Real-time PCRs and fingerprinting assays for the detection and characterization of Salmonella Genomic Island-1 encoding multidrug resistance: application to 445 European isolates of Salmonella, Escherichia coli, Shigella, and Proteus

Microb Drug Resist. 2008 Jun;14(2):79-92. doi: 10.1089/mdr.2008.0812.


Salmonella Genomic Island-1 (SGI-1) harbors a cluster of genes encoding multidrug resistance (MDR). SGI-1 is horizontally transmissible and is therefore of significant public health concern. This study presents two novel realtime PCRs detecting three SGI-1 protein-coding genes and a SGI-1 fingerprinting assay. These assays were applied to 445 European enterobacterial isolates. Results from real-time PCRs were comparable to those obtained from gelbased PCRs used for the detection of SGI-1, but were rapid to perform and suitable for large-scale screening. Furthermore, real-time PCRs also detected SGI-1 even when only part of the island was present in bacterial isolates. No trace of SGI-1 was detected in isolates other than Salmonella enterica. The fingerprints showed that regions of SGI-1 outside the MDR region exhibited genomic variations between isolates. In conclusion, the realtime PCRs described here are suitable for the detection of SGI-1 in bacterial isolates. Further studies are necessary to elucidate divergence in its non-MDR region.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology
  • DNA Fingerprinting / methods*
  • DNA, Bacterial / analysis
  • Drug Resistance, Multiple / genetics*
  • Enterobacteriaceae / classification
  • Enterobacteriaceae / drug effects
  • Enterobacteriaceae / genetics
  • Enterobacteriaceae / isolation & purification
  • Europe
  • Genomic Islands / genetics*
  • Humans
  • Polymerase Chain Reaction / methods*
  • Proteus
  • Salmonella enterica / classification
  • Salmonella enterica / drug effects
  • Salmonella enterica / genetics*
  • Salmonella enterica / isolation & purification


  • Anti-Bacterial Agents
  • DNA, Bacterial