Veterinary antibiotic residues in food-animal feces: insight into global use patterns, environmental release and...

Veterinary antibiotic use in food-animal production is a major driver of antimicrobial resistance (AMR), yet global patterns of antibiotic use and environmental release remain poorly characterized. Because antibiotics are typically incompletely metabolized and excreted in feces, fecal residues provide a direct indicator of antibiotic use and potential environmental release. Here, we conducted the first global analysis of veterinary antibiotic residues in food-animal feces, compiling 1334 fecal residue records for 84 antibiotics from 88 studies across 28 countries. Monitoring coverage was highly uneven, with 42% of studies conducted in China, and 28% in Europe, while several major meat-producing countries lacked measurements. Tetracyclines exhibited the highest fecal residue levels globally, with median concentrations of doxycycline, chlortetracycline, and oxytetracycline reaching 382, 284, and 260 μg/kg dry weight, respectively. Pigs generally showed the highest overall antibiotic residues. Despite lower reported veterinary antibiotic use and stricter regulatory controls in Europe, fecal-residue levels did not differ significantly from those observed in China. Temporal analysis revealed significant declines in residues of several tetracyclines and sulfonamides in China. These findings reveal substantial limitations in current monitoring coverage and demonstrate the potential of fecal-residue surveillance to strengthen assessment of veterinary antibiotic use, environmental loading, and associated AMR-selection pressure.