Update in Infectious Diseases

TO THE EDITOR:

Dr. Bartlett's update on infectious diseases (1) was very much appreciated, but I was troubled by its omission of any mention of the link between antibiotic resistance and the widespread use of antibiotics to promote growth in livestock. Roughly one third of all antibiotics produced in the United States are fed to animals solely to enhance weight gain (2). A September 1999 advertisement in Swine Practitioner boasted about a product containing a tetracycline, a sulfonamide, and penicillin to enhance “growth and feed efficiency”—available without a prescription. Since 1998, the European Union has prohibited for use in animal growth promotion all antibiotics used in human medicine (3). The United States, by contrast, allows 19 different antibiotics to be used for growth promotion, and of these, 7 are from classes used in human medicine (3). The economic use of antibiotics, not to cure sick animals but to promote weight gain, is especially problematic in an age of unprecedented antibiotic resistance. Although this practice translates into cheaper meat prices, the economic advantage seems to be minimal. Denmark has banned the use of human antibiotics for growth promotion for 5 years and has seen productivity actually increase (3). A National Research Council study (4) estimated that a similar ban in the United States would increase per capita costs by $5 to $10 per year. Use of antibiotics as growth promoters in livestock has been linked to the emergence of antibiotic-resistant diseases, helping the Centers for Disease Control and Prevention to conclude that antimicrobial use in food animals is the dominant source of antibiotic resistance among foodborne pathogens (5). Both the Centers for Disease Control and Prevention and the World Health Organization have called for an end to the use of antibiotics for growth promotion in animals. It is time for our leaders in medicine to include this problem in discussions about antibiotic resistance.