Doctors seek ban on drug promoting growth in livestock

CHENNAI: Infectious disease experts are pushing the Centre to ban the rampant use of colistin – an antibiotic used to promote growth in fish and animals – after a study found that nearly 50% of the meat, vegetables and fruit sold in the retail market in the city contained bacteria resistant to the drug.
Earlier this week, at the European Congress of Clinical Microbiology and Infectious Diseases in Madrid, Chennai-based infectious disease expert Dr Abdul Ghafur presented the findings of a study on the presence of colistin-resistant bacteria called Klebsiella pneumoniae in fresh food samples such as chicken, fish and vegetables picked from shops and house kitchens.

Researchers also found that a ‘rogue’ gene made the bacteria drug-resistant. While medical literature identifies mobilized colistin resistance (mcr) as the gene responsible for resistance, many colistin-resistant bacterial agents had another gene called mgrB.

“It’s not time to panic yet, but it’s time to worry. The government must act firmly and ban it immediately. China banned the use of colistin a few months ago. We now import it and the drug is available across Indian farms at a low cost,” said Dr Ghafur, who is a technical advisory member of the national antibiotic policy. “There is nothing people can do about it. Changing food habits will not help,” he said.

Out of 110 food samples collected in Chennai and analysed by a team of scientists including those from Christian Medical College, Vellore, 46% grew colistin-resistant bacteria like Escherichia coli, Enterobacter spp and Klebsiella spp. Colistin is considered the last resort for particularly dangerous types of ‘superbugs’ including a family of bacteria known as CRE. Doctors say poultry litter used as fertilizer in farms could have contaminated vegetables.

Meat dishes are safe because high heat kills the bacteria but there is a possibility that infections can spread. “If a cook uses a knife to cut infected meat and then to chop vegetables, the bacteria will get on your plate (through the vegetables),” infectious diseases expert Dr V Ramasubramanian said.