Effect of enterobacterial common antigen on mouse virulence of Salmonella typhimurium

Abstract

A series of nearly isogenic O 4,12 and O 6,7 Salmonella typhimurium strains differing in regard to the enterobacterial common antigen (ECA) were constructed by conjugation. When tested in intraperitoneal infection of mice, the O 4,12 strains containing ECA were more virulent than their O 4,12 sister recombinants without ECA (P = <0.001). The same difference could be shown with ECA positive and ECA negative S. typhimurium derivatives, whose O antigens were of the group C type (O 6,7). The ECA positive and ECA negative O 4,12 strains did not differ in their growth rates in broth or clearance rates in vivo.