Subtyping of Salmonella enterica isolated from humans and food animals using Pulsed-Field Gel Electrophoresis

Document Type : Original Articles


1 Department of Microbiology, Faculty of Science, Islamin Azad University, Varamin Branch, Varamin, Iran

2 Department of Microbiology, Razi Vaccine & Serum Research Institute, Karaj, Iran


Salmonella infections are the second leading cause of zoonotic bacterial foodborne illness. Main source of infection in human is contaminated food products. The aim of this study was sub typing isolates of Salmonella entericaobtained during our previous study byPulsed Field Gel Electrophoresis (PFGE) technique. All 46 Salmonella isolates were serotyped and then subjected to PFGE. Total isolates were analyzed by means of the molecular technique XbaI PFGE. In this study, PFGE and serotyping were used to subtype 46 Salmonella isolates belonging to 27different serovars and derived from human and different food origins. Among these isolates, S. Typhimurium was found to be the most predominant serovar. 40 PFGE patterns out of 46 isolates were obtained. The Discrimination Index obtained by serotyping (DI = 0.93) was lower than PFGE (DI = 0.99). Subtyping of Salmonella enterica is very important and shows that animal origin can be one of a reservoir that potentially could be transferred to human through the food chain. In addition, results of this study also revealed that this procedure is a golden standard for genotyping of such salmonellaserotypes.


Article Title [French]

Sous-typage des isolats de Salmonella enterica d’origines humaine et animale par électrophorèse sur gel à champ pulsé

Abstract [French]

Les infections à la Salmonella représentent la seconde cause de zoonoses bactériennes issues de l’alimentation. Les principales sources de contamination chez l’homme sont d’origine alimentaire. Le but de cette étude est le sous-typage des isolats de Salmonella enterica issus de nos précédentes études par électrophorèse sur gel à champ pulsé (PFGE). Pour ceci, 46 isolats de Salmonella ont été sérotypés et analysés par PFGE. Tous les isolats ont été soumis à la technique moléculaire dite XbaI PFGE. Dans cette étude, les méthodes PFGE et de sérotypage ont été utilisés pour définir le sous-type de 46 isolats de Salmonella appartenant à 27 sérotypes différents, d’origine humaine et alimentaire. Parmi ces isolats, S. typhimurium s’est révélé être le plus répandu. Quarante profiles PFGE ont été obtenus à partir des 46 isolats. L’index de discrimination issu de la méthode de sérotypage (DI = 0.93) était plus faible que celui obtenu par PFGE (DI = 0.99). Nos résultats montrent que le sous-typage de Salmonella enterica est d’une grande utilité dans l’identification des aliments d’origines animales susceptibles de transmettre l’infection à l’homme. De plus, l’approche analytique utilisée dans cette étude peut constituer une procédure de référence pour le génotypage des différents sérotypes de Salmonella.

Keywords [French]

  • PFGE
  • Salmonella enterica
  • Sérotypage
  • Sous-typage
  • Humain
  • Aliments d’origine animale
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