New Delhi: Claiming that it found several antibiotic residues in chickens tested in Delhi-NCR region, an environment body on Wednesday said “large-scale and indiscriminate” use of antibiotics in poultry industry might be “strongly linked” to growing antibiotic resistance in Indians.

Seventeen per cent of the samples tested had more than one drug, found the Centre for Science and Environment (CSE) study, Antibiotics in Chicken: From Farm to Fork, which was released on Wednesday.

Animals are fed antibiotics to add to growth and bulk, which causes resistance in bacteria in animals, which then gets transferred to humans through food. Annual healthcare cost due to antibiotic resistance is estimated to be US $20 billion.

It said that 70 chicken samples from Delhi-NCR region were tested for six commonly used antibiotics during a recent study. While 40 per cent tested positive, residues of more than one antibiotic were found in 17 per cent samples.

Cooking chicken at temperatures between 70° and 100°C for at least two minutes at the centre kills most bacteria, says the World Health Organisation.

Some bacteria, however, can survive on kitchen surfaces or in storage areas where the temperatures is below 60°C.

The New Delhi-based research and advocacy think-tank said that antibiotics which are important to treat diseases in humans, like ciprofloxacin, are being rampantly used by the industry. This is leading to increased cases of antibiotic resistance in India.

“Antibiotics are no more restricted to humans nor limited to treating diseases. The poultry industry uses antibiotics as a growth promoter. Chickens are fed antibiotics so that they gain weight and grow faster,” said Sunita Narain, Director General while releasing the study conducted by CSE’s Pollution Monitoring Laboratory (PML).

The CSE said that India has no regulation on controlling antibiotic use in the poultry industry or to control sales of antibiotics to the industry while it has not set any limits for antibiotic residues in chicken.

Giving details, CSE said that PML tested 70 samples of chicken in Delhi and NCR out of which 36 samples were picked from Delhi, 12 from Noida, eight from Gurgaon and seven each from Faridabad and Ghaziabad.

Three tissues — muscle, liver and kidney, were tested for the presence of six antibiotics widely used in poultry — oxytetracycline, chlortetracycline and doxycycline (class tetracyclines), enrofloxacin and ciprofloxacin (class fluoroquinolones) and neomycin, an aminoglycoside.

“Residues of five of the six antibiotics were found in all the three tissues of the chicken samples. They were in the range of 3.37-131.75 g/kg. Of the 40 per cent samples found tainted with antibiotic residues, 22.9 per cent contained residues of only one antibiotic while the remaining 17.1 per cent samples had residues of more than one antibiotic, the study said.

“Public health experts have long suspected that such rampant use of antibiotics in animals could be a reason for increasing antibiotic resistance in India,” said Chandra Bhushan, CSE’s deputy director general.

“But the government has no data on the use of antibiotics in the country, let alone on the prevalence of antibiotic resistance. Our study proves the rampant use and also shows that this can be strongly linked to growing antibiotic resistance in humans in India,” he added.

Explaining the fallout of this, CSE officials said that large-scale misuse and overuse of antibiotics in poultry industry is leading to the emergence of antibiotic-resistant bacteria in the chicken itself.

These bacteria are then transmitted to humans through food or environment. Additionally, eating small doses of antibiotics through chicken can also lead to development of antibiotic-resistant bacteria in humans, the study said.

It said that in India, there is growing evidence that resistance to fluoroquinolones such as ciprofloxacin is rapidly increasing.

Treating fatal diseases like sepsis, pneumonia and tuberculosis (TB) with fluoroquinolones is becoming tough because microbes that cause these diseases are increasingly becoming resistant to fluoroquinolones, the study said.

CSE researchers point out that antibiotics are frequently pumped into chicken during its life cycle of 35-42 days. They are occasionally given as a drug to treat infections regularly mixed with feed to promote growth and routinely administered to all birds for several days to prevent infections.

“Our study is only the tip of the iceberg. There are many more antibiotics that are rampantly used that the lab has not tested,” Bhushan said.

The CSE also recommended banning the use of antibiotics as growth promoters and for mass disease prevention, not allowing antibiotics critical for humans in poultry industry, not using antibiotics as a feed additive, regulation of poultry feed industry by the government and not selling unlicensed and unlabelled antibiotics in market among others.