Washington/New Delhi, July 20: High levels of antibiotic-resistant pathogens in chickens raised for both meat and eggs on Indian farms are raising serious health concerns for humans, a team of researchers has warned.

The study by researchers from the Centre for Disease Dynamics, Economics and Policy (CDDEP), a public health research organisation with headquarters in Washington D.C., and New Delhi, found high levels of antibiotic-resistance on poultry farms in Punjab.

"This study has serious implications, not only for India but globally. Overuse of antibiotics in animal farms endangers all of us," said study author and CDDEP Director Ramanan Laxminarayan.

"We must remove antibiotics from the human food chain, except to treat sick animals, or face the increasingly real prospect of a post-antibiotic world," Laxminarayan added.

Previous CDDEP studies have projected that antibiotic consumption in food animal production will rise globally by 67 per cent by 2030, including more than a tripling of use in India.

For the new study, published in the journal Environmental Health Perspectives on Thursday, 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.

The CDDEP researchers found high levels of multi-drug resistance, ranging from 39 per cent 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 per cent of E. coli isolates analysed contained these enzymes.

"Use of antibiotics for growth promotion in farm animals has increased worldwide in response to rising demand for food animal products," the team noted.

Indian poultry farms breeding antibiotic-resistant pathogens