External Societal Costs of Antimicrobial Resistance in Humans Attributable to Antimicrobial Use in Livestock

Antimicrobial use in animal agriculture contributes to antimicrobial resistance in humans, which imposes significant health and economic costs on society. These costs are negative externalities. We review the relevant literature and develop a model to quantify the external costs of antimicrobial use in animal agriculture on antimicrobial resistance in humans. Parameters required for this estimate include: 1) the health and economic burden of antimicrobial resistance in humans, 2) the impact of antimicrobial use in animal agriculture on antimicrobial resistance in animals, 3) the fraction of antimicrobial resistance in humans attributable to animal agriculture, and 4) antimicrobial use in animals. We use a well-documented historic case to estimate an externality cost of about $1500 per kilogram of fluoroquinolones administered in US broiler chicken production. Enhanced data collection, particularly on parameters 3) and 4), would be highly useful to quantify more fully the externalities of antimicrobial use in animal agriculture.