Swine were infected with Salmonella typhimurium, USDA #295, and treated with virginiamycin medicated feed continuously at a level of 55 g/metric ton for approximately 2 months. The incidence and persistence of shedding of this organism in the feces and in selected tissues were determined. No significant changes in the course of the infection were detected when virginiamycin treated animals were compared to nonmedicated infected controls. (

The purpose of this study was to determine the effect of virginiamycin on the course of an experimentally induced infection of Salmonella typhimurium in broilers. Several parameters were evaluated, including effects on the persistence and duration of shedding of the infecting Salmonella organism and its antibiotic resistance patterns. Virginiamycin was administered to the experimentally infected group for 8 weeks in feed at concentrations of 25 g/ton. This was compared to an infected control group not receiving the antibiotic. No effects were exhibited by virginiamycin on Salmonella typhimurium shedding and antibiotic resistance patterns.