摘要

城市河流受到影响的生态系统可能作为抗生素抗性（AR）细菌的水库发挥重要作用。这项研究的主要目的是描述沿污水污染的城市河流中抗生素耐药性的流行情况。选择Zenne河（比利时）的七个地点来研究1年期间AR大肠杆菌和淡水细菌的流行情况。使用培养依赖的方法来估计对阿莫西林，磺胺甲恶唑，萘啶酮酸和四环素耐药的大肠杆菌和异养细菌。在研究的河流中已经量化了这四种抗生素的浓度。抗生素抗性基因（ARG），sul1，sul2，tetW，tetO，blaTEM和qnrS也在颗粒附着（PAB）和自由生活（FLB）细菌中定量。我们的结果显示，处理过的废水释放对沿河抗生素耐药性的传播有影响。尽管从上游到下游位点观察到AR大肠杆菌和抗性异养菌的丰度增加，但这些差异仅对AR大肠杆菌有意义。 AR大肠杆菌和抗性异养细菌之间也发现显着的正回归。对于颗粒附着（PAB）和自由活菌（FLB），ARG的浓度从上游到下游位点增加。特别是，在穿过城市区域之后观察到的六个ARG中，四个的丰度显着增加。尽管四环素的浓度与四环素抗性基因显着相关，但抗生素水平可能太低而无法解释这种相关性。对于tetO和sul2基因，不同级分中ARG的分析显示PAB与FLB相比显着更高的丰度。这项研究表明，即使在已经受影响的河流中，城市活动也可能增加抗生素耐药性的传播。

Urban rivers are impacted ecosystems which may play an important role as reservoirs for antibiotic-resistant (AR) bacteria. The main objective of this study was to describe the prevalence of antibiotic resistance along a sewage-polluted urban river. Seven sites along the Zenne River (Belgium) were selected to study the prevalence of AR Escherichia coli and freshwater bacteria over a 1-year period. Culture-dependent methods were used to estimateE. coli and heterotrophic bacteria resistant to amoxicillin, sulfamethoxazole, nalidixic acid and tetracycline. The concentrations of these four antibiotics have been quantified in the studied river. The antibiotic resistance genes (ARGs), sul1, sul2, tetW, tetO, blaTEM andqnrS were also quantified in both particle-attached (PAB) and free-living (FLB) bacteria. Our results showed an effect of treated wastewaters release on the spread of antibiotic resistance along the river. Although an increase in the abundance of both AR E. coli and resistant heterotrophic bacteria was observed from upstream to downstream sites, the differences were only significant for AR E. coli. A significant positive regression was also found between AR E. coli and resistant heterotrophic bacteria. The concentration of ARGs increased from upstream to downstream sites for both particle-attached (PAB) and free-living bacteria (FLB). Particularly, a significant increase in the abundance of four among six ARGs analyzed was observed after crossing urban area. Although concentrations of tetracycline significantly correlated with tetracycline resistance genes, the antibiotic levels were likely too low to explain this correlation. The analysis of ARGs in different fractions revealed a significantly higher abundance in PAB compared to FLB for tetO and sul2 genes. This study demonstrated that urban activities may increase the spread of antibiotic resistance even in an already impacted river.

https://www.sciencedirect.com/science/article/pii/S004896971830473X