摘要

微生物对环境中的抗生素残留物的生物降解可能导致抗生素抗性基因（ARG）的产生，这对人类健康非常重要。本研究的目的是确定抗生素多西环素（DOX）的降解能力与微生物中抗性基因的发展之间是否存在关联。我们从蔬菜田中分离和鉴定了10个菌株，这些菌株长期接受肥料施肥并能够在一系列DOX浓度（25,50,80和100 mg / L）下存活。我们的结果表明，DOX降解能力与具有高DOX降解能力的分离微生物之间抗性基因的发育之间没有证据相关性（P> 0.05）。这是基于大肠杆菌的事实。和假丝酵母菌属。是最有效的降解DOX的菌株（分别为92.52％和91.63％），但是他们的四环素抗性基因在7天实验中表现出相对较低的抗生素抗性风险。此外，这两种优势细菌所携带的核糖体保护蛋白基因的tetM高出其他分离株的5倍（P <0.05）。除埃希氏菌属外，三种分离株的DOX和tet抗性基因的Ct / C0之间的Pearson相关性。和念珠菌属（Candida sp。）显示出显着的负相关性（P <0.05），这主要是因为在DOX降解过程中tetG显着增加。我们的结果得出结论，抗生素残留物的生物降解可能不一定会导致ARG在环境中的发展。另外，我们分离出的两种细菌，即埃希氏菌属。和假丝酵母属（Candida sp。），都是潜在的环保细菌工程候选者。

Biodegradation of antibiotic residues in the environment by microorganisms may lead to the generation of antibiotic resistance genes (ARGs), which are of great concern to human health. The aim of this study was to determine whether there is a relationship between the ability to degrade antibiotic doxycycline (DOX) and the development of resistance genes in microorganisms. We isolated and identified ten bacterial strains from a vegetable field that had received long-term manure application as fertilizer and were capable of surviving in a series of DOX concentrations (25, 50, 80, and 100 mg/L). Our results showed no evidential correlation between DOX degradation ability and the development of resistance genes among the isolated microorganisms that had high DOX degradation capability (P > 0.05). This was based on the fact that Escherichia sp. andCandida sp. were the most efficient bacterial strains to degrade DOX (92.52% and 91.63%, respectively), but their tetracycline resistance genes showed a relatively low risk of antibiotic resistance in a 7-day experiment. Moreover, the tetM of the ribosomal protection protein genes carried by these two preponderant bacteria was five-fold higher than that carried by other isolates (P < 0.05). Pearson correlations between the Ct/C0 of DOX and tet resistance genes of three isolates, except for Escherichia sp. and Candidasp., showed remarkable negative correlations (P < 0.05), mainly because tetG markedly increased during the DOX degradation process. Our results concluded that the biodegradation of antibiotic residues may not necessarily lead to the development of ARGs in the environment. In addition, the two bacteria that we isolated, namely,Escherichia sp. and Candida sp., are potential candidates for the engineering of environmentally friendly bacteria.

https://www.sciencedirect.com/science/article/pii/S0147651317305948