Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China.
Environ Int. 2019 Apr;125:117-124. doi: 10.1016/j.envint.2019.01.054. Epub 2019 Feb 1.
Biofilter, an essential water treatment process, is reported to be the harbor of bacterial antibiotic resistance genes (ARGs). Due to the oligotrophic characteristic of source water, filter biofilm is largely influenced by the concentration of organic carbon. The objective of this study was to investigate the effect of organic carbon concentration on shaping bacterial antibiotic resistome in filter biofilm. Our study was based on pilot-scale sand filters, and we investigated the antibiotic resistome using high-throughput qPCR. A total of 180 resistance genes from eight categories of antibiotics were detected in 15 biofilm samples of three sand filters. The results indicated that higher concentration of influent organic carbon led to lower diversity of bacterial community and richness of antibiotic resistance genes (ARGs) in biofilm. We discovered a negative correlation (p ≤ 0.01) between the richness of ARGs and the corresponding TOC level. Moreover, the absolute abundance of ARGs was positively correlated (p ≤ 0.05) with the abundance of 16S rRNA gene and was determined by the organic carbon concentration. Sand filters with gradient influent organic carbon concentration led to the formation of different antibiotic resistomes and canonical correspondence analysis (CCA) indicated that difference in bacterial community composition was likely the main reason behind this difference. We also observed a similar trend in the relative abundance of ARGs, which increased with the depth of sand filters. However, this trend was more pronounced in filters with low organic carbon concentrations. Overall, this study revealed that the organic carbon concentration determined the absolute abundance of ARGs and also shaped the diversity and relative abundance of ARGs in drinking water sand filters. These results may provide new insights into the mechanism of persistent bacterial antibiotic resistance in drinking water treatment.
生物滤池是一种重要的水处理工艺，据报道是细菌抗生素抗性基因（ARGs）的宿主。由于原水的贫营养特性，滤料生物膜很大程度上受到有机碳浓度的影响。本研究旨在探讨有机碳浓度对滤料生物膜中细菌抗生素抗性组形成的影响。我们的研究基于中试规模的砂滤池，使用高通量 qPCR 研究抗生素抗性组。在三个砂滤池的 15 个生物膜样本中检测到了来自八种抗生素类别的 180 个抗性基因。结果表明，较高浓度的进水有机碳导致生物膜中细菌群落多样性和抗生素抗性基因（ARGs）丰富度降低。我们发现 ARGs 的丰富度与相应的 TOC 水平呈负相关（p≤0.01）。此外，ARGs 的绝对丰度与 16S rRNA 基因的丰度呈正相关（p≤0.05），并受有机碳浓度的影响。具有梯度进水有机碳浓度的砂滤池导致形成不同的抗生素抗性组，典范对应分析（CCA）表明细菌群落组成的差异可能是造成这种差异的主要原因。我们还观察到 ARGs 的相对丰度也呈现出类似的趋势，随着砂滤池深度的增加而增加。然而，这种趋势在有机碳浓度较低的滤池中更为明显。总的来说，本研究揭示了有机碳浓度决定了 ARGs 的绝对丰度，同时也塑造了饮用水砂滤池中 ARGs 的多样性和相对丰度。这些结果可能为饮用水处理中持久性细菌抗生素抗性的机制提供新的见解。
