virginiamycin and Salmonella-Infections--Animal

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.

Topics: Animals; Anti-Bacterial Agents; Chickens; Drug Resistance, Microbial; Food Additives; Poultry Diseases; Salmonella Infections, Animal; Salmonella typhimurium; Virginiamycin

Swine from a herd routinely fed subtherapeutic levels of chlortetracycline (CTC) were fed a diet containing 55 mg of CTC/kg, a diet containing 55 mg of virginiamycin/kg, or a control diet. All animals were inoculated with Salmonella typhimurium that was susceptible to tetracycline. The quantity, duration and prevalence of shedding of S. typhimurium were determined. The infecting organism was first recovered from the animals fed CTC or the control diet on d 2, from animals fed virginiamycin on d 7 and from animals in a second control group on d 10. The infecting organism was recovered in fewer samples obtained during the initial 7 d postinfection than in those obtained during the last 24 d of the study. Little transfer of resistance to the infecting organism seemed to have occurred from the resident microflora because only two isolates (1%) had resistant patterns that differed from that of the infecting organism. Feeding CTC or virginiamycin to swine did not significantly increase or prolong shedding of an experimentally infected tetracycline-susceptible strain of S. typhimurium. Neither antibiotic affected the drug resistance of the infecting organism.

Topics: Animals; Chlortetracycline; Diet; Drug Resistance, Microbial; Food Additives; Salmonella Infections, Animal; Salmonella typhimurium; Swine; Swine Diseases; Virginiamycin

Topics: Animals; Chickens; Feces; Poultry Diseases; Salmonella Infections; Salmonella Infections, Animal; Salmonella typhimurium; Virginiamycin

Topics: Administration, Oral; Animal Feed; Animals; Drug Resistance, Microbial; Escherichia coli; Feces; Housing, Animal; Salmonella Infections, Animal; Salmonella typhimurium; Swine; Swine Diseases; Virginiamycin