Different IncI1 plasmids from Escherichia coli carry IS Ecp1-blaCTX-M-15 associated with different Tn 2 -derived elements

Publication date: Available online 27 April 2015 Source:Plasmid Author(s): Zhiyong Zong , Andrew N. Ginn , Hana Dobiasova , Jonathan R. Iredell , Sally R. Partridge The bla CTX-M-15 gene, encoding the globally dominant CTX-M-15 extended-spectrum β-lactamase, has generally been found in a 2.971-kb ISEcp1-bla CTX-M-15-orf477Δ transposition unit, with ISEcp1 providing a promoter. In available IncF plasmid sequences from Escherichia coli, this transposition unit interrupts a truncated copy of transposon Tn2 that lies within larger multiresistance regions. In E. coli, bla CTX-M-15 is also commonly associated with IncI1 plasmids and here three such plasmids from E. coli clinical isolates from western Sydney 2006–2007 have been sequenced. The plasmid backbones are organised similarly to those of other IncI1 plasmids, but have insertions and/or deletions and sequence differences. Each plasmid also has a different insertion carrying bla CTX-M-15. pJIE113 (IncI1 sequence type ST31) is almost identical to plasmids isolated from the 2011 E. coli O104:H4 outbreak in Europe, where the typical bla CTX-M-15 transposition unit interrupts a complete Tn2 inserted directly in the plasmid backbone. In the novel plasmid pJIE139 (ST88), ISEcp1-bla CTX-M-15-orf477Δ lies within a Tn2/3 hybrid transposon. Homologous recombination could explain movement of ISEcp1-bla CTX-M-15-orf477Δ between copies of Tn2 on IncF and IncI1 plasmids and generation of the Tn2/3 hybrid. pJIE174 (ST37) is al...
Source: Plasmid - Category: Biotechnology Source Type: research