NEW DELHI: Overuse of antibiotics for growth promotion in poultry is leading to development of drug resistance in humans, scientists have warned.Researchers from the US-based Center for Disease Dynamics, Economics and Policy ( CDDEP ) collected samples from 530 birds in 18 poultry farms in Punjab and tested them for resistance to a range of antibiotic medications critical to human medicine.They found high levels of antibiotic resistant pathogens in chickens being raised for eggs and meat in poultry farms in Punjab, posing serious health hazards for humans. Two-thirds of the farms reported using antibiotic factors for growth promotion, researchers said.Samples from the farms, which reported using antibiotic factors, were three times more likely to be multidrug resistant than samples from farms that did not use antibiotics to promote growth, researchers found. The team found reservoirs of resistance across both types of farms, but meat farms had twice the rates of antimicrobial resistance than egg-producing farms, as well as higher rates of multidrug resistance.They also found high levels of multi-drug resistance, ranging from 39% for ciprofloxacin —used to treat endocarditis, gastroenteritis, cellulitis and other infections – to 86% 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 to treat E coli, bacterial pneumonia, and other infections. Almost 60% of E coli isolates analysed contained these enzymes, researchers said.“This study has serious implications, not only for India but globally,” said Ramanan Laxminarayan, director at CDDEP. “Overuse of antibiotics in animal farms endangers all of us. 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,” he added. Use of antibiotics for growth promotion in farm animals has increased worldwide in response to rising demand for food animal products, researchers said.Previous studies have projected that antibiotic consumption in food animal production will rise globally by 67% by 2030, including more than a tripling of use in India. The study has been published in the latest issue of the journal ‘Environmental Health Perspectives’.