September 25, 2017
Antibiotic misuse in poultry farms breeds multidrug-resistant bacteria, says study
A new study from the New Delhi, India-based Centre for Science and Environment (CSE) has found that these multidrug-resistant bacteria are spreading in the environment because of unsafe disposal of poultry litter and waste in agricultural fields. "This has a potential to infect human beings", the study warned.
Chandra Bhushan, CSE deputy director general, said that antibiotic misuse was common in the poultry sector. "What makes the situation worse is the fact that the sector is also plagued with poor waste management", he added.
The study, therefore, sought to determine 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.
It found that 100% of the E. coli, 92% of Klebsiella pneumoniae and 78% of Staphylococcus lentus bacteria isolated from the poultry environment were multi-drug resistant.
About 40% of E. coli and 30% of Klebsiella pneumoniae isolates were resistant to at least 10 out of 13 antibiotics against which these bacteria were tested for resistance. Also, both E. coli and Klebsiella pneumoniae 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 also 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 indicates that the multidrug-resistant E. coli being created in the poultry farms is entering the environment through litter", said Amit Khurana, senior programme manager, food safety and toxins team, CSE.
Public health threat
"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", he added.
However, no such similarity in the resistance pattern of Klebsiella pneumoniae and Staphylococcus lentus in litter and agricultural soil was found. It also did not find such similarity in the resistance pattern between the control samples and the study samples. Bhushan pointed out that this aspect needed further research: "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. The study also suggests that untreated litter was being used in agricultural fields. Clearly, India needs an antibiotic resistance-centric approach to waste management from poultry farms".
The CSE study recommends controlling rampant antibiotic misuse as the most effective step to contain spread of resistance from farms.
"There should be complete prohibition of disposal of untreated litter into the fields and use of litter as feed in aquaculture",
Khurana said, adding that less risky manure management options--such as bio-gas generation--should be promoted.
"Composting should only be done if other options are not available. This too should be done under a high degree of supervision, supported by adequate laws on site approval and process validation" Khurana also said.
"The bottom line is that we must eliminate the use of antibiotics as growth promoter in the poultry industry. Antibiotics should be used as a last resort to control the disease. This is the only way we can reduce the creation and spread of antibiotics resistance," Bhushan added.