Guangzhou Center for Disease Control and Prevention, Guangzhou 510440, Guangdong, PR China.
School of Public Health, Sun Yat-sen University, Guangzhou 510006, Guangdong, PR China.
Environ Int. 2020 Jun;139:105625. doi: 10.1016/j.envint.2020.105625. Epub 2020 Apr 3.
Environmental antibiotic resistance genes (ARGs) have received much attention, while the characteristics of ARGs carried by particulate matter (PM) as a function of urban functional region are almost unknown. In this study, ARGs carried by PM and PM in an urban hospital, a nearby urban community and the nearest suburban community were detected using metagenomics. In total, 643 ARG subtypes belonging to 22 different ARG types were identified. The chloramphenicol exporter gene, sul1, bacA, and lnuA were the most abundant ARG subtypes in all air samples. The hospital exhibited higher ARG abundance and richness than the nearby communities. ARG profiles depended on functional region: hospital and suburban samples clustered separately, and samples from the nearby urban community interspersed among them. The representation of multidrug and quinolone resistance genes decayed with distance from the hospital to the urban community to the suburban community, indicating that hospital PM may be a hotspot for ARGs encoding proteins conferring multidrug and quinolone resistance. Airborne ARGs carried by PM in the hospital environment were more closely associated with clinically important pathogens than were those in nearby communities. In particular, carbapenemase genes, including bla,bla,bla,bla,and bla, were discovered in hospital PM. In the suburban community, crAssphage, a human host-specific bacteriophage, was applied to predict ARG abundance and found to be enriched due to anthropogenic pollution but showed no clear evidence for ARG selection. In the hospital and the nearby urban community, the drivers of ARGs were complex. Our results highlighted that PM ARGs were closely related to human activities and revealed a potential hotspot, which could provide new evidence for further research and consequently mitigate the formation of airborne ARGs and transfer risks.
环境抗生素抗性基因（ARGs）受到了广泛关注，而作为城市功能区的颗粒物（PM）所携带的 ARGs 的特征却几乎未知。本研究采用宏基因组学方法检测了城市医院、附近城市社区和最近的郊区社区 PM 中携带的 ARGs。共鉴定出属于 22 种不同 ARG 类型的 643 种 ARG 亚型。所有空气样本中最丰富的 ARG 亚型是氯霉素外排基因 sul1、bacA 和 lnuA。医院的 ARG 丰度和丰富度均高于附近社区。ARG 谱取决于功能区：医院和郊区样本聚类分离，而附近城市社区的样本则分散在其中。多药和喹诺酮类抗性基因的代表随着距离从医院到城市社区到郊区社区的衰减，表明医院 PM 可能是编码多药和喹诺酮类抗性蛋白的 ARGs 的热点。医院环境中 PM 携带的空气传播 ARGs 与临床上重要的病原体的相关性比附近社区的 ARGs 更为密切。特别是，在医院 PM 中发现了碳青霉烯酶基因，包括 bla、bla、bla、bla 和 bla。在郊区社区，人类特异性噬菌体 crAssphage 被用于预测 ARG 丰度，发现由于人为污染而富集，但没有明显的 ARG 选择证据。在医院和附近城市社区，ARG 的驱动因素较为复杂。我们的研究结果表明，PM ARGs 与人类活动密切相关，并揭示了一个潜在的热点，这可为进一步研究提供新的证据，从而减轻空气传播 ARGs 的形成和转移风险。
