Experimental model of oral antityphoid vaccination with live streptomycin-dependent Salmonella typhimurium in C57BL/6 mice.

The present experimental model offered the opportunity to study particular aspects concerning the avirulence stability of live streptomycin-dependent (Sm D) Salmonella vaccines, under conditions resembling human enteric fever. The results seem to indicate that, in practice, the risk of reversion to a virulent form during oral antityphoid vaccination with Sm D strains remains slight even after the interruption of concomitant streptomycin administration.