State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
South China Sea Resource Exploitation and Protection Collaborative Innovation Center, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China.
Environ Int. 2019 Jun;127:333-339. doi: 10.1016/j.envint.2019.03.006. Epub 2019 Apr 3.
Antibiotic resistance genes (ARGs) have emerged as a global health concern. A large volume of work has already been devoted to ARGs in aquatic ecosystems. However, ARG dispersal patterns in air remain to be largely unknown despite of its greater role in transmission. This work aims to investigate time-resolved airborne spread of ARGs and their corresponding subtype bacterial carriers in highly polluted air. Time-resolved air samples (20 m each with three samples) were collected using a high volume sampler (1 m/min) every 4 h continuously (both day and night) during low (14-93 μg/m) and high PM (36-205 μg/m) pollution times (over 6 days with a total of 69 air samples) in Beijing. All air samples were subjected to 16S rRNA sequence analysis for 39 ARG subtypes. Pure culturable bacterial isolates from Beijing and Shijiazhuang were Sanger sequenced for species identification and also subjected to high throughput ARG subtype detection. ARG and its subtype relative abundances in the air were observed to differ greatly (up to 3 folds for abundance) both day and night, and the blaTEM gene was found to lead the ARG abundance. For an early morning time, the multi-drug resistant NDM-1 gene was detected up to 30% of total ARG abundance in highly polluted air. Identified as a major NDM-1 and vanB gene carrier, Bacillus halotolerans were also shown to disseminate more ARG subtypes. On another front, tnpA and intI1 were shown to vary greatly in abundance, while the sul3 gene was found widespread among the culturable Bacillus isolates in the air. Principal component analysis (PCA) showed different gene co-occurrence networks for different PM pollution episodes, e.g., tnpA and intI1 for gene transfer and integration, respectively, were found more abundant for the high PM pollution episode. This study highlights a serious yet previously unidentified public health threat from time-resolved airborne spread of ARGs. Further work is urgently warranted to track the sources of ARGs for their optimized control during high PM pollution episodes.
抗生素耐药基因 (ARGs) 已成为全球关注的健康问题。大量工作已经致力于研究水生生态系统中的 ARGs。然而，尽管空气中的 ARG 传播在传播中起着更大的作用，但空气中 ARG 的扩散模式在很大程度上仍然未知。本研究旨在调查高度污染空气中 ARGs 及其相应亚型细菌载体的时间分辨 airborne 传播。使用高容量采样器（1 m/min）在低（14-93μg/m）和高 PM（36-205μg/m）污染时间（北京共 6 天 69 个空气样本）期间每 4 小时连续（白天和黑夜）采集时间分辨的空气样本（每个样本 20m，每个样本 3 个样本）。对所有空气样本进行 16S rRNA 序列分析，以检测 39 种 ARG 亚型。从北京和石家庄分离的纯可培养细菌分离物进行 Sanger 测序以鉴定物种，并进行高通量 ARG 亚型检测。结果表明，空气中的 ARG 及其亚型相对丰度差异很大（丰度高达 3 倍），并且 blaTEM 基因主导了 ARG 丰度。对于清晨时间，在高度污染的空气中，检测到多达 30%的总 ARG 丰度的多药耐药 NDM-1 基因。作为主要的 NDM-1 和 vanB 基因载体，耐盐芽孢杆菌也被证明传播了更多的 ARG 亚型。另一方面，tnpA 和 intI1 的丰度差异很大，而 sul3 基因在空气中可培养芽孢杆菌分离物中广泛存在。主成分分析 (PCA) 显示不同 PM 污染事件的基因共现网络不同，例如，tnpA 和 intI1 分别分别为基因转移和整合，在高 PM 污染事件中更为丰富。本研究强调了空气中 ARGs 的时间分辨 airborne 传播带来的严重但以前未被识别的公共卫生威胁。迫切需要进一步开展工作，以跟踪 ARGs 的来源，以便在高 PM 污染事件期间对其进行优化控制。
