摘要

在多重抗性鲍曼不动杆菌中，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簇。对于一种类型，统称为AbaR，祖先形式AbaR0在20世纪70年代中期进入全球克隆1（GC1）的成员并继续原位进化形成许多变体。在AbaR0中，抗生素和汞离子抗性基因位于镉 - 锌抗性转座子Tn6018的拷贝之间，并且该复合转座子位于III类转座子Tn6019中，携带砷酸盐/亚砷酸盐抗性基因和5个tni转座基因。 AbaR0和衍生的AbaR3构型中的抗生素抗性基因是aphA1b，blaTEM，catA1，sul1，tetA（A）和盒相关的aacC1和aadA1基因。这些基因是来自众所周知的转座子的片段的特定排列，例如，在IncM1质粒中产生的Tn1，Tn1721，Tn1696和Tn2670。所有已知的GC1谱系1分离株携带AbaR0或AbaR3，其在1990年左右出现，或者衍生自其中之一的变体。通过三个内部IS26之一引起的缺失，通过重复拷贝的sul1或Tn6018之间的重组，或通过添加或替换基因盒，产生变体。一些GC2分离株还携带具有不同盒相关基因aaA4和oxa20的AbaR岛。

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, blaTEM, 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.

https://www.ncbi.nlm.nih.gov/pubmed/30472242