摘要
目标
大环内酯类药物在动物和人类中的使用历史悠久。从源头到海洋的水道中大环内酯类抗生素耐药性基因（ARGs）的动态尚未报道。
方法
通过培养法测定耐药菌率，并对环境DNA中大环内酯类ARGs、mef（A）、erm（B）、mph（B），mef（C）-mph（G）以及可移动遗传元件（MGEs）traI和IntI1的拷贝数进行定量。通过16S rRNA基因宏基因组测序研究了每个位点的群落组成。在宜兰地区，对抗生素进行了定量。
后果
对台湾南部和北部地区从养猪场到大海的地表水样本进行了监测。在水产养殖池塘和河流中，耐大环内酯类细菌占总菌落形成细菌的3%-28%，而在养猪场废水中，这一比例为26%-100%。在养猪场中经常检测到三种常见的大环内酯ARGs mef（A）、erm（B）和mph（B），以及相对较新的mef（C）-mph（G），但在养殖池塘和海洋中没有检测到。接收养猪废水的河流显示出类似于养猪场的ARG污染。在MGE中，IntI1经常分布在所有位点，并且与mef（A）、erm（B）和mph（B）呈正相关，但与mef（C）-mph（G）不呈正相关。
结论
养猪场是大环内酯类ARGs的来源，尽管大环内酯污染程度较低。由于在北部地区的养猪场中检测到林可霉素，由于对林可霉霉素的交叉耐药性，大环内酯类ARGs的增加是未来关注的问题。水产养殖池塘中的ARGs丰度较低，尽管检测到了MGE。IntI1与ARG的关系表明，ARG与特定MGE的收敛可能是时间/历史相关的。
ABSTRACT
Objectives
Macrolides have a long history of use in animals and humans. Dynamics of macrolide-antibiotic resistance genes (ARGs) in waterways from the origin to the sea has not been reported.

Methods
Resistant bacterial rate was measured by culture method, and copy numbers of macrolide-ARGs, mef(A), erm(B), mph(B), mef(C)-mph(G), and mobile genetic elements (MGEs) traI and IntI1 were quantitated in environmental DNA. Community composition in each site was investigated by 16S rRNA gene metagenomic sequencing. In Yilan area, antibiotics were quantitated.

Results
Surface water samples from pig farms to the sea in southern and northern areas in Taiwan were monitored. Macrolide-resistant bacteria accounted for 3%–28% of total colony-forming bacteria in aquaculture ponds and rivers, whereas in pig farm wastewater it was 26%–100%. Three common macrolide-ARGs mef(A), erm(B), and mph(B) and the relatively new mef(C)-mph(G) were frequently detected in pig farms, but not in aquaculture ponds and the sea. Rivers receiving pig wastewater showed ARG contamination similar to the pig farms. Among the MGEs, IntI1 was frequently distributed in all sites and was positively related to mef(A), erm(B), and mph(B) but not to mef(C)-mph(G).

Conclusion
Pig farms are the origin of macrolide-ARGs, although macrolide contamination is low. Since lincomycin was detected in pig farms in the northern area, the increase of macrolide-ARGs is a future concern due to cross-resistance to lincomycin. ARGs abundance in aquaculture ponds was low, though MGEs were detected. Relation of IntI1 to ARG suggests convergence of ARGs to specific MGEs might be time/history dependent.

https://www.sciencedirect.com/science/article/pii/S2213716522000996