九龙江河口及厦门污水处理设施抗生素抗性基因污染分析

Studies on the pollution levels of antibiotic resistance genes in Jiulong River estuary and wastewater treatment plants in Xiamen

摘要:

【目的】近年来由于抗生素的滥用, 导致了多药物抗性超级细菌的产生, 有关抗生素抗性基因(Antibiotic resistance genes, ARGs)在环境介质中分布、迁移和扩散已经引起人们的广泛关注。针对九龙江河口及厦门污水处理设施抗生素抗性基因污染情况开展研究。【方法】通过定性PCR研究九龙江河口水体、沉积物和厦门污水处理设施活性污泥中4种磺胺类、13种四环素类ARGs及2种整合子基因的污染情况, 并选择四环素类tet(W)基因进行克隆文库测序分析。【结果】除tet(O)和tet(S)外, 其他基因均被检出。不同环境介质中的ARGs及整合子基因检出率为活性污泥(0.86)>沉积物(0.57)>水体(0.24)。在淡水和淡盐水中, sul(l)、int(1)、tet(A)、tet(C)、tet(E)、tet(M)和tet(W)的检出率要高于海水, 表明九龙江上游可能是ARGs的污染源之一。【结论】主成分分析表明污水处理设施是ARGs的高发载体; 沉积物是ARGs的稳定载体; 而水体中的ARGs易于分解。此外, tet(W)基因克隆文库分析表明, 厦门污水处理设施也可能是九龙江河口及厦门沿岸的ARG污染源。

Abstract:

[Objective] Recently, as the prevalence of multiple antibiotic resistant bacteria in environments are induced by the extensive use of antibiotics by human, a better understanding of the distribution, transport and dissemination of antibiotic resistance genes (ARGs) in environments is warranted. The objective of this study was to determine the pollution levels of antibiotic resistance genes in Jiulong River estuary and wastewater treatment plants (WWTPs) in Xiamen. [Methods] Polymerase chain reaction (PCR) assays were employed to identify the distribution patterns of four sulfonamide, thirteen tetracycline ARGs and two integron genes in water, sediments of Jiulong River estuary and five activated sludges in WWTPs of Xiamen. Clone libraries of the tet(W) gene were also generated from three sediments of Jiulong River estuary and five WWTPs in Xiamen. [Results] The all ARGs has been dectected except tet(O) and tet(S). The results demonstrated that the frequency of detection (FOD) of ARGs and integron genes in environmental samples with the highest FOD in activated sludges (0.86), moderate FOD in sediments (0.57) and the lowest FOD in water (0.24). Furthermore, the FODs of sul(l), int(1), tet(A), tet(C), tet(E), tet(M) and tet(W) were higher in freshwater and brackish water than those in seawater, suggesting that ARGs may be transported from the upstream of Jiulong River. [Conclusion] Principle component analysis also supported the suggestions that WWTPs contained the highest ARGs, and ARGs are enriched in sediments but unstable in water. In addition, the results of tet(W) libraries indicated that WWTPs may be a point source of ARGs into Jiulong River estuary and Xiamen sea.