污水处理厂中红霉素抗药性基因的污染特征及选择性因子

采用固相萃取-高效液相色谱串联质谱(SPE-HPLC-MS/MS)检测分析了上海某污水处理厂中12种不同药品和个人护理品(pharmaceutical and personal care products,PPCPs)的含量水平和分布特征,采用实时荧光定量PCR方法定量检测分析了7种红霉素抗药性基因(ERY-ARGs)在污水处理厂中的分布和丰度变化.结果表明,在污水处理厂中共检出5种PPCPs(包括磺胺甲唑、红霉素、四环素、卡马西平和三氯生),浓度范围分别为24.5~38.7、47.5~49.2、43.1~85.4、2.5~3.9和423.2~8 973.3ng·L-1.两段A/O生物处理工艺对三氯生具有较好的去除效果,但对其余4种PPCPs的去除效果较差.与此同时,目标ERY-ARGs在污水处理厂中均被检出,在原水中的丰度达9.28×103(erm A)~1.83×108(ere A)copies·L-1,虽然两段A/O工艺能够显著降低污水中的ERY-ARGs(1.19 log~3.97 log),但其在最终处理出水中的浓度仍然较高.通过相关性分析可知,ERY-ARGs与红霉素和三氯生之间均具有显著相关性(P<0.05),表明污水处理厂中红霉素对ERY-ARGs的产生和传播具有重要影响,而三氯生对ERY-ARGs可能存在交叉选择性作用.

Investigation of Pollution Characteristics of Erythromycin Resistance Genes in a Sewage Treatment Plant and the Relevant Selective Factors

Occurrence and distribution of twelve pharmaceutical and personal care products (PPCPs) were investigated in a sewage treatment plant in Shanghai using solid-phase extraction combined with high-performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS). Quantitative PCR (qPCR) was used to determine the distribution and removal of seven erythromycin resistance genes (ERY-ARGs). The results showed that five PPCPs including sulfamethoxazole, erythromycin, tetracycline, carbamazepine and triclosan were detected in the collected wastewater samples with concentrations in the ranges of 24.5-38.7, 47.5-49.2, 43.1-85.4, 2.5-3.9 and 423.2-8973.3 ng·L^-1, respectively. During the wastewater treatment process, a significant reduction of triclosan was observed, but the removal efficiencies for the other detected PPCPs were relatively low. Additionally, all target ERY-ARGs were detected in the wastewater samples ranging from 9.28×10³ (ermA) to 1.83×10⁸(ereA) copies·L^-1 in raw influent. Though significant reductions (1.19 log-3.97 log) of ERY-ARGs were obtained, their concentrations found in the final effluent were still high. Moreover, the concentration of ERY-ARGs exhibited significant positive correlation with the concentration of erythromycin and triclosan (P<0.05), respectively, elucidating that erythromycin played an important role in the occurrence and spread of ERY-ARGs, while triclosan may confer cross-selection for ERY-ARGs.