Antibiotic Misuse In Poultry Farms Leading To Multi-drug Resistant Bacteria - Study

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Misuse of antibiotics in poultry farms is leading to a proliferation of multi-drug resistant bacteria.

To make matters worse, these bacteria are now spreading in the environment because of unsafe disposal of poultry litter and waste in agricultural fields-this has a potential to infect human beings, says a new study from Centre for Science and Environment (CSE).

The study - titled 'Antibiotic Resistance in Poultry Environment' - conducted by CSE's Pollution Monitoring Laboratory, collected samples of litter and soil from in and around 12 randomly selected poultry farms. These were located in four key poultry-producing states in north India - Uttar Pradesh, Haryana, Rajasthan and Punjab.

A total of 217 isolates of three types of bacteria - E.coli, Klebsiellapneumoniae and Staphylococcus lentus were extracted and tested for resistance against 16 antibiotics. Ten of these antibiotics have been declared Critically Important (CI) for humans by the World Health Organization (WHO).

CSE researchers found that antibiotics were being used in these poultry farms, and that the litter was used as manure in neighbouring agricultural lands. As a control, the study also collected 12 soil samples at a distance of 10 to 20 kilometres from the respective farms, where the litter was not being used as manure.

Releasing the findings of the study, Chandra Bhushan, deputy director general, CSE, said: "Antibiotic misuse is common in the poultry sector. What makes the situation worse is the fact that the sector is also plagued with poor waste management. Therefore we first wanted to understand the extent of antibiotic resistance in the poultry environment, and then establish if the resistance bacteria is moving out of the poultry farms into the environment through waste disposal."

Study Result:
The study found that 100 per cent of the E. coli, 92 per cent of Klebsiellapneumoniae and 78 per cent of Staphylococcus lentus isolated from the poultry environment were multi-drug resistant.

About 40 percent of E.coli and 30 percent of Klebsiellapneumoniae isolates were resistant to at least 10 out of 13 antibiotics against which these bacteria were tested for resistance. Also, both E. coli and Klebsiellapneumoniae had very high resistance to antibiotics of critical importance to humans such as penicillins, fluoroquinolones, third and fourth generation cephalosporins and carbapenems, which is a last resort antibiotic used in hospitals.

The study found strong similarity in the resistance pattern of E. coli from the litter and from agricultural soil in the surrounding areas where the litter was used as manure. This similarity was statistically established by the study. "This indicates that the multi-drug resistant E. coli being created in the poultry farms is entering the environment through litter.

From the agricultural fields, these bacteria can go anywhere - into groundwater and food - and can infect agricultural workers and animals,thereby becoming a public health threat," says Amit Khurana, senior programme manager, food safety and toxins team, CSE.

"Our findings on E.coli clearly establish that resistance is moving out of farms to fields through litter. More studies are required to understand the behaviour of the other two bacteria" he further added.