摘要

从人为来源向环境中传播抗生素抗性细菌，对公众健康构成了新的威胁。抗生素抗性基因（ARG）和基因捕获系统如整合子相关整合酶基因（intI）在微生物群落的改变和抗生素抗性细菌向环境中的传播中起关键作用。为了评估人为活动对不列颠哥伦比亚省西南部流域的影响，在农业，城市影响和受保护流域的微生物组中分析了推定的抗生素抗性和整合酶基因的存在。使用宏基因组学方法和高通量定量PCR（HT qPCR）筛选抗性元件，包括ARG和intI。细菌基因组DNA的宏基因组测序用于表征1年内流域中存在的微生物群落的抗性组。相对于微生物群体，ARG的患病率较低（<1％）。对宏基因组序列的分析在所有流域位置检测到总共60个抗性元件，包括46个ARG，intI1和groEL / intI1基因和12个季铵化合物（qac）抗性基因。与城市和受保护的流域相比，农业受影响流域的ARG的相对丰度和丰富度最高。在干旱月份，在受影响的流域（城市和农业）中观察到下游运输模式。与其他报告相似，本研究发现intI1和ARGs（例如sul1）之间存在密切关联，这种关联可用作人类活动的代表。三种主要抗生素水样的化学分析均低于检测限。然而，受影响地点的ARG的高丰度和基因拷贝数（GCN）表明，即使在水柱中低浓度的抗微生物剂，流出物对微生物群落的影响也在发生。在为期一年的宏基因组研究中，抗生素抗性和整合酶基因表明，ARG主要受来自农业和城市流域人为化地点的环境因素驱动。土地利用和水质参数等环境因素占流域地区变异的45％。

The dissemination of antibiotic resistant bacteria from anthropogenic sources into the environment poses an emerging public health threat. Antibiotic resistance genes (ARGs) and gene-capturing systems such as integron-associated integrase genes (intI) play a key role in alterations of microbial communities and the spread of antibiotic resistant bacteria into the environment. In order to assess the effect of anthropogenic activities on watersheds in southwestern British Columbia, the presence of putative antibiotic resistance and integrase genes was analyzed in the microbiome of agricultural, urban influenced, and protected watersheds. A metagenomics approach and high-throughput quantitative PCR (HT qPCR) were used to screen for elements of resistance including ARGs and intI. Metagenomic sequencing of bacterial genomic DNA was used to characterize the resistome of microbial communities present in watersheds over a 1-year period. There was a low prevalence of ARGs relative to the microbial population (<1%). Analysis of the metagenomic sequences detected a total of 60 elements of resistance including 46 ARGs, intI1, and groEL/intI1 genes and 12 quaternary ammonium compounds (qac) resistance genes across all watershed locations. The relative abundance and richness of ARGs was found to be highest in agriculture impacted watersheds compared to urban and protected watersheds. A downstream transport pattern was observed in the impacted watersheds (urban and agricultural) during dry months. Similar to other reports, this study found a strong association between intI1 and ARGs (e.g., sul1), an association which may be used as a proxy for anthropogenic activities. Chemical analysis of water samples for three major groups of antibiotics was below the detection limit. However, the high richness and gene copy numbers (GCNs) of ARGs in impacted sites suggest that the effects of effluents on microbial communities are occurring even at low concentrations of antimicrobials in the water column. Antibiotic resistance and integrase genes in a year-long metagenomic study showed that ARGs were driven mainly by environmental factors from anthropogenized sites in agriculture and urban watersheds. Environmental factors such as land-use and water quality parameters accounted for 45% of the variability observed in watershed locations.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5938356/