摘要

研究表明，在高浓度的抗生素作用下，生物污水处理系统可以诱导和筛选出抗药性。然而，关于在废水处理过程中选择抗生素耐药性的最低抗生素浓度的报道却很少。本文研究了土霉素、链霉素和螺旋霉素在生物膜型废水处理系统中选择抗生素耐药性的最低进水浓度，在606天内，分别将抗生素逐级加入废水中，抗生素用量从0增加到0.1、1、5、25、50mg/L。根据宏基因组测序，链霉素和土霉素在0.1 mg/L剂量下的耐药基因总丰度显著增加（p<0.01），而导致耐药菌比率显著增加的抗生素浓度水平较高（p<0.05）：链霉素为5 mg/L，土霉素为25 mg/L土霉素。虽然随着螺旋霉素剂量的增加，抗性丰度增加，但相应的大环内酯类林可酰胺链球菌素（MLS）抗性基因和耐药菌比例均未明显增加。部分典型对应分析表明，在链霉素和土霉素存在下，细菌群落的迁移和可移动基因元件的改变都有助于抗性基因的富集。对于以革兰氏阳性菌为主要靶点的螺旋霉素，革兰氏阴性菌生物膜固有的优势可能是在螺旋霉素胁迫下MLS抗性决定因子不明确变化的原因所在。结果表明，控制进水链霉素和土霉素浓度在0.1 mg/L以下，可以防止废水处理过程中产生耐药性，为抗生素生产废水的治理提供了一条可行的途径。

It has been demonstrated that antibiotic resistance could be induced and selected under high antibiotic concentrations in biological wastewater treatment systems. However, little is available regarding the minimum concentrations of antibiotics for selecting antibiotic resistance during wastewater treatment. Herein, the minimum influent concentrations of oxytetracycline, streptomycin, and spiramycin in selecting antibiotic resistance in biofilm type wastewater treatment systems were investigated by spiking respective antibiotic into wastewater with an antibiotic dose increasing from 0 to 0.1, 1, 5, 25, 50 mg/L stepwise over a period of 606 days. Significant increase (p < .01) in the total abundance of antibiotic resistance genes was observed for both streptomycin and oxytetracycline at a dose of 0.1 mg/L according to metagenomic sequencing, while the concentration levels leading to significant increases (p < .05) in resistant bacteria ratio were higher: 5 mg/L for streptomycin and 25 mg/L for oxytetracycline. Although resistome abundance increased with the increase of spiramycin dose, neither the corresponding Macrolide-Lincosamide-Streptogramin (MLS) resistance genes nor the resistant bacteria ratio showed perceptible increase. Partial canonical correspondence analysis showed that both bacterial community shift and mobile genetic elements alteration contributed to the enrichment of resistomes under the presence of streptomycin and oxytetracycline. Regarding spiramycin which is mainly targeting on Gram-positive bacteria, the dominance of the intrinsically resisting Gram-negative bacteria in the biofilm microbiota might be responsible for the vague change of MLS resistant determinants under the spiramycin stress. The results demonstrated that it is possible to prevent the development of antibiotic resistance during wastewater treatment by controlling the influent streptomycin and oxytetracyline concentrations below 0.1 mg/L. This work proposed an actionable approach for the management of antibiotic production wastewater.

https://www.sciencedirect.com/science/article/pii/S0048969720310421