Characterization of the IncA/C plasmid pCC416 encoding VIM-4 and CMY-4 beta-lactamases

J Antimicrob Chemother. 2007 Aug;60(2):258-62. doi: 10.1093/jac/dkm171. Epub 2007 May 31.

Abstract

Objectives: To characterize the antibiotic resistance regions of pCC416, a VIM-4- and CMY-4-encoding plasmid from clinical enterobacteria, and to elucidate its relation with the CMY-encoding plasmids widely diffused in Salmonella.

Methods: The enterobacterial multiresistant plasmid pCC416 was derived from an Escherichia coli transconjugant and characterized. Conventional and long-range PCR assays were performed using primers specific for VIM-4- and CMY-4-encoding segments of pCC416. Amplicons were characterized by sequencing. blaVIM-4, blaCMY-4 and IntI1-specific probes were prepared from PCR products and used for the identification of various pCC416 clones. VIM- and CMY-positive BamHI and Sau3AI fragments of pCC416 were cloned into pACYC184 and their sequences were determined by gene walking.

Results: The pCC416 plasmid contained two distinct resistant loci carrying beta-lactamase genes. The blaVIM-4 gene was part of an integron located in a complex, multidrug-resistant region of novel structure, interspersed with mobile elements or remnants thereof and being similar to various regions of other resistance plasmids. Nevertheless, a region in the 3' end of this structure resembled the respective region found in a CMY-2-encoding plasmid from Salmonella. The blaCMY-4 gene was identified within an 11.3 kb region also related to the CMY-2-encoding plasmids.

Conclusions: pCC416 probably evolved from an IncA/C2, CMY-encoding plasmid through acquisition of a VIM-encoding In4-type integron providing an example of accretion of resistance determinants in a single replicon.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cloning, Molecular
  • DNA Transposable Elements / genetics
  • DNA, Bacterial / genetics
  • Drug Resistance, Multiple, Bacterial / genetics
  • Enterobacteriaceae / enzymology
  • Enterobacteriaceae / genetics
  • Escherichia coli / genetics
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Plasmids / genetics
  • Polymorphism, Restriction Fragment Length
  • Reverse Transcriptase Polymerase Chain Reaction
  • beta-Lactamases / genetics*

Substances

  • DNA Transposable Elements
  • DNA, Bacterial
  • beta-Lactamases
  • beta-lactamase CMY-4, Salmonella enterica
  • beta-lactamase bla(VIM-4), Pseudomonas aeruginosa

Associated data

  • GENBANK/AJ875405