The FDA believes what pathway is the most significant exposure pathway to bacteria that have emerged or been selected as a consequence of antimicrobial drug use in animals?

• A. Inhalation of aerosols from farm environments
• B. Direct contact with treated animals
• C. Water ingestion
• D. Ingestion of antimicrobial resistant bacteria from animal derived foods

Answer: (D)

The exposure that matters most to the public is ingestion of antimicrobial resistant bacteria through foods of animal origin. When animals are treated with antimicrobial drugs, resistant bacteria can emerge in their intestines and contaminate meat, milk, eggs, and other animal-derived products during slaughter, processing, and handling. People can acquire these bacteria by consuming or handling contaminated foods, and some may become colonized or infected, spreading resistance further.

Other routes, like inhaling aerosols from farm environments or direct contact with treated animals, are important for specific groups (such as farm workers) but affect fewer people overall. Waterborne exposure can occur, yet the foodborne route from animal-derived foods represents the largest pathway for the general population.