Large-scale unregulated use of antibiotics in the poultry industry could be contributing to Indians developing resistance to antibiotics and falling prey to a host of otherwise curable ailments, according to the results of a new study released on Wednesday by the Centre for Science and Environment (CSE).
In the biggest study done in India to test residues of antibiotics in chicken the CSE lab study found residues of antibiotics in 40 per cent of the samples of chicken that were tested.
Releasing the findings of the study which has been conducted by CSE’s Pollution Monitoring Laboratory (PML), Sunita Narain, director general of the Centre said: ``Antibiotics are no more restricted to humans nor limited to treating diseases. The poultry industry, for instance, uses antibiotics as a growth promoter. Chickens are fed antibiotics so that they gain weight and grow faster.”
The test results
PML tested 70 samples of chicken in Delhi and NCR: 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 μg/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.
In one sample purchased from Gurgaon, a cocktail of three antibiotics — oxytetracycline, doxycycline and enrofloxacin — was found. This indicates rampant use of multiple antibiotics in the poultry industry.
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, even when there are no signs of it.
``Our study is only the tip of the iceberg. There are many more antibiotics that are rampantly used that the lab has not tested,” added CSE’s deputy director general and head of the lab Chandra Bhushan.
Large-scale misuse and overuse of antibiotics in chicken 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.
To ascertain the linkage between overuse of antibiotics in poultry farms and antibiotic resistance in humans, CSE researchers reviewed 13 studies conducted by various government and private hospitals across the country between 2002 and 2013. They found that resistance was very high against ciprofloxacin, doxycycline and tetracyclines. These are the same antibiotics that were detected in the chicken samples.
The problem is compounded by the fact that many essential and important antibiotics for humans are being used by the poultry industry.
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 CSE study found two fluoroquinolone antibiotics — enrofloxacin and ciprofloxacin — in 28.6 per cent of the chicken samples tested.
Worldwide governments are adopting regulations to control the use of antibiotics. But only those countries have shown signs of improvement that have taken stringent actions. EU, for instance, has banned the use of antibiotics as growth promoters. The World Health Organization (WHO) recommends that antibiotics that are critical for human use should not be used in animals.
CSE researchers point out that the poultry industry in India is growing at 10 per cent per annum. Poultry constitutes more than 50 per cent of all the meat consumed in India.
Noted Mr. Bhushan: ``India will have to adopt a comprehensive approach to tackle this problem. The biggest problem is the emergence of resistant bacteria in animals and its transmission through food and environment. Till the time we keep misusing antibiotics in animals, we will not be able to solve the problem of antibiotic resistance. For India, therefore, the priority should be to put systems in place to reduce the use of antibiotics in poultry and other food animals.”