發(fā)布者：抗性基因網(wǎng) 時間：2023-06-12 瀏覽量：454
摘要
目標(biāo)
印第安納州耐多藥（MDR）腸炎沙門氏菌血清型的出現(xiàn)引起了全球的關(guān)注。移動遺傳元件（MGE）在加速細(xì)菌群落中抗性基因的傳播方面發(fā)揮著至關(guān)重要的作用。該研究旨在提高我們對潛在耐藥性機(jī)制的理解，并表征耐多藥印第安納分離株中的MGE。
方法
在此，我們報道了一種耐多藥致病性印第安納S.Indiana分離株的特征。測定了S.Indiana QT6365的抗菌藥敏模式。通過全基因組測序分析了染色體和質(zhì)粒的基因組結(jié)構(gòu)、血清型和多基因座序列類型。通過反向聚合酶鏈反應(yīng)和測序證實了來源于IS26側(cè)翼轉(zhuǎn)座子的環(huán)狀。
后果
S.Indiana QT6365對除氨曲南、阿米卡星、多粘菌素和替加環(huán)素外的所有測試的抗菌藥物均表現(xiàn)出耐藥性，被定義為MDR，屬于ST17。S.Indiana QT6365與食物資源S.Indiana C629親緣關(guān)系密切，具有相似的抗性基因圖譜。多重抗性基因主要由位于染色體上的新型轉(zhuǎn)座子Tn7540和IncHI2/HI2A/N質(zhì)粒攜帶。序列分析和形成的環(huán)狀中間體表明，Tn7540可能通過IS26結(jié)合的可易位單元（IS26-fosA-IS26-intI1-dfrA12-aadA2-sul1-ISCR1-blaNDM-9-IS26）的同源重組產(chǎn)生。
結(jié)論
據(jù)我們所知，這是首次從人類標(biāo)本中分離到印第安納州南部具有blaNDM-9和fosA3的新型染色體轉(zhuǎn)座子，這可能有助于抗性基因的傳播，應(yīng)該引起人們的重視。
ABSTRACT
Objectives
Emergence of multidrug-resistant (MDR) Salmonella enterica serovar Indiana has raised global concern. Mobile genetic elements (MGEs) play vital roles in accelerating the dissemination of resistance genes in bacteria communities. The study aims to improve our understanding of the underlying resistance mechanisms and characterize the MGEs in a MDR S. Indiana isolate.
Methods
Here, we report the characteristics of a MDR pathogenic S. Indiana isolate. The antimicrobial susceptibility pattern of S. Indiana QT6365 was determined. The genomic structure of the chromosome and the plasmid, serotype, and multi-locus sequence type were analysed by whole genome sequencing. The circular form derived from IS26-flanked transposon was confirmed by reverse polymerase chain reaction and sequencing.
Results
S. Indiana QT6365 exhibited resistance to all tested antimicrobials except for aztreonam, amikacin, polymyxin, and tigecycline, was defined as MDR, and belonged to ST17. S. Indiana QT6365 was closely related with food resource S. Indiana C629 with similar resistance gene profiles. Multiple resistance genes are mainly carried by a novel transposon Tn7540 located on the chromosome and an IncHI2/HI2A/N plasmid. Sequence analysis and the formed circular intermediate suggested Tn7540 might be generated through homologous recombination by IS26-bounded translocatable units (IS26-fosA-IS26-intI1-dfrA12-aadA2-sul1-ISCR1-blaNDM-9-IS26).
Conclusions
To the best of our knowledge, this is the first report of the novel chromosomal transposon possessing blaNDM-9 and fosA3 in S. Indiana isolated from human specimen, which might facilitate the dissemination of resistance genes and should arouse serious awareness.
https://www.sciencedirect.com/science/article/pii/S2213716523000176