Four different integrative recombination events involved in the mobilization of the gonococcal 5.2kb beta-lactamase plasmid pSJ5.2 in Escherichia coli

Abstract

We identified and characterized four different recombination mechanisms involved in the cointegrative transfer of the Neisseria gonorrhoeae beta-lactamase plasmid pSJ5.2 by the gonococcal 41 kb tet(M) and the Gram negative self-transmissible plasmids N3 and R64 drd-33 using an Escherichia coli recA-background. Mobilization of pSJ5.2 by the tet(M) plasmid occurred by cointegration through a replicative transposition of two IS1 elements inserted upstream from the betalactamase gene of pSJ5.2 and creating a IS1::beta-lactamase hybrid promoter. Two types of recombinational events occurred within the 1.8 kb BamH1-HindIII fragment of pSJ5.2 with the N3 and R64 plasmids. A non-homologous recombination was found at coordinates 1817 and 2849 of pSJ5.2 with sequences from R64. A non-homologous recombination combined with an IS26-mediated one-ended transposition was found at coordinates 1817 and 3010 of pSJ5.2 with N3. In both recombinational events, a deletion of over 1 kb of pSJ5.2 occurred. The fourth recombination event was detected in the 1.0 kb BamH1-HindIII fragment of pSJ5.2 by homologous recombination between DNA from the truncated Tn3 resolvase gene of pSJ5.2 and the resolvase sequences from R64 and N3.

A Survey of Drug Resistance bla Genes Originating from Synthetic Plasmid Vectors in Six Chinese Rivers

“…The plasmid is an extra-chromosomal DNA molecule associated with prokaryotes and some unicellular organisms, which carries a variety of resistance genes and plays an important role in genetic diffusion of the resistance phenotypes. − Such exchange of genomic information has been shown to occur via conjugation and transformation processes, as well as through the actions of transposons and integrons. ,− Plasmids have been exploited as experimental tools to facilitate rapid and efficient genetic engineering. To improve transforming efficiency and clone yields, synthetic plasmid vectors were developed with series of selectable genetic markers, − among which antibiotic resistance sequences proved especially useful .…”

There are three major Neisseria gonorrhoeae β-lactamase plasmid variants which are associated with specific lineages and carry distinct TEM alleles

“…p bla .3 transfer has been reported [67], and co-integration into pConj, mediated by IS 1 , was described as a transfer mechanism of p bla .3 in E. coli [53, 68]. However, IS 1 is not found in the gonococcal genome, and further experiments are required to investigate possible mechanisms for p bla .3 transfer.…”

“…The deletion of the mob region indicates this variant might not be mobilised by pConj, with the observed distribution resulting from clonal expansion of the Ng_cgc_400. pbla.3 transfer has been reported [67], and co-integration into pConj, mediated by IS1, was described as a transfer mechanism of pbla.3 in E. coli [53,68]. However, IS1 is not found in the gonococcal genome, and further experiments are required to investigate possible mechanisms for pbla.3 transfer.…”