AbaR-type genomic islands (AbaRs) are prevalent and associated with multiple antimicrobial resistance in Acinetobacter baumannii. AbaRs feature varied structural configurations involving different but closely related backbones with acquisition of diverse mobile genetic elements (MGEs) and antimicrobial resistance genes. This study aimed to understand the structural modulation patterns of AbaRs. A total of 442 intact AbaRs, including nonresistance but closely related islands, were mapped to backbones Tn6019, Tn6022, Tn6172/Tn6173, and AbGRI1-0 followed by alien sequence characterization. Genetic configurations were then examined and compared. The AbaRs fall into 53 genetic configurations, among which 26 were novel, including one Tn6019-type, nine Tn6022-type, three Tn6172/Tn6173-type, nine AbGRI1-type, and four new transposons that could not be mapped to the known backbones. The newly identified genetic configurations involved insertions of novel MGEs like ISAcsp2, ISAba42, ISAba17, and ISAba10, novel structural modulations driven by known MGEs such as ISCR2, Tn2006, and even another AbaR, and different backbone deletions. Recombination events in AbGRI1-type elements were also examined by identifying hybrid sequences from different backbones. Moreover, we found that the content and context features of AbaRs including the profiles of the MGEs driving the plasticity of these elements and the consequently acquired antimicrobial resistance genes, insertion sites, and clonal distribution displayed backbone-specific patterns. This study provides a comprehensive view of the genetic features of AbaRs.

中文翻译：

---

AbaR型基因组孤岛的比较分析揭示了具有不同骨干元素的遗传特征的独特模式。

AbaR型基因组岛（AbaRs）在鲍曼不动杆菌中普遍存在并与多种抗药性有关。AbaRs具有多种结构构型，涉及不同但密切相关的骨架，并具有多种移动遗传元件（MGE）和抗菌素耐药基因。这项研究旨在了解AbaRs的结构调制模式。总共442个完整的AbaR（包括非抗性但密切相关的岛）被映射到主干Tn 6019，Tn 6022，Tn 6172 / Tn 6173和AbGRI1-0，然后进行外来序列表征。然后检查和比较遗传结构。AbaRs属于53种遗传构型，其中26种是新颖的，包括1个Tn 6019型，9个Tn 6022型，3个Tn 6172 / Tn 6173型，9个AbGRI1型和4个无法定位的新转座子。到已知的骨干网。新近确定的遗传结构涉及插入新的MGE如IS Acsp2，IS Aba42，IS Aba17和IS Aba10，由已知MGE如IS CR2，Tn 2006驱动的新颖结构调节，甚至另一个AbaR，以及不同的骨架删除。还通过鉴定来自不同骨架的杂合序列来检查AbGRI1型元件中的重组事件。此外，我们发现AbaRs的内容和背景特征，包括驱动这些元素可塑性的MGEs的概况以及因此获得的抗菌素耐药基因，插入位点和克隆分布均显示了骨干特异性模式。这项研究提供了对AbaRs遗传特征的全面了解。