Antimicrobial resistance (AMR) poses a worldwide threat to human health and biosecurity. The spread of antibiotic resistance genes (ARGs) via conjugative plasmid transfer is a major contributor to the evolution of this resistance. Although permitted as safe food additives, compounds such as saccharine, sucralose, aspartame, and acesulfame potassium that are commonly used as nonnutritive sweeteners have recently been associated with shifts in the gut microbiota similar to those caused by antibiotics. As antibiotics can promote the spread of antibiotic resistance genes (ARGs), we hypothesize that these nonnutritive sweeteners could have a similar effect. Here, we demonstrate for the first time that saccharine, sucralose, aspartame, and acesulfame potassium could promote plasmid-mediated conjugative transfer in three established conjugation models between the same and different phylogenetic strains. The real-time dynamic conjugation process was visualized at the single-cell level. Bacteria exposed to the tested compounds exhibited increased reactive oxygen species (ROS) production, the SOS response, and gene transfer. In addition, cell membrane permeability increased in both parental bacteria under exposure to the tested compounds. The expression of genes involved in ROS detoxification, the SOS response, and cell membrane permeability was significantly upregulated under sweetener treatment. In conclusion, exposure to nonnutritive sweeteners enhances conjugation in bacteria. Our findings provide insight into AMR spread and indicate the potential risk associated with the presence of nonnutritive sweeteners.

抗菌素耐药性 (AMR) 对人类健康和生物安全构成了全球威胁。抗生素抗性基因 (ARG) 通过接合质粒转移的传播是这种抗性进化的主要原因。尽管糖精、三氯蔗糖、阿斯巴甜和乙酰磺胺酸钾等常被用作非营养性甜味剂的化合物被允许作为安全的食品添加剂，但最近它们与肠道微生物群的变化有关，类似于抗生素引起的变化。由于抗生素可以促进抗生素抗性基因 (ARG) 的传播，我们假设这些非营养性甜味剂可能具有类似的效果。在这里，我们首次证明糖精、三氯蔗糖、阿斯巴甜、和乙酰磺胺酸钾可以促进相同和不同系统发育菌株之间三种已建立的结合模型中质粒介导的结合转移。实时动态偶联过程在单细胞水平上可视化。暴露于测试化合物的细菌表现出增加的活性氧 (ROS) 产生、SOS 反应和基因转移。此外，在暴露于测试化合物的情况下，两种亲代细菌的细胞膜通透性都增加了。在甜味剂处理下，参与 ROS 解毒、SOS 反应和细胞膜通透性的基因表达显着上调。总之，接触非营养性甜味剂会增强细菌的结合。