Evolution in situ of ARI-A in pB2-1, a type 1 IncC plasmid recovered from Klebsiella pneumoniae, and stability of Tn4352B
Evolution in situ of ARI-A in pB2-1, a type 1 IncC plasmid recovered from Klebsiella pneumoniae, and stability of Tn4352B
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DOI：
10.1016/j.plasmid.2017.10.001
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发表时间：
2017-11-01
期刊：
影响因子：
2.6
通讯作者：
Hall, Ruth M.
中科院分区：
文献类型：
--
作者：
Harmer, Christopher J.;Hall, Ruth M.
IncC质粒pB 2 -1，来自1995年之前在布里斯班回收的肺炎克雷伯氏菌分离株，属于1型IncC质粒的亚型，这里称为Ia型，其包括携带碳青霉烯抗性基因如bla（NDM）和bla（KPC）的那些。pB 2 -1在rhs 1基因中携带2358 bp的缺失，该缺失在其它四种1a型IncC质粒中发现。pB 2 -1赋予对氨苄青霉素、庆大霉素、卡那霉素、新霉素、妥布霉素、磺胺甲恶唑、四环素和甲氧苄啶的抗性。它以每个供体4.7 × 10 ~（-3）个转移接合子的频率转移，类似于另一种Ia型质粒pDGO 100，但比其最接近的亲戚pRMH 760低10倍。这种差异可能是由于TraL中的单个氨基酸取代。pB 2 -1在dsbC基因中具有ISEc 52插入，表明dsbC对于转移不是必需的。pB 2 -1缺少ARI-B插入，因此缺少sul 2基因。抗性基因sell、dfrA 10、aphA 1a、bla（TEM）、aad B和tetA（B）都在ARI-A岛中，其构型是从pRMH 760的ARI-A经两步进化而来的。从catA 1基因延伸到pDUmer模块末端的10.3 kb片段通过两个拷贝的IS 4321之间的同源重组丢失。另外，从IS 1326延伸至Tn 4352 B左端的5.3kb片段被替换为一端由IS 1和另一端由IS 26界定的含泰特（B）的18.7kb片段。转座子Tn 4352 B在K. pneumoniae中观察到的高不稳定性相反。杆菌
The IncC plasmid pB2-1, from a Kiebsiella pneumoniae isolate recovered in Brisbane prior to 1995, belongs to a subtype of type 1 IncC plasmids, here designated type la, that includes those carrying carbapenem resistance genes such as bla(NDM) and bla(KPC). pB2-1 carries a 2358 bp deletion in the rhs1 gene found in four other type la IncC plasmids. pB2-1 confers resistance to ampicillin, gentamicin, kanamycin, neomycin, tobramycin, sulfamethoxazole, tetracycline and trimethoprim. It transferred at a frequency of 4.7 x 10(-3) transconjugants per donor, similar to that of another type la plasmid pDGO100 but ten-fold lower than for its closest relative pRMH760. This difference may be due to a single amino acid substitution in TraL. pB2-1 has an ISEc52 insertion in the dsbC gene, demonstrating that dsbC is not essential for transfer. pB2-1 lacks the ARI-B insertion and hence the sul2 gene. The resistance genes sell, dfrA10, aphA1a, bla(TEM), aadB, and tetA(B) are all in the ARI-A island, in a configuration that has evolved from ARI-A of pRMH760 in two steps. A 10.3 kb segment extending from the catA1 gene to the end of pDUmer module was lost via homologous recombination between two copies of IS4321. In addition, a 5.3 kb segment extending from IS1326 to the left end of Tn4352B was replaced with an 18.7 kb tet (B)-containing segment bounded on one end by IS1 and on the other by IS26. The IS26-bounded transposon Tn4352B was shown to be stable in K. pneumoniae in contrast to the high instability observed in E. coli.