摘要:
抗性基因的转移传播使得污水处理厂成为其重要的储存库,对人类健康存在潜在风险。实验采用序批式厌氧反应器,温度设定分别为15℃、中温(30℃和36℃)、高温(50℃和60℃),探究温度对污泥厌氧条件下8种抗生素去除效果的影响,以及四环素类抗性基因(tet A、tet G、tet L、tet M、tet O、tet Q、tet W、tet X)、磺胺类抗性基因(sul I、sul II)和Ⅰ类整合子整合酶基因(intI 1)的行为特征。研究发现温度升高有利于抗生素及抗性基因的去除,15℃、中温和高温下总抗生素的平均去除率分别为45%、59%和78%;15℃、中温和高温下四环素类抗性基因分别削减0.52 log、0.90 log和1.50 log,磺胺类抗性基因分别削减0.56log、0.78 log和1.31 log。相关性分析发现,总抗性基因与总氮、氨氮、SCOD(溶解性COD)均存在显著相关性(R2=0.744、0.760、0.315,P<0.05),而与总磷无显著相关性(P>0.05)。intI 1与总氮、氨氮、SCOD皆存在显著相关性(R2=0.698、0.795、0.269,P<0.05),而与总磷无显著相关性(P>0.05)。说明微生物生长环境中的营养元素一定程度上影响着抗性基因的传播和扩散。
关键词:
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抗生素
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抗性基因
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厌氧环境
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温度
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序批式
Abstract:
Sewage treatment plant became the important storage depot of antibiotic resistance genes (ARGs) because of the transfer and spread of ARGs, which may bring the potential risk to human health. In this study, sequencing batch anaerobic digestion is the main experimental method. Operating temperatures of anaerobic condition were 15℃, 30℃, 36℃, 50℃ and 60℃. In the process, liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) was taken to analyze 8 kinds of antibiotics concentrations in the sludge samples. The abundances of tetracycline resistance genes (tet A, tet G, tet L, tet M, tet O, tet Q, tet W, tet X), sulfonamide resistance genes (sul I, sul II) and class 1 integron (intI 1) were quantified by real-time polymerase chain reaction. The results showed that the degradation rate of antibiotics increased as the temperature increased. The average removal rates of total antibiotics under 15℃, mesophilic condition (30℃, 36℃) and thermophilic condition (50℃, 60℃) were 45%, 59% and 78%, respectively. The reductions of total tet genes under 15℃, mesophilic condition and thermophilic condition were 0.52 log, 0.90 log and 1.50 log, while for sul genes the reductions were 0.56 log, 0.78 log and 1.31 log, respectively. Correlation analysis showed, total resistance genes had positive correlations with TN, NH3-N and SCOD (R2=0.744, 0.760 and 0.315, P<0.05), while they had no correlations with TP (P>0.05). intI 1 had positive correlations with TN, NH3-N and SCOD (R2=0.698, 0.795 and 0.269, P<0.05), while they had no correlations with TP (P>0.05). Nutrient elements in environment influenced the transfer and spread of ARGs in a degree.
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