發(fā)布者：抗性基因網(wǎng) 時(shí)間：2023-06-12 瀏覽量：488
摘要
? ? ? 大型污水處理廠每年向地表水中排放數(shù)百噸總懸浮固體。此外，在聯(lián)合下水道系統(tǒng)的情況下，暴雨期間下水道溢流釋放的量相當(dāng)。隨著沉降，附著顆粒的微生物及其抗生素抗性基因（ARGs）隨之被輸送到接收水的河床。為了更好地了解這一過程的動(dòng)力學(xué)，在間歇反應(yīng)器中加入了一種顆粒廢水部分，該反應(yīng)器之前充滿了天然河流沉積物和自來水。同時(shí)，對(duì)抗生素（AB）（紅霉素、四環(huán)素、環(huán)丙沙星、羅紅霉素、青霉素V和磺胺甲惡唑）進(jìn)行加標(biāo)，以研究其選擇耐藥性的能力。使用定量PCR對(duì)水中和沉積物中六種ARG（ermB、tetM、blaTEM、sul1、CTX-M-32和qnrS）以及總細(xì)菌（16S rDNA）的豐度進(jìn)行了為期兩個(gè)月的監(jiān)測(cè)。盡管連續(xù)暴露于AB（每個(gè)5μg/L），但ARGs的豐度仍然不受影響。廢水顆粒的添加導(dǎo)致水中（3-5個(gè)對(duì)數(shù)單位）和沉積物（1-4個(gè)對(duì)數(shù)單位。我們的研究結(jié)果表明，受納河流中ARG豐度的增加是污水處理廠排放或下水道溢流事件中ARG持續(xù)輸入的結(jié)果。它們進(jìn)一步表明，如果去除這種持續(xù)輸入，ARG的升高不會(huì)在接收河流中持續(xù)存在。鑒于在本地人口中觀察到穩(wěn)定的ARGs背景濃度，這似乎僅適用于廢水引入的ARGs。
Abstract
Large-scale wastewater treatment plants (WWTPs) discharge hundreds of tons of total suspended solids (TSS) into surface waters every year. Additionally, a comparable amount is released by sewer overflows during heavy rain events in case of combined sewer systems. Along with sedimentation, particle-attached microorganisms and their antibiotic resistance genes (ARGs) are herewith transported to the riverbed of the receiving water. To better understand the dynamics of this process, a particulate wastewater fraction was added into batch reactors, which were previously filled with natural river sediments and tap water. In parallel, antibiotics (ABs) (erythromycin, tetracycline, ciprofloxacin, roxithromycin, penicillin V, and sulfamethoxazole) were spiked to investigate their capability to select for resistance. The abundance of six ARGs (ermB, tetM, blaTEM, sul1, CTX-M-32, and qnrS) as well as total bacteria (16S rDNA) was monitored in waters and in sediments for a duration of two months using quantitative PCR. Despite a continuous exposure to ABs (5 μg/L each), the abundance of ARGs remained unaffected. Addition of wastewater particles resulted in a sudden and strong increase of ARGs in waters (3–5 log units) and sediments (1–4 log units), however, elevated ARGs underwent a particular and complete decay. Our results indicate that the increased ARG abundances in receiving rivers are the result of a continuous import of ARGs from WWTP discharges or sewer overflow events. They further imply that elevated ARGs do not persist in receiving rivers, if this continuous import is removed. This seems to be the case merely for ARGs introduced by wastewater, given that a stable background concentration of ARGs was observed for the native population.
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https://www.ifg.kit.edu/english/3901_7629.php