Comparison of virulence states between hyperinfectious and conventionally virulent salmonellae following transfer from nonpermissive to permissive conditions for the hypervirulent phenotype.

aHyperinfectious S. Choleraesuis χ3246 and S. Bovismorbificans 158 as well as conventionally virulent S. Typhimurium reference strain 14028 were grown overnight in LB medium. The stationary-phase cells were transferred without dilution, into permissive conditions for the hypervirulent phenotype (LPM pH 5.5 medium). Virulence was assessed as a function of time (h) post-transfer to LPM pH 5.5 medium via i.p. competitive index (CI) virulence assays as in Table 1.