摘要

       抗生素抗性细菌 (ARB) 和抗生素抗性基因 (ARG) 是新出现的环境问题污染物。活性污泥中的异养细菌在污水处理厂 (WWTP) 中具有重要作用。然而，WWPTs 过程中可培养的异养 ARB 和 ARGs 的命运仍不清楚。在本研究中，我们研究了来自三个污水处理厂进水和出水的可培养异养细菌的抗生素抗性表型，并分析了 ARB 和来自缺氧、厌氧和好氧隔室的活性污泥中的 13 个 ARG。从三个工厂的每个进水或出水样品中，随机测试 200 个分离株对 12 种抗生素的敏感性。在这些样本中，5% 到 64% 的分离株显示出对 >9 种抗生素的耐药性，并且来自流出液的分离株中的 >9 种耐药菌的比例低于进水分离株。在来自一个污水处理厂的进水 (n = 94) 和出水 (n = 94) 的 188 个分离物中鉴定出 18 个属。在进水和出水样品中均检测到 6 个属（气单胞菌属、芽孢杆菌属、赖氨酸杆菌属、微杆菌属、普罗维登西亚属和葡萄球菌属）。革兰氏阴性和阳性分离株分别在流入物和流出物中占主导地位。除 sulA 和 CTX-M 外，进水 ARB 中检测到的 13 个四环素、磺胺、链霉素和 β-内酰胺抗性基因的频率高于出水，而一般而言，活性污泥中 ARG 的丰度来自三株植物中的两株在需氧隔间中高于缺氧隔间，表明过量的雪橇和/或无法培养的细菌中存在大量的 ARG。这些发现可能有助于阐明污水处理厂对 ARB 和 ARG 的影响。

       Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are emerging contaminants of environmental concern. Heterotrophic bacteria in activated sludge have an important role in wastewater treatment plants (WWTPs). However, the fate of cultivable heterotrophic ARB and ARGs in WWPTs process remains unclear. In the present study, we investigated the antibiotic-resistant phenotypes of cultivable heterotrophic bacteria from influent and effluent water of three WWTPs and analysed thirteen ARGs in ARB and in activated sludge from anoxic, anaerobic and aerobic compartments. From each influent or effluent sample of the three plants, 200 isolates were randomly tested for susceptibility to 12 antibiotics. In these samples, between 5% and 64% isolates showed resistance to >9 antibiotics and the proportion of >9-drug-resistant bacteria was lower in isolates from effluent than from influent. Eighteen genera were identified in 188 isolates from influent (n = 94) and effluent (n = 94) of one WWTP. Six genera (Aeromonas, Bacillus, Lysinibacillus, Microbacterium, Providencia, and Staphylococcus) were detected in both influent and effluent samples. Gram-negative and -positive isolates dominated in influent and effluent, respectively. The 13 tetracycline-, sulphonamide-, streptomycin- and β-lactam-resistance genes were detected at a higher frequency in ARB from influent than from effluent, except for sulA and CTX-M, while in general, the abundances of ARGs in activated sludge from two of the three plants were higher in aerobic compartments than in anoxic ones, indicating abundant ARGs exit in the excess sledges and/or in uncultivable bacteria. These findings may be useful for elucidating the effect of WWTP on ARB and ARGs.
https://www.sciencedirect.com/science/article/abs/pii/S0045653515002891