摘要

     背景：
     点源，如废水处理厂（WWTPs）通常将其废水排放到河流中。它们的废物可能包括抗生素残留物、消毒剂、抗药性细菌（ARB）和抗药性基因（ARG）。有证据表明ARG存在于自然环境中，但缺乏对特定点源的归属。
     目标：
     本研究的目的是评估智利南部三个污水处理厂通过两条途径释放和传播精氨酸：河流系统和野生鸟类。
     方法：
     进行了纵向研究，从每个污水处理厂的上游和下游收集不同距离的河流沉积物样本。在13个月的时间里，每个月从一个污水处理厂的周围采集一次野生鸟类样本。采用微流控q-PCR方法对48个不同耐药分子机制的基因进行了定量分析，并采用排序法和线性混合回归模型对数据进行了分析。
     结果：
     17个ARG的污水处理厂下游有统计学意义的显著增加（p<0.05），但通过河流的下游扩散尚不清楚。β-内酰胺酶基因blaKPC、blaTEM和blaSHV在鸟类中最为丰富，迁徙物种中blaSHV的丰度高于常住物种（p<0.05）。与污水处理厂基因图谱相比，候鸟和留鸟的基因图谱更为相似。
     结论：
     虽然研究结果表明污水处理厂对河流中ARG丰度有影响，但这种增加的生物学意义和污水处理厂的影响程度尚不清楚。此外，虽然无法确定与特定污水处理厂的关系，但野生鸟类在传播ARGs方面发挥了作用。

BACKGROUND:

Point sources such as wastewater treatment plants (WWTPs) commonly discharge their effluent into rivers. Their waste may include antibiotic residues, disinfectants, antibiotic resistant bacteria (ARB), and Antimicrobial Resistance Genes (ARG). There is evidence that ARG can be found in the natural environment, but attribution to specific point sources is lacking.

OBJECTIVES:

The goal of this study was to assess the release and dissemination of ARG from three WWTPs in southern Chile via two pathways: through the river systems, and through wild birds.

METHODS:

A longitudinal study was conducted, collecting river sediment samples at different distances both upstream and downstream from each WWTP. Wild birds were sampled from around one of the WWTPs once a month for 13 months. A microfluidic q-PCR approach was used to quantify 48 genes covering different molecular mechanisms of resistance, and data was analyzed using ordination methods and linear mixed regression models.

RESULTS:

There was a statistically significant increase downstream from the WWTPs (p < 0.05) for 17 ARG, but the downstream dissemination through the rivers was not clear. Beta-lactamase genes bla_KPC, bla_TEM, and bla_SHV were the most abundant in birds, with higher abundance of bla_SHV in migratory species compared to resident species (p < 0.05). The gene profile was more similar between the migratory and resident bird groups compared to the WWTP gene profile.

CONCLUSIONS:

While results from this study indicate an influence of WWTPs on ARG abundance in the rivers, the biological significance of this increase and the extent of the WWTPs influence are unclear. In addition, wild birds were found to play a role in disseminating ARG, although association to the specific WWTP could not be ascertained.

        https://linkinghub.elsevier.com/retrieve/pii/S1438-4639(19)30702-3