Antibiotic use in animal feed and its impact on human health

Antibiotic resistance in bacteria that cause disease in man is an issue of major concern. Although misuse of antibiotics in human medicine is the prin cipal cause of the problem, antibiotic-resistant bacteria originating in an imals are contributory factors, with some types of resistance in some speci es of bacteria. Antibiotics are added to animal feeds to treat and prevent infections and to improve growth and production. Until recently, the major concerns about incorporation of antibiotics in animal feeds related to anti biotic residues in products from treated animals. Although, in 1969, the Sw ann (1969) report drew attention to the potential for antibiotic-resistant bacteria to spread from treated animals via the food chain, there was littl e response until the detection of vancomycin-resistant enterococci in anima ls fed a related glycopeptide, avoparcin. Subsequently, attention started t o focus on the issue and other examples of transfer of resistant bacteria t hrough the food chain, such as enterococci resistant to quinupristin-dalfop ristin or to everninomicin, fluoroquinolone-resistant campylobacters and mu ltiresistant Escherichia coli, and salmonella such as Salmonella typhimuriu m DT104. Reviews and committees in many countries have highlighted the need for better control of licensing of antibiotics, and codes for prudent use of antibiotics by veterinary practitioners and farmers. The continued use o f antibiotic growth promoters has been questioned and there is a need to en sure that antibiotics important in human medicine are not used therapeutica lly or prophylactically in animals.