SuperbugsIncreasing use of antibiotics in livestock undermines effectiveness of antimicrobials in humans

Published 2 April 2015

Antibiotic consumption in livestock worldwide could rise by 67 percent between 2010 and 2030, and possibly endanger the effectiveness of antimicrobials in humans, according to researchers. Five countries — Brazil, Russia, India, China, and South Africa — will experience a growth of 99 percent in antibiotic consumption, compared with an expected 13 percent growth in their human populations over the same period. In the United States, antibiotic consumption in animals currently represents up to 80 percent of total antimicrobial sales. “The discovery and development of antibiotics was a major public health revolution of the twentieth century,” says one of the researchers. “Their effectiveness — and the lives of millions of people around the world — are now in danger due to the increasing global problem of antibiotic resistance, which is being driven by antibiotic consumption.”

Antibiotic consumption in livestock worldwide could rise by 67 percent between 2010 and 2030, and possibly endanger the effectiveness of antimicrobials in humans, according to researchers from Princeton University, the International Livestock Research Institute, the Université Libre de Bruxelles and the Center for Disease Dynamics, Economics and Policy.

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

A Princeton University release reports that 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. Global demand for animal protein is rising dramatically, and antimicrobials are used routinely in modern animal production for disease prevention and as growth promoters. The study focused on cattle, chickens, and pigs, and identified the latter two as the main contributors to antibiotic consumption.

The discovery and development of antibiotics was a major public health revolution of the twentieth century,” said senior author Ramanan Laxminarayan, a senior research scholar in the Princeton Environmental Institute. “Their effectiveness — and the lives of millions of people around the world — are now in danger due to the increasing global problem of antibiotic resistance, which is being driven by antibiotic consumption.”

The study is based on a limited data set of veterinary-antimicrobials sales from thirty-two countries, all with developed economies. Before now there has been no quantitative measurement of global antimicrobial consumption by livestock — a critical component in assessing the potential consequences of widespread animal antibiotic use. Numerous studies have suggested links between the use of antimicrobials and antibiotic-resistant bacteria originating from livestock as well as their potential consequences for human health.

Two thirds, or 66 percent, 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.