Different IncI1 plasmids from Escherichia coli carry ISEcp1-blaCTX-M-15 associated with different Tn2-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 2006-7 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 almost ide...

Source: Plasmid - April 28, 2015 Category: Biotechnology Source Type: research