强氯精对对虾养殖用水中抗生素抗性基因的影响

Effect of trichloroisocyanouracic acid on antibiotic resistance genes in aquaculture water of shrimp

为探讨渔用氧化剂——强氯精(三氯异氰脲酸,C_(3)Cl_(3)N_(3)O_(3))对养殖水体环境中抗生素抗性基因(Antibiotic resistant genes,ARGs)的去除并控制其传播的可行性,采用实时荧光定量PCR技术,分别对近海水源水、蓄水沉淀池水体、氧化消毒后养殖备用水中的ARGs浓度进行为期29 d的监测分析,其中氧化消毒时的强氯精使用质量浓度为40 mg·L^(−1)。测定的ARGs包括sul1、sul2、tetX、tetM、floR、cmlA和qnrA 7种养殖环境中常见的ARGs。结果显示,sul1、sul2、floR及tetX为上述3种水样中的优势ARGs。近海水源水中ARGs的种类数量及总浓度均最高;蓄水沉淀池水体中ARGs的总浓度低于水源水,sul2和floR的浓度分别较水源水降低了0.86和0.34 lg;经氧化消毒后水体中ARGs的总浓度也有所下降,sul2和floR的浓度与水源水相比分别降低了1.58和1.30 lg。可见,近海水源水是池塘环境中ARGs的主要来源,使用强氯精对其进行氧化消毒,可明显降低水体中常见ARGs水平,有助于防控ARGs在养殖环境中的传播。

In order to explore the feasibility of removing and controlling the spread of antibiotic resistant genes(ARGs)by the fishing oxidant trichloroisocyanuric acid(C_(3)Cl_(3)N_(3)O_(3))in the aquaculture water environment,we applied the real-time quantitative PCR to monitor and determine the ARGs concentrations in the offshore source water,storage water of sedimentation tank and reserved water after oxidation and disinfection for 29 d.The final concentration of trichloroisocyanuric acid used for oxidation and disinfection was 40 mg·L^(−1).The target ARGs were commonly found in the aquaculture environments,including sul1,sul2,tetX,tetM,floR,cmlA and qnrA.The results show that sul1,sul2,floR and tetX were the dominant ARGs among the above mentioned water samples.The number of types and total concentration of ARGs were the highest in offshore source water.The total concentrations of ARGs in the storage water of sedimentation tank were lower than those in the offshore source water,especially that the concentrations of sul2 and floR were 0.86 and 0.34 lg lower than those in the offshore source water,respectively.After the oxidation and disinfection by trichloroisocyanuric acid,the total concentrations of ARGs in the reserved water decreased,and compared with the offshore source water,the concentrations of sul2 and floR decreased by 1.58 and 1.30 lg,respectively.The results indicate that offshore source water is the main source of ARGs in the aquaculture environment.Oxidation and disinfection treatment on offshore source water with trichloroisocyanuric acid can reduce the concentrations of common ARGs in the aquaculture water significantly,which is helpful to prevent and control the spread of ARGs in aquaculture environments.