Nanjing Institute of Environmental Science, Ministry of Environmental Protection, Nanjing 210042, China; Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Environmental Protection of China, Nanjing 210042, China.
Chinese Society for Environmental Sciences, Beijing 100082, China.
Sci Total Environ. 2018 Jan 15;612:119-128. doi: 10.1016/j.scitotenv.2017.08.229. Epub 2017 Sep 1.
Pharmaceutical wastewater treatment plants (PWWTPs), which receive wastewater containing extremely high levels of antibiotics, are regarded as potential hot spots for antibiotic-resistance development in the environment. Six sampling campaigns in six PWWTPs in Southeastern China were carried out to assess the prevalence and fate of antibiotic resistance genes (ARGs). Different genes were monitored in different PWWTPs (PWWTP A: lincosamides; PWWTP B: aminoglycosides and macrolides; PWWTP C: quinolones; PWWTP D: macrolides and quinolones; PWWTP E: cephalosporins; and PWWTP F: quinolones and macrolides) using real-time quantitative polymerase chain reactions (PCRs), according to the antibiotic type produced. The levels of typical ARG subtypes in the final effluents ranged from (1.03±0.91)×10 to (6.78±0.21)×10copies/mL. The absolute abundance of ARGs in effluents accounted for 0%-577% of influents to the six PWWTPs with a median value of 6%. Most of the ARGs are transported to the dewatered sludge, with concentrations from (1.38±0.21)×10 to (6.84±0.43)×10copies/g dry weight (dw). In different treatment units (before/after biological units), a clear trend of proliferation or attenuation was not observed for the ARGs, aside from a strong attenuation in moving bed bio-film reactor (MBBR) in PWWTP C. Through correlation analyses, this study demonstrated that the bacterial abundance and antibiotic concentrations within the PWWTPs influenced the fate of the associated ARGs, and this was possibly related primarily to the intrinsic resistance mechanisms of corresponding ARGs. Macrolide ARGs, which tend to locate in plasmids and transposons, positively correlate weakly with total macrolide antibiotic concentrations but positively correlate strongly with 16S rRNA concentrations. Furthermore, ARG concentrations in the wastewater from fermentation were significantly higher than in the wastewater from chemical synthesis and preparation. This is the first comprehensive study on the behavior of antibiotic resistance genes under extremely high-level antibiotic selection pressures in pharmaceutical wastewater treatment plants (PWWTPs) in Southeastern China.
制药废水处理厂（PWWTP）接收含有极高水平抗生素的废水，被认为是环境中抗生素抗性发展的潜在热点。在中国东南部的 6 个 PWWTP 进行了 6 次采样活动，以评估抗生素抗性基因（ARGs）的流行情况和归宿。根据抗生素类型，在不同的 PWWTP 中监测不同的基因（PWWTP A：林可酰胺类；PWWTP B：氨基糖苷类和大环内酯类；PWWTP C：喹诺酮类；PWWTP D：大环内酯类和喹诺酮类；PWWTP E：头孢菌素类；PWWTP F：喹诺酮类和大环内酯类），采用实时定量聚合酶链反应（PCR）。最终流出物中典型的 ARG 亚类水平范围为（1.03±0.91）×10 至（6.78±0.21）×10 拷贝/mL。流出物中 ARG 的绝对丰度占 6 个 PWWTP 进水的 0%-577%，中位数为 6%。大多数 ARG 被运输到脱水污泥中，浓度范围为（1.38±0.21）×10 至（6.84±0.43）×10 拷贝/g 干重（dw）。在不同的处理单元（生物单元前后）中，除了 PWWTP C 中的移动床生物膜反应器（MBBR）表现出强烈的衰减外，ARGs 没有明显的增殖或衰减趋势。通过相关分析，本研究表明，PWWTP 内的细菌丰度和抗生素浓度影响相关 ARG 的归宿，这可能主要与相应 ARG 的固有抗性机制有关。大环内酯类 ARG 倾向于定位在质粒和转座子中，与大环内酯类抗生素的总浓度呈弱正相关，但与 16S rRNA 浓度呈强正相关。此外，发酵废水的 ARG 浓度明显高于化学合成和制剂废水。这是中国东南部制药废水处理厂（PWWTP）在极高水平抗生素选择压力下抗生素抗性基因行为的首次综合研究。
