摘要
      动物滥用抗生素可诱导抗生素抗性基因（ARGs）和抗生素抗性细菌（ARB）的产生，安赛蜜钾（ACE）是动物饲料中广泛使用的人工甜味剂。一般来说，ACE和ARB经常共存于牲畜废水中，然而，ACE和ARB共存对ARGs传播的影响仍然未知。在本研究中，评估了ACE对垂直基因转移（VGT）和水平基因转移（HGT）的影响。对于VGT，ACE可能通过阻断ARB的生长来阻碍sul基因在假单胞菌HLS-6中的传播。对于HGT（从大肠杆菌DH5α到假单胞菌HLS-6），环境相关的ACE浓度可以促进偶联转移。HGT的潜在机制以细胞膜通透性增强、活性氧过量产生、SOS反应、能量供应为特征，相关基因转录水平的变化进一步证实了这一点。有趣的是，在ACE处理的交配系统中，首次发现供体菌株中的细胞内Mg2+作为接合发生的指标。这项研究可能为ACE在ARGs增殖中的作用提供新的见解，并强调其潜在的环境影响。
Abstract
The abuse of antibiotics on animals could induce the development of antibiotic resistant genes (ARGs) and antibiotic resistant bacteria (ARB), and acesulfame potassium (ACE) is the widely used artificial sweetener in animal feed. Generally speaking, ACE and ARB often coexist in livestock wastewater, however, the impact of the co-occurrence of ACE and ARB on the transmission of ARGs is still unknown. In this study, the effects of ACE on vertical gene transfer (VGT) and horizontal gene transfer (HGT) were both evaluated. For VGT, ACE may hinder the spread of sul gene in Pseudomonas HLS-6 by blocking ARB growth. As for HGT (from Escherichia coli DH5α to Pseudomonas HLS-6), environmentally relevant ACE concentration could facilitate the conjugative transfer. The underlying mechanisms of HGT were characterized by enhanced cell membrane permeability, reactive oxygen species overproduction, SOS response, energy supply, which were all further verified by the changes in transcription levels of related genes. Interestingly, intracellular Mg2+ in donor strain was found for the first time as an indicator for the conjugation occurrence in ACE treated mating system. This study may provide new insights into the role of ACE on ARGs proliferation and highlight its potential environmental impacts.

https://www.sciencedirect.com/science/article/abs/pii/S0304389421019105