Genetic Difference among Salmonella Typhimurium Phage Types

Phage typing of Salmonella Typhimurium has been used for more than four decades as a rapid, low cost approach for the epidemiological surveillance. Bacterial resistance to phages may be related to lack of suitable receptors on the bacterial surface, host restriction modification, clusters of regulatory interspaced short palindromic repeats and superinfection exclusion systems. we are investigating variation in these systems that might be associated with the evolution of the bacterial host.