The study, published in Environmental Health Perspectives, finds high levels of antibiotic-resistant pathogens in chickens raised for both meat and eggs on farms in India’s Punjab state.
Researchers collected samples from 530 birds on 18 poultry farms and tested them for resistance to a range of antibiotic medications critical to human medicine. Two-thirds of the farms reported using antibiotic factors for growth promotion; samples from those farms were three times more likely to be multidrug-resistant than samples from farms that did not use antibiotics to promote growth.
Although the researchers found reservoirs of resistance across both types of farms, meat farms had twice the rates of antimicrobial resistance that egg-producing farms had, as well as higher rates of multidrug resistance.
Across the board, the CDDEP researchers found high levels of multidrug resistance, ranging from 39 percent for ciprofloxacin, used to treat endocarditis, gastroenteritis, cellulitis and respiratory tract infections, and other infections, to 86 percent for nalidixic acid, a common treatment for urinary tract infections.
Additional testing revealed the presence of certain enzymes that confer drug resistance to medications used, for example, to treat E. coli, bacterial pneumonia, and other infections. Almost 60 percent of E. coli isolates analyzed contained these enzymes.
Use of antibiotics for growth promotion in farm animals has increased worldwide in response to rising demand for food animal products. Previous CDDEP studies have projected that antibiotic consumption in food animal production will rise globally by 67 percent by 2030, including more than a tripling of use in India.