Antimicrobial use in agriculture: controlling the transfer of antimicrobial resistance to humans.

Salmonella and Campylobacter infections occur commonly in children. Some of these infections are severe, requiring treatment with antimicrobial agents. Many classes of antimicrobial agents that are used in humans also are used in food animals for growth promotion, disease prevention, and therapy. The use of such antimicrobial agents in food animals increases the likelihood that human bacterial pathogens that have food animal reservoirs, such as Salmonella or Campylobacter, will develop cross-resistance to drugs approved for use in human medicine. Resistance determinants also may be transmitted from food animals to humans through the food supply with bacteria that usually are commensal, such as Escherichia coli and enterococci. Clinicians should be aware that antimicrobial resistance is increasing in food-borne pathogens and that patients who are taking antimicrobial agents for any reason are at increased risk for acquiring antimicrobial-resistant food-borne infections. Several European countries have demonstrated that restricting the use of antimicrobial agents in food animals can be followed by a decrease in antimicrobial resistance in humans without compromising animal health or significantly increasing the cost of production. Appropriate use of antimicrobial agents in humans and food animals is an important factor in maintaining their effectiveness.