Avoparcin

Avoparcin is a narrow-spectrum glycopeptide antibiotic active against Gram-positive bacteria, used mainly for growth-promoting purposes in chickens, turkeys, swine, and calves, where it improves absorption of nutrients from the gastrointestinal tract. It remains virtually unabsorbed in the gut and is quickly excreted unchanged, so no withdrawal period was required. Its agricultural use was nevertheless banned in the EU over fears that glycopeptide resistance could transfer from animal bacteria to human pathogens, undermining last-resort antibiotics such as vancomycin. The avoparcin case became a landmark in the antibiotic-resistance debate and helped drive global restrictions on growth-promoting antibiotics in livestock.