The Association between Sub-Therapeutic Antibiotics and Salmonella Typhimurium in Market-Weight Swine: A Systematic Review and Summation of Evidence from 1950 to 2007


A. O’Connor. Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA. Tel.: +1 515 294 5290; Fax: +1 515 294 1072; E-mail:


A systematic review approach was used to evaluate the association between sub-therapeutic antibiotics in feed and Salmonella Typhimurium isolation in market-weight finisher swine raised in modern swine production systems. Fourteen challenge trials described the efficacy of different antibiotics after challenge with S. Typhimurium. The studies identified were of limited evidentiary value for the review question because they were not relevant to the review question, i.e. conducted in artificial settings on small numbers of young pigs. None of the studies reported using blinding during outcome assessment. No antibiotic regimen was evaluated more than once. The association between sub-therapeutic antibiotics and Salmonella outcomes in market-weight swine raised in modern production systems cannot be summarized using the currently available literature. Many available studies fail to report critical study design features such as blinding and/or to take into account the data generated from longitudinal studies.