Bacteriophages play integral roles in the ecosystem; however, their precise involvement in horizontal gene transfer and the spread of antibiotic resistance genes (ARGs) are not fully understood. In this study, a coculture system involving consortia of bacteriophages and multidrug-resistant bacteria from an aerobic tank in a municipal wastewater treatment plant (WWTP) was established to investigate the functions of bacteriophages in ARG transfer and spread. The results of the cocultivation of the MRB and bacteriophage consortia indicated that the bacterial community remained stable throughout the whole process, but the addition of bacteriophages significantly increased ARG abundance, especially in bacteriophage DNA. Nine out of the 11 identified ARGs significantly increased, indicating that more bacteriophage particles carried ARGs in the system after cocultivation. In addition, 686 plasmids were detected during cocultivation, of which only 3.36 % were identified as conjugative plasmids, which is significantly lower than the proportion found among previously published plasmids (25.2 %, totaling 14,029 plasmids). Our findings revealed that bacteriophages may play important roles in the horizontal transfer of ARGs through both bacteriophage-mediated conduction and an increase in extracellular ARGs; however, conjugative transfer may not be the main mechanism by which multidrug-resistant bacteria acquire and spread ARGs. Unlike in most previous reports, a coculture system of diverse bacteria and bacteriophages was established in this study to assess bacteriophage functions in ARG transfer and dissemination in the environment, overcoming the limitations associated with the isolation of bacteria and bacteriophages, as well as the specificity of bacteriophage hosts.

中文翻译：

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噬菌体在促进城市污水处理厂抗生素耐药基因水平转移中的作用


噬菌体在生态系统中起着不可或缺的作用;然而，它们参与水平基因转移和抗生素耐药基因 （ARG） 传播的确切参与尚不完全清楚。在这项研究中，建立了一个涉及城市污水处理厂 （WWTP） 好氧罐的噬菌体和多重耐药细菌联盟的共培养系统，以研究噬菌体在 ARG 转移和传播中的功能。MRB 和噬菌体联合体的共培养结果表明，细菌群落在整个过程中保持稳定，但噬菌体的加入显著提高了 ARG 丰度，尤其是在噬菌体 DNA 中。鉴定出的 11 种 ARGs 中有 9 种显著增加，表明共培养后系统中携带 ARGs 的噬菌体颗粒更多。此外，在共培养过程中检测到 686 个质粒，其中只有 3.36% 被鉴定为共轭质粒，这明显低于在以前发表的质粒中发现的比例（25.2%，共 14,029 个质粒）。我们的研究结果表明，噬菌体可能通过噬菌体介导的传导和细胞外 ARGs 的增加在 ARGs 的水平转移中发挥重要作用;然而，结合转移可能不是多重耐药细菌获得和传播 ARGs 的主要机制。与之前的大多数报道不同，本研究建立了多种细菌和噬菌体的共培养系统，以评估噬菌体在 ARG 在环境中转移和传播的功能，克服了与细菌和噬菌体分离相关的限制，以及噬菌体宿主的特异性。