Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection
Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection
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DOI：
10.3390/w9070547
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发表时间：
2017-07-01
期刊：
影响因子：
3.4
通讯作者：
Sei, Kazunari
中科院分区：
文献类型：
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作者：
Furukawa, Takashi;Jikumaru, Atsushi;Sei, Kazunari
本研究的目的是阐明使用氯化（一种广泛用于各种水处理设施的消毒方法）对万古霉素耐药肠球菌（VRE）的抗生素耐药基因（vanA）的灭活效果。通过将 VRE 添加到磷酸盐缓冲盐水或废水处理厂的灭菌二级废水中来制备 VRE 悬浮液。灭活实验在几种氯浓度和搅拌时间下进行。测定了肠球菌浓度和 vanA 的存在。肠球菌浓度随着氯浓度和搅拌次数的增加而降低，在0.5 mg Cl-2/L搅拌40 min、1.0 mg Cl-2/L搅拌20 min、3.0 mg Cl-2/L搅拌3 min条件下，肠球菌浓度降低7.0以上。在二级污水中悬浮VRE的灭活实验中，可培养的肠球菌比悬浮VRE的情况需要更高的氯浓度和更长的处理时间才能完全消毒。然而，VRE 的所有氯化悬浮液中均检测到了 vanA，即使在培养基琼脂平板上不存在肠球菌菌落的样品中也是如此。氯消毒无法破坏抗生素抗性基因，但它可以灭活并减少抗生素抗性细菌（ARB）的细菌数量。因此，建议可将氯消毒池后灭活的细菌细胞中残留的ARB和/或抗生素抗性基因排放到水环境中。
The aim of this study was to elucidate the inactivation effects on the antibiotic-resistance gene (vanA) of vancomycin-resistant enterococci (VRE) using chlorination, a disinfection method widely used in various water treatment facilities. Suspensions of VRE were prepared by adding VRE to phosphate-buffered saline, or the sterilized secondary effluent of a wastewater treatment plant. The inactivation experiments were carried out at several chlorine concentrations and stirring time. Enterococci concentration and presence of vanA were determined. The enterococci concentration decreased as chlorine concentrations and stirring times increased, with more than 7.0 log reduction occurring under the following conditions: 40 min stirring at 0.5 mg Cl-2/L, 20 min stirring at 1.0 mg Cl-2/L, and 3 min stirring at 3.0 mg Cl-2/L. In the inactivation experiment using VRE suspended in secondary effluent, the culturable enterococci required much higher chlorine concentration and longer treatment time for complete disinfection than the cases of suspension of VRE. However, vanA was detected in all chlorinated suspensions of VRE, even in samples where no enterococcal colonies were present on the medium agar plate. The chlorine disinfection was not able to destroy antibiotic-resistance genes, though it can inactivate and decrease bacterial counts of antibiotic-resistant bacteria (ARB). Therefore, it was suggested that remaining ARB and/or antibiotic-resistance gene in inactivated bacterial cells after chlorine disinfection tank could be discharged into water environments.