摘要
      废水处理厂（WWTP）不断接收包括药物在内的各种污染物，是抗生素耐药性基因（ARGs）的潜在宿主。这有利于通过水平基因转移开发耐多药细菌（MRB）。在2020年9月和2021年1月收集了来自五种不同污水处理厂工艺的样本，以监测在八种不同抗生素存在下的ARG耐药性和可培养的MRB。基于纳米孔的ARG丰度和细菌群落分析表明，ARG的积累有利于MRB的产生。活性污泥和混合污泥往往具有较低的细菌多样性和ARG丰度，因为在曝气过程中有利于特定微生物生长的选择性力。富含WWTP的大肠杆菌菌株（高达71%）在所有样本中占主导地位，而氯单胞菌物种仅在厌氧消化的污泥样本中高度丰富（60%-79%）。两种ARG类型[磺酰胺抗性基因（sul1）和氨基糖苷类抗性基因（aadA1、aadA13和aadA2）]在所有过程中普遍存在。在好氧污水处理厂过程中，可培养MRB的总计数逐渐增加，如Niabella、Enterococcus、Bacillus和Chryseobacterium物种。从样本中分离出的所有MRB的基因组分析显示，肠球菌属的耐药组携带最多的ARGs（7-18个ARGs），通常编码ant（6）-la、lnu（B）、erm（B）和tet（S/M）。另一方面，在没有ARGs的情况下，Niablella菌株可能具有内在抗性表型。所有MRB都具有源自相同移动遗传元件的ARGs，这表明WWTP是ARGs迁移和MRB出现的热点。
Abstract
Wastewater treatment plants (WWTPs) constantly receive a wide variety of contaminants, including pharmaceuticals, and are potential reservoirs of antibiotic resistance genes (ARGs). This favors the development of multidrug-resistant bacteria (MRB) through horizontal gene transfer. Samples from five different WWTP processes were collected in September 2020 and January 2021 to monitor ARG resistomes and culturable MRB in the presence of eight different antibiotics. Nanopore-based ARG abundance and bacterial community analyses suggested that ARG accumulation favors the generation of MRB. Activated and mixed sludges tended to have lower bacterial diversity and ARG abundance because of selective forces that favored the growth of specific microorganisms during aeration processes. Escherichia strains enriched in WWTPs (up to 71%) were dominant in all the samples, whereas Cloacamonas species were highly abundant only in anaerobically digested sludge samples (60%–79%). Two ARG types [sulfonamide resistance genes (sul1) and aminoglycoside resistance genes (aadA1, aadA13, and aadA2)] were prevalent in all the processes. The total counts of culturable MRB, such as Niabella, Enterococcus, Bacillus, and Chryseobacterium species, gradually increased during aerobic WWTP processes. Genomic analyses of all MRB isolated from the samples revealed that the resistome of Enterococcus species harbored the highest number of ARGs (7–18 ARGs), commonly encoding ant(6)-la, lnu(B), erm(B), and tet(S/M). On the other hand, Niablella strains possibly had intrinsic resistant phenotypes without ARGs. All MRB possessed ARGs originating from the same mobile genetic elements, suggesting that WWTPs are hotspots for the migration of ARGs and emergence of MRB.

https://www.sciencedirect.com/science/article/abs/pii/S0048969721074088