Characterization of IS26-composite transposons and multidrug resistance in conjugative plasmids from Enterobacter cloacae

Chih Ming Chen, Wen Liang Yu, Mei Huang, Jau Jin Liu, I. Chien Chen, Huei Fen Chen, Lii Tzu Wu

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6 Citations (Scopus)


SHV-12 is the most widespread resistance determinant of Enterobacter cloacae in Taiwan; however, blaSHV-12 has rarely been mobilized. Six multidrug-resistant E. cloacae isolates were collected. After conjugal transfer, plasmid profiling and analysis of incompatibility groups was performed to characterize the genetic context of blaSHV-12-containing fragments. The presence of mobile genetic elements was demonstrated by PCR, cloning, sequencing and bioinformatics analyses. Four different β-lactamase genes (blaTEM-1, blaSHV-12, blaCTX-M-3 and/or blaCTX-M-14) were observed in the conjugative plasmids belonging to the IncHI2 (n=4), IncI1 or IncP incompatibility groups. The IS26-blaSHV-12-IS26 locus was located in five different genetic environments. A novel structural organization of a class 1 integron with the aac(6')-IIc cassette truncated by IS26 was identified in one isolate. Thus, blaSHV-12 was obtained from different plasmids through IS26-mediated homologous recombination. IS26 plays a vital role in the distribution of mobile resistance elements between different plasmids found in multidrug-resistant E. cloacae isolates.

Original languageEnglish
Pages (from-to)516-525
Number of pages10
JournalMicrobiology and Immunology
Issue number9
Publication statusPublished - Sep 1 2015



  • bla<inf>SHV-12</inf>
  • Enterobacter cloacae
  • Homologous recombination
  • IS26-bla<inf>SHV-12</inf>-IS26 locus

ASJC Scopus subject areas

  • Immunology
  • Microbiology
  • Virology

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