Physical linkage of Tn3 and part of Tn1721 in a tetracycline and ampicillin resistance plasmid from Salmonella Typhimurium
Physical linkage of Tn3 and part of Tn1721 in a tetracycline and ampicillin resistance plasmid from Salmonella Typhimurium
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DOI：
10.1093/jac/dkh553
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发表时间：
2005-04-01
影响因子：
5.2
通讯作者：
Schwarz, S
中科院分区：
文献类型：
--
作者：
Pasquali, F;Kehrenberg, C;Schwarz, S
目的：克隆肠道沙门氏菌肠亚种（Salmonella enterica subsp.测定了介导四环素类和氨苄青霉素抗性的肠道血清型鼠伤寒沙门氏菌。方法：将质粒pFPTB 1转化大肠杆菌JM 109，经酶切后，将重叠片段克隆到大肠杆菌JM 109中，经酶切鉴定，获得重组质粒pFPTB 1。coli质粒载体并测序。结果：质粒pFPTB 1含有一个完整的Tn 3样转座子，全长4950 bp，由左末端重复序列、Tn 3相关的转座基因tnpR和tnpA、一个新的氨苄青霉素抗性基因bla（TEM-135）和右末端重复序列组成。紧接着下游，检测到Tn 1721样转座子右端的末端5215 bp，包括右端重复序列、截短的转座酶基因以及四环素抗性基因泰特（A）和tetR。一个5 bp的直接重复，TAAAA，被认为是紧上游的Tn 3部分和紧下游的Tn 1721部分。结论：质粒pFPTB 1是目前国内少数几个测序完整的肺炎克雷伯菌质粒之一。具有一种新的转座子样结构，由含有氨苄青霉素抗性bla（TEM-135）基因的Tn 3相关部分和含有四环素抗性tetR-tet（A）基因的Tn 1721相关部分组成。
Objectives: The complete nucleotide sequence of the 12 656 bp plasmid pFPTB1 from Salmonella enterica subsp. enterica serovar Typhimurium, which mediates resistance to tetracyclines and ampicillin, was determined. The plasmid was analysed for potential reading frames and structural features indicative of transposons and transposon relics.Methods: Plasmid pFPTB1 was transformed into Escherichia coli JM109, overlapping restriction fragments were cloned into E. coli plasmid vectors and sequenced. In vitro susceptibility testing was carried out to confirm the resistance phenotype mediated by this plasmid.Results: Plasmid pFPTB1 contains a complete Tn3-like transposon of 4950 bp consisting of the left terminal repeat, Tn3-related tnpR and tnpA genes for transposition functions, a novel gene for ampicillin resistance bla(TEM-135), and the right terminal repeat. Immediately downstream, the terminal 5215 bp at the right end of a Tn1721-like transposon, including the right terminal repeat, a truncated transposase gene, as well as the genes tet(A) and tetR for tetracycline resistance, were detected. A 5 bp direct repeat, TAAAA, was seen immediately upstream of the Tn3 part and immediately downstream of the Tn1721 part. Plasmid pFPTB1 also carries a replication region similar to that of the Klebsiella pneumoniae plasmid pJHCMW1.Conclusion: Plasmid pFPTB1 is one of the few completely sequenced plasmids from S. Typhimurium and harbours a novel transposon-like structure consisting of a Tn3-related part containing the bla(TEM-135) gene for ampicillin resistance and a Tn1721-related part containing the tetR-tet(A) genes for tetracycline resistance.