摘要
      海洋是抗生素耐药性基因（ARGs）的全球宝库。只有少数研究调查了黑海水柱中ARGs的动力学，黑海是一个独特的环境，具有独特的地质、生物学和人为污染历史。在这项研究中，我们分析了两次采样活动（2013年和2019年）的宏基因组数据，这些采样活动在西黑海的三个不同地点收集，深度从5米到2000米不等。这些数据被处理以注释ARGs、金属抗性基因（MRGs）和整合子整合酶基因。ARG在深水层的丰度显著较高，深度是ARG和MRGβ多样性的主要驱动因素。此外，ARG和MRG的丰度强相关（r=0.95）。整合子整合酶基因的丰度和组成不受水深的影响，也与ARG无关。对获得的MAG的分析表明，其中一些携带intI基因以及几种ARG和MRG，这表明存在多药耐药细菌，并且MRG和整合素可能参与ARG的选择。这些结果表明，黑海不仅是ARGs的重要储层，而且它们在深水层中积累，在那里，与MRG的共同选择可以被认为是它们持续存在的相关机制。
Abstract
Seas and oceans are a global reservoir of antibiotic resistance genes (ARGs). Only a few studies investigated the dynamics of ARGs along the water column of the Black Sea, a unique environment, with a peculiar geology, biology and history of anthropogenic pollution. In this study, we analyzed metagenomic data from two sampling campaigns (2013 and 2019) collected across three different sites in the Western Black Sea at depths ranging from 5 to 2000 m. The data were processed to annotate ARGs, metal resistance genes (MRGs) and integron integrase genes. The ARG abundance was significantly higher in the deep water layers and depth was the main driver of beta-diversity both for ARGs and MRGs. Moreover, ARG and MRG abundances strongly correlated (r = 0.95). The integron integrase gene abundances and composition were not influenced by the water depth and did not correlate with ARGs. The analysis of the obtained MAGs showed that some of them harbored intI gene together with several ARGs and MRGs, suggesting the presence of multidrug resistant bacteria and that MRGs and integrons could be involved in the selection of ARGs. These results demonstrate that the Black Sea is not only an important reservoir of ARGs, but also that they accumulate in the deep water layers where co-selection with MRGs could be assumed as a relevant mechanism of their persistence.

https://www.sciencedirect.com/science/article/abs/pii/S0269749122012477