IncI1 plasmids are known disseminators of the extended-spectrum cephalosporin resistance (ESC) gene bla_CTX-M-1, among species of the Enterobacteriaceae family. In several IncI1 plasmids, this gene was found incorporated into the transposition unit, ISEcp1-bla_CTX-M-1-orf477, interrupting a shufflon region, a hallmark of IncI1 conjugative plasmids. The shufflon diversifies pilV gene that encodes the adhesine-type protein found on the tip of the conjugative pilus. To further elucidate the shufflon rearrangement, we examined to what extent the shufflon rearrangement was affected by the transposition-unit insertion. As expected, the interrupted shufflons generated a lower number of shufflon variants and exhibited an altered segment-deletion pattern compared to the non-interrupted shufflon. Interestingly, segment-loss frequency of the interrupted shufflons was distinctive in different plasmid hosts. Finally, the analysis of the 3′ end of the pilV gene revealed that shufflon rearrangement favoured segment A to complete pilV partial open reading frame regardless of the shufflon. Thereby, it could be assumed that the A-segment has greater importance during conjugation, however, this remained a hypothesis. Further exploration of shufflon rearrangement and its importance in the plasmid-recipient selection during conjugation would be beneficial as the knowledge could be applied in developing a strategy to limit IncI1 mediated antimicrobial resistance dissemination.

IncI1 质粒是肠杆菌科物种中广谱头孢菌素抗性 (ESC) 基因bla _{CTX-M-1 的}已知传播者。在几个 IncI1 质粒中，发现该基因并入转座单元 IS Ecp1-bla _CTX-M-1 -orf477 中，中断了 shufflon 区域，这是 IncI1 接合质粒的标志。shufflon 使pilV多样化编码在接合菌毛尖端发现的粘附素型蛋白质的基因。为了进一步阐明 shufflon 重排，我们检查了 shufflon 重排在多大程度上受转座单元插入的影响。正如预期的那样，与非中断的 shufflon 相比，中断的 shufflon 产生了较少数量的 shufflon 变体，并表现出改变的片段删除模式。有趣的是，在不同的质粒宿主中，被打断的 shufflons 的片段丢失频率是不同的。最后，对pilV基因3' 端的分析表明，shufflon 重排有利于片段 A 完成pilV无论shufflon如何，部分开放阅读框。因此，可以假设 A 段在缀合过程中具有更大的重要性，然而，这仍然是一个假设。进一步探索 shufflon 重排及其在结合过程中质粒受体选择中的重要性将是有益的，因为这些知识可用于制定限制 IncI1 介导的抗微生物药物耐药性传播的策略。