Rapid evolution of a host-adapted bacterial pathogen associated with decreased risk to food safety

Salmonella enterica serovar Typhimurium (S. Typhimurium), is a major cause of foodborne illness worldwide, with pigs a major zoonotic reservoir. Two variants, S. Typhimurium phage type U288 and monophasic S. Typhimurium (S. 4,[5],12:i:-) ST34 accounted for the vast majority of isolates from pigs in the UK in the past two decades, but have distinct host range and risk to food safety. This study uses WGS to examine the genotypic bases for these distinc phenotypes.