Salmonella enterica Serotype Typhimurium and Its Host-Adapted Variants

Salmonella enterica serotypes form a group of pathogens that differ widely in their host range within mammals and birds (Table 1).Members of S. enterica seem to lie along a spectrum in terms of host range.At one end of this spectrum, S. enterica serotype Typhi is perhaps the most highly host-adapted pathogen of this group, causing disease only in humans and higher primates ( 23).Serotypes that have the ability to cause disease and persist in multiple different species have a broad host range and thus define the other end of this spectrum.Traditionally, S. enterica serotype Typhimurium has been thought of as the prototypical broad-host-range serotype, since it is frequently associated with disease in numerous species, including humans, livestock, domestic fowl, rodents, and birds (Table 1).However, here we present the alternate view that some serotype Typhimurium variants have a very narrow host range, while others are clearly able to infect and persist in multiple species.Therefore, it may be more accurate to describe serotype Typhimurium as a collection of variants that vary significantly in their host range and their degree of host adaptation.