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Comparison of genotyping methods by application to Salmonella livingstone strains associated with an outbreak of human salmonellosis

Eriksson, John LU ; Löfström, Charlotta LU ; Aspan, A; Gunnarsson, A; Karlsson, I; Borch, E; de Jong, B and Rådström, Peter LU (2005) In International Journal of Food Microbiology 104(1). p.93-103
Abstract
During 2000 and 2001, an outbreak of human salmonellosis occurred in Sweden and Norway, caused by Salmonella livingstone. In this study, the genotypic differences between three strains obtained from food sources during the outbreak, two human strains and 27 more or less unrelated strains were analysed, using the three methods; automated ribotyping, pulsed field get electrophoresis (PFGE) and randomly amplified polymorphic DNA (RAPD). Each method was evaluated regarding its discriminatory ability, reproducibility and typeability. Simpson's discriminatory index calculated for each method was 0.556 for automated ribotyping, 0.766 for PFGE and 0.236 for RAPD. The reproducibility, defined as the minimum similarity between individual replicates... (More)
During 2000 and 2001, an outbreak of human salmonellosis occurred in Sweden and Norway, caused by Salmonella livingstone. In this study, the genotypic differences between three strains obtained from food sources during the outbreak, two human strains and 27 more or less unrelated strains were analysed, using the three methods; automated ribotyping, pulsed field get electrophoresis (PFGE) and randomly amplified polymorphic DNA (RAPD). Each method was evaluated regarding its discriminatory ability, reproducibility and typeability. Simpson's discriminatory index calculated for each method was 0.556 for automated ribotyping, 0.766 for PFGE and 0.236 for RAPD. The reproducibility, defined as the minimum similarity between individual replicates in a cluster analysis, was 96% for automated ribotyping and PFGE, and 90% for RAPD. All the strains were typeable with each method. When combining results for the three genotyping methods, it was found that RAPD did not increase the discriminatory index and was therefore excluded from further analysis. Using a combination of the results obtained from ribotyping and PFGE (D = 0.855), two strains that had been isolated from feed factories during 1998 were shown to be identical to the outbreak strain, indicating a possible route of contamination due to a clone of Salmonella livingstone persisting in feed producing facilities. No connection to poultry was established. (c) 2005 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
International Journal of Food Microbiology
volume
104
issue
1
pages
93 - 103
publisher
Elsevier
external identifiers
  • wos:000232407800008
  • pmid:15978689
  • scopus:23944438621
ISSN
0168-1605
DOI
10.1016/j.ijfoodmicro.2005.01.011
language
English
LU publication?
yes
id
ac49cb9e-3eb9-41f4-8ffb-72a6915e18fd (old id 151221)
date added to LUP
2007-06-28 11:41:04
date last changed
2017-05-28 03:43:38
@article{ac49cb9e-3eb9-41f4-8ffb-72a6915e18fd,
  abstract     = {During 2000 and 2001, an outbreak of human salmonellosis occurred in Sweden and Norway, caused by Salmonella livingstone. In this study, the genotypic differences between three strains obtained from food sources during the outbreak, two human strains and 27 more or less unrelated strains were analysed, using the three methods; automated ribotyping, pulsed field get electrophoresis (PFGE) and randomly amplified polymorphic DNA (RAPD). Each method was evaluated regarding its discriminatory ability, reproducibility and typeability. Simpson's discriminatory index calculated for each method was 0.556 for automated ribotyping, 0.766 for PFGE and 0.236 for RAPD. The reproducibility, defined as the minimum similarity between individual replicates in a cluster analysis, was 96% for automated ribotyping and PFGE, and 90% for RAPD. All the strains were typeable with each method. When combining results for the three genotyping methods, it was found that RAPD did not increase the discriminatory index and was therefore excluded from further analysis. Using a combination of the results obtained from ribotyping and PFGE (D = 0.855), two strains that had been isolated from feed factories during 1998 were shown to be identical to the outbreak strain, indicating a possible route of contamination due to a clone of Salmonella livingstone persisting in feed producing facilities. No connection to poultry was established. (c) 2005 Elsevier B.V. All rights reserved.},
  author       = {Eriksson, John and Löfström, Charlotta and Aspan, A and Gunnarsson, A and Karlsson, I and Borch, E and de Jong, B and Rådström, Peter},
  issn         = {0168-1605},
  language     = {eng},
  number       = {1},
  pages        = {93--103},
  publisher    = {Elsevier},
  series       = {International Journal of Food Microbiology},
  title        = {Comparison of genotyping methods by application to Salmonella livingstone strains associated with an outbreak of human salmonellosis},
  url          = {http://dx.doi.org/10.1016/j.ijfoodmicro.2005.01.011},
  volume       = {104},
  year         = {2005},
}