typhoid (FT) and substantial economic loss in Korea due to egg drop syndrome and
mortality. Despite the extensive use of vaccines, FT still occurs in the field. Therefore, the
emergence of more pathogenic SG or the recovered pathogenicity of a vaccine strain has
been suspected. SpvB, an ADP-ribosyl transferase, is a major pathogenesis determinant,
and the length of the polyproline linker (PPL) of SpvB affects pathogenic potency. SG strains …