Salmonella enterica serovar Typhimurium typing by prophage-specific PCR

Recent data from microarray analysis have shown that integrated prophages are the most frequent sources of genomic variation between different strains of Salmonella enterica serovar Typhimurium (S. Typhimurium). This led us to hypothesize that PCR detection of the integrated prophages might be an efficient typing tool that could be used as an alternative to PFGE. In this study, we optimized four triplex PCRs specific for 12 target sequences of mostly prophage origin, and tested them in 102 field strains. The same set of strains was also characterized by PFGE. Among the strains, 22 different multiplex PCR, and 25 different PFGE profiles, were identified. Despite the fact that the PFGE was slightly more discriminatory, multiplex PCR typing, owing to its simplicity and potential of simple data sharing between laboratories, represents an interesting user-friendly alternative to PFGE typing of S. Typhimurium.