摘要
      抗微生物耐药性基因（ARGs）和毒力因子基因（VFGs）对公众健康构成严重威胁，据预测，气候变化将影响携带ARGs和VFGs的细菌病原体的增加。然而，对冻土区细菌病原体及其ARGs和VFGs的研究却受到了有限的关注。在这项研究中，将宏基因组方法应用于一项综合调查，以检测活动层和永久冻土中潜在的ARGs、VFGs和携带ARGs和VFGs的致病性抗生素抗性细菌（PARB）。总体而言，在北极永久冻土区检测到70种针对18种抗菌药物类别的独特ARG和599种VFG，分类为38种毒力因子。鉴定了8个携带ARGs的具有移动遗传元件（MGE）的基因；大多数MGE被归类为噬菌体。在宏基因组组装的基因组中，证实了15个PARB的存在。土壤剖面显示，下层土壤中ARGs和VFGs的百万转录物（TPM）值显著低于表层土壤。基于每个基因的TPM值，鉴定了北极永久冻土区PARB中的主要ARG、VFG和这些基因，并确认了它们的分布。确定了ARGs、VFGs和PARB的主要宿主细菌。将ARGs和VFG的百分比同一性分布与参考数据库进行比较表明，北极土壤中的ARGs或VFG与先前鉴定的基因不同。我们的研究结果可能有助于了解北极永久冻土区PARB中ARGs、VFG和这些基因的特征和分布。这一发现表明，北极永久冻土区可能是ARGs、VFG和PARB的潜在储层。如果这些基因因全球变暖而被永久冻土融化释放并传播到其他地区，可能会对人类健康构成新的威胁。
Abstract
Antimicrobial resistance genes (ARGs) and virulence factor genes (VFGs) constitute a serious threat to public health, and climate change has been predicted to affect the increase in bacterial pathogens harboring ARGs and VFGs. However, studies on bacterial pathogens and their ARGs and VFGs in permafrost region have received limited attention. In this study, a metagenomic approach was applied to a comprehensive survey to detect potential ARGs, VFGs, and pathogenic antibiotic resistant bacteria (PARB) carrying both ARGs and VFGs in the active layer and permafrost. Overall, 70 unique ARGs against 18 antimicrobial drug classes and 599 VFGs classified as 38 virulence factors were detected in the Arctic permafrost region. Eight genes with mobile genetic elements (MGEs) carrying ARGs were identified; most MGEs were classified as phages. In the metagenome-assembled genomes, the presence of 15 PARB was confirmed. The soil profile showed that the transcripts per million (TPM) values of ARGs and VFGs in the sub-soil horizon were significantly lower than those in the top soil horizon. Based on the TPM value of each gene, major ARGs, VFGs, and these genes in PARB from the Arctic permafrost region were identified and their distribution was confirmed. The major host bacteria for ARGs and VFGs and PARB were identified. A comparison of the percentage identity distribution of ARGs and VFGs to reference databases indicated that ARGs and VFGs in the Arctic soils differ from previously identified genes. Our results may help understand the characteristics and distribution of ARGs, VFGs, and these genes in PARB in the Arctic permafrost region. This findings suggest that the Arctic permafrost region may serve as potential reservoirs for ARGs, VFGs, and PARB. These genes could pose a new threat to human health if they are released by permafrost thawing owing to global warming and propagate to other regions.

https://www.sciencedirect.com/science/article/abs/pii/S0269749121022168