摘要

       抗生素抗性基因 (ARG) 是在动物饲养场周围的水和沉积物中发现的新兴污染物。在这项研究中，猪排泄物中释放的五种四环素抗性基因和 16S-rRNA 基因在模拟不同自然接收水体的 12 个中层环境中的水柱和生物膜中监测了 21 天。一式三份地采用四种处理：两次曝光（亮/暗）和两种加载场景（单次/定期）。如前所述，光照对水柱和生物膜中 tet 基因的消失率有显着影响，尽管生物膜中的绝对率明显较低。此外，周期性与单一加载事件导致相关坦克中的 tet 基因水平高出 2 个数量级以上。不管治疗如何，ARGs 都迅速迁移到生物膜，分别在第 1 天和第 4 天在生物膜中发现了 3% 和 >85% 的检测到的 tet 决定簇。总体而言，这些是关于生物膜中特定 ARG 消失率的第一个定量数据，也是在典型的天然接收水体的负载条件下生物膜中 ARG 水平逐渐积累的第一个证据。总之，ARGs 快速迁移到生物膜，在那里它们比邻近水域持续时间更长，这表明生物膜可能在自然界中充当 ARGs 的储库。

       Antibiotic resistance genes (ARGs) are emerging contaminants found in the water and sediments surrounding animal feedlots. In this study, the fate of five tetracycline-resistance and 16S-rRNA genes released in swine waste were monitored for 21 days in the water column and biofilms in 12 mesocosms mimicking different natural receiving water bodies. Four treatments were employed in triplicate: two light exposures (light/dark) and two loading scenarios (single/periodic). As seen previously, light exposure had a significant effect on disappearance rates of tet genes in both the water column and biofilms, although absolute rates were significantly lower in the biofilms. Further, periodic versus single loading events resulted in >2 orders of magnitude higher tet gene levels in associated tanks. Regardless of treatment, ARGs migrated quickly to biofilms, with 3% and >85% of detected tet determinants found in biofilms on days 1 and 4, respectively. Overall, these are the first quantitative data on specific ARG disappearance rates in biofilms, and also the first evidence of progressively accumulating ARG levels in biofilms under loading conditions typical of natural receiving waters. In summary, ARGs migrate rapidly to biofilms where they persist longer than adjacent waters, which suggests biofilms likely act as reservoirs for ARGs in nature.

https://pubs.acs.org/doi/abs/10.1021/es9014508