Degradation and Deactivation of Bacterial Antibiotic Resistance Genes during Exposure to Free Chlorine, Monochloramine, Chlorine Dioxide, Ozone, Ultraviolet Light, and Hydroxyl Radical
Degradation and Deactivation of Bacterial Antibiotic Resistance Genes during Exposure to Free Chlorine, Monochloramine, Chlorine Dioxide, Ozone, Ultraviolet Light, and Hydroxyl Radical
复制标题
DOI：
10.1021/acs.est.8b04393
复制
发表时间：
2019-02-19
影响因子：
11.4
通讯作者：
Dodd, Michael C.
中科院分区：
文献类型：
--
作者：
He, Huan;Zhou, Peiran;Dodd, Michael C.
本研究使用多重耐药枯草芽孢杆菌1A 189的染色体ARG（blt），研究了游离有效氯（FAC）、NH 2Cl、O-3、ClO 2和UV光（254 nm）对细胞外和细胞内抗生素耐药基因（eARG和iARG）的降解（通过qPCR测量）和生物失活（通过基于培养物的自然转化测量），以及（OH）-O-中心点对eARG的降解（通过qPCR测量）和生物失活。邻近或包含acfA突变的四个266-1017 bp扩增子的降解速率常数使blt过表达与#AT+GC bps/扩增子成比例地增加，或与#5 '-GG-3'或5 '-TT-3'双联体/扩增子成比例地增加，对于（OH）-O-中心点，相应值范围为0.59至2.3（× 10（11）M-1 s（-1）），在pH 7时，O-3为1.8-6.9（x10（4）s（-1）），FAC为3.9-9.2（x10（3）M-1 s（-1）），ClO 2为0.35-1.2（x10（1）M-1 s（-1）），UV为2.0-8.8（x10（-2）cm（2）/mJ），pH 8时NH 2Cl为1.7-4.4 M（-1）s（-1）。对于FAC、NH 2Cl、O-3、ClO 2和UV，ARG失活导致扩增子降解，该扩增子近似于B中自然转化所需的800-1000 bp acfA侧翼序列。而（OH）-O-中心点的失活超过降解。在实际的消毒剂暴露下，eARGs和iARGs被FAC、O-3和UV降解/失活>= 90%，但对NH 2Cl和ClO 2不敏感。iARG降解/失活始终滞后于细胞失活。这些研究结果提供了一个定量框架，用于评估ARG的命运在消毒/氧化，并支持使用qPCR作为代理跟踪ARG失活仔细选择的情况下。
This work investigated degradation (measured by qPCR) and biological deactivation (measured by culture based natural transformation) of extra- and intracellular antibiotic resistance genes (eARGs and iARGs) by free available chlorine (FAC), NH2Cl, O-3, ClO2, and UV light (254 nm), and of eARGs by (OH)-O-center dot, using a chromosomal ARG (blt) of multidrug-resistant Bacillus subtilis 1A189. Rate constants for degradation of four 266-1017 bp amplicons adjacent to or encompassing the acfA mutation enabling blt overexpression increased in proportion to #AT+GC bps/amplicon, or in proportion to #5'-GG-3' or 5'-TT-3' doublets/amplicon, with respective values ranging from 0.59 to 2.3 (x10(11) M-1 s(-1)) for (OH)-O-center dot, 1.8-6.9 (x10(4) s(-1)) for O-3, 3.9-9.2 (x10(3) M-1 s(-1)) for FAC, 0.35-1.2(x10(1) M-1 s(-1)) for ClO2, and 2.0-8.8 (x10(-2) cm(2)/mJ) for UV at pH 7, and from 1.7-4.4 M(-1)s(-1) for NH2Cl at pH 8. For FAC, NH2Cl, O-3, ClO2, and UV, ARG deactivation paralleled degradation of amplicons approximating a similar to 800-1000 bp acfA-flanking sequence required for natural transformation in B. subtilis, whereas deactivation outpaced degradation for (OH)-O-center dot. At practical disinfectant exposures, eARGs and iARGs were >= 90% degraded/deactivated by FAC, O-3, and UV, but recalcitrant to NH2Cl and ClO2. iARG degradation/deactivation always lagged cell inactivation. These findings provide a quantitative framework for evaluating ARG fate during disinfection/oxidation, and support using qPCR as a proxy for tracking ARG deactivation under carefully selected circumstances.