Bioaerosol is an important transmission route of antibiotic resistance genes in pig farms

• Published in: Environment international 2021-09, Vol.154, p.106559-106559, Article 106559
• Main Authors: Song, Lu, Wang, Can, Jiang, Guanyu, Ma, Jinbiao, Li, Yunfei, Chen, Hong, Guo, Jianhua
• Format: Article
• Language: English
• Subjects: Antibiotic resistance genes; Bioaerosol; Fecal contribution; Transmission route
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/j.envint.2021.106559

[Display omitted] •The influences of environmental factors on the dissemination of airborne ARGs were investigated.•The fecal contribution to airborne bacteria is 19.9% and 59.4% in pig farms during summer and winter.•Horizontal gene transfer plays an important role during winter in pig farms atmosphere.•The transmission routes and the control strategy of airborne ARGs are described in pig farms. Although pig farms are hotspots of antibiotic resistance due to intensive use of antibiotics, little is known about the abundance, diversity and transmission of airborne antibiotic resistance genes (ARGs). This study reports that bioaerosol is an important spread route of ARGs in pig farms. ARGs, mobile genetic elements (MGEs), and bacterial communities were investigated in both air and feces samples during winter and summer. The average concentration of airborne ARGs and MGEs during winter is higher than that during summer when using the ventilation system. The tetM is identified as the predominant airborne ARG with abundance of 6.3 ± 1.2 log copies/m3. Clostridium and Streptococcus are two dominant bacteria and several opportunistic pathogens are detected in air samples. High temperature is favorable for more diverse bacterial communities, but relative humidity has negative effects. The wind speed promotes the spread of airborne ARGs. The network analysis results show the average fecal contribution to airborne bacteria is 19.9% and 59.4% during summer and winter, respectively. Horizontal gene transfer plays an important role in the dissemination of airborne ARGs during winter (77.8% possibility), while a lower possibility of 12.0% in summer.