School of Molecular and Microbial Biosciences, The University of Sydney, NSW 2006, Australia; The ithree institute, University of Technology Sydney, Ultimo 2007, NSW, Australia.
School of Molecular and Microbial Biosciences, The University of Sydney, NSW 2006, Australia.
Drug Resist Updat. 2018 Nov;41:26-39. doi: 10.1016/j.drup.2018.10.003. Epub 2018 Nov 2.
In multiply resistant Acinetobacter baumannii, complex transposons located in the chromosomal comM gene carry antibiotic and heavy metal resistance determinants. For one type, known collectively as AbaR, the ancestral form, AbaR0, entered a member of global clone 1 (GC1) in the mid 1970s and continued to evolve in situ forming many variants. In AbaR0, antibiotic and mercuric ion resistance genes are located between copies of a cadmium-zinc resistance transposon, Tn6018, and this composite transposon is in a class III transposon, Tn6019, carrying arsenate/arsenite resistance genes and five tni transposition genes. The antibiotic resistance genes in the AbaR0 and derived AbaR3 configurations are aphA1b, bla, catA1, sul1, tetA(A), and cassette-associated aacC1 and aadA1 genes. These genes are in a specific arrangement of fragments from well-known transposons, e.g. Tn1, Tn1721, Tn1696 and Tn2670, that arose in an IncM1 plasmid. All known GC1 lineage 1 isolates carry AbaR0 or AbaR3, which arose around 1990, or a variant derived from one of them. Variants arose via deletions caused by one of three internal IS26s, by recombination between duplicate copies of sul1 or Tn6018, or by gene cassette addition or replacement. A few GC2 isolates also carry an AbaR island with different cassette-associated genes, aacA4 and oxa20.
在多重耐药的鲍曼不动杆菌中，位于染色体 comM 基因中的复杂转座子携带抗生素和重金属抗性决定因子。对于一种被称为 AbaR 的类型，其原始形式 AbaR0 在 20 世纪 70 年代中期进入了全球克隆 1（GC1）的一个成员中，并在原位继续进化，形成了许多变体。在 AbaR0 中，抗生素和汞离子抗性基因位于镉-锌抗性转座子 Tn6018 的两个拷贝之间，而这个复合转座子位于携带砷酸盐/亚砷酸盐抗性基因和五个 tni 转位基因的 III 类转座子 Tn6019 中。AbaR0 和衍生的 AbaR3 构型中的抗生素抗性基因是 aphA1b、bla、catA1、sul1、tetA(A)和与盒相关的 aacC1 和 aadA1 基因。这些基因位于来自著名转座子的片段的特定排列中，例如 Tn1、Tn1721、Tn1696 和 Tn2670，这些转座子出现在 IncM1 质粒中。所有已知的 GC1 谱系 1 分离株携带 AbaR0 或 AbaR3，这两种变体大约在 1990 年出现，或者是由它们之一衍生而来的变体。变体是由三个内部 IS26 之一引起的缺失、sul1 或 Tn6018 的重复拷贝之间的重组、基因盒的添加或替换引起的。少数 GC2 分离株也携带带有不同与盒相关基因 aacA4 和 oxa20 的 AbaR 岛。
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