In 1986 Sweden became the first country to ban antibiotics for growth promotion. Earlier this year, Denmark followed Sweden's lead. Canada should be joining these countries in setting an example for the world to follow. The change in practice will require considerable effort and a substantial investment into finding alternatives to ensure optimal animal growth. It should be recognized that, important as antibiotic use in animals may be in the evolution of antimicrobial resistance, both antibiotic use and the failure to control the dissemination of resistant clones or genes in human populations are of greater consequence.
Human consumption accounts for the majority of all antibiotic use.
4 Antibiotic use not only selects for resistance within a patient's own microflora but also provides a niche for resistant bacteria that come into contact with the patient during therapy. Thus, antibiotic pressure and transmission of resistant clones work synergistically to increase overall resistance. Until recently, many of us believed that resistant strains were less likely to be virulent than others and that the acquisition of resistance carried with it a price to the organism, such that antibiotic resistance would be lost once antibiotic pressure was removed. There is, however, increasing in vitro data to indicate that neither of these beliefs is true. There is also an increasing number of examples of worldwide spread of virulent clones of such multiply-resistant organisms as Salmonella typhimurium DT104, S. pneumoniae and Staphylococcus aureus .