The most infected meat comes from Africa and Asia—and particularly China—and South America, regions that have seen a massive upturn in protein consumption in recent years.
Antibiotic-resistant bacteria in chickens and pigs from the regions have tripled between 2000 and 2018, which means antibiotics are failing more than half the time in 40 percent of chickens and one-third of pigs raised for human consumption.
Researchers at Princeton University's Environmental Institute focused on four common bacteria—including Salmonella and E. coli—which can cause serious illness in people.
They reviewed more than a thousand previously published papers to map antimicrobial resistance in developing countries, with the greatest resistance in livestock in India and China. More than half the world's chicken and pigs are in Asia.
Meat production now accounts for 73 percent of global antibiotic use.
Affluent nations should be supporting a transition towards sustainable farming, possibly through a global fund, the researchers say.