The intensive use of silver nanoparticles (AgNPs) in cosmetics and textiles causes their release into sewer networks of urban water systems. Although a few studies have investigated antimicrobial activities of nanoparticles against environmental bacteria, little is known about potential impacts of the released AgNPs on sulfate reducing bacteria in sewers. Here, we investigated the effect of AgNPs on Desulfovibrio vulgaris Hidenborough (D. vulgaris), a typical sulfate-reducing bacterium (SRB) in sewer systems. We found AgNPs stimulated the proliferation of D. vulgaris, rather than exerting inhibitory or biocidal effects. Based on flow cytometer detections, both the cell growth rate and the viable cell ratio of D. vulgaris increased during exposure to AgNPs at concentrations of up to 100 mg/L. The growth stimulation was dependent on the AgNP concentration. These results imply that the presence of AgNPs in sewage may affect SRB abundance in sewer networks. Our findings also shed new lights on the interactions of nanoparticles and bacteria.

银纳米颗粒（AgNPs）在化妆品和纺织品中的大量使用导致其释放到城市供水系统的下水道网络中。尽管少数研究已经研究了纳米颗粒对环境细菌的抗菌活性，但对释放的AgNPs对下水道中硫酸盐还原细菌的潜在影响知之甚少。在这里，我们调查了AgNPs对下水道系统中典型的硫酸盐还原菌（SRB）的Desulfovibrio vulgaris Hidenborough（D. vulgaris）的影响。我们发现AgNPs刺激了D. vulgaris的增殖，而不是发挥抑制作用或杀生物作用。根据流式细胞仪检测，寻常小球藻的细胞生长速率和活细胞比率在暴露于浓度高达100 mg / L的AgNPs期间增加。生长刺激取决于AgNP浓度。这些结果表明污水中存在AgNPs可能会影响下水道网络中SRB的丰度。我们的发现也为纳米颗粒与细菌之间的相互作用提供了新的思路。