Time-resolved spread of antibiotic resistance genes in highly polluted air

Ting Zhang; Xinyue Li; Minfei Wang; Haoxuan Chen; Ying Yang; Qing-Lin Chen; Maosheng Yao

doi:10.1016/j.envint.2019.03.006

Time-resolved spread of antibiotic resistance genes in highly polluted air

Environ Int. 2019 Jun:127:333-339. doi: 10.1016/j.envint.2019.03.006. Epub 2019 Apr 3.

Authors

Ting Zhang¹, Xinyue Li¹, Minfei Wang¹, Haoxuan Chen¹, Ying Yang², Qing-Lin Chen³, Maosheng Yao⁴

Affiliations

¹ State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
² South China Sea Resource Exploitation and Protection Collaborative Innovation Center, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China.
³ Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
⁴ State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China. Electronic address: yao@pku.edu.cn.

PMID: 30953816
DOI: 10.1016/j.envint.2019.03.006

Abstract

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 m³ each with three samples) were collected using a high volume sampler (1 m³/min) every 4 h continuously (both day and night) during low (14-93 μg/m³) and high PM_2.5 (36-205 μg/m³) 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_2.5 pollution episodes, e.g., tnpA and intI1 for gene transfer and integration, respectively, were found more abundant for the high PM_2.5 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_2.5 pollution episodes.

Keywords: Air pollution; Antibiotic resistance genes; Particulate matter; Time-resolved ARGs.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Microbiology*
Air Pollution
Anti-Bacterial Agents / pharmacology*
Bacillus / drug effects*
Bacillus / genetics*
Beijing
Drug Resistance, Bacterial / genetics*
Gene Expression Regulation, Bacterial
Genes, Bacterial
RNA, Ribosomal, 16S / genetics

Substances

Anti-Bacterial Agents
RNA, Ribosomal, 16S