Tracing the infectious source of salmonella food poisoning outbreak using pulse field gel electrophoresis

Objective To trace the infectious source of Salmonella food poisoning that occurred in Shenzhen using pulsed field gel electrophoresis(PFGE).Methods XbaI was used to digest the total DNA of Salmonella enteritidis strains isolated from the food poisoning samples.PFGE was used to analyze the relatedness of the strains.BioNumerics was used to analyze the PFGE fingerprints and trace the infectious source.Results PFGE patterns of 242 Salmonella strains isolated from the patients were identical,which meant that those patients' diarrhea were caused by the same pathogen.9 isolates from some food such as sandwiches had the same PFGE'fingerprints' as the patients',which meant that sandwiches from the same factory were the infectious sources.Conclusions PFGE is a useful technique with good discrimination and reproducibility for investigating the epidemiological relationship of strains and tracing the infectious sources.