerful antibiotics to date, while 53.05% of airborne culturable bacteria were susceptible to ampicillin (β-lactams). Different bacteria demonstrated very different ARG distribution patterns of more or less skewed toward certain one ARG type. On the other hand, the vancomycin resistance gene vanB was detected both in H. influenza and P. fluorescens, however these bacteria did not exhibit anti-vancomycin phenotype. Furthermore, the resistance to ciprofloxacin (quinolones) was not observed in P. aeruginosa and P. fluorescens although these bacteria harbor abundant quinolone resistance gene qepA. Experimental data from this work show that air represents an important active reservoir of diverse ARGs, and some bacterial aerosols are harboring vancomycin resistance gene though not expressed. Results from human respiratory pathogens have further demonstrated similar findings. This work underscores the serious concern of airborne dissemination of ARBs including those resistant to vancomycin in polluted ambient environments, while revealing abundances and patterns of various ARGs in both pathogenic and non-pathogenic bacteria.

https://www.sciencedirect.com/science/article/abs/pii/S002185022100656X