Association of colistin residues and manure treatment with the abundance of mcr-1 gene in swine feedlots

文献类型： 外文期刊

第一作者： Xia, Xi

作者： Xia, Xi;Wang, Zheng;Fu, Yulin;Zhou, Yuqing;He, Junjia;Wang, Yang;Shen, Jianzhong;Jiang, Haiyang;Du, Xiang-Dang;Gao, Binwen;Wu, Yongning

作者机构：

关键词： Colistin; mcr-1 gene; Wastewater treat process; Swine feedlot; Bacterial community

期刊名称：ENVIRONMENT INTERNATIONAL （ 影响因子：9.621； 五年影响因子：10.72 ）

ISSN： 0160-4120

年卷期： 2019 年 127 卷

页码：

收录情况： SCI

摘要： Background: The extensive use of colistin in swine production may have contributed to the recent emergence of corresponding mobile resistance gene mcr-1. The use of colistin as a feed additive was banned in China in April 2017. Objectives: To examine the occurrence of colistin and dissemination of mcr-1 in swine feedlots before and after the colistin ban and effects of different manure treatments. Methods: Environmental samples were collected from swine feedlots before (December 2016) and after (December 2017) the colistin ban. Colistin concentrations were determined by ultra-high performance liquid chromatography coupled to tandem mass spectrometry. The prevalence of mcr-1 were determined by quantitative PCR analysis, while bacterial community composition was investigated by 16S rRNA sequencing. Results: In 2016, colistin was detected in feed and fresh manure samples at 67 mg/kg and 17 mg/kg, respectively, but was absent from all samples in 2017. In 2016, the relative abundance of mcr-1 in fresh manure was lower than that in solid samples after natural drying, while a higher relative abundance was detected in fresh manure samples compared with biogas slurry samples. A strong correlation between colistin concentration and relative abundance of mcr-1 was observed in fresh manure. The samples collected in 2017 showed a lower relative abundance of mcr-1 compared with those collected in 2016. Bacterial community analysis showed that the abundance of Enterobacteriaceae, which act as a vehicle and reservoir of mcr-1, increased with natural dying but decreased with anaerobic digestion. Conclusions: The presence of colistin exerts direct selection pressure for the accumulation of mcr-1 in manure, while the ban on colistin likely halted the dissemination of mcr-1 on pig farms. Anaerobic digestion is an effective waste treatment process for removing mcr-1, which might be mainly driven by the shift in bacterial community structure.

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