纳米氧化物降低屎肠球菌对四环素的耐受能力  

The Tolerance of Enterococcus faecium to Tetracycline Reduced by Nano-metal Oxides

作　　者：林群超 王艺 施慧敏 侯高林 张熠璨 袁青彬 LIN Qunchao;WANG Yi;SHI Huimin;HOU Gaolin;ZHANG Yican;YUAN Qingbin(College of Environmental Science and Technology,Nanjing Tech University,Nanjing 211816,China)

机构地区：[1]南京工业大学环境科学与工程学院,江苏南京211816

出　　处：《环境科学与技术》2022年第8期24-30,共7页Environmental Science & Technology

基　　金：国家自然科学基金项目(42177348);江苏省自然科学基金(BK20201367);国家级大学生创新创业训练计划项目成果(202110291037Z)。

摘　　要：纳米材料的大量生产和使用使其在环境中广泛存在,其生态环境效应受到广泛关注。在污水处理过程中,纳米材料和另一类新污染物——耐药细菌及其基因充分接触和相互作用,但对纳米材料如何影响耐药细菌的研究却十分有限。该研究考察了4种纳米氧化物(nTiO_(2)、nCuO、nZnO和nAl_(2)O_(3))对污水中耐四环素屎肠球菌的耐受抗生素能力的影响,并探索了纳米氧化物浓度、粒径和赋存时间等因素的影响机制。结果表明,所有纳米氧化物均造成耐四环素屎肠球菌EC_(50)(四环素的耐受能力)显著下降,其中nTiO_(2)(100 mg/L)、nCuO(100 mg/L)对耐四环素屎肠球菌耐药能力的影响较大,使EC_(50)下降44.1%和41.6%,而nZnO(10 mg/L)、nAl_(2)O_(3)(10 mg/L)使EC_(50)下降较小(36.9%和24.8%);纳米氧化物浓度越高,颗粒粒径越大,在污水中赋存时间越长,对耐四环素屎肠球菌EC_(50)下降的影响越显著。纳米氧化物溶解释放的金属离子具有毒性,与耐药细菌接触后诱导细胞产生应激反应破坏细胞膜,细胞通透性提高,抗生素更容易进入,因此细菌对抗生素的耐受能力下降。The massive production and consumption of nanomaterials results in their wide occurrence in the environment,is triggering extensive concerns on the potential ecological and environmental effects.During wastewater treatment processes,nanomaterials fully contact and interact with another emerging contaminants,antibiotic resistant bacteria(ARB)and related genes.However,studies on how nanomaterials affect ARB is very limited.This study investigated the effects of four kinds of nano-metal oxides(NMOs)(nTiO_(2),nCuO,nZnO and nAl_(2)O_(3))on the antibiotic tolerance potential tetracycline resistant Enterococcus faecium in wastewater,and explored the influence and mechanism of NMOs’concentration,size and storage period of nano-oxides.Results showed that all NMOs reduced the antibiotic concentration for EC_(50)(50%of maximal effect)of tetracycline resistant Enterococcus faecium,and nTiO_(2)(100 mg/L)and nCuO(100 mg/L)decreased EC_(50) of tetracycline resistant Enterococcus faecium more significantly(44.1%and 41.6%)than nZnO(10 mg/L)and nAl_(2)O_(3)(10 mg/L)(36.9% and24.8%).In addition,the influence on the decrease of EC_(50) increased with the exposure concentration,size and storage period.In terms of the mechanism,nano-oxides released toxic metal ions by dissolution,which interacted with ARB and induced bacterial stress response.Consequently,cell membrane was destroyed and cell permeability was improved,leading to the easier entrance for antibiotics and thus the reduction in bacterial resistance to antibiotics.

关 键 词：耐药细菌 金属纳米氧化物 半抑制浓度 细胞膜通透性 

分 类 号：X171.1[环境科学与工程—环境科学]