摘要

处理过的污水的排放导致抗生素抗性细菌，抗性基因和抗生素残留物释放到环境中。但是，尚不清楚污水和污水影响环境中抗生素抗性基因的丰度增加是由于残留抗生素在现场选择压力所致，还是仅仅是粪便中被耐药菌污染所致。在这里，我们使用crAssphage序列作为人类粪便污染的标志物（crAssphage是一种在人类粪便中异常丰富的噬菌体），在可公开获得的宏基因组学数据中分析了相对抗性基因丰度和粪便污染的伴随程度。我们发现，抗性基因的存在很大程度上可以由粪便污染来解释，在环境中没有明显的选择迹象，除了被制造过程中产生的高水平抗生素污染的环境外，还有明显的选择。我们的结果表明，有必要考虑粪便污染水平，以避免对抗生素耐药性的环境选择做出错误的假设。

Discharge of treated sewage leads to release of antibiotic resistant bacteria, resistance genes and antibiotic residues to the environment. However, it is unclear whether increased abundance of antibiotic resistance genes in sewage and sewage-impacted environments is due to on-site selection pressure by residual antibiotics, or is simply a result of fecal contamination with resistant bacteria. Here we analyze relative resistance gene abundance and accompanying extent of fecal pollution in publicly available metagenomic data, using crAssphage sequences as a marker of human fecal contamination (crAssphage is a bacteriophage that is exceptionally abundant in, and specific to, human feces). We find that the presence of resistance genes can largely be explained by fecal pollution, with no clear signs of selection in the environment, with the exception of environments polluted by very high levels of antibiotics from manufacturing, where selection is evident. Our results demonstrate the necessity to take into account fecal pollution levels to avoid making erroneous assumptions regarding environmental selection of antibiotic resistance.

https://www.nature.com/articles/s41467-018-07992-3