Wang Mianzhi, Xiong Wenguang, Liu Peng, Xie Xiying, Zeng Jiaxiong, Sun Yongxue, Zeng Zhenling
National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou, China.
Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.
Front Microbiol. 2018 Oct 16;9:2474. doi: 10.3389/fmicb.2018.02474. eCollection 2018.
In this study, we examined the types of antibiotic resistance genes (ARGs) possessed by bacteria and bacteriophages in swine feedlot wastewater before and after treatment using a metagenomics approach. We found that the relative abundance of ARGs in bacterial DNA in all water samples was significantly higher than that in phages DNA (>10.6-fold), and wastewater treatment did not significantly change the relative abundance of bacterial- or phage-associated ARGs. We further detected the distribution and diversity of the different types of ARGs according to the class of antibiotics to which they confer resistance, the tetracycline resistance genes were the most abundant resistance genes and phages were more likely to harbor ATP-binding cassette transporter family and ribosomal protection genes. Moreover, the colistin resistance gene was also detected in the phage population. When assessing the contribution of phages in spreading different groups of ARGs, β-lactamase resistance genes had a relatively high spreading ability even though the abundance was low. These findings possibly indicated that phages not only could serve as important reservoir of ARG but also carry particular ARGs in swine feedlot wastewater, and this phenomenon is independent of the environment.
在本研究中，我们采用宏基因组学方法，检测了养猪场废水处理前后细菌和噬菌体所携带的抗生素抗性基因（ARGs）类型。我们发现，所有水样中细菌DNA中ARGs的相对丰度显著高于噬菌体DNA中的相对丰度（>10.6倍），并且废水处理并未显著改变细菌或噬菌体相关ARGs的相对丰度。我们进一步根据ARGs所赋予抗性的抗生素类别，检测了不同类型ARGs的分布和多样性，四环素抗性基因是最丰富的抗性基因，噬菌体更有可能携带ATP结合盒转运蛋白家族和核糖体保护基因。此外，在噬菌体群体中还检测到了黏菌素抗性基因。在评估噬菌体在传播不同组ARGs中的作用时，β-内酰胺酶抗性基因尽管丰度较低，但具有相对较高的传播能力。这些发现可能表明，噬菌体不仅可作为ARGs的重要储存库，而且在养猪场废水中携带特定的ARGs，并且这种现象与环境无关。
