摘要

水产养殖中抗生素和重金属的滥用已引起广泛关注，并可能加剧抗性基因在环境中的传播。为了研究抗生素抗性基因（ARG）和重金属抗性基因（HMRG）的发生和增殖，设计了三种常用抗生素（四环素，磺胺，头孢噻肟）和两种重金属（Zn和Cu）包括5个独立的四环素（tet），磺胺（sul），头孢噻肟（cef），Cu，Zn和四环素+磺胺（tet + sul），四环素+磺胺+头孢噻肟（tet + （+ sul + cef），四环素+磺胺+铜（tet + sul + Cu），四环素+磺胺+锌（tet + sul +锌）以及180天实验期对照。对 19个ARG（tetA，tetB，tetC，tetD，tetE，tetG，tetM，tetO，tetQ，tetS，tetW，tetX，tetY，sul1，sul2，sul3，blaDHA，blaMOX，blaFOX），两个HMRG（copA，czcA）和鱼缸水中的1类整合子基因（intI 1）进行了调查。结果表明，抗生素和重金属的残留率分别为0.03％〜2.46％和9.25％〜52.97％，与抗生素初始浓度和种类呈正相关。四环素耐药基因对抗生素更敏感，比磺胺抗药基因和AmpCβ-内酰胺酶耐药基因更易诱导和发展。综合应力暴露池（tet + sul，tet + sul + cef，tet + sul + Cu，tet + sul + Zn）中ARGs的总相对丰度比它们各自的总和大约1.01-1.55倍。头孢噻肟对四环素抗性基因的丰度和多样性的选择性效应强于Zn和Cu。此外，多元相关分析显示tetO，tetQ，tetW和sul3与Cu和Zn浓度呈显着相关（r = 0.882-0.992，p <0.05或p <0.01）。 tetO和intI1（p <0.01），tetW和intI1（p <0.05）以及sul3和intI1（p <0.05）之间的显着相关性暗示了ARG的核糖体保护蛋白基因可能存在严重的不良传播风险。

Abuse of antibiotics and heavy metals in aquaculture has been widely concerned and might aggravate the spread of resistance genes in environment. To investigate the occurrence and proliferation of antibiotic resistance genes (ARGs) and heavy metal resistance genes (HMRGs), three commonly used antibiotics (tetracycline, sulfanilamide, cefotaxime) and two heavy metals (Zn and Cu) were designed to add individually or jointly in nine fish tanks including five individual exposure tanks of tetracycline (tet), sulfanilamide (sul), cefotaxime (cef), Cu, Zn and four combination exposure tanks of tetracycline + sulfanilamide (tet + sul), tetracycline + sulfanilamide + cefotaxime (tet + sul + cef), tetracycline + sulfanilamide + Cu (tet + sul + Cu), tetracycline + sulfanilamide + Zn (tet + sul + Zn) as well as the control during the experiment period of 180 days. Nineteen ARGs (tetA, tetB, tetC, tetD, tetE, tetG, tetM, tetO, tetQ, tetS, tetW, tetX,tetY, sul1, sul2, sul3, blaDHA, blaMOX, blaFOX), two HMRGs (copA, czcA) and the class 1 integron gene (intI 1) in fish tanks water were investigated. The results showed that the residual rate of antibiotics and heavy metals ranged from 0.03% to 2.46% and 9.25%–52.97%, respectively, positively related to their original concentration and types. Tetracycline resistance genes were more sensitive to antibiotics and easier to be induced and developed than sulfanilamide resistance genes and AmpC β-lactamase resistance genes. The total relative abundances of ARGs in combined stresses exposure tanks (tet + sul, tet + sul + cef, tet + sul + Cu, tet + sul + Zn) were about 1.01–1.55 times more than the sum of their individual ones. The co-selective effects of cefotaxime on the abundance and diversity of tetracycline resistance genes were stronger than Zn and Cu. Besides, multivariate correlation analysis revealed that tetO, tetQ, tetW and sul3were in significant correlation with the concentrations of Cu and Zn (r = 0.882–0.992, p < 0.05 or p < 0.01). The significant correlations between tetO and intI1 (p < 0.01), tetW and intI1 (p < 0.05), and sul3 and intI1 (p < 0.05) hinted a potentially serious and undesirable dissemination risk of ribosomal protection proteins gene of ARGs.

https://www.sciencedirect.com/science/article/pii/S0043135417306218