Tang Na, Wei Dawei, Zeng Yuan, Zhang Gang, Wang Chao, Feng Jie, Song Yuqin
State Key Laboratory of Microbial Resources, Institute of Microbiology Chinese Academy of Sciences Beijing China.
College of Life Science University of Chinese Academy of Sciences Beijing China.
mLife. 2024 Mar 18;3(1):101-109. doi: 10.1002/mlf2.12114. eCollection 2024 Mar.
Insertion sequences (ISs) promote the transmission of antimicrobial resistance genes (ARGs) across bacterial populations. However, their contributions and dynamics during the transmission of resistance remain unclear. In this study, we selected IS as a representative transposable element to decipher the relationship between ISs and ARGs and to investigate their transfer features and transmission trends. We retrieved 2656 translocatable IS -bounded units with ARGs (tIS-bUs-ARGs) in complete bacterial genomes from the NCBI RefSeq database. In total, 124 ARGs spanning 12 classes of antibiotics were detected, and the average contribution rate of IS to these genes was 41.2%. We found that IS -bounded units (IS-bUs) mediated extensive ARG dissemination within the bacteria of the class, showing strong transfer potential between strains, species, and even phyla. The IS-bUs expanded in bacterial populations over time, and their temporal expansion trend was significantly correlated with antibiotic usage. This wide dissemination could be due to the nonspecific target site preference of IS. Finally, we experimentally confirmed that the introduction of a single copy of IS could lead to the formation of a composite transposon mediating the transmission of "passenger" genes. These observations extend our knowledge of the IS and provide new insights into the mediating role of ISs in the dissemination of antibiotic resistance.
插入序列（ISs）促进了抗菌药物耐药基因（ARGs）在细菌群体中的传播。然而，它们在耐药性传播过程中的作用和动态仍不清楚。在本研究中，我们选择IS作为代表性转座元件，以阐明ISs与ARGs之间的关系，并研究它们的转移特征和传播趋势。我们从NCBI RefSeq数据库的完整细菌基因组中检索到2656个带有ARGs的可转座IS边界单元（tIS-bUs-ARGs）。总共检测到12类抗生素中的124个ARGs，IS对这些基因的平均贡献率为41.2%。我们发现，IS边界单元（IS-bUs）在该类细菌中介导了广泛的ARG传播，在菌株、物种甚至门之间显示出强大的转移潜力。IS-bUs随时间在细菌群体中扩展，其时间扩展趋势与抗生素使用显著相关。这种广泛传播可能是由于IS的非特异性靶位点偏好。最后，我们通过实验证实，引入单个IS拷贝可导致形成复合转座子，介导“乘客”基因的传播。这些观察结果扩展了我们对IS的认识，并为ISs在抗生素耐药性传播中的介导作用提供了新的见解。
