Identification of putative virulence attributes using suppression subtractive hybridization using Salmonella Typhimurium isolates from septicemic and healthy pigs

摘要

In this study, we used the suppression subtractive hybridization (SSH) method to identify DNA restriction fragments present in a Salmonella Typhimurium isolate from septicemic pig but absent in a S. Typhimurium isolate recovered from a healthy animal at slaughter. Thirteen different clone inserts were identified and 5 clones had similarities with sequences with predicted functions. Two fragments showed similarities with genes found on plasmids. The putative functions are those of a DNA restriction subunit of a type III restriction and modification system for one clone and a replication protein for the other one. Three fragments showed similarities with genes found on the chromosome. The putative genes are pgtA, stbD and emrB. Seven fragments have unknown function. One plasmid of the septicemic isolate used in the SSH was characterized as it was present in another septicemic isolate that lacked the classical virulence plasmid. It contained several genes of unknown function that will need further investigation to assess their putative role in virulence.