Effectiveness imperiled as use is expected to increase

Five countries — Brazil, Russia, India, China and South Africa — will experience a growth of 99% in antibiotic consumption, compared with an expected 13% growth in their human populations over the same period, the study authors report in the journal “Proceedings of the National Academy of Sciences”. In the United States, antibiotic consumption in animals currently represents up to 80% of total antimicrobial sales.

Because of the incredible volume involved, this increase in antimicrobial use in animals raises serious concerns about preserving antimicrobial effectiveness in the next decades, the researchers report. The study focused on cattle, chickens and pigs, and identified the latter two as the main contributors to antibiotic consumption.

The study is based on a limited data set of veterinary-antimicrobials sales from 32 countries, all with developed economies.

Two thirds, or 66%, of the projected global increase in antimicrobial consumption is due to the growing number of animals raised for food production. The remaining third is attributable to a shift in farming practices, with a larger proportion of animals projected to be raised in "intensive farming systems," or factory farms.

Having reliable global data is essential for scientists and policymakers to both measure the extent of the problem and assess potential solutions, said lead author Thomas Van Boeckel, a Fulbright research scholar in Princeton's Department of Ecology and Evolutionary Biology.

The study, "Global trends in antimicrobial use in food animals," was published March 19 in “Proceedings of the National Academy of Sciences”.