摘要

       ARGs的水平转移通常被认为是通过三种途径介导的，即转化、接合和通过噬菌体的转导，在这三种途径中，噬菌体对环境中基因转移的贡献尚不清楚，甚至还存在疑问。本研究从城市污水处理系统中分离到一株多重耐药大肠杆菌及其噬菌体（YZ1）。噬菌体YZ1的形态和基因组分析结果表明，该噬菌体是自蚜亚科T7病毒属的一员。其基因组在结构和序列上与大肠杆菌噬菌体K1F相似，不编码ARGs。然而，在与ARGs结合的原始测序数据中，有28对成对读取，其中包括促进β-内酰胺、氨基糖苷和氟喹诺酮耐药性的测序数据。定量PCR结果表明，ARGs存在于噬菌体DNA中（约103 拷贝/mL），并在宿主DNA中检测到。结果提示，虽然不常见，但一些携带ARG的转化噬菌体可能是由于耐药菌感染过程中的错误包装而产生的，这可能会造成ARGs水平转移的可能性。

       Horizontal transfer of ARGs was generally considered to be mediated by three methods - transformation, conjugation and transduction through phages - during which the contribution of bacteriophages to gene transfer in the environment is unclear or even questioned. In this study, a multiple-antibiotic-resistant Escherichia coli strain and its phage (YZ1) were isolated from a municipal wastewater treatment system. The results of the morphological and genomic analyses of phage YZ1 showed that it is a member of the T7 viral genus in the subfamily Autographivirinae. Its genome is similar to that of the E. coli phage K1F in both organization and sequence and does not encode ARGs. However, 28 paired reads in the raw sequencing data aligned to ARGs, including those promoting β-lactam, aminoglycoside, and fluoroquinolone resistance, among others. Quantitative PCR showed that ARGs were present in bacteriophage DNA (approximately 10³ copies/mL) and were also detected in the bacterial host DNA. The results suggested that while infrequent, some ARG-carrying transducing phages were presumably generated by erroneous packaging during infection of antibiotic-resistant bacteria, which may create the possibility of horizontal transfer of ARGs.

       https://www.sciencedirect.com/science/article/pii/S0048969718318643?via%3Dihub